diff --git a/Cargo.lock b/Cargo.lock
index 2b9b8f6384..5bca4768e0 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1304,6 +1304,7 @@ dependencies = [
  "arrow-flight",
  "async-stream",
  "common-base",
+ "common-catalog",
  "common-error",
  "common-grpc",
  "common-grpc-expr",
@@ -6697,6 +6698,7 @@ name = "session"
 version = "0.1.0"
 dependencies = [
  "arc-swap",
+ "common-catalog",
  "common-telemetry",
 ]
 
@@ -6938,9 +6940,9 @@ dependencies = [
 
 [[package]]
 name = "sqlness"
-version = "0.1.1"
+version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3ffa69a2ae10018ec72a3cb7574e3a33a3fc322ed03740f6e435fd7f0c1db4a7"
+checksum = "16a494ea677f9de93e8c25ec33b1073f8f72d61466d4595ecf1462ba877fe924"
 dependencies = [
  "async-trait",
  "derive_builder 0.11.2",
@@ -6962,7 +6964,10 @@ dependencies = [
  "common-error",
  "common-grpc",
  "common-query",
+ "common-time",
+ "serde",
  "sqlness",
+ "tinytemplate",
  "tokio",
 ]
 
diff --git a/benchmarks/src/bin/nyc-taxi.rs b/benchmarks/src/bin/nyc-taxi.rs
index 4d857aa561..368dde8ce3 100644
--- a/benchmarks/src/bin/nyc-taxi.rs
+++ b/benchmarks/src/bin/nyc-taxi.rs
@@ -32,7 +32,6 @@ use indicatif::{MultiProgress, ProgressBar, ProgressStyle};
 use parquet::arrow::arrow_reader::ParquetRecordBatchReaderBuilder;
 use tokio::task::JoinSet;
 
-const DATABASE_NAME: &str = "greptime";
 const CATALOG_NAME: &str = "greptime";
 const SCHEMA_NAME: &str = "public";
 const TABLE_NAME: &str = "nyc_taxi";
@@ -100,7 +99,6 @@ async fn write_data(
         let record_batch = record_batch.unwrap();
         let (columns, row_count) = convert_record_batch(record_batch);
         let request = InsertRequest {
-            schema_name: "public".to_string(),
             table_name: TABLE_NAME.to_string(),
             region_number: 0,
             columns,
@@ -424,7 +422,7 @@ fn main() {
         .unwrap()
         .block_on(async {
             let client = Client::with_urls(vec![&args.endpoint]);
-            let db = Database::new(DATABASE_NAME, client);
+            let db = Database::with_client(client);
 
             if !args.skip_write {
                 do_write(&args, &db).await;
diff --git a/src/api/greptime/v1/database.proto b/src/api/greptime/v1/database.proto
index 56db558293..354cd9861e 100644
--- a/src/api/greptime/v1/database.proto
+++ b/src/api/greptime/v1/database.proto
@@ -5,11 +5,19 @@ package greptime.v1;
 import "greptime/v1/ddl.proto";
 import "greptime/v1/column.proto";
 
+message RequestHeader {
+  // The `catalog` that is selected to be used in this request.
+  string catalog = 1;
+  // The `schema` that is selected to be used in this request.
+  string schema = 2;
+}
+
 message GreptimeRequest {
+  RequestHeader header = 1;
   oneof request {
-    InsertRequest insert = 1;
-    QueryRequest query = 2;
-    DdlRequest ddl = 3;
+    InsertRequest insert = 2;
+    QueryRequest query = 3;
+    DdlRequest ddl = 4;
   }
 }
 
@@ -21,8 +29,7 @@ message QueryRequest {
 }
 
 message InsertRequest {
-  string schema_name = 1;
-  string table_name = 2;
+  string table_name = 1;
 
   // Data is represented here.
   repeated Column columns = 3;
diff --git a/src/client/Cargo.toml b/src/client/Cargo.toml
index ac83eb2610..bf56b1ead3 100644
--- a/src/client/Cargo.toml
+++ b/src/client/Cargo.toml
@@ -9,6 +9,7 @@ api = { path = "../api" }
 arrow-flight.workspace = true
 async-stream.workspace = true
 common-base = { path = "../common/base" }
+common-catalog = { path = "../common/catalog" }
 common-error = { path = "../common/error" }
 common-grpc = { path = "../common/grpc" }
 common-grpc-expr = { path = "../common/grpc-expr" }
diff --git a/src/client/examples/logical.rs b/src/client/examples/logical.rs
index 368104d52a..07debec679 100644
--- a/src/client/examples/logical.rs
+++ b/src/client/examples/logical.rs
@@ -65,13 +65,12 @@ async fn run() {
         region_ids: vec![0],
     };
 
-    let db = Database::new("create table", client.clone());
+    let db = Database::with_client(client);
     let result = db.create(create_table_expr).await.unwrap();
     event!(Level::INFO, "create table result: {:#?}", result);
 
     let logical = mock_logical_plan();
     event!(Level::INFO, "plan size: {:#?}", logical.len());
-    let db = Database::new("greptime", client);
     let result = db.logical_plan(logical).await.unwrap();
 
     event!(Level::INFO, "result: {:#?}", result);
diff --git a/src/client/src/database.rs b/src/client/src/database.rs
index 956c1db5b0..bdf63b748e 100644
--- a/src/client/src/database.rs
+++ b/src/client/src/database.rs
@@ -19,9 +19,10 @@ use api::v1::greptime_request::Request;
 use api::v1::query_request::Query;
 use api::v1::{
     AlterExpr, CreateTableExpr, DdlRequest, DropTableExpr, GreptimeRequest, InsertRequest,
-    QueryRequest,
+    QueryRequest, RequestHeader,
 };
 use arrow_flight::{FlightData, Ticket};
+use common_catalog::consts::{DEFAULT_CATALOG_NAME, DEFAULT_SCHEMA_NAME};
 use common_error::prelude::*;
 use common_grpc::flight::{flight_messages_to_recordbatches, FlightDecoder, FlightMessage};
 use common_query::Output;
@@ -34,83 +35,89 @@ use crate::{error, Client, Result};
 
 #[derive(Clone, Debug)]
 pub struct Database {
-    name: String,
+    // The "catalog" and "schema" to be used in processing the requests at the server side.
+    // They are the "hint" or "context", just like how the "database" in "USE" statement is treated in MySQL.
+    // They will be carried in the request header.
+    catalog: String,
+    schema: String,
+
     client: Client,
 }
 
 impl Database {
-    pub fn new(name: impl Into<String>, client: Client) -> Self {
+    pub fn new(catalog: impl Into<String>, schema: impl Into<String>, client: Client) -> Self {
         Self {
-            name: name.into(),
+            catalog: catalog.into(),
+            schema: schema.into(),
             client,
         }
     }
 
-    pub fn name(&self) -> &str {
-        &self.name
+    pub fn with_client(client: Client) -> Self {
+        Self::new(DEFAULT_CATALOG_NAME, DEFAULT_SCHEMA_NAME, client)
+    }
+
+    pub fn set_schema(&mut self, schema: impl Into<String>) {
+        self.schema = schema.into();
     }
 
     pub async fn insert(&self, request: InsertRequest) -> Result<Output> {
-        self.do_get(GreptimeRequest {
-            request: Some(Request::Insert(request)),
-        })
-        .await
+        self.do_get(Request::Insert(request)).await
     }
 
     pub async fn sql(&self, sql: &str) -> Result<Output> {
-        self.do_get(GreptimeRequest {
-            request: Some(Request::Query(QueryRequest {
-                query: Some(Query::Sql(sql.to_string())),
-            })),
-        })
+        self.do_get(Request::Query(QueryRequest {
+            query: Some(Query::Sql(sql.to_string())),
+        }))
         .await
     }
 
     pub async fn logical_plan(&self, logical_plan: Vec<u8>) -> Result<Output> {
-        self.do_get(GreptimeRequest {
-            request: Some(Request::Query(QueryRequest {
-                query: Some(Query::LogicalPlan(logical_plan)),
-            })),
-        })
+        self.do_get(Request::Query(QueryRequest {
+            query: Some(Query::LogicalPlan(logical_plan)),
+        }))
         .await
     }
 
     pub async fn create(&self, expr: CreateTableExpr) -> Result<Output> {
-        self.do_get(GreptimeRequest {
-            request: Some(Request::Ddl(DdlRequest {
-                expr: Some(DdlExpr::CreateTable(expr)),
-            })),
-        })
+        self.do_get(Request::Ddl(DdlRequest {
+            expr: Some(DdlExpr::CreateTable(expr)),
+        }))
         .await
     }
 
     pub async fn alter(&self, expr: AlterExpr) -> Result<Output> {
-        self.do_get(GreptimeRequest {
-            request: Some(Request::Ddl(DdlRequest {
-                expr: Some(DdlExpr::Alter(expr)),
-            })),
-        })
+        self.do_get(Request::Ddl(DdlRequest {
+            expr: Some(DdlExpr::Alter(expr)),
+        }))
         .await
     }
 
     pub async fn drop_table(&self, expr: DropTableExpr) -> Result<Output> {
-        self.do_get(GreptimeRequest {
-            request: Some(Request::Ddl(DdlRequest {
-                expr: Some(DdlExpr::DropTable(expr)),
-            })),
-        })
+        self.do_get(Request::Ddl(DdlRequest {
+            expr: Some(DdlExpr::DropTable(expr)),
+        }))
         .await
     }
 
-    async fn do_get(&self, request: GreptimeRequest) -> Result<Output> {
+    async fn do_get(&self, request: Request) -> Result<Output> {
+        let request = GreptimeRequest {
+            header: Some(RequestHeader {
+                catalog: self.catalog.clone(),
+                schema: self.schema.clone(),
+            }),
+            request: Some(request),
+        };
+        let request = Ticket {
+            ticket: request.encode_to_vec(),
+        };
+
         let mut client = self.client.make_client()?;
 
         // TODO(LFC): Streaming get flight data.
         let flight_data: Vec<FlightData> = client
             .mut_inner()
-            .do_get(Ticket {
-                ticket: request.encode_to_vec(),
-            })
+            .do_get(request)
             .and_then(|response| response.into_inner().try_collect())
             .await
             .map_err(|e| {
diff --git a/src/cmd/src/metasrv.rs b/src/cmd/src/metasrv.rs
index a7c726e2fb..52be21f279 100644
--- a/src/cmd/src/metasrv.rs
+++ b/src/cmd/src/metasrv.rs
@@ -13,7 +13,7 @@
 // limitations under the License.
 
 use clap::Parser;
-use common_telemetry::{info, logging};
+use common_telemetry::{info, logging, warn};
 use meta_srv::bootstrap;
 use meta_srv::metasrv::MetaSrvOptions;
 use snafu::ResultExt;
@@ -58,6 +58,8 @@ struct StartCommand {
     config_file: Option<String>,
     #[clap(short, long)]
     selector: Option<String>,
+    #[clap(long)]
+    use_memory_store: bool,
 }
 
 impl StartCommand {
@@ -100,6 +102,11 @@ impl TryFrom<StartCommand> for MetaSrvOptions {
             info!("Using {} selector", selector_type);
         }
 
+        if cmd.use_memory_store {
+            warn!("Using memory store for Meta. Make sure you are in running tests.");
+            opts.use_memory_store = true;
+        }
+
         Ok(opts)
     }
 }
@@ -118,6 +125,7 @@ mod tests {
             store_addr: Some("127.0.0.1:2380".to_string()),
             config_file: None,
             selector: Some("LoadBased".to_string()),
+            use_memory_store: false,
         };
         let options: MetaSrvOptions = cmd.try_into().unwrap();
         assert_eq!("127.0.0.1:3002".to_string(), options.bind_addr);
@@ -137,6 +145,7 @@ mod tests {
                 "{}/../../config/metasrv.example.toml",
                 std::env::current_dir().unwrap().as_path().to_str().unwrap()
             )),
+            use_memory_store: false,
         };
         let options: MetaSrvOptions = cmd.try_into().unwrap();
         assert_eq!("127.0.0.1:3002".to_string(), options.bind_addr);
diff --git a/src/common/grpc-expr/src/alter.rs b/src/common/grpc-expr/src/alter.rs
index 0c40e9f959..16fc2ca86c 100644
--- a/src/common/grpc-expr/src/alter.rs
+++ b/src/common/grpc-expr/src/alter.rs
@@ -29,16 +29,8 @@ use crate::error::{
 
 /// Convert an [`AlterExpr`] to an [`AlterTableRequest`]
 pub fn alter_expr_to_request(expr: AlterExpr) -> Result<AlterTableRequest> {
-    let catalog_name = if expr.catalog_name.is_empty() {
-        None
-    } else {
-        Some(expr.catalog_name)
-    };
-    let schema_name = if expr.schema_name.is_empty() {
-        None
-    } else {
-        Some(expr.schema_name)
-    };
+    let catalog_name = expr.catalog_name;
+    let schema_name = expr.schema_name;
     let kind = expr.kind.context(MissingFieldSnafu { field: "kind" })?;
     match kind {
         Kind::AddColumns(add_columns) => {
@@ -219,8 +211,8 @@ mod tests {
         };
 
         let alter_request = alter_expr_to_request(expr).unwrap();
-        assert_eq!(None, alter_request.catalog_name);
-        assert_eq!(None, alter_request.schema_name);
+        assert_eq!(alter_request.catalog_name, "");
+        assert_eq!(alter_request.schema_name, "");
         assert_eq!("monitor".to_string(), alter_request.table_name);
         let add_column = match alter_request.alter_kind {
             AlterKind::AddColumns { mut columns } => columns.pop().unwrap(),
@@ -250,8 +242,8 @@ mod tests {
         };
 
         let alter_request = alter_expr_to_request(expr).unwrap();
-        assert_eq!(Some("test_catalog".to_string()), alter_request.catalog_name);
-        assert_eq!(Some("test_schema".to_string()), alter_request.schema_name);
+        assert_eq!(alter_request.catalog_name, "test_catalog");
+        assert_eq!(alter_request.schema_name, "test_schema");
         assert_eq!("monitor".to_string(), alter_request.table_name);
 
         let mut drop_names = match alter_request.alter_kind {
diff --git a/src/common/grpc-expr/src/insert.rs b/src/common/grpc-expr/src/insert.rs
index 959f1a5a40..4295ec6f7c 100644
--- a/src/common/grpc-expr/src/insert.rs
+++ b/src/common/grpc-expr/src/insert.rs
@@ -21,7 +21,6 @@ use api::v1::{
     InsertRequest as GrpcInsertRequest,
 };
 use common_base::BitVec;
-use common_catalog::consts::DEFAULT_CATALOG_NAME;
 use common_time::timestamp::Timestamp;
 use common_time::{Date, DateTime};
 use datatypes::data_type::{ConcreteDataType, DataType};
@@ -31,7 +30,7 @@ use datatypes::value::Value;
 use datatypes::vectors::MutableVector;
 use snafu::{ensure, OptionExt, ResultExt};
 use table::metadata::TableId;
-use table::requests::{AddColumnRequest, AlterKind, AlterTableRequest, InsertRequest};
+use table::requests::InsertRequest;
 
 use crate::error::{
     ColumnDataTypeSnafu, CreateVectorSnafu, DuplicatedTimestampColumnSnafu, IllegalInsertDataSnafu,
@@ -81,20 +80,6 @@ pub fn find_new_columns(schema: &SchemaRef, columns: &[Column]) -> Result<Option
     }
 }
 
-/// Build a alter table rqeusts that adding new columns.
-#[inline]
-pub fn build_alter_table_request(
-    table_name: &str,
-    columns: Vec<AddColumnRequest>,
-) -> AlterTableRequest {
-    AlterTableRequest {
-        catalog_name: None,
-        schema_name: None,
-        table_name: table_name.to_string(),
-        alter_kind: AlterKind::AddColumns { columns },
-    }
-}
-
 pub fn column_to_vector(column: &Column, rows: u32) -> Result<VectorRef> {
     let wrapper = ColumnDataTypeWrapper::try_new(column.datatype).context(ColumnDataTypeSnafu)?;
     let column_datatype = wrapper.datatype();
@@ -281,9 +266,11 @@ pub fn build_create_expr_from_insertion(
     Ok(expr)
 }
 
-pub fn to_table_insert_request(request: GrpcInsertRequest) -> Result<InsertRequest> {
-    let catalog_name = DEFAULT_CATALOG_NAME;
-    let schema_name = &request.schema_name;
+pub fn to_table_insert_request(
+    catalog_name: &str,
+    schema_name: &str,
+    request: GrpcInsertRequest,
+) -> Result<InsertRequest> {
     let table_name = &request.table_name;
     let row_count = request.row_count as usize;
 
@@ -617,13 +604,12 @@ mod tests {
     fn test_to_table_insert_request() {
         let (columns, row_count) = mock_insert_batch();
         let request = GrpcInsertRequest {
-            schema_name: "public".to_string(),
             table_name: "demo".to_string(),
             columns,
             row_count,
             region_number: 0,
         };
-        let insert_req = to_table_insert_request(request).unwrap();
+        let insert_req = to_table_insert_request("greptime", "public", request).unwrap();
 
         assert_eq!("greptime", insert_req.catalog_name);
         assert_eq!("public", insert_req.schema_name);
diff --git a/src/common/grpc-expr/src/lib.rs b/src/common/grpc-expr/src/lib.rs
index b237290fa3..80833e1f31 100644
--- a/src/common/grpc-expr/src/lib.rs
+++ b/src/common/grpc-expr/src/lib.rs
@@ -17,6 +17,4 @@ pub mod error;
 pub mod insert;
 
 pub use alter::{alter_expr_to_request, create_expr_to_request, create_table_schema};
-pub use insert::{
-    build_alter_table_request, build_create_expr_from_insertion, column_to_vector, find_new_columns,
-};
+pub use insert::{build_create_expr_from_insertion, column_to_vector, find_new_columns};
diff --git a/src/datanode/src/error.rs b/src/datanode/src/error.rs
index 1589306246..4d40f311c7 100644
--- a/src/datanode/src/error.rs
+++ b/src/datanode/src/error.rs
@@ -80,7 +80,10 @@ pub enum Error {
     },
 
     #[snafu(display("Table not found: {}", table_name))]
-    TableNotFound { table_name: String },
+    TableNotFound {
+        table_name: String,
+        backtrace: Backtrace,
+    },
 
     #[snafu(display("Column {} not found in table {}", column_name, table_name))]
     ColumnNotFound {
diff --git a/src/datanode/src/instance.rs b/src/datanode/src/instance.rs
index a75ceab75d..0d40cac50a 100644
--- a/src/datanode/src/instance.rs
+++ b/src/datanode/src/instance.rs
@@ -53,7 +53,7 @@ use crate::sql::SqlHandler;
 
 mod grpc;
 mod script;
-mod sql;
+pub mod sql;
 
 pub(crate) type DefaultEngine = MitoEngine<EngineImpl<RaftEngineLogStore>>;
 
diff --git a/src/datanode/src/instance/grpc.rs b/src/datanode/src/instance/grpc.rs
index e55f3effc8..1c5ba0a40a 100644
--- a/src/datanode/src/instance/grpc.rs
+++ b/src/datanode/src/instance/grpc.rs
@@ -15,14 +15,13 @@
 use api::v1::ddl_request::Expr as DdlExpr;
 use api::v1::greptime_request::Request as GrpcRequest;
 use api::v1::query_request::Query;
-use api::v1::{CreateDatabaseExpr, DdlRequest, GreptimeRequest, InsertRequest};
+use api::v1::{CreateDatabaseExpr, DdlRequest, InsertRequest};
 use async_trait::async_trait;
-use common_catalog::consts::DEFAULT_CATALOG_NAME;
 use common_query::Output;
 use query::parser::QueryLanguageParser;
 use query::plan::LogicalPlan;
 use servers::query_handler::grpc::GrpcQueryHandler;
-use session::context::QueryContext;
+use session::context::QueryContextRef;
 use snafu::prelude::*;
 use substrait::{DFLogicalSubstraitConvertor, SubstraitPlan};
 use table::requests::CreateDatabaseRequest;
@@ -50,26 +49,31 @@ impl Instance {
             .context(ExecuteSqlSnafu)
     }
 
-    async fn handle_query(&self, query: Query) -> Result<Output> {
+    async fn handle_query(&self, query: Query, ctx: QueryContextRef) -> Result<Output> {
         Ok(match query {
             Query::Sql(sql) => {
                 let stmt = QueryLanguageParser::parse_sql(&sql).context(ExecuteSqlSnafu)?;
-                self.execute_stmt(stmt, QueryContext::arc()).await?
+                self.execute_stmt(stmt, ctx).await?
             }
             Query::LogicalPlan(plan) => self.execute_logical(plan).await?,
         })
     }
 
-    pub async fn handle_insert(&self, request: InsertRequest) -> Result<Output> {
+    pub async fn handle_insert(
+        &self,
+        request: InsertRequest,
+        ctx: QueryContextRef,
+    ) -> Result<Output> {
+        let catalog = &ctx.current_catalog();
+        let schema = &ctx.current_schema();
         let table_name = &request.table_name.clone();
-        // TODO(LFC): InsertRequest should carry catalog name, too.
         let table = self
             .catalog_manager
-            .table(DEFAULT_CATALOG_NAME, &request.schema_name, table_name)
+            .table(catalog, schema, table_name)
             .context(error::CatalogSnafu)?
             .context(error::TableNotFoundSnafu { table_name })?;
 
-        let request = common_grpc_expr::insert::to_table_insert_request(request)
+        let request = common_grpc_expr::insert::to_table_insert_request(catalog, schema, request)
             .context(error::InsertDataSnafu)?;
 
         let affected_rows = table
@@ -96,19 +100,16 @@ impl Instance {
 impl GrpcQueryHandler for Instance {
     type Error = error::Error;
 
-    async fn do_query(&self, query: GreptimeRequest) -> Result<Output> {
-        let request = query.request.context(error::MissingRequiredFieldSnafu {
-            name: "GreptimeRequest.request",
-        })?;
+    async fn do_query(&self, request: GrpcRequest, ctx: QueryContextRef) -> Result<Output> {
         match request {
-            GrpcRequest::Insert(request) => self.handle_insert(request).await,
+            GrpcRequest::Insert(request) => self.handle_insert(request, ctx).await,
             GrpcRequest::Query(query_request) => {
                 let query = query_request
                     .query
                     .context(error::MissingRequiredFieldSnafu {
                         name: "QueryRequest.query",
                     })?;
-                self.handle_query(query).await
+                self.handle_query(query, ctx).await
             }
             GrpcRequest::Ddl(request) => self.handle_ddl(request).await,
         }
@@ -124,6 +125,7 @@ mod test {
     };
     use common_recordbatch::RecordBatches;
     use datatypes::prelude::*;
+    use session::context::QueryContext;
 
     use super::*;
     use crate::tests::test_util::{self, MockInstance};
@@ -133,67 +135,61 @@ mod test {
         let instance = MockInstance::new("test_handle_ddl").await;
         let instance = instance.inner();
 
-        let query = GreptimeRequest {
-            request: Some(GrpcRequest::Ddl(DdlRequest {
-                expr: Some(DdlExpr::CreateDatabase(CreateDatabaseExpr {
-                    database_name: "my_database".to_string(),
-                    create_if_not_exists: true,
-                })),
+        let query = GrpcRequest::Ddl(DdlRequest {
+            expr: Some(DdlExpr::CreateDatabase(CreateDatabaseExpr {
+                database_name: "my_database".to_string(),
+                create_if_not_exists: true,
             })),
-        };
-        let output = instance.do_query(query).await.unwrap();
+        });
+        let output = instance.do_query(query, QueryContext::arc()).await.unwrap();
         assert!(matches!(output, Output::AffectedRows(1)));
 
-        let query = GreptimeRequest {
-            request: Some(GrpcRequest::Ddl(DdlRequest {
-                expr: Some(DdlExpr::CreateTable(CreateTableExpr {
-                    catalog_name: "greptime".to_string(),
-                    schema_name: "my_database".to_string(),
-                    table_name: "my_table".to_string(),
-                    desc: "blabla".to_string(),
-                    column_defs: vec![
-                        ColumnDef {
-                            name: "a".to_string(),
-                            datatype: ColumnDataType::String as i32,
-                            is_nullable: true,
-                            default_constraint: vec![],
-                        },
-                        ColumnDef {
-                            name: "ts".to_string(),
-                            datatype: ColumnDataType::TimestampMillisecond as i32,
-                            is_nullable: false,
-                            default_constraint: vec![],
-                        },
-                    ],
-                    time_index: "ts".to_string(),
-                    ..Default::default()
-                })),
+        let query = GrpcRequest::Ddl(DdlRequest {
+            expr: Some(DdlExpr::CreateTable(CreateTableExpr {
+                catalog_name: "greptime".to_string(),
+                schema_name: "my_database".to_string(),
+                table_name: "my_table".to_string(),
+                desc: "blabla".to_string(),
+                column_defs: vec![
+                    ColumnDef {
+                        name: "a".to_string(),
+                        datatype: ColumnDataType::String as i32,
+                        is_nullable: true,
+                        default_constraint: vec![],
+                    },
+                    ColumnDef {
+                        name: "ts".to_string(),
+                        datatype: ColumnDataType::TimestampMillisecond as i32,
+                        is_nullable: false,
+                        default_constraint: vec![],
+                    },
+                ],
+                time_index: "ts".to_string(),
+                ..Default::default()
             })),
-        };
-        let output = instance.do_query(query).await.unwrap();
+        });
+        let output = instance.do_query(query, QueryContext::arc()).await.unwrap();
         assert!(matches!(output, Output::AffectedRows(0)));
 
-        let query = GreptimeRequest {
-            request: Some(GrpcRequest::Ddl(DdlRequest {
-                expr: Some(DdlExpr::Alter(AlterExpr {
-                    catalog_name: "greptime".to_string(),
-                    schema_name: "my_database".to_string(),
-                    table_name: "my_table".to_string(),
-                    kind: Some(alter_expr::Kind::AddColumns(AddColumns {
-                        add_columns: vec![AddColumn {
-                            column_def: Some(ColumnDef {
-                                name: "b".to_string(),
-                                datatype: ColumnDataType::Int32 as i32,
-                                is_nullable: true,
-                                default_constraint: vec![],
-                            }),
-                            is_key: true,
-                        }],
-                    })),
+        let query = GrpcRequest::Ddl(DdlRequest {
+            expr: Some(DdlExpr::Alter(AlterExpr {
+                catalog_name: "greptime".to_string(),
+                schema_name: "my_database".to_string(),
+                table_name: "my_table".to_string(),
+                kind: Some(alter_expr::Kind::AddColumns(AddColumns {
+                    add_columns: vec![AddColumn {
+                        column_def: Some(ColumnDef {
+                            name: "b".to_string(),
+                            datatype: ColumnDataType::Int32 as i32,
+                            is_nullable: true,
+                            default_constraint: vec![],
+                        }),
+                        is_key: true,
+                    }],
                 })),
             })),
-        };
-        let output = instance.do_query(query).await.unwrap();
+        });
+        let output = instance.do_query(query, QueryContext::arc()).await.unwrap();
         assert!(matches!(output, Output::AffectedRows(0)));
 
         let output = instance
@@ -232,7 +228,6 @@ mod test {
             .unwrap();
 
         let insert = InsertRequest {
-            schema_name: "public".to_string(),
             table_name: "demo".to_string(),
             columns: vec![
                 Column {
@@ -274,10 +269,8 @@ mod test {
             ..Default::default()
         };
 
-        let query = GreptimeRequest {
-            request: Some(GrpcRequest::Insert(insert)),
-        };
-        let output = instance.do_query(query).await.unwrap();
+        let query = GrpcRequest::Insert(insert);
+        let output = instance.do_query(query, QueryContext::arc()).await.unwrap();
         assert!(matches!(output, Output::AffectedRows(3)));
 
         let output = instance
@@ -305,27 +298,23 @@ mod test {
             .await
             .unwrap();
 
-        let query = GreptimeRequest {
-            request: Some(GrpcRequest::Query(QueryRequest {
-                query: Some(Query::Sql(
-                    "INSERT INTO demo(host, cpu, memory, ts) VALUES \
+        let query = GrpcRequest::Query(QueryRequest {
+            query: Some(Query::Sql(
+                "INSERT INTO demo(host, cpu, memory, ts) VALUES \
                             ('host1', 66.6, 1024, 1672201025000),\
                             ('host2', 88.8, 333.3, 1672201026000)"
-                        .to_string(),
-                )),
-            })),
-        };
-        let output = instance.do_query(query).await.unwrap();
+                    .to_string(),
+            )),
+        });
+        let output = instance.do_query(query, QueryContext::arc()).await.unwrap();
         assert!(matches!(output, Output::AffectedRows(2)));
 
-        let query = GreptimeRequest {
-            request: Some(GrpcRequest::Query(QueryRequest {
-                query: Some(Query::Sql(
-                    "SELECT ts, host, cpu, memory FROM demo".to_string(),
-                )),
-            })),
-        };
-        let output = instance.do_query(query).await.unwrap();
+        let query = GrpcRequest::Query(QueryRequest {
+            query: Some(Query::Sql(
+                "SELECT ts, host, cpu, memory FROM demo".to_string(),
+            )),
+        });
+        let output = instance.do_query(query, QueryContext::arc()).await.unwrap();
         let Output::Stream(stream) = output else { unreachable!() };
         let recordbatch = RecordBatches::try_collect(stream).await.unwrap();
         let expected = "\
diff --git a/src/datanode/src/instance/sql.rs b/src/datanode/src/instance/sql.rs
index c9abf05ca3..9e28c1802f 100644
--- a/src/datanode/src/instance/sql.rs
+++ b/src/datanode/src/instance/sql.rs
@@ -13,7 +13,6 @@
 // limitations under the License.
 
 use async_trait::async_trait;
-use common_catalog::consts::{DEFAULT_CATALOG_NAME, DEFAULT_SCHEMA_NAME};
 use common_query::Output;
 use common_recordbatch::RecordBatches;
 use common_telemetry::logging::info;
@@ -25,7 +24,7 @@ use snafu::prelude::*;
 use sql::ast::ObjectName;
 use sql::statements::statement::Statement;
 use table::engine::TableReference;
-use table::requests::CreateDatabaseRequest;
+use table::requests::{CreateDatabaseRequest, DropTableRequest};
 
 use crate::error::{self, BumpTableIdSnafu, ExecuteSqlSnafu, Result, TableIdProviderNotFoundSnafu};
 use crate::instance::Instance;
@@ -89,12 +88,11 @@ impl Instance {
                 let name = c.name.clone();
                 let (catalog, schema, table) = table_idents_to_full_name(&name, query_ctx.clone())?;
                 let table_ref = TableReference::full(&catalog, &schema, &table);
-                let request = self.sql_handler.create_to_request(table_id, c, table_ref)?;
+                let request = self
+                    .sql_handler
+                    .create_to_request(table_id, c, &table_ref)?;
                 let table_id = request.id;
-                info!(
-                    "Creating table, catalog: {:?}, schema: {:?}, table name: {:?}, table id: {}",
-                    catalog, schema, table, table_id
-                );
+                info!("Creating table: {table_ref}, table id = {table_id}",);
 
                 self.sql_handler
                     .execute(SqlRequest::CreateTable(request), query_ctx)
@@ -110,7 +108,13 @@ impl Instance {
                     .await
             }
             QueryStatement::Sql(Statement::DropTable(drop_table)) => {
-                let req = self.sql_handler.drop_table_to_request(drop_table);
+                let (catalog_name, schema_name, table_name) =
+                    table_idents_to_full_name(drop_table.table_name(), query_ctx.clone())?;
+                let req = DropTableRequest {
+                    catalog_name,
+                    schema_name,
+                    table_name,
+                };
                 self.sql_handler
                     .execute(SqlRequest::DropTable(req), query_ctx)
                     .await
@@ -138,16 +142,14 @@ impl Instance {
             QueryStatement::Sql(Statement::ShowCreateTable(_stmt)) => {
                 unimplemented!("SHOW CREATE TABLE is unimplemented yet");
             }
-            QueryStatement::Sql(Statement::Use(schema)) => {
-                let catalog = query_ctx.current_catalog();
-                let catalog = catalog.as_deref().unwrap_or(DEFAULT_CATALOG_NAME);
-
+            QueryStatement::Sql(Statement::Use(ref schema)) => {
+                let catalog = &query_ctx.current_catalog();
                 ensure!(
-                    self.is_valid_schema(catalog, &schema)?,
+                    self.is_valid_schema(catalog, schema)?,
                     error::DatabaseNotFoundSnafu { catalog, schema }
                 );
 
-                query_ctx.set_current_schema(&schema);
+                query_ctx.set_current_schema(schema);
 
                 Ok(Output::RecordBatches(RecordBatches::empty()))
             }
@@ -168,18 +170,18 @@ impl Instance {
 // TODO(LFC): Refactor consideration: move this function to some helper mod,
 // could be done together or after `TableReference`'s refactoring, when issue #559 is resolved.
 /// Converts maybe fully-qualified table name (`<catalog>.<schema>.<table>`) to tuple.
-fn table_idents_to_full_name(
+pub fn table_idents_to_full_name(
     obj_name: &ObjectName,
     query_ctx: QueryContextRef,
 ) -> Result<(String, String, String)> {
     match &obj_name.0[..] {
         [table] => Ok((
-            DEFAULT_CATALOG_NAME.to_string(),
-            query_ctx.current_schema().unwrap_or_else(|| DEFAULT_SCHEMA_NAME.to_string()),
+            query_ctx.current_catalog(),
+            query_ctx.current_schema(),
             table.value.clone(),
         )),
         [schema, table] => Ok((
-            DEFAULT_CATALOG_NAME.to_string(),
+            query_ctx.current_catalog(),
             schema.value.clone(),
             table.value.clone(),
         )),
@@ -229,6 +231,7 @@ impl SqlQueryHandler for Instance {
 mod test {
     use std::sync::Arc;
 
+    use common_catalog::consts::{DEFAULT_CATALOG_NAME, DEFAULT_SCHEMA_NAME};
     use session::context::QueryContext;
 
     use super::*;
@@ -244,10 +247,7 @@ mod test {
         let bare = ObjectName(vec![my_table.into()]);
 
         let using_schema = "foo";
-        let query_ctx = Arc::new(QueryContext::with(
-            DEFAULT_CATALOG_NAME.to_owned(),
-            using_schema.to_string(),
-        ));
+        let query_ctx = Arc::new(QueryContext::with(DEFAULT_CATALOG_NAME, using_schema));
         let empty_ctx = Arc::new(QueryContext::new());
 
         assert_eq!(
diff --git a/src/datanode/src/sql.rs b/src/datanode/src/sql.rs
index 8f99e9b059..e5d8ad74d9 100644
--- a/src/datanode/src/sql.rs
+++ b/src/datanode/src/sql.rs
@@ -26,7 +26,8 @@ use table::engine::{EngineContext, TableEngineRef, TableReference};
 use table::requests::*;
 use table::TableRef;
 
-use crate::error::{ExecuteSqlSnafu, GetTableSnafu, Result, TableNotFoundSnafu};
+use crate::error::{self, ExecuteSqlSnafu, GetTableSnafu, Result, TableNotFoundSnafu};
+use crate::instance::sql::table_idents_to_full_name;
 
 mod alter;
 mod create;
@@ -81,17 +82,29 @@ impl SqlHandler {
                 show_databases(stmt, self.catalog_manager.clone()).context(ExecuteSqlSnafu)
             }
             SqlRequest::ShowTables(stmt) => {
-                show_tables(stmt, self.catalog_manager.clone(), query_ctx).context(ExecuteSqlSnafu)
+                show_tables(stmt, self.catalog_manager.clone(), query_ctx.clone())
+                    .context(ExecuteSqlSnafu)
             }
             SqlRequest::DescribeTable(stmt) => {
-                describe_table(stmt, self.catalog_manager.clone()).context(ExecuteSqlSnafu)
+                let (catalog, schema, table) =
+                    table_idents_to_full_name(stmt.name(), query_ctx.clone())?;
+                let table = self
+                    .catalog_manager
+                    .table(&catalog, &schema, &table)
+                    .context(error::CatalogSnafu)?
+                    .with_context(|| TableNotFoundSnafu {
+                        table_name: stmt.name().to_string(),
+                    })?;
+                describe_table(table).context(ExecuteSqlSnafu)
+            }
+            SqlRequest::Explain(stmt) => {
+                explain(stmt, self.query_engine.clone(), query_ctx.clone())
+                    .await
+                    .context(ExecuteSqlSnafu)
             }
-            SqlRequest::Explain(stmt) => explain(stmt, self.query_engine.clone(), query_ctx)
-                .await
-                .context(ExecuteSqlSnafu),
         };
         if let Err(e) = &result {
-            error!("Datanode execution error: {:?}", e);
+            error!(e; "{query_ctx}");
         }
         result
     }
diff --git a/src/datanode/src/sql/alter.rs b/src/datanode/src/sql/alter.rs
index a68b0ccf3d..43f6e568fa 100644
--- a/src/datanode/src/sql/alter.rs
+++ b/src/datanode/src/sql/alter.rs
@@ -13,7 +13,6 @@
 // limitations under the License.
 
 use catalog::RenameTableRequest;
-use common_catalog::consts::{DEFAULT_CATALOG_NAME, DEFAULT_SCHEMA_NAME};
 use common_query::Output;
 use snafu::prelude::*;
 use sql::statements::alter::{AlterTable, AlterTableOperation};
@@ -27,12 +26,10 @@ use crate::sql::SqlHandler;
 impl SqlHandler {
     pub(crate) async fn alter(&self, req: AlterTableRequest) -> Result<Output> {
         let ctx = EngineContext {};
-        let catalog_name = req.catalog_name.as_deref().unwrap_or(DEFAULT_CATALOG_NAME);
-        let schema_name = req.schema_name.as_deref().unwrap_or(DEFAULT_SCHEMA_NAME);
         let table_name = req.table_name.clone();
         let table_ref = TableReference {
-            catalog: catalog_name,
-            schema: schema_name,
+            catalog: &req.catalog_name,
+            schema: &req.schema_name,
             table: &table_name,
         };
 
@@ -98,8 +95,8 @@ impl SqlHandler {
             },
         };
         Ok(AlterTableRequest {
-            catalog_name: Some(table_ref.catalog.to_string()),
-            schema_name: Some(table_ref.schema.to_string()),
+            catalog_name: table_ref.catalog.to_string(),
+            schema_name: table_ref.schema.to_string(),
             table_name: table_ref.table.to_string(),
             alter_kind,
         })
@@ -134,10 +131,13 @@ mod tests {
         let handler = create_mock_sql_handler().await;
         let alter_table = parse_sql("ALTER TABLE my_metric_1 ADD tagk_i STRING Null;");
         let req = handler
-            .alter_to_request(alter_table, TableReference::bare("my_metric_1"))
+            .alter_to_request(
+                alter_table,
+                TableReference::full("greptime", "public", "my_metric_1"),
+            )
             .unwrap();
-        assert_eq!(req.catalog_name, Some("greptime".to_string()));
-        assert_eq!(req.schema_name, Some("public".to_string()));
+        assert_eq!(req.catalog_name, "greptime");
+        assert_eq!(req.schema_name, "public");
         assert_eq!(req.table_name, "my_metric_1");
 
         let alter_kind = req.alter_kind;
@@ -159,10 +159,13 @@ mod tests {
         let handler = create_mock_sql_handler().await;
         let alter_table = parse_sql("ALTER TABLE test_table RENAME table_t;");
         let req = handler
-            .alter_to_request(alter_table, TableReference::bare("test_table"))
+            .alter_to_request(
+                alter_table,
+                TableReference::full("greptime", "public", "test_table"),
+            )
             .unwrap();
-        assert_eq!(req.catalog_name, Some("greptime".to_string()));
-        assert_eq!(req.schema_name, Some("public".to_string()));
+        assert_eq!(req.catalog_name, "greptime");
+        assert_eq!(req.schema_name, "public");
         assert_eq!(req.table_name, "test_table");
 
         let alter_kind = req.alter_kind;
diff --git a/src/datanode/src/sql/create.rs b/src/datanode/src/sql/create.rs
index 6b9af20bfe..bf011a94f9 100644
--- a/src/datanode/src/sql/create.rs
+++ b/src/datanode/src/sql/create.rs
@@ -122,7 +122,7 @@ impl SqlHandler {
         &self,
         table_id: TableId,
         stmt: CreateTable,
-        table_ref: TableReference,
+        table_ref: &TableReference,
     ) -> Result<CreateTableRequest> {
         let mut ts_index = usize::MAX;
         let mut primary_keys = vec![];
@@ -259,7 +259,7 @@ mod tests {
                        PRIMARY KEY(host)) engine=mito with(regions=1);"#,
         );
         let c = handler
-            .create_to_request(42, parsed_stmt, TableReference::bare("demo_table"))
+            .create_to_request(42, parsed_stmt, &TableReference::bare("demo_table"))
             .unwrap();
         assert_eq!("demo_table", c.table_name);
         assert_eq!(42, c.id);
@@ -282,7 +282,7 @@ mod tests {
                       TIME INDEX (ts)) engine=mito with(regions=1);"#,
         );
         let c = handler
-            .create_to_request(42, parsed_stmt, TableReference::bare("demo_table"))
+            .create_to_request(42, parsed_stmt, &TableReference::bare("demo_table"))
             .unwrap();
         assert!(c.primary_key_indices.is_empty());
         assert_eq!(c.schema.timestamp_index(), Some(1));
@@ -300,7 +300,7 @@ mod tests {
         );
 
         let error = handler
-            .create_to_request(42, parsed_stmt, TableReference::bare("demo_table"))
+            .create_to_request(42, parsed_stmt, &TableReference::bare("demo_table"))
             .unwrap_err();
         assert_matches!(error, Error::KeyColumnNotFound { .. });
     }
@@ -322,7 +322,7 @@ mod tests {
         let handler = create_mock_sql_handler().await;
 
         let error = handler
-            .create_to_request(42, create_table, TableReference::full("c", "s", "demo"))
+            .create_to_request(42, create_table, &TableReference::full("c", "s", "demo"))
             .unwrap_err();
         assert_matches!(error, Error::InvalidPrimaryKey { .. });
     }
@@ -344,7 +344,7 @@ mod tests {
         let handler = create_mock_sql_handler().await;
 
         let request = handler
-            .create_to_request(42, create_table, TableReference::full("c", "s", "demo"))
+            .create_to_request(42, create_table, &TableReference::full("c", "s", "demo"))
             .unwrap();
 
         assert_eq!(42, request.id);
diff --git a/src/datanode/src/sql/drop_table.rs b/src/datanode/src/sql/drop_table.rs
index 93b7548d5f..8f4c7d8720 100644
--- a/src/datanode/src/sql/drop_table.rs
+++ b/src/datanode/src/sql/drop_table.rs
@@ -17,7 +17,6 @@ use common_error::prelude::BoxedError;
 use common_query::Output;
 use common_telemetry::info;
 use snafu::ResultExt;
-use sql::statements::drop::DropTable;
 use table::engine::{EngineContext, TableReference};
 use table::requests::DropTableRequest;
 
@@ -60,12 +59,4 @@ impl SqlHandler {
 
         Ok(Output::AffectedRows(1))
     }
-
-    pub fn drop_table_to_request(&self, drop_table: DropTable) -> DropTableRequest {
-        DropTableRequest {
-            catalog_name: drop_table.catalog_name,
-            schema_name: drop_table.schema_name,
-            table_name: drop_table.table_name,
-        }
-    }
 }
diff --git a/src/datanode/src/tests/instance_test.rs b/src/datanode/src/tests/instance_test.rs
index e4eedd4dc6..bb2cee88f5 100644
--- a/src/datanode/src/tests/instance_test.rs
+++ b/src/datanode/src/tests/instance_test.rs
@@ -647,10 +647,7 @@ async fn try_execute_sql_in_db(
     sql: &str,
     db: &str,
 ) -> Result<Output, crate::error::Error> {
-    let query_ctx = Arc::new(QueryContext::with(
-        DEFAULT_CATALOG_NAME.to_owned(),
-        db.to_string(),
-    ));
+    let query_ctx = Arc::new(QueryContext::with(DEFAULT_CATALOG_NAME, db));
     instance.inner().execute_sql(sql, query_ctx).await
 }
 
diff --git a/src/datanode/src/tests/promql_test.rs b/src/datanode/src/tests/promql_test.rs
index 9ae533fef7..1a16aed9bf 100644
--- a/src/datanode/src/tests/promql_test.rs
+++ b/src/datanode/src/tests/promql_test.rs
@@ -12,9 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use std::sync::Arc;
-
-use common_catalog::consts::{DEFAULT_CATALOG_NAME, DEFAULT_SCHEMA_NAME};
 use common_query::Output;
 use session::context::QueryContext;
 
@@ -23,10 +20,7 @@ use crate::tests::test_util::{check_output_stream, setup_test_instance};
 #[tokio::test(flavor = "multi_thread")]
 async fn sql_insert_promql_query_ceil() {
     let instance = setup_test_instance("test_execute_insert").await;
-    let query_ctx = Arc::new(QueryContext::with(
-        DEFAULT_CATALOG_NAME.to_owned(),
-        DEFAULT_SCHEMA_NAME.to_owned(),
-    ));
+    let query_ctx = QueryContext::arc();
     let put_output = instance
         .inner()
         .execute_sql(
diff --git a/src/frontend/src/error.rs b/src/frontend/src/error.rs
index 4498ba580c..d45f34eed1 100644
--- a/src/frontend/src/error.rs
+++ b/src/frontend/src/error.rs
@@ -20,6 +20,12 @@ use store_api::storage::RegionId;
 #[derive(Debug, Snafu)]
 #[snafu(visibility(pub))]
 pub enum Error {
+    #[snafu(display("{source}"))]
+    External {
+        #[snafu(backtrace)]
+        source: BoxedError,
+    },
+
     #[snafu(display("Failed to request Datanode, source: {}", source))]
     RequestDatanode {
         #[snafu(backtrace)]
@@ -401,6 +407,7 @@ impl ErrorExt for Error {
             Error::InvokeDatanode { source } => source.status_code(),
             Error::ColumnDefaultValue { source, .. } => source.status_code(),
             Error::ColumnNoneDefaultValue { .. } => StatusCode::InvalidArguments,
+            Error::External { source } => source.status_code(),
             Error::DeserializePartition { source, .. } | Error::FindTableRoute { source, .. } => {
                 source.status_code()
             }
diff --git a/src/frontend/src/instance.rs b/src/frontend/src/instance.rs
index d4603076ed..7018f14828 100644
--- a/src/frontend/src/instance.rs
+++ b/src/frontend/src/instance.rs
@@ -25,17 +25,16 @@ use std::time::Duration;
 use api::v1::alter_expr::Kind;
 use api::v1::ddl_request::Expr as DdlExpr;
 use api::v1::greptime_request::Request;
-use api::v1::{
-    AddColumns, AlterExpr, Column, DdlRequest, DropTableExpr, GreptimeRequest, InsertRequest,
-};
+use api::v1::{AddColumns, AlterExpr, Column, DdlRequest, DropTableExpr, InsertRequest};
 use async_trait::async_trait;
 use catalog::remote::MetaKvBackend;
 use catalog::CatalogManagerRef;
-use common_catalog::consts::DEFAULT_CATALOG_NAME;
+use common_error::ext::BoxedError;
 use common_grpc::channel_manager::{ChannelConfig, ChannelManager};
 use common_query::Output;
 use common_recordbatch::RecordBatches;
 use common_telemetry::logging::{debug, info};
+use datanode::instance::sql::table_idents_to_full_name;
 use datanode::instance::InstanceRef as DnInstanceRef;
 use distributed::DistInstance;
 use meta_client::client::{MetaClient, MetaClientBuilder};
@@ -194,10 +193,14 @@ impl Instance {
     }
 
     /// Handle batch inserts
-    pub async fn handle_inserts(&self, requests: Vec<InsertRequest>) -> Result<Output> {
+    pub async fn handle_inserts(
+        &self,
+        requests: Vec<InsertRequest>,
+        ctx: QueryContextRef,
+    ) -> Result<Output> {
         let mut success = 0;
         for request in requests {
-            match self.handle_insert(request).await? {
+            match self.handle_insert(request, ctx.clone()).await? {
                 Output::AffectedRows(rows) => success += rows,
                 _ => unreachable!("Insert should not yield output other than AffectedRows"),
             }
@@ -205,20 +208,12 @@ impl Instance {
         Ok(Output::AffectedRows(success))
     }
 
-    async fn handle_insert(&self, request: InsertRequest) -> Result<Output> {
-        let schema_name = &request.schema_name;
-        let table_name = &request.table_name;
-        let catalog_name = DEFAULT_CATALOG_NAME;
-
-        let columns = &request.columns;
-
-        self.create_or_alter_table_on_demand(catalog_name, schema_name, table_name, columns)
+    async fn handle_insert(&self, request: InsertRequest, ctx: QueryContextRef) -> Result<Output> {
+        self.create_or_alter_table_on_demand(ctx.clone(), &request.table_name, &request.columns)
             .await?;
 
-        let query = GreptimeRequest {
-            request: Some(Request::Insert(request)),
-        };
-        GrpcQueryHandler::do_query(&*self.grpc_query_handler, query).await
+        let query = Request::Insert(request);
+        GrpcQueryHandler::do_query(&*self.grpc_query_handler, query, ctx).await
     }
 
     // check if table already exist:
@@ -226,11 +221,13 @@ impl Instance {
     // - if table exist, check if schema matches. If any new column found, alter table by inferred `AlterExpr`
     async fn create_or_alter_table_on_demand(
         &self,
-        catalog_name: &str,
-        schema_name: &str,
+        ctx: QueryContextRef,
         table_name: &str,
         columns: &[Column],
     ) -> Result<()> {
+        let catalog_name = &ctx.current_catalog();
+        let schema_name = &ctx.current_schema();
+
         let table = self
             .catalog_manager
             .table(catalog_name, schema_name, table_name)
@@ -241,7 +238,7 @@ impl Instance {
                     "Table {}.{}.{} does not exist, try create table",
                     catalog_name, schema_name, table_name,
                 );
-                self.create_table_by_columns(catalog_name, schema_name, table_name, columns)
+                self.create_table_by_columns(ctx, table_name, columns)
                     .await?;
                 info!(
                     "Successfully created table on insertion: {}.{}.{}",
@@ -258,13 +255,8 @@ impl Instance {
                         "Find new columns {:?} on insertion, try to alter table: {}.{}.{}",
                         add_columns, catalog_name, schema_name, table_name
                     );
-                    self.add_new_columns_to_table(
-                        catalog_name,
-                        schema_name,
-                        table_name,
-                        add_columns,
-                    )
-                    .await?;
+                    self.add_new_columns_to_table(ctx, table_name, add_columns)
+                        .await?;
                     info!(
                         "Successfully altered table on insertion: {}.{}.{}",
                         catalog_name, schema_name, table_name
@@ -278,11 +270,13 @@ impl Instance {
     /// Infer create table expr from inserting data
     async fn create_table_by_columns(
         &self,
-        catalog_name: &str,
-        schema_name: &str,
+        ctx: QueryContextRef,
         table_name: &str,
         columns: &[Column],
     ) -> Result<Output> {
+        let catalog_name = &ctx.current_catalog();
+        let schema_name = &ctx.current_schema();
+
         // Create table automatically, build schema from data.
         let create_expr = self
             .create_expr_factory
@@ -295,18 +289,18 @@ impl Instance {
         );
 
         self.grpc_query_handler
-            .do_query(GreptimeRequest {
-                request: Some(Request::Ddl(DdlRequest {
+            .do_query(
+                Request::Ddl(DdlRequest {
                     expr: Some(DdlExpr::CreateTable(create_expr)),
-                })),
-            })
+                }),
+                ctx,
+            )
             .await
     }
 
     async fn add_new_columns_to_table(
         &self,
-        catalog_name: &str,
-        schema_name: &str,
+        ctx: QueryContextRef,
         table_name: &str,
         add_columns: AddColumns,
     ) -> Result<Output> {
@@ -315,25 +309,24 @@ impl Instance {
             add_columns, table_name
         );
         let expr = AlterExpr {
+            catalog_name: ctx.current_catalog(),
+            schema_name: ctx.current_schema(),
             table_name: table_name.to_string(),
-            schema_name: schema_name.to_string(),
-            catalog_name: catalog_name.to_string(),
             kind: Some(Kind::AddColumns(add_columns)),
         };
 
         self.grpc_query_handler
-            .do_query(GreptimeRequest {
-                request: Some(Request::Ddl(DdlRequest {
+            .do_query(
+                Request::Ddl(DdlRequest {
                     expr: Some(DdlExpr::Alter(expr)),
-                })),
-            })
+                }),
+                ctx,
+            )
             .await
     }
 
     fn handle_use(&self, db: String, query_ctx: QueryContextRef) -> Result<Output> {
-        let catalog = query_ctx.current_catalog();
-        let catalog = catalog.as_deref().unwrap_or(DEFAULT_CATALOG_NAME);
-
+        let catalog = &query_ctx.current_catalog();
         ensure!(
             self.catalog_manager
                 .schema(catalog, &db)
@@ -380,34 +373,28 @@ impl Instance {
             | Statement::DescribeTable(_)
             | Statement::Explain(_)
             | Statement::Query(_)
-            | Statement::Insert(_) => {
+            | Statement::Insert(_)
+            | Statement::Alter(_) => {
                 return self.sql_handler.do_statement_query(stmt, query_ctx).await;
             }
-            Statement::Alter(alter_stmt) => {
-                let expr =
-                    AlterExpr::try_from(alter_stmt).context(error::AlterExprFromStmtSnafu)?;
-                return self
-                    .grpc_query_handler
-                    .do_query(GreptimeRequest {
-                        request: Some(Request::Ddl(DdlRequest {
-                            expr: Some(DdlExpr::Alter(expr)),
-                        })),
-                    })
-                    .await;
-            }
             Statement::DropTable(drop_stmt) => {
+                let (catalog_name, schema_name, table_name) =
+                    table_idents_to_full_name(drop_stmt.table_name(), query_ctx.clone())
+                        .map_err(BoxedError::new)
+                        .context(error::ExternalSnafu)?;
                 let expr = DropTableExpr {
-                    catalog_name: drop_stmt.catalog_name,
-                    schema_name: drop_stmt.schema_name,
-                    table_name: drop_stmt.table_name,
+                    catalog_name,
+                    schema_name,
+                    table_name,
                 };
                 return self
                     .grpc_query_handler
-                    .do_query(GreptimeRequest {
-                        request: Some(Request::Ddl(DdlRequest {
+                    .do_query(
+                        Request::Ddl(DdlRequest {
                             expr: Some(DdlExpr::DropTable(expr)),
-                        })),
-                    })
+                        }),
+                        query_ctx,
+                    )
                     .await;
             }
             Statement::ShowCreateTable(_) => error::NotSupportedSnafu { feat: query }.fail(),
diff --git a/src/frontend/src/instance/distributed.rs b/src/frontend/src/instance/distributed.rs
index 897d48cd86..bd9350b15b 100644
--- a/src/frontend/src/instance/distributed.rs
+++ b/src/frontend/src/instance/distributed.rs
@@ -25,8 +25,10 @@ use catalog::{CatalogList, CatalogManager};
 use chrono::DateTime;
 use client::Database;
 use common_catalog::consts::{DEFAULT_CATALOG_NAME, DEFAULT_SCHEMA_NAME};
+use common_error::prelude::BoxedError;
 use common_query::Output;
 use common_telemetry::{debug, error, info};
+use datanode::instance::sql::table_idents_to_full_name;
 use datatypes::prelude::ConcreteDataType;
 use datatypes::schema::RawSchema;
 use meta_client::client::MetaClient;
@@ -119,7 +121,7 @@ impl DistInstance {
 
         for datanode in table_route.find_leaders() {
             let client = self.datanode_clients.get_client(&datanode).await;
-            let client = Database::new("greptime", client);
+            let client = Database::with_client(client);
 
             let regions = table_route.find_leader_regions(&datanode);
             let mut create_expr_for_region = create_table.clone();
@@ -168,7 +170,19 @@ impl DistInstance {
             Statement::ShowTables(stmt) => {
                 show_tables(stmt, self.catalog_manager.clone(), query_ctx)
             }
-            Statement::DescribeTable(stmt) => describe_table(stmt, self.catalog_manager.clone()),
+            Statement::DescribeTable(stmt) => {
+                let (catalog, schema, table) = table_idents_to_full_name(stmt.name(), query_ctx)
+                    .map_err(BoxedError::new)
+                    .context(error::ExternalSnafu)?;
+                let table = self
+                    .catalog_manager
+                    .table(&catalog, &schema, &table)
+                    .context(CatalogSnafu)?
+                    .with_context(|| TableNotFoundSnafu {
+                        table_name: stmt.name().to_string(),
+                    })?;
+                describe_table(table)
+            }
             Statement::Explain(stmt) => {
                 explain(Box::new(stmt), self.query_engine.clone(), query_ctx).await
             }
@@ -346,16 +360,21 @@ impl DistInstance {
     // GRPC InsertRequest to Table InsertRequest, than split Table InsertRequest, than assemble each GRPC InsertRequest, is rather inefficient,
     // should operate on GRPC InsertRequest directly.
     // Also remember to check the "region_number" carried in InsertRequest, too.
-    async fn handle_dist_insert(&self, request: InsertRequest) -> Result<Output> {
+    async fn handle_dist_insert(
+        &self,
+        request: InsertRequest,
+        ctx: QueryContextRef,
+    ) -> Result<Output> {
+        let catalog = &ctx.current_catalog();
+        let schema = &ctx.current_schema();
         let table_name = &request.table_name;
-        // TODO(LFC): InsertRequest should carry catalog name, too.
         let table = self
             .catalog_manager
-            .table(DEFAULT_CATALOG_NAME, &request.schema_name, table_name)
+            .table(catalog, schema, table_name)
             .context(CatalogSnafu)?
             .context(TableNotFoundSnafu { table_name })?;
 
-        let request = common_grpc_expr::insert::to_table_insert_request(request)
+        let request = common_grpc_expr::insert::to_table_insert_request(catalog, schema, request)
             .context(ToTableInsertRequestSnafu)?;
 
         let affected_rows = table.insert(request).await.context(TableSnafu)?;
diff --git a/src/frontend/src/instance/distributed/grpc.rs b/src/frontend/src/instance/distributed/grpc.rs
index a3e3eed9b2..77a8e98f0a 100644
--- a/src/frontend/src/instance/distributed/grpc.rs
+++ b/src/frontend/src/instance/distributed/grpc.rs
@@ -14,10 +14,10 @@
 
 use api::v1::ddl_request::Expr as DdlExpr;
 use api::v1::greptime_request::Request;
-use api::v1::GreptimeRequest;
 use async_trait::async_trait;
 use common_query::Output;
 use servers::query_handler::grpc::GrpcQueryHandler;
+use session::context::QueryContextRef;
 use snafu::OptionExt;
 
 use crate::error::{self, Result};
@@ -27,12 +27,9 @@ use crate::instance::distributed::DistInstance;
 impl GrpcQueryHandler for DistInstance {
     type Error = error::Error;
 
-    async fn do_query(&self, query: GreptimeRequest) -> Result<Output> {
-        let request = query.request.context(error::IncompleteGrpcResultSnafu {
-            err_msg: "Missing 'request' in GreptimeRequest",
-        })?;
+    async fn do_query(&self, request: Request, ctx: QueryContextRef) -> Result<Output> {
         match request {
-            Request::Insert(request) => self.handle_dist_insert(request).await,
+            Request::Insert(request) => self.handle_dist_insert(request, ctx).await,
             Request::Query(_) => {
                 unreachable!("Query should have been handled directly in Frontend Instance!")
             }
diff --git a/src/frontend/src/instance/grpc.rs b/src/frontend/src/instance/grpc.rs
index 4372820e62..462c2b5ce3 100644
--- a/src/frontend/src/instance/grpc.rs
+++ b/src/frontend/src/instance/grpc.rs
@@ -14,12 +14,11 @@
 
 use api::v1::greptime_request::Request;
 use api::v1::query_request::Query;
-use api::v1::GreptimeRequest;
 use async_trait::async_trait;
 use common_query::Output;
 use servers::query_handler::grpc::GrpcQueryHandler;
 use servers::query_handler::sql::SqlQueryHandler;
-use session::context::QueryContext;
+use session::context::QueryContextRef;
 use snafu::{ensure, OptionExt};
 
 use crate::error::{self, Result};
@@ -29,12 +28,9 @@ use crate::instance::Instance;
 impl GrpcQueryHandler for Instance {
     type Error = error::Error;
 
-    async fn do_query(&self, query: GreptimeRequest) -> Result<Output> {
-        let request = query.request.context(error::IncompleteGrpcResultSnafu {
-            err_msg: "Missing field 'GreptimeRequest.request'",
-        })?;
+    async fn do_query(&self, request: Request, ctx: QueryContextRef) -> Result<Output> {
         let output = match request {
-            Request::Insert(request) => self.handle_insert(request).await?,
+            Request::Insert(request) => self.handle_insert(request, ctx).await?,
             Request::Query(query_request) => {
                 let query = query_request
                     .query
@@ -43,8 +39,7 @@ impl GrpcQueryHandler for Instance {
                     })?;
                 match query {
                     Query::Sql(sql) => {
-                        let mut result =
-                            SqlQueryHandler::do_query(self, &sql, QueryContext::arc()).await;
+                        let mut result = SqlQueryHandler::do_query(self, &sql, ctx).await;
                         ensure!(
                             result.len() == 1,
                             error::NotSupportedSnafu {
@@ -62,10 +57,8 @@ impl GrpcQueryHandler for Instance {
                 }
             }
             Request::Ddl(request) => {
-                let query = GreptimeRequest {
-                    request: Some(Request::Ddl(request)),
-                };
-                GrpcQueryHandler::do_query(&*self.grpc_query_handler, query).await?
+                let query = Request::Ddl(request);
+                GrpcQueryHandler::do_query(&*self.grpc_query_handler, query, ctx).await?
             }
         };
         Ok(output)
@@ -86,6 +79,7 @@ mod test {
     use catalog::helper::{TableGlobalKey, TableGlobalValue};
     use common_query::Output;
     use common_recordbatch::RecordBatches;
+    use session::context::QueryContext;
 
     use super::*;
     use crate::table::DistTable;
@@ -111,93 +105,83 @@ mod test {
     }
 
     async fn test_handle_ddl_request(instance: &Arc<Instance>) {
-        let query = GreptimeRequest {
-            request: Some(Request::Ddl(DdlRequest {
-                expr: Some(DdlExpr::CreateDatabase(CreateDatabaseExpr {
-                    database_name: "database_created_through_grpc".to_string(),
-                    create_if_not_exists: true,
-                })),
+        let query = Request::Ddl(DdlRequest {
+            expr: Some(DdlExpr::CreateDatabase(CreateDatabaseExpr {
+                database_name: "database_created_through_grpc".to_string(),
+                create_if_not_exists: true,
             })),
-        };
-        let output = GrpcQueryHandler::do_query(instance.as_ref(), query)
+        });
+        let output = GrpcQueryHandler::do_query(instance.as_ref(), query, QueryContext::arc())
             .await
             .unwrap();
         assert!(matches!(output, Output::AffectedRows(1)));
 
-        let query = GreptimeRequest {
-            request: Some(Request::Ddl(DdlRequest {
-                expr: Some(DdlExpr::CreateTable(CreateTableExpr {
-                    catalog_name: "greptime".to_string(),
-                    schema_name: "database_created_through_grpc".to_string(),
-                    table_name: "table_created_through_grpc".to_string(),
-                    column_defs: vec![
-                        ColumnDef {
-                            name: "a".to_string(),
-                            datatype: ColumnDataType::String as _,
+        let query = Request::Ddl(DdlRequest {
+            expr: Some(DdlExpr::CreateTable(CreateTableExpr {
+                catalog_name: "greptime".to_string(),
+                schema_name: "database_created_through_grpc".to_string(),
+                table_name: "table_created_through_grpc".to_string(),
+                column_defs: vec![
+                    ColumnDef {
+                        name: "a".to_string(),
+                        datatype: ColumnDataType::String as _,
+                        is_nullable: true,
+                        default_constraint: vec![],
+                    },
+                    ColumnDef {
+                        name: "ts".to_string(),
+                        datatype: ColumnDataType::TimestampMillisecond as _,
+                        is_nullable: false,
+                        default_constraint: vec![],
+                    },
+                ],
+                time_index: "ts".to_string(),
+                ..Default::default()
+            })),
+        });
+        let output = GrpcQueryHandler::do_query(instance.as_ref(), query, QueryContext::arc())
+            .await
+            .unwrap();
+        assert!(matches!(output, Output::AffectedRows(0)));
+
+        let query = Request::Ddl(DdlRequest {
+            expr: Some(DdlExpr::Alter(AlterExpr {
+                catalog_name: "greptime".to_string(),
+                schema_name: "database_created_through_grpc".to_string(),
+                table_name: "table_created_through_grpc".to_string(),
+                kind: Some(alter_expr::Kind::AddColumns(AddColumns {
+                    add_columns: vec![AddColumn {
+                        column_def: Some(ColumnDef {
+                            name: "b".to_string(),
+                            datatype: ColumnDataType::Int32 as _,
                             is_nullable: true,
                             default_constraint: vec![],
-                        },
-                        ColumnDef {
-                            name: "ts".to_string(),
-                            datatype: ColumnDataType::TimestampMillisecond as _,
-                            is_nullable: false,
-                            default_constraint: vec![],
-                        },
-                    ],
-                    time_index: "ts".to_string(),
-                    ..Default::default()
+                        }),
+                        is_key: false,
+                    }],
                 })),
             })),
-        };
-        let output = GrpcQueryHandler::do_query(instance.as_ref(), query)
+        });
+        let output = GrpcQueryHandler::do_query(instance.as_ref(), query, QueryContext::arc())
             .await
             .unwrap();
         assert!(matches!(output, Output::AffectedRows(0)));
 
-        let query = GreptimeRequest {
-            request: Some(Request::Ddl(DdlRequest {
-                expr: Some(DdlExpr::Alter(AlterExpr {
-                    catalog_name: "greptime".to_string(),
-                    schema_name: "database_created_through_grpc".to_string(),
-                    table_name: "table_created_through_grpc".to_string(),
-                    kind: Some(alter_expr::Kind::AddColumns(AddColumns {
-                        add_columns: vec![AddColumn {
-                            column_def: Some(ColumnDef {
-                                name: "b".to_string(),
-                                datatype: ColumnDataType::Int32 as _,
-                                is_nullable: true,
-                                default_constraint: vec![],
-                            }),
-                            is_key: false,
-                        }],
-                    })),
-                })),
-            })),
-        };
-        let output = GrpcQueryHandler::do_query(instance.as_ref(), query)
-            .await
-            .unwrap();
-        assert!(matches!(output, Output::AffectedRows(0)));
-
-        let query = GreptimeRequest {
-            request: Some(Request::Query(QueryRequest {
-                query: Some(Query::Sql("INSERT INTO database_created_through_grpc.table_created_through_grpc (a, b, ts) VALUES ('s', 1, 1672816466000)".to_string()))
-            }))
-        };
-        let output = GrpcQueryHandler::do_query(instance.as_ref(), query)
+        let query = Request::Query(QueryRequest {
+            query: Some(Query::Sql("INSERT INTO database_created_through_grpc.table_created_through_grpc (a, b, ts) VALUES ('s', 1, 1672816466000)".to_string()))
+        });
+        let output = GrpcQueryHandler::do_query(instance.as_ref(), query, QueryContext::arc())
             .await
             .unwrap();
         assert!(matches!(output, Output::AffectedRows(1)));
 
-        let query = GreptimeRequest {
-            request: Some(Request::Query(QueryRequest {
-                query: Some(Query::Sql(
-                    "SELECT ts, a, b FROM database_created_through_grpc.table_created_through_grpc"
-                        .to_string(),
-                )),
-            })),
-        };
-        let output = GrpcQueryHandler::do_query(instance.as_ref(), query)
+        let query = Request::Query(QueryRequest {
+            query: Some(Query::Sql(
+                "SELECT ts, a, b FROM database_created_through_grpc.table_created_through_grpc"
+                    .to_string(),
+            )),
+        });
+        let output = GrpcQueryHandler::do_query(instance.as_ref(), query, QueryContext::arc())
             .await
             .unwrap();
         let Output::Stream(stream) = output else { unreachable!() };
@@ -327,12 +311,10 @@ CREATE TABLE {table_name} (
     }
 
     async fn create_table(frontend: &Arc<Instance>, sql: String) {
-        let query = GreptimeRequest {
-            request: Some(Request::Query(QueryRequest {
-                query: Some(Query::Sql(sql)),
-            })),
-        };
-        let output = GrpcQueryHandler::do_query(frontend.as_ref(), query)
+        let query = Request::Query(QueryRequest {
+            query: Some(Query::Sql(sql)),
+        });
+        let output = GrpcQueryHandler::do_query(frontend.as_ref(), query, QueryContext::arc())
             .await
             .unwrap();
         assert!(matches!(output, Output::AffectedRows(0)));
@@ -340,7 +322,6 @@ CREATE TABLE {table_name} (
 
     async fn test_insert_and_query_on_existing_table(instance: &Arc<Instance>, table_name: &str) {
         let insert = InsertRequest {
-            schema_name: "public".to_string(),
             table_name: table_name.to_string(),
             columns: vec![
                 Column {
@@ -377,22 +358,18 @@ CREATE TABLE {table_name} (
             ..Default::default()
         };
 
-        let query = GreptimeRequest {
-            request: Some(Request::Insert(insert)),
-        };
-        let output = GrpcQueryHandler::do_query(instance.as_ref(), query)
+        let query = Request::Insert(insert);
+        let output = GrpcQueryHandler::do_query(instance.as_ref(), query, QueryContext::arc())
             .await
             .unwrap();
         assert!(matches!(output, Output::AffectedRows(8)));
 
-        let query = GreptimeRequest {
-            request: Some(Request::Query(QueryRequest {
-                query: Some(Query::Sql(format!(
-                    "SELECT ts, a FROM {table_name} ORDER BY ts"
-                ))),
-            })),
-        };
-        let output = GrpcQueryHandler::do_query(instance.as_ref(), query)
+        let query = Request::Query(QueryRequest {
+            query: Some(Query::Sql(format!(
+                "SELECT ts, a FROM {table_name} ORDER BY ts"
+            ))),
+        });
+        let output = GrpcQueryHandler::do_query(instance.as_ref(), query, QueryContext::arc())
             .await
             .unwrap();
         let Output::Stream(stream) = output else { unreachable!() };
@@ -461,7 +438,6 @@ CREATE TABLE {table_name} (
 
     async fn test_insert_and_query_on_auto_created_table(instance: &Arc<Instance>) {
         let insert = InsertRequest {
-            schema_name: "public".to_string(),
             table_name: "auto_created_table".to_string(),
             columns: vec![
                 Column {
@@ -490,16 +466,13 @@ CREATE TABLE {table_name} (
         };
 
         // Test auto create not existed table upon insertion.
-        let query = GreptimeRequest {
-            request: Some(Request::Insert(insert)),
-        };
-        let output = GrpcQueryHandler::do_query(instance.as_ref(), query)
+        let query = Request::Insert(insert);
+        let output = GrpcQueryHandler::do_query(instance.as_ref(), query, QueryContext::arc())
             .await
             .unwrap();
         assert!(matches!(output, Output::AffectedRows(3)));
 
         let insert = InsertRequest {
-            schema_name: "public".to_string(),
             table_name: "auto_created_table".to_string(),
             columns: vec![
                 Column {
@@ -528,22 +501,18 @@ CREATE TABLE {table_name} (
         };
 
         // Test auto add not existed column upon insertion.
-        let query = GreptimeRequest {
-            request: Some(Request::Insert(insert)),
-        };
-        let output = GrpcQueryHandler::do_query(instance.as_ref(), query)
+        let query = Request::Insert(insert);
+        let output = GrpcQueryHandler::do_query(instance.as_ref(), query, QueryContext::arc())
             .await
             .unwrap();
         assert!(matches!(output, Output::AffectedRows(3)));
 
-        let query = GreptimeRequest {
-            request: Some(Request::Query(QueryRequest {
-                query: Some(Query::Sql(
-                    "SELECT ts, a, b FROM auto_created_table".to_string(),
-                )),
-            })),
-        };
-        let output = GrpcQueryHandler::do_query(instance.as_ref(), query)
+        let query = Request::Query(QueryRequest {
+            query: Some(Query::Sql(
+                "SELECT ts, a, b FROM auto_created_table".to_string(),
+            )),
+        });
+        let output = GrpcQueryHandler::do_query(instance.as_ref(), query, QueryContext::arc())
             .await
             .unwrap();
         let Output::Stream(stream) = output else { unreachable!() };
diff --git a/src/frontend/src/instance/influxdb.rs b/src/frontend/src/instance/influxdb.rs
index c64593cae6..1da96e2143 100644
--- a/src/frontend/src/instance/influxdb.rs
+++ b/src/frontend/src/instance/influxdb.rs
@@ -16,15 +16,20 @@ use async_trait::async_trait;
 use common_error::prelude::BoxedError;
 use servers::influxdb::InfluxdbRequest;
 use servers::query_handler::InfluxdbLineProtocolHandler;
+use session::context::QueryContextRef;
 use snafu::ResultExt;
 
 use crate::instance::Instance;
 
 #[async_trait]
 impl InfluxdbLineProtocolHandler for Instance {
-    async fn exec(&self, request: &InfluxdbRequest) -> servers::error::Result<()> {
+    async fn exec(
+        &self,
+        request: &InfluxdbRequest,
+        ctx: QueryContextRef,
+    ) -> servers::error::Result<()> {
         let requests = request.try_into()?;
-        self.handle_inserts(requests)
+        self.handle_inserts(requests, ctx)
             .await
             .map_err(BoxedError::new)
             .context(servers::error::ExecuteGrpcQuerySnafu)?;
@@ -68,10 +73,9 @@ monitor1,host=host1 cpu=66.6,memory=1024 1663840496100023100
 monitor1,host=host2 memory=1027 1663840496400340001";
         let request = InfluxdbRequest {
             precision: None,
-            db: "public".to_string(),
             lines: lines.to_string(),
         };
-        instance.exec(&request).await.unwrap();
+        instance.exec(&request, QueryContext::arc()).await.unwrap();
 
         let mut output = instance
             .do_query(
diff --git a/src/frontend/src/instance/opentsdb.rs b/src/frontend/src/instance/opentsdb.rs
index a6519d2147..f72c7cbdcd 100644
--- a/src/frontend/src/instance/opentsdb.rs
+++ b/src/frontend/src/instance/opentsdb.rs
@@ -17,6 +17,7 @@ use common_error::prelude::BoxedError;
 use servers::error as server_error;
 use servers::opentsdb::codec::DataPoint;
 use servers::query_handler::OpentsdbProtocolHandler;
+use session::context::QueryContext;
 use snafu::prelude::*;
 
 use crate::instance::Instance;
@@ -25,7 +26,7 @@ use crate::instance::Instance;
 impl OpentsdbProtocolHandler for Instance {
     async fn exec(&self, data_point: &DataPoint) -> server_error::Result<()> {
         let request = data_point.as_grpc_insert();
-        self.handle_insert(request)
+        self.handle_insert(request, QueryContext::arc())
             .await
             .map_err(BoxedError::new)
             .with_context(|_| server_error::ExecuteQuerySnafu {
diff --git a/src/frontend/src/instance/prometheus.rs b/src/frontend/src/instance/prometheus.rs
index 62c8b04db3..de7d38bd2c 100644
--- a/src/frontend/src/instance/prometheus.rs
+++ b/src/frontend/src/instance/prometheus.rs
@@ -15,7 +15,7 @@
 use api::prometheus::remote::read_request::ResponseType;
 use api::prometheus::remote::{Query, QueryResult, ReadRequest, ReadResponse, WriteRequest};
 use api::v1::greptime_request::Request;
-use api::v1::{query_request, GreptimeRequest, QueryRequest};
+use api::v1::{query_request, QueryRequest};
 use async_trait::async_trait;
 use common_error::prelude::BoxedError;
 use common_query::Output;
@@ -26,6 +26,7 @@ use servers::error::{self, Result as ServerResult};
 use servers::prometheus::{self, Metrics};
 use servers::query_handler::grpc::GrpcQueryHandler;
 use servers::query_handler::{PrometheusProtocolHandler, PrometheusResponse};
+use session::context::QueryContextRef;
 use snafu::{OptionExt, ResultExt};
 
 use crate::instance::Instance;
@@ -74,26 +75,24 @@ async fn to_query_result(table_name: &str, output: Output) -> ServerResult<Query
 impl Instance {
     async fn handle_remote_queries(
         &self,
-        db: &str,
+        ctx: QueryContextRef,
         queries: &[Query],
     ) -> ServerResult<Vec<(String, Output)>> {
         let mut results = Vec::with_capacity(queries.len());
 
         for query in queries {
-            let (table_name, sql) = prometheus::query_to_sql(db, query)?;
+            let (table_name, sql) = prometheus::query_to_sql(query)?;
             logging::debug!(
                 "prometheus remote read, table: {}, sql: {}",
                 table_name,
                 sql
             );
 
-            let query = GreptimeRequest {
-                request: Some(Request::Query(QueryRequest {
-                    query: Some(query_request::Query::Sql(sql.to_string())),
-                })),
-            };
+            let query = Request::Query(QueryRequest {
+                query: Some(query_request::Query::Sql(sql.to_string())),
+            });
             let output = self
-                .do_query(query)
+                .do_query(query, ctx.clone())
                 .await
                 .map_err(BoxedError::new)
                 .context(error::ExecuteGrpcQuerySnafu)?;
@@ -106,22 +105,24 @@ impl Instance {
 
 #[async_trait]
 impl PrometheusProtocolHandler for Instance {
-    async fn write(&self, database: &str, request: WriteRequest) -> ServerResult<()> {
-        let requests = prometheus::to_grpc_insert_requests(database, request.clone())?;
-        self.handle_inserts(requests)
+    async fn write(&self, request: WriteRequest, ctx: QueryContextRef) -> ServerResult<()> {
+        let requests = prometheus::to_grpc_insert_requests(request.clone())?;
+        self.handle_inserts(requests, ctx)
             .await
             .map_err(BoxedError::new)
             .context(error::ExecuteGrpcQuerySnafu)?;
         Ok(())
     }
 
-    async fn read(&self, database: &str, request: ReadRequest) -> ServerResult<PrometheusResponse> {
+    async fn read(
+        &self,
+        request: ReadRequest,
+        ctx: QueryContextRef,
+    ) -> ServerResult<PrometheusResponse> {
         let response_type = negotiate_response_type(&request.accepted_response_types)?;
 
         // TODO(dennis): use read_hints to speedup query if possible
-        let results = self
-            .handle_remote_queries(database, &request.queries)
-            .await?;
+        let results = self.handle_remote_queries(ctx, &request.queries).await?;
 
         match response_type {
             ResponseType::Samples => {
@@ -159,6 +160,7 @@ mod tests {
 
     use api::prometheus::remote::label_matcher::Type as MatcherType;
     use api::prometheus::remote::{Label, LabelMatcher, Sample};
+    use common_catalog::consts::DEFAULT_CATALOG_NAME;
     use servers::query_handler::sql::SqlQueryHandler;
     use session::context::QueryContext;
 
@@ -190,18 +192,19 @@ mod tests {
         };
 
         let db = "prometheus";
+        let ctx = Arc::new(QueryContext::with(DEFAULT_CATALOG_NAME, db));
 
         assert!(SqlQueryHandler::do_query(
             instance.as_ref(),
             "CREATE DATABASE IF NOT EXISTS prometheus",
-            QueryContext::arc()
+            ctx.clone(),
         )
         .await
         .get(0)
         .unwrap()
         .is_ok());
 
-        instance.write(db, write_request).await.unwrap();
+        instance.write(write_request, ctx.clone()).await.unwrap();
 
         let read_request = ReadRequest {
             queries: vec![
@@ -236,7 +239,7 @@ mod tests {
             ..Default::default()
         };
 
-        let resp = instance.read(db, read_request).await.unwrap();
+        let resp = instance.read(read_request, ctx).await.unwrap();
         assert_eq!(resp.content_type, "application/x-protobuf");
         assert_eq!(resp.content_encoding, "snappy");
         let body = prometheus::snappy_decompress(&resp.body).unwrap();
diff --git a/src/frontend/src/instance/standalone.rs b/src/frontend/src/instance/standalone.rs
index f088595777..fdfa92b72b 100644
--- a/src/frontend/src/instance/standalone.rs
+++ b/src/frontend/src/instance/standalone.rs
@@ -14,7 +14,7 @@
 
 use std::sync::Arc;
 
-use api::v1::GreptimeRequest;
+use api::v1::greptime_request::Request as GreptimeRequest;
 use async_trait::async_trait;
 use common_query::Output;
 use datanode::error::Error as DatanodeError;
@@ -77,9 +77,9 @@ impl StandaloneGrpcQueryHandler {
 impl GrpcQueryHandler for StandaloneGrpcQueryHandler {
     type Error = error::Error;
 
-    async fn do_query(&self, query: GreptimeRequest) -> Result<Output> {
+    async fn do_query(&self, query: GreptimeRequest, ctx: QueryContextRef) -> Result<Output> {
         self.0
-            .do_query(query)
+            .do_query(query, ctx)
             .await
             .context(error::InvokeDatanodeSnafu)
     }
diff --git a/src/frontend/src/table.rs b/src/frontend/src/table.rs
index 08f5a9113f..557260cb6d 100644
--- a/src/frontend/src/table.rs
+++ b/src/frontend/src/table.rs
@@ -20,7 +20,6 @@ use async_trait::async_trait;
 use catalog::helper::{TableGlobalKey, TableGlobalValue};
 use catalog::remote::KvBackendRef;
 use client::Database;
-use common_catalog::consts::DEFAULT_CATALOG_NAME;
 use common_error::prelude::BoxedError;
 use common_query::error::Result as QueryResult;
 use common_query::logical_plan::Expr;
@@ -117,15 +116,16 @@ impl Table for DistTable {
             .map_err(BoxedError::new)
             .context(TableOperationSnafu)?;
 
+        let table_name = &self.table_name;
         let mut partition_execs = Vec::with_capacity(datanodes.len());
         for (datanode, _regions) in datanodes.iter() {
             let client = self.datanode_clients.get_client(datanode).await;
-            let db = Database::new(&self.table_name.schema_name, client);
+            let db = Database::new(&table_name.catalog_name, &table_name.schema_name, client);
             let datanode_instance = DatanodeInstance::new(Arc::new(self.clone()) as _, db);
 
             // TODO(LFC): Pass in "regions" when Datanode supports multi regions for a table.
             partition_execs.push(Arc::new(PartitionExec {
-                table_name: self.table_name.clone(),
+                table_name: table_name.clone(),
                 datanode_instance,
                 projection: projection.cloned(),
                 filters: filters.to_vec(),
@@ -258,10 +258,8 @@ impl DistTable {
             }
         );
         for datanode in leaders {
-            let db = Database::new(
-                DEFAULT_CATALOG_NAME,
-                self.datanode_clients.get_client(&datanode).await,
-            );
+            let client = self.datanode_clients.get_client(&datanode).await;
+            let db = Database::with_client(client);
             debug!("Sending {:?} to {:?}", expr, db);
             let result = db
                 .alter(expr.clone())
@@ -405,6 +403,7 @@ mod test {
     use partition::range::RangePartitionRule;
     use partition::route::TableRoutes;
     use partition::PartitionRuleRef;
+    use session::context::QueryContext;
     use sql::parser::ParserContext;
     use sql::statements::statement::Statement;
     use store_api::storage::RegionNumber;
@@ -921,13 +920,15 @@ mod test {
             },
         ];
         let request = InsertRequest {
-            schema_name: table_name.schema_name.clone(),
             table_name: table_name.table_name.clone(),
             columns,
             row_count,
             region_number: 0,
         };
-        dn_instance.handle_insert(request).await.unwrap();
+        dn_instance
+            .handle_insert(request, QueryContext::arc())
+            .await
+            .unwrap();
     }
 
     #[tokio::test(flavor = "multi_thread")]
diff --git a/src/frontend/src/table/insert.rs b/src/frontend/src/table/insert.rs
index 011bf5557e..228e0982e6 100644
--- a/src/frontend/src/table/insert.rs
+++ b/src/frontend/src/table/insert.rs
@@ -35,13 +35,15 @@ impl DistTable {
         &self,
         inserts: HashMap<RegionNumber, InsertRequest>,
     ) -> Result<Output> {
+        let table_name = &self.table_name;
         let route = self
             .partition_manager
             .find_table_route(&self.table_name)
             .await
             .with_context(|_| FindTableRouteSnafu {
-                table_name: self.table_name.to_string(),
+                table_name: table_name.to_string(),
             })?;
+
         let mut joins = Vec::with_capacity(inserts.len());
         for (region_id, insert) in inserts {
             let datanode = route
@@ -57,7 +59,7 @@ impl DistTable {
                 .context(error::FindDatanodeSnafu { region: region_id })?;
 
             let client = self.datanode_clients.get_client(&datanode).await;
-            let db = Database::new(&self.table_name.schema_name, client);
+            let db = Database::new(&table_name.catalog_name, &table_name.schema_name, client);
             let instance = DatanodeInstance::new(Arc::new(self.clone()) as _, db);
 
             // TODO(fys): a separate runtime should be used here.
@@ -136,7 +138,6 @@ fn to_grpc_insert_request(
     let table_name = insert.table_name.clone();
     let (columns, row_count) = insert_request_to_insert_batch(&insert)?;
     Ok(GrpcInsertRequest {
-        schema_name: insert.schema_name,
         table_name,
         region_number,
         columns,
diff --git a/src/meta-srv/src/bootstrap.rs b/src/meta-srv/src/bootstrap.rs
index 1ddb5944df..028219a9df 100644
--- a/src/meta-srv/src/bootstrap.rs
+++ b/src/meta-srv/src/bootstrap.rs
@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::sync::Arc;
+
 use api::v1::meta::heartbeat_server::HeartbeatServer;
 use api::v1::meta::router_server::RouterServer;
 use api::v1::meta::store_server::StoreServer;
@@ -24,6 +26,7 @@ use crate::election::etcd::EtcdElection;
 use crate::metasrv::{MetaSrv, MetaSrvOptions};
 use crate::service::admin;
 use crate::service::store::etcd::EtcdStore;
+use crate::service::store::memory::MemStore;
 use crate::{error, Result};
 
 // Bootstrap the rpc server to serve incoming request
@@ -58,10 +61,16 @@ pub fn router(meta_srv: MetaSrv) -> Router {
 }
 
 pub async fn make_meta_srv(opts: MetaSrvOptions) -> Result<MetaSrv> {
-    let kv_store = EtcdStore::with_endpoints([&opts.store_addr]).await?;
-    let election = EtcdElection::with_endpoints(&opts.server_addr, [&opts.store_addr]).await?;
+    let (kv_store, election) = if opts.use_memory_store {
+        (Arc::new(MemStore::new()) as _, None)
+    } else {
+        (
+            EtcdStore::with_endpoints([&opts.store_addr]).await?,
+            Some(EtcdElection::with_endpoints(&opts.server_addr, [&opts.store_addr]).await?),
+        )
+    };
     let selector = opts.selector.clone().into();
-    let meta_srv = MetaSrv::new(opts, kv_store, Some(selector), Some(election), None).await;
+    let meta_srv = MetaSrv::new(opts, kv_store, Some(selector), election, None).await;
     meta_srv.start().await;
     Ok(meta_srv)
 }
diff --git a/src/meta-srv/src/metasrv.rs b/src/meta-srv/src/metasrv.rs
index 4b05605ae3..8e9fcfaaca 100644
--- a/src/meta-srv/src/metasrv.rs
+++ b/src/meta-srv/src/metasrv.rs
@@ -40,6 +40,7 @@ pub struct MetaSrvOptions {
     pub store_addr: String,
     pub datanode_lease_secs: i64,
     pub selector: SelectorType,
+    pub use_memory_store: bool,
 }
 
 impl Default for MetaSrvOptions {
@@ -50,6 +51,7 @@ impl Default for MetaSrvOptions {
             store_addr: "127.0.0.1:2379".to_string(),
             datanode_lease_secs: 15,
             selector: SelectorType::default(),
+            use_memory_store: false,
         }
     }
 }
diff --git a/src/mito/src/engine.rs b/src/mito/src/engine.rs
index 757cb6196b..b297b624e6 100644
--- a/src/mito/src/engine.rs
+++ b/src/mito/src/engine.rs
@@ -16,7 +16,6 @@ use std::collections::HashMap;
 use std::sync::{Arc, RwLock};
 
 use async_trait::async_trait;
-use common_catalog::consts::{DEFAULT_CATALOG_NAME, DEFAULT_SCHEMA_NAME};
 use common_error::ext::BoxedError;
 use common_telemetry::logging;
 use datatypes::schema::SchemaRef;
@@ -489,9 +488,9 @@ impl<S: StorageEngine> MitoEngineInner<S> {
     }
 
     async fn alter_table(&self, _ctx: &EngineContext, req: AlterTableRequest) -> Result<TableRef> {
-        let catalog_name = req.catalog_name.as_deref().unwrap_or(DEFAULT_CATALOG_NAME);
-        let schema_name = req.schema_name.as_deref().unwrap_or(DEFAULT_SCHEMA_NAME);
-        let table_name = &req.table_name.clone();
+        let catalog_name = &req.catalog_name;
+        let schema_name = &req.schema_name;
+        let table_name = &req.table_name;
 
         if let AlterKind::RenameTable { new_table_name } = &req.alter_kind {
             let table_ref = TableReference {
@@ -562,6 +561,7 @@ impl<S: StorageEngine> MitoEngineInner<S> {
 
 #[cfg(test)]
 mod tests {
+    use common_catalog::consts::{DEFAULT_CATALOG_NAME, DEFAULT_SCHEMA_NAME};
     use common_query::physical_plan::SessionContext;
     use common_recordbatch::util;
     use datatypes::prelude::ConcreteDataType;
@@ -982,8 +982,8 @@ mod tests {
 
     fn new_add_columns_req(new_tag: &ColumnSchema, new_field: &ColumnSchema) -> AlterTableRequest {
         AlterTableRequest {
-            catalog_name: None,
-            schema_name: None,
+            catalog_name: DEFAULT_CATALOG_NAME.to_string(),
+            schema_name: DEFAULT_SCHEMA_NAME.to_string(),
             table_name: TABLE_NAME.to_string(),
             alter_kind: AlterKind::AddColumns {
                 columns: vec![
@@ -1061,8 +1061,8 @@ mod tests {
 
         // Then remove memory and my_field from the table.
         let req = AlterTableRequest {
-            catalog_name: None,
-            schema_name: None,
+            catalog_name: DEFAULT_CATALOG_NAME.to_string(),
+            schema_name: DEFAULT_SCHEMA_NAME.to_string(),
             table_name: TABLE_NAME.to_string(),
             alter_kind: AlterKind::DropColumns {
                 names: vec![String::from("memory"), String::from("my_field")],
@@ -1116,8 +1116,8 @@ mod tests {
             .expect("create table must succeed");
         // test renaming a table with an existing name.
         let req = AlterTableRequest {
-            catalog_name: None,
-            schema_name: None,
+            catalog_name: DEFAULT_CATALOG_NAME.to_string(),
+            schema_name: DEFAULT_SCHEMA_NAME.to_string(),
             table_name: TABLE_NAME.to_string(),
             alter_kind: AlterKind::RenameTable {
                 new_table_name: another_name.to_string(),
@@ -1132,8 +1132,8 @@ mod tests {
         let new_table_name = "test_table";
         // test rename table
         let req = AlterTableRequest {
-            catalog_name: None,
-            schema_name: None,
+            catalog_name: DEFAULT_CATALOG_NAME.to_string(),
+            schema_name: DEFAULT_SCHEMA_NAME.to_string(),
             table_name: TABLE_NAME.to_string(),
             alter_kind: AlterKind::RenameTable {
                 new_table_name: new_table_name.to_string(),
diff --git a/src/query/src/datafusion/planner.rs b/src/query/src/datafusion/planner.rs
index 36b4576fad..fb77ac4630 100644
--- a/src/query/src/datafusion/planner.rs
+++ b/src/query/src/datafusion/planner.rs
@@ -112,8 +112,7 @@ impl DfContextProviderAdapter {
 
 impl ContextProvider for DfContextProviderAdapter {
     fn get_table_provider(&self, name: TableReference) -> DfResult<Arc<dyn TableSource>> {
-        let schema = self.query_ctx.current_schema();
-        self.state.get_table_provider(schema.as_deref(), name)
+        self.state.get_table_provider(self.query_ctx.clone(), name)
     }
 
     fn get_function_meta(&self, name: &str) -> Option<Arc<ScalarUDF>> {
diff --git a/src/query/src/query_engine/state.rs b/src/query/src/query_engine/state.rs
index e2f38543c9..0e0921a038 100644
--- a/src/query/src/query_engine/state.rs
+++ b/src/query/src/query_engine/state.rs
@@ -35,6 +35,7 @@ use datafusion_optimizer::optimizer::Optimizer;
 use datafusion_sql::planner::ContextProvider;
 use datatypes::arrow::datatypes::DataType;
 use promql::extension_plan::PromExtensionPlanner;
+use session::context::QueryContextRef;
 
 use crate::datafusion::DfCatalogListAdapter;
 use crate::optimizer::TypeConversionRule;
@@ -115,15 +116,19 @@ impl QueryEngineState {
 
     pub(crate) fn get_table_provider(
         &self,
-        schema: Option<&str>,
+        query_ctx: QueryContextRef,
         name: TableReference,
     ) -> DfResult<Arc<dyn TableSource>> {
-        let name = if let (Some(schema), TableReference::Bare { table }) = (schema, name) {
-            TableReference::Partial { schema, table }
+        let state = self.df_context.state();
+        if let TableReference::Bare { table } = name {
+            let name = TableReference::Partial {
+                schema: &query_ctx.current_schema(),
+                table,
+            };
+            state.get_table_provider(name)
         } else {
-            name
-        };
-        self.df_context.state().get_table_provider(name)
+            state.get_table_provider(name)
+        }
     }
 
     pub(crate) fn get_function_meta(&self, name: &str) -> Option<Arc<ScalarUDF>> {
diff --git a/src/query/src/sql.rs b/src/query/src/sql.rs
index aefe2be7c2..4164a5309e 100644
--- a/src/query/src/sql.rs
+++ b/src/query/src/sql.rs
@@ -15,7 +15,7 @@
 use std::sync::Arc;
 
 use catalog::CatalogManagerRef;
-use common_catalog::consts::{DEFAULT_CATALOG_NAME, DEFAULT_SCHEMA_NAME};
+use common_catalog::consts::DEFAULT_CATALOG_NAME;
 use common_query::Output;
 use common_recordbatch::RecordBatches;
 use datatypes::prelude::*;
@@ -24,10 +24,10 @@ use datatypes::vectors::{Helper, StringVector};
 use once_cell::sync::Lazy;
 use session::context::QueryContextRef;
 use snafu::{ensure, OptionExt, ResultExt};
-use sql::statements::describe::DescribeTable;
 use sql::statements::explain::Explain;
 use sql::statements::show::{ShowDatabases, ShowKind, ShowTables};
 use sql::statements::statement::Statement;
+use table::TableRef;
 
 use crate::error::{self, Result};
 use crate::parser::QueryStatement;
@@ -129,15 +129,11 @@ pub fn show_tables(
     let schema = if let Some(database) = stmt.database {
         database
     } else {
-        query_ctx
-            .current_schema()
-            .unwrap_or_else(|| DEFAULT_SCHEMA_NAME.to_string())
+        query_ctx.current_schema()
     };
     // TODO(sunng87): move this function into query_ctx
-    let catalog = query_ctx.current_catalog();
-    let catalog = catalog.as_deref().unwrap_or(DEFAULT_CATALOG_NAME);
     let schema = catalog_manager
-        .schema(catalog, &schema)
+        .schema(&query_ctx.current_catalog(), &schema)
         .context(error::CatalogSnafu)?
         .context(error::SchemaNotFoundSnafu { schema })?;
     let mut tables = schema.table_names().context(error::CatalogSnafu)?;
@@ -170,24 +166,7 @@ pub async fn explain(
     query_engine.execute(&plan).await
 }
 
-pub fn describe_table(stmt: DescribeTable, catalog_manager: CatalogManagerRef) -> Result<Output> {
-    let catalog = stmt.catalog_name.as_str();
-    let schema = stmt.schema_name.as_str();
-    catalog_manager
-        .catalog(catalog)
-        .context(error::CatalogSnafu)?
-        .context(error::CatalogNotFoundSnafu { catalog })?;
-    let schema = catalog_manager
-        .schema(catalog, schema)
-        .context(error::CatalogSnafu)?
-        .context(error::SchemaNotFoundSnafu { schema })?;
-    let table = schema
-        .table(&stmt.table_name)
-        .context(error::CatalogSnafu)?
-        .context(error::TableNotFoundSnafu {
-            table: &stmt.table_name,
-        })?;
-
+pub fn describe_table(table: TableRef) -> Result<Output> {
     let table_info = table.table_info();
     let columns_schemas = table_info.meta.schema.column_schemas();
     let columns = vec![
@@ -263,10 +242,6 @@ fn describe_column_semantic_types(
 mod test {
     use std::sync::Arc;
 
-    use catalog::local::{MemoryCatalogManager, MemoryCatalogProvider, MemorySchemaProvider};
-    use catalog::{CatalogList, CatalogManagerRef, CatalogProvider, SchemaProvider};
-    use common_catalog::consts::{DEFAULT_CATALOG_NAME, DEFAULT_SCHEMA_NAME};
-    use common_error::ext::ErrorExt;
     use common_query::Output;
     use common_recordbatch::{RecordBatch, RecordBatches};
     use common_time::timestamp::TimeUnit;
@@ -274,8 +249,8 @@ mod test {
     use datatypes::schema::{ColumnDefaultConstraint, ColumnSchema, Schema, SchemaRef};
     use datatypes::vectors::{StringVector, TimestampMillisecondVector, UInt32Vector, VectorRef};
     use snafu::ResultExt;
-    use sql::statements::describe::DescribeTable;
     use table::test_util::MemTable;
+    use table::TableRef;
 
     use crate::error;
     use crate::error::Result;
@@ -284,94 +259,8 @@ mod test {
         SEMANTIC_TYPE_TIME_INDEX, SEMANTIC_TYPE_VALUE,
     };
 
-    #[test]
-    fn test_describe_table_catalog_not_found() -> Result<()> {
-        let catalog_name = DEFAULT_CATALOG_NAME.to_string();
-        let schema_name = DEFAULT_SCHEMA_NAME.to_string();
-        let table_name = "test_table";
-        let table_schema = SchemaRef::new(Schema::new(vec![ColumnSchema::new(
-            "test_col",
-            ConcreteDataType::uint32_datatype(),
-            false,
-        )]));
-        let data = vec![Arc::new(UInt32Vector::from_vec(vec![0])) as _];
-        let catalog_manager =
-            prepare_describe_table(&catalog_name, &schema_name, table_name, table_schema, data);
-
-        let stmt = DescribeTable::new("unknown".to_string(), schema_name, table_name.to_string());
-
-        let err = describe_table(stmt, catalog_manager).err().unwrap();
-        let err = err.as_any().downcast_ref::<error::Error>().unwrap();
-
-        if let error::Error::CatalogNotFound { catalog, .. } = err {
-            assert_eq!(catalog, "unknown");
-        } else {
-            panic!("describe table returned incorrect error");
-        }
-
-        Ok(())
-    }
-
-    #[test]
-    fn test_describe_table_schema_not_found() -> Result<()> {
-        let catalog_name = DEFAULT_CATALOG_NAME.to_string();
-        let schema_name = DEFAULT_SCHEMA_NAME.to_string();
-        let table_name = "test_table";
-        let table_schema = SchemaRef::new(Schema::new(vec![ColumnSchema::new(
-            "test_col",
-            ConcreteDataType::uint32_datatype(),
-            false,
-        )]));
-        let data = vec![Arc::new(UInt32Vector::from_vec(vec![0])) as _];
-        let catalog_manager =
-            prepare_describe_table(&catalog_name, &schema_name, table_name, table_schema, data);
-
-        let stmt = DescribeTable::new(catalog_name, "unknown".to_string(), table_name.to_string());
-
-        let err = describe_table(stmt, catalog_manager).err().unwrap();
-        let err = err.as_any().downcast_ref::<error::Error>().unwrap();
-
-        if let error::Error::SchemaNotFound { schema, .. } = err {
-            assert_eq!(schema, "unknown");
-        } else {
-            panic!("describe table returned incorrect error");
-        }
-
-        Ok(())
-    }
-
-    #[test]
-    fn test_describe_table_table_not_found() -> Result<()> {
-        let catalog_name = DEFAULT_CATALOG_NAME.to_string();
-        let schema_name = DEFAULT_SCHEMA_NAME.to_string();
-        let table_name = "test_table";
-        let table_schema = SchemaRef::new(Schema::new(vec![ColumnSchema::new(
-            "test_col",
-            ConcreteDataType::uint32_datatype(),
-            false,
-        )]));
-        let data = vec![Arc::new(UInt32Vector::from_vec(vec![0])) as _];
-        let catalog_manager =
-            prepare_describe_table(&catalog_name, &schema_name, table_name, table_schema, data);
-
-        let stmt = DescribeTable::new(catalog_name, schema_name, "unknown".to_string());
-
-        let err = describe_table(stmt, catalog_manager).err().unwrap();
-        let err = err.as_any().downcast_ref::<error::Error>().unwrap();
-
-        if let error::Error::TableNotFound { table, .. } = err {
-            assert_eq!(table, "unknown");
-        } else {
-            panic!("describe table returned incorrect error");
-        }
-
-        Ok(())
-    }
-
     #[test]
     fn test_describe_table_multiple_columns() -> Result<()> {
-        let catalog_name = DEFAULT_CATALOG_NAME;
-        let schema_name = DEFAULT_SCHEMA_NAME;
         let table_name = "test_table";
         let schema = vec![
             ColumnSchema::new("t1", ConcreteDataType::uint32_datatype(), true),
@@ -401,38 +290,23 @@ mod test {
             ])) as _,
         ];
 
-        describe_table_test_by_schema(
-            catalog_name,
-            schema_name,
-            table_name,
-            schema,
-            data,
-            expected_columns,
-        )
+        describe_table_test_by_schema(table_name, schema, data, expected_columns)
     }
 
     fn describe_table_test_by_schema(
-        catalog_name: &str,
-        schema_name: &str,
         table_name: &str,
         schema: Vec<ColumnSchema>,
         data: Vec<VectorRef>,
         expected_columns: Vec<VectorRef>,
     ) -> Result<()> {
         let table_schema = SchemaRef::new(Schema::new(schema));
-        let catalog_manager =
-            prepare_describe_table(catalog_name, schema_name, table_name, table_schema, data);
+        let table = prepare_describe_table(table_name, table_schema, data);
 
         let expected =
             RecordBatches::try_from_columns(DESCRIBE_TABLE_OUTPUT_SCHEMA.clone(), expected_columns)
                 .context(error::CreateRecordBatchSnafu)?;
 
-        let stmt = DescribeTable::new(
-            catalog_name.to_string(),
-            schema_name.to_string(),
-            table_name.to_string(),
-        );
-        if let Output::RecordBatches(res) = describe_table(stmt, catalog_manager)? {
+        if let Output::RecordBatches(res) = describe_table(table)? {
             assert_eq!(res.take(), expected.take());
         } else {
             panic!("describe table must return record batch");
@@ -442,28 +316,11 @@ mod test {
     }
 
     fn prepare_describe_table(
-        catalog_name: &str,
-        schema_name: &str,
         table_name: &str,
         table_schema: SchemaRef,
         data: Vec<VectorRef>,
-    ) -> CatalogManagerRef {
+    ) -> TableRef {
         let record_batch = RecordBatch::new(table_schema, data).unwrap();
-        let table = Arc::new(MemTable::new(table_name, record_batch));
-
-        let schema_provider = Arc::new(MemorySchemaProvider::new());
-        let catalog_provider = Arc::new(MemoryCatalogProvider::new());
-        let catalog_manager = Arc::new(MemoryCatalogManager::default());
-        schema_provider
-            .register_table(table_name.to_string(), table)
-            .unwrap();
-        catalog_provider
-            .register_schema(schema_name.to_string(), schema_provider)
-            .unwrap();
-        catalog_manager
-            .register_catalog(catalog_name.to_string(), catalog_provider)
-            .unwrap();
-
-        catalog_manager
+        Arc::new(MemTable::new(table_name, record_batch))
     }
 }
diff --git a/src/servers/src/grpc/flight.rs b/src/servers/src/grpc/flight.rs
index e9f05c5179..bbaabd3ca3 100644
--- a/src/servers/src/grpc/flight.rs
+++ b/src/servers/src/grpc/flight.rs
@@ -17,7 +17,7 @@ mod stream;
 use std::pin::Pin;
 use std::sync::Arc;
 
-use api::v1::GreptimeRequest;
+use api::v1::{GreptimeRequest, RequestHeader};
 use arrow_flight::flight_service_server::FlightService;
 use arrow_flight::{
     Action, ActionType, Criteria, Empty, FlightData, FlightDescriptor, FlightInfo,
@@ -29,7 +29,8 @@ use common_query::Output;
 use common_runtime::Runtime;
 use futures::Stream;
 use prost::Message;
-use snafu::ResultExt;
+use session::context::{QueryContext, QueryContextRef};
+use snafu::{OptionExt, ResultExt};
 use tokio::sync::oneshot;
 use tonic::{Request, Response, Status, Streaming};
 
@@ -92,6 +93,11 @@ impl FlightService for FlightHandler {
         let request =
             GreptimeRequest::decode(ticket.as_slice()).context(error::InvalidFlightTicketSnafu)?;
 
+        let query = request.request.context(error::InvalidQuerySnafu {
+            reason: "Expecting non-empty GreptimeRequest.",
+        })?;
+        let query_ctx = create_query_context(request.header.as_ref());
+
         let (tx, rx) = oneshot::channel();
         let handler = self.handler.clone();
 
@@ -99,7 +105,7 @@ impl FlightService for FlightHandler {
         // 1. prevent the execution from being cancelled unexpected by Tonic runtime;
         // 2. avoid the handler blocks the gRPC runtime incidentally.
         self.runtime.spawn(async move {
-            let result = handler.do_query(request).await;
+            let result = handler.do_query(query, query_ctx).await;
 
             // Ignore the sending result.
             // Usually an error indicates the rx at Tonic side is dropped (due to request timeout).
@@ -166,3 +172,17 @@ fn to_flight_data_stream(output: Output) -> TonicStream<FlightData> {
         }
     }
 }
+
+fn create_query_context(header: Option<&RequestHeader>) -> QueryContextRef {
+    let ctx = QueryContext::arc();
+    if let Some(header) = header {
+        if !header.catalog.is_empty() {
+            ctx.set_current_catalog(&header.catalog);
+        }
+
+        if !header.schema.is_empty() {
+            ctx.set_current_schema(&header.schema);
+        }
+    };
+    ctx
+}
diff --git a/src/servers/src/http.rs b/src/servers/src/http.rs
index 6ac52c55e9..c33b2aedbb 100644
--- a/src/servers/src/http.rs
+++ b/src/servers/src/http.rs
@@ -30,7 +30,6 @@ use axum::body::BoxBody;
 use axum::error_handling::HandleErrorLayer;
 use axum::response::{Html, Json};
 use axum::{routing, BoxError, Extension, Router};
-use common_catalog::consts::{DEFAULT_CATALOG_NAME, DEFAULT_SCHEMA_NAME};
 use common_error::prelude::ErrorExt;
 use common_error::status_code::StatusCode;
 use common_query::Output;
@@ -71,10 +70,7 @@ pub(crate) fn query_context_from_db(
         let (catalog, schema) = super::parse_catalog_and_schema_from_client_database_name(db);
 
         match query_handler.is_valid_schema(catalog, schema) {
-            Ok(true) => Ok(Arc::new(QueryContext::with(
-                catalog.to_owned(),
-                schema.to_owned(),
-            ))),
+            Ok(true) => Ok(Arc::new(QueryContext::with(catalog, schema))),
             Ok(false) => Err(JsonResponse::with_error(
                 format!("Database not found: {db}"),
                 StatusCode::DatabaseNotFound,
@@ -85,10 +81,7 @@ pub(crate) fn query_context_from_db(
             )),
         }
     } else {
-        Ok(Arc::new(QueryContext::with(
-            DEFAULT_CATALOG_NAME.to_owned(),
-            DEFAULT_SCHEMA_NAME.to_owned(),
-        )))
+        Ok(QueryContext::arc())
     }
 }
 
diff --git a/src/servers/src/http/influxdb.rs b/src/servers/src/http/influxdb.rs
index 65d9dae55f..c517f037fa 100644
--- a/src/servers/src/http/influxdb.rs
+++ b/src/servers/src/http/influxdb.rs
@@ -13,11 +13,13 @@
 // limitations under the License.
 
 use std::collections::HashMap;
+use std::sync::Arc;
 
 use axum::extract::{Query, State};
 use axum::http::StatusCode;
-use common_catalog::consts::DEFAULT_SCHEMA_NAME;
+use common_catalog::consts::{DEFAULT_CATALOG_NAME, DEFAULT_SCHEMA_NAME};
 use common_grpc::writer::Precision;
+use session::context::QueryContext;
 
 use crate::error::{Result, TimePrecisionSnafu};
 use crate::influxdb::InfluxdbRequest;
@@ -32,17 +34,15 @@ pub async fn influxdb_write(
     let db = params
         .remove("db")
         .unwrap_or_else(|| DEFAULT_SCHEMA_NAME.to_string());
+    let ctx = Arc::new(QueryContext::with(DEFAULT_CATALOG_NAME, &db));
 
     let precision = params
         .get("precision")
         .map(|val| parse_time_precision(val))
         .transpose()?;
-    let request = InfluxdbRequest {
-        precision,
-        lines,
-        db,
-    };
-    handler.exec(&request).await?;
+    let request = InfluxdbRequest { precision, lines };
+
+    handler.exec(&request, ctx).await?;
     Ok((StatusCode::NO_CONTENT, ()))
 }
 
diff --git a/src/servers/src/http/prometheus.rs b/src/servers/src/http/prometheus.rs
index 90431f2707..db66144fed 100644
--- a/src/servers/src/http/prometheus.rs
+++ b/src/servers/src/http/prometheus.rs
@@ -12,15 +12,18 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::sync::Arc;
+
 use api::prometheus::remote::{ReadRequest, WriteRequest};
 use axum::extract::{Query, RawBody, State};
 use axum::http::{header, StatusCode};
 use axum::response::IntoResponse;
-use common_catalog::consts::DEFAULT_SCHEMA_NAME;
+use common_catalog::consts::{DEFAULT_CATALOG_NAME, DEFAULT_SCHEMA_NAME};
 use hyper::Body;
 use prost::Message;
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
+use session::context::QueryContext;
 use snafu::prelude::*;
 
 use crate::error::{self, Result};
@@ -48,10 +51,13 @@ pub async fn remote_write(
 ) -> Result<(StatusCode, ())> {
     let request = decode_remote_write_request(body).await?;
 
-    handler
-        .write(params.db.as_deref().unwrap_or(DEFAULT_SCHEMA_NAME), request)
-        .await?;
+    let ctx = if let Some(db) = params.db {
+        Arc::new(QueryContext::with(DEFAULT_CATALOG_NAME, &db))
+    } else {
+        QueryContext::arc()
+    };
 
+    handler.write(request, ctx).await?;
     Ok((StatusCode::NO_CONTENT, ()))
 }
 
@@ -76,9 +82,13 @@ pub async fn remote_read(
 ) -> Result<PrometheusResponse> {
     let request = decode_remote_read_request(body).await?;
 
-    handler
-        .read(params.db.as_deref().unwrap_or(DEFAULT_SCHEMA_NAME), request)
-        .await
+    let ctx = if let Some(db) = params.db {
+        Arc::new(QueryContext::with(DEFAULT_CATALOG_NAME, &db))
+    } else {
+        QueryContext::arc()
+    };
+
+    handler.read(request, ctx).await
 }
 
 async fn decode_remote_write_request(body: Body) -> Result<WriteRequest> {
diff --git a/src/servers/src/influxdb.rs b/src/servers/src/influxdb.rs
index 3cb9de060e..986d5ce6de 100644
--- a/src/servers/src/influxdb.rs
+++ b/src/servers/src/influxdb.rs
@@ -27,7 +27,6 @@ pub const DEFAULT_TIME_PRECISION: Precision = Precision::Nanosecond;
 #[derive(Debug)]
 pub struct InfluxdbRequest {
     pub precision: Option<Precision>,
-    pub db: String,
     pub lines: String,
 }
 
@@ -37,8 +36,6 @@ impl TryFrom<&InfluxdbRequest> for Vec<GrpcInsertRequest> {
     type Error = Error;
 
     fn try_from(value: &InfluxdbRequest) -> Result<Self, Self::Error> {
-        let schema_name = value.db.to_string();
-
         let mut writers: HashMap<TableName, LinesWriter> = HashMap::new();
         let lines = parse_lines(&value.lines)
             .collect::<influxdb_line_protocol::Result<Vec<_>>>()
@@ -111,7 +108,6 @@ impl TryFrom<&InfluxdbRequest> for Vec<GrpcInsertRequest> {
             .map(|(table_name, writer)| {
                 let (columns, row_count) = writer.finish();
                 GrpcInsertRequest {
-                    schema_name: schema_name.clone(),
                     table_name,
                     region_number: 0,
                     columns,
@@ -140,7 +136,6 @@ monitor2,host=host3 cpu=66.5 1663840496100023102
 monitor2,host=host4 cpu=66.3,memory=1029 1663840496400340003";
 
         let influxdb_req = &InfluxdbRequest {
-            db: "public".to_string(),
             precision: None,
             lines: lines.to_string(),
         };
@@ -149,7 +144,6 @@ monitor2,host=host4 cpu=66.3,memory=1029 1663840496400340003";
         assert_eq!(2, requests.len());
 
         for request in requests {
-            assert_eq!("public", request.schema_name);
             match &request.table_name[..] {
                 "monitor1" => assert_monitor_1(&request.columns),
                 "monitor2" => assert_monitor_2(&request.columns),
diff --git a/src/servers/src/mysql/federated.rs b/src/servers/src/mysql/federated.rs
index 0cb225b97d..651b64160e 100644
--- a/src/servers/src/mysql/federated.rs
+++ b/src/servers/src/mysql/federated.rs
@@ -260,9 +260,7 @@ fn check_others(query: &str, query_ctx: QueryContextRef) -> Option<Output> {
     let recordbatches = if SELECT_VERSION_PATTERN.is_match(query) {
         Some(select_function("version()", MYSQL_VERSION))
     } else if SELECT_DATABASE_PATTERN.is_match(query) {
-        let schema = query_ctx
-            .current_schema()
-            .unwrap_or_else(|| "NULL".to_string());
+        let schema = query_ctx.current_schema();
         Some(select_function("database()", &schema))
     } else if SELECT_TIME_DIFF_FUNC_PATTERN.is_match(query) {
         Some(select_function(
diff --git a/src/servers/src/opentsdb/codec.rs b/src/servers/src/opentsdb/codec.rs
index 42fc491f93..eeaca6649c 100644
--- a/src/servers/src/opentsdb/codec.rs
+++ b/src/servers/src/opentsdb/codec.rs
@@ -14,7 +14,6 @@
 
 use api::v1::column::SemanticType;
 use api::v1::{column, Column, ColumnDataType, InsertRequest as GrpcInsertRequest};
-use common_catalog::consts::DEFAULT_SCHEMA_NAME;
 
 use crate::error::{self, Result};
 
@@ -126,7 +125,6 @@ impl DataPoint {
     }
 
     pub fn as_grpc_insert(&self) -> GrpcInsertRequest {
-        let schema_name = DEFAULT_SCHEMA_NAME.to_string();
         let mut columns = Vec::with_capacity(2 + self.tags.len());
 
         let ts_column = Column {
@@ -167,7 +165,6 @@ impl DataPoint {
         }
 
         GrpcInsertRequest {
-            schema_name,
             table_name: self.metric.clone(),
             region_number: 0,
             columns,
diff --git a/src/servers/src/prometheus.rs b/src/servers/src/prometheus.rs
index 3cd0b13c3d..6c90b28121 100644
--- a/src/servers/src/prometheus.rs
+++ b/src/servers/src/prometheus.rs
@@ -41,7 +41,7 @@ pub struct Metrics {
 
 /// Generate a sql from a remote request query
 /// TODO(dennis): maybe use logical plan in future to prevent sql injection
-pub fn query_to_sql(db: &str, q: &Query) -> Result<(String, String)> {
+pub fn query_to_sql(q: &Query) -> Result<(String, String)> {
     let start_timestamp_ms = q.start_timestamp_ms;
     let end_timestamp_ms = q.end_timestamp_ms;
 
@@ -100,9 +100,7 @@ pub fn query_to_sql(db: &str, q: &Query) -> Result<(String, String)> {
 
     Ok((
         table_name.to_string(),
-        format!(
-            "select * from {db}.{table_name} where {conditions} order by {TIMESTAMP_COLUMN_NAME}",
-        ),
+        format!("select * from {table_name} where {conditions} order by {TIMESTAMP_COLUMN_NAME}",),
     ))
 }
 
@@ -284,21 +282,12 @@ fn recordbatch_to_timeseries(table: &str, recordbatch: RecordBatch) -> Result<Ve
     Ok(timeseries_map.into_values().collect())
 }
 
-pub fn to_grpc_insert_requests(
-    database: &str,
-    mut request: WriteRequest,
-) -> Result<Vec<GrpcInsertRequest>> {
+pub fn to_grpc_insert_requests(mut request: WriteRequest) -> Result<Vec<GrpcInsertRequest>> {
     let timeseries = std::mem::take(&mut request.timeseries);
-
-    timeseries
-        .into_iter()
-        .map(|timeseries| to_grpc_insert_request(database, timeseries))
-        .collect()
+    timeseries.into_iter().map(to_grpc_insert_request).collect()
 }
 
-fn to_grpc_insert_request(database: &str, mut timeseries: TimeSeries) -> Result<GrpcInsertRequest> {
-    let schema_name = database.to_string();
-
+fn to_grpc_insert_request(mut timeseries: TimeSeries) -> Result<GrpcInsertRequest> {
     // TODO(dennis): save exemplars into a column
     let labels = std::mem::take(&mut timeseries.labels);
     let samples = std::mem::take(&mut timeseries.samples);
@@ -355,7 +344,6 @@ fn to_grpc_insert_request(database: &str, mut timeseries: TimeSeries) -> Result<
     }
 
     Ok(GrpcInsertRequest {
-        schema_name,
         table_name: table_name.context(error::InvalidPromRemoteRequestSnafu {
             msg: "missing '__name__' label in timeseries",
         })?,
@@ -467,7 +455,7 @@ mod tests {
             matchers: vec![],
             ..Default::default()
         };
-        let err = query_to_sql("public", &q).unwrap_err();
+        let err = query_to_sql(&q).unwrap_err();
         assert!(matches!(err, error::Error::InvalidPromRemoteRequest { .. }));
 
         let q = Query {
@@ -480,9 +468,9 @@ mod tests {
             }],
             ..Default::default()
         };
-        let (table, sql) = query_to_sql("public", &q).unwrap();
+        let (table, sql) = query_to_sql(&q).unwrap();
         assert_eq!("test", table);
-        assert_eq!("select * from public.test where greptime_timestamp>=1000 AND greptime_timestamp<=2000 order by greptime_timestamp", sql);
+        assert_eq!("select * from test where greptime_timestamp>=1000 AND greptime_timestamp<=2000 order by greptime_timestamp", sql);
 
         let q = Query {
             start_timestamp_ms: 1000,
@@ -506,9 +494,9 @@ mod tests {
             ],
             ..Default::default()
         };
-        let (table, sql) = query_to_sql("public", &q).unwrap();
+        let (table, sql) = query_to_sql(&q).unwrap();
         assert_eq!("test", table);
-        assert_eq!("select * from public.test where greptime_timestamp>=1000 AND greptime_timestamp<=2000 AND job~'*prom*' AND instance!='localhost' order by greptime_timestamp", sql);
+        assert_eq!("select * from test where greptime_timestamp>=1000 AND greptime_timestamp<=2000 AND job~'*prom*' AND instance!='localhost' order by greptime_timestamp", sql);
     }
 
     #[test]
@@ -518,11 +506,8 @@ mod tests {
             ..Default::default()
         };
 
-        let exprs = to_grpc_insert_requests("prometheus", write_request).unwrap();
+        let exprs = to_grpc_insert_requests(write_request).unwrap();
         assert_eq!(3, exprs.len());
-        assert_eq!("prometheus", exprs[0].schema_name);
-        assert_eq!("prometheus", exprs[1].schema_name);
-        assert_eq!("prometheus", exprs[2].schema_name);
         assert_eq!("metric1", exprs[0].table_name);
         assert_eq!("metric2", exprs[1].table_name);
         assert_eq!("metric3", exprs[2].table_name);
diff --git a/src/servers/src/query_handler.rs b/src/servers/src/query_handler.rs
index c678d7885c..bc7dd1df82 100644
--- a/src/servers/src/query_handler.rs
+++ b/src/servers/src/query_handler.rs
@@ -20,6 +20,7 @@ use std::sync::Arc;
 use api::prometheus::remote::{ReadRequest, WriteRequest};
 use async_trait::async_trait;
 use common_query::Output;
+use session::context::QueryContextRef;
 
 use crate::error::Result;
 use crate::influxdb::InfluxdbRequest;
@@ -51,7 +52,7 @@ pub trait ScriptHandler {
 pub trait InfluxdbLineProtocolHandler {
     /// A successful request will not return a response.
     /// Only on error will the socket return a line of data.
-    async fn exec(&self, request: &InfluxdbRequest) -> Result<()>;
+    async fn exec(&self, request: &InfluxdbRequest, ctx: QueryContextRef) -> Result<()>;
 }
 
 #[async_trait]
@@ -70,9 +71,9 @@ pub struct PrometheusResponse {
 #[async_trait]
 pub trait PrometheusProtocolHandler {
     /// Handling prometheus remote write requests
-    async fn write(&self, database: &str, request: WriteRequest) -> Result<()>;
+    async fn write(&self, request: WriteRequest, ctx: QueryContextRef) -> Result<()>;
     /// Handling prometheus remote read requests
-    async fn read(&self, database: &str, request: ReadRequest) -> Result<PrometheusResponse>;
+    async fn read(&self, request: ReadRequest, ctx: QueryContextRef) -> Result<PrometheusResponse>;
     /// Handling push gateway requests
     async fn ingest_metrics(&self, metrics: Metrics) -> Result<()>;
 }
diff --git a/src/servers/src/query_handler/grpc.rs b/src/servers/src/query_handler/grpc.rs
index d40d277d82..b82ff4c379 100644
--- a/src/servers/src/query_handler/grpc.rs
+++ b/src/servers/src/query_handler/grpc.rs
@@ -14,10 +14,11 @@
 
 use std::sync::Arc;
 
-use api::v1::GreptimeRequest;
+use api::v1::greptime_request::Request as GreptimeRequest;
 use async_trait::async_trait;
 use common_error::prelude::*;
 use common_query::Output;
+use session::context::QueryContextRef;
 
 use crate::error::{self, Result};
 
@@ -28,7 +29,11 @@ pub type ServerGrpcQueryHandlerRef = GrpcQueryHandlerRef<error::Error>;
 pub trait GrpcQueryHandler {
     type Error: ErrorExt;
 
-    async fn do_query(&self, query: GreptimeRequest) -> std::result::Result<Output, Self::Error>;
+    async fn do_query(
+        &self,
+        query: GreptimeRequest,
+        ctx: QueryContextRef,
+    ) -> std::result::Result<Output, Self::Error>;
 }
 
 pub struct ServerGrpcQueryHandlerAdaptor<E>(GrpcQueryHandlerRef<E>);
@@ -46,9 +51,9 @@ where
 {
     type Error = error::Error;
 
-    async fn do_query(&self, query: GreptimeRequest) -> Result<Output> {
+    async fn do_query(&self, query: GreptimeRequest, ctx: QueryContextRef) -> Result<Output> {
         self.0
-            .do_query(query)
+            .do_query(query, ctx)
             .await
             .map_err(BoxedError::new)
             .context(error::ExecuteGrpcQuerySnafu)
diff --git a/src/servers/tests/http/influxdb_test.rs b/src/servers/tests/http/influxdb_test.rs
index 979b6b31ee..f12cfc7712 100644
--- a/src/servers/tests/http/influxdb_test.rs
+++ b/src/servers/tests/http/influxdb_test.rs
@@ -35,11 +35,11 @@ struct DummyInstance {
 
 #[async_trait]
 impl InfluxdbLineProtocolHandler for DummyInstance {
-    async fn exec(&self, request: &InfluxdbRequest) -> Result<()> {
+    async fn exec(&self, request: &InfluxdbRequest, ctx: QueryContextRef) -> Result<()> {
         let requests: Vec<InsertRequest> = request.try_into()?;
 
         for expr in requests {
-            let _ = self.tx.send((expr.schema_name, expr.table_name)).await;
+            let _ = self.tx.send((ctx.current_schema(), expr.table_name)).await;
         }
 
         Ok(())
diff --git a/src/servers/tests/http/prometheus_test.rs b/src/servers/tests/http/prometheus_test.rs
index a57b70136d..46df57753b 100644
--- a/src/servers/tests/http/prometheus_test.rs
+++ b/src/servers/tests/http/prometheus_test.rs
@@ -37,18 +37,18 @@ struct DummyInstance {
 
 #[async_trait]
 impl PrometheusProtocolHandler for DummyInstance {
-    async fn write(&self, db: &str, request: WriteRequest) -> Result<()> {
+    async fn write(&self, request: WriteRequest, ctx: QueryContextRef) -> Result<()> {
         let _ = self
             .tx
-            .send((db.to_string(), request.encode_to_vec()))
+            .send((ctx.current_schema(), request.encode_to_vec()))
             .await;
 
         Ok(())
     }
-    async fn read(&self, db: &str, request: ReadRequest) -> Result<PrometheusResponse> {
+    async fn read(&self, request: ReadRequest, ctx: QueryContextRef) -> Result<PrometheusResponse> {
         let _ = self
             .tx
-            .send((db.to_string(), request.encode_to_vec()))
+            .send((ctx.current_schema(), request.encode_to_vec()))
             .await;
 
         let response = ReadResponse {
diff --git a/src/session/Cargo.toml b/src/session/Cargo.toml
index 26965b30f6..f6dff95e46 100644
--- a/src/session/Cargo.toml
+++ b/src/session/Cargo.toml
@@ -6,4 +6,5 @@ license.workspace = true
 
 [dependencies]
 arc-swap = "1.5"
+common-catalog = { path = "../common/catalog" }
 common-telemetry = { path = "../common/telemetry" }
diff --git a/src/session/src/context.rs b/src/session/src/context.rs
index 1abe63f6b1..d6af508486 100644
--- a/src/session/src/context.rs
+++ b/src/session/src/context.rs
@@ -12,18 +12,20 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::fmt::{Display, Formatter};
 use std::net::SocketAddr;
 use std::sync::Arc;
 
-use arc_swap::ArcSwapOption;
-use common_telemetry::info;
+use arc_swap::ArcSwap;
+use common_catalog::consts::{DEFAULT_CATALOG_NAME, DEFAULT_SCHEMA_NAME};
+use common_telemetry::debug;
 
 pub type QueryContextRef = Arc<QueryContext>;
 pub type ConnInfoRef = Arc<ConnInfo>;
 
 pub struct QueryContext {
-    current_catalog: ArcSwapOption<String>,
-    current_schema: ArcSwapOption<String>,
+    current_catalog: ArcSwap<String>,
+    current_schema: ArcSwap<String>,
 }
 
 impl Default for QueryContext {
@@ -32,6 +34,17 @@ impl Default for QueryContext {
     }
 }
 
+impl Display for QueryContext {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "QueryContext{{catalog: {}, schema: {}}}",
+            self.current_catalog(),
+            self.current_schema()
+        )
+    }
+}
+
 impl QueryContext {
     pub fn arc() -> QueryContextRef {
         Arc::new(QueryContext::new())
@@ -39,39 +52,37 @@ impl QueryContext {
 
     pub fn new() -> Self {
         Self {
-            current_catalog: ArcSwapOption::new(None),
-            current_schema: ArcSwapOption::new(None),
+            current_catalog: ArcSwap::new(Arc::new(DEFAULT_CATALOG_NAME.to_string())),
+            current_schema: ArcSwap::new(Arc::new(DEFAULT_SCHEMA_NAME.to_string())),
         }
     }
 
-    pub fn with(catalog: String, schema: String) -> Self {
+    pub fn with(catalog: &str, schema: &str) -> Self {
         Self {
-            current_catalog: ArcSwapOption::new(Some(Arc::new(catalog))),
-            current_schema: ArcSwapOption::new(Some(Arc::new(schema))),
+            current_catalog: ArcSwap::new(Arc::new(catalog.to_string())),
+            current_schema: ArcSwap::new(Arc::new(schema.to_string())),
         }
     }
 
-    pub fn current_schema(&self) -> Option<String> {
-        self.current_schema.load().as_deref().cloned()
+    pub fn current_schema(&self) -> String {
+        self.current_schema.load().as_ref().clone()
     }
 
-    pub fn current_catalog(&self) -> Option<String> {
-        self.current_catalog.load().as_deref().cloned()
+    pub fn current_catalog(&self) -> String {
+        self.current_catalog.load().as_ref().clone()
     }
 
     pub fn set_current_schema(&self, schema: &str) {
-        let last = self.current_schema.swap(Some(Arc::new(schema.to_string())));
-        info!(
+        let last = self.current_schema.swap(Arc::new(schema.to_string()));
+        debug!(
             "set new session default schema: {:?}, swap old: {:?}",
             schema, last
         )
     }
 
     pub fn set_current_catalog(&self, catalog: &str) {
-        let last = self
-            .current_catalog
-            .swap(Some(Arc::new(catalog.to_string())));
-        info!(
+        let last = self.current_catalog.swap(Arc::new(catalog.to_string()));
+        debug!(
             "set new session default catalog: {:?}, swap old: {:?}",
             catalog, last
         )
diff --git a/src/sql/src/parser.rs b/src/sql/src/parser.rs
index 7e02272832..1cc9a1caa0 100644
--- a/src/sql/src/parser.rs
+++ b/src/sql/src/parser.rs
@@ -26,7 +26,6 @@ use crate::statements::drop::DropTable;
 use crate::statements::explain::Explain;
 use crate::statements::show::{ShowCreateTable, ShowDatabases, ShowKind, ShowTables};
 use crate::statements::statement::Statement;
-use crate::statements::table_idents_to_full_name;
 
 /// GrepTime SQL parser context, a simple wrapper for Datafusion SQL parser.
 pub struct ParserContext<'a> {
@@ -267,12 +266,7 @@ impl<'a> ParserContext<'a> {
                 name: table_idents.to_string(),
             }
         );
-        let (catalog_name, schema_name, table_name) = table_idents_to_full_name(&table_idents)?;
-        Ok(Statement::DescribeTable(DescribeTable {
-            catalog_name,
-            schema_name,
-            table_name,
-        }))
+        Ok(Statement::DescribeTable(DescribeTable::new(table_idents)))
     }
 
     fn parse_explain(&mut self) -> Result<Statement> {
@@ -310,12 +304,7 @@ impl<'a> ParserContext<'a> {
             }
         );
 
-        let (catalog_name, schema_name, table_name) = table_idents_to_full_name(&table_ident)?;
-        Ok(Statement::DropTable(DropTable {
-            catalog_name,
-            schema_name,
-            table_name,
-        }))
+        Ok(Statement::DropTable(DropTable::new(table_ident)))
     }
 
     // Report unexpected token
@@ -384,8 +373,9 @@ impl<'a> ParserContext<'a> {
 mod tests {
     use std::assert_matches::assert_matches;
 
-    use common_catalog::consts::{DEFAULT_CATALOG_NAME, DEFAULT_SCHEMA_NAME};
-    use sqlparser::ast::{Query as SpQuery, Statement as SpStatement, WildcardAdditionalOptions};
+    use sqlparser::ast::{
+        Ident, ObjectName, Query as SpQuery, Statement as SpStatement, WildcardAdditionalOptions,
+    };
     use sqlparser::dialect::GenericDialect;
 
     use super::*;
@@ -584,11 +574,7 @@ mod tests {
         let mut stmts = result.unwrap();
         assert_eq!(
             stmts.pop().unwrap(),
-            Statement::DropTable(DropTable {
-                catalog_name: DEFAULT_CATALOG_NAME.to_string(),
-                schema_name: DEFAULT_SCHEMA_NAME.to_string(),
-                table_name: "foo".to_string()
-            })
+            Statement::DropTable(DropTable::new(ObjectName(vec![Ident::new("foo")])))
         );
 
         let sql = "DROP TABLE my_schema.foo";
@@ -596,11 +582,10 @@ mod tests {
         let mut stmts = result.unwrap();
         assert_eq!(
             stmts.pop().unwrap(),
-            Statement::DropTable(DropTable {
-                catalog_name: DEFAULT_CATALOG_NAME.to_string(),
-                schema_name: "my_schema".to_string(),
-                table_name: "foo".to_string()
-            })
+            Statement::DropTable(DropTable::new(ObjectName(vec![
+                Ident::new("my_schema"),
+                Ident::new("foo")
+            ])))
         );
 
         let sql = "DROP TABLE my_catalog.my_schema.foo";
@@ -608,11 +593,11 @@ mod tests {
         let mut stmts = result.unwrap();
         assert_eq!(
             stmts.pop().unwrap(),
-            Statement::DropTable(DropTable {
-                catalog_name: "my_catalog".to_string(),
-                schema_name: "my_schema".to_string(),
-                table_name: "foo".to_string()
-            })
+            Statement::DropTable(DropTable::new(ObjectName(vec![
+                Ident::new("my_catalog"),
+                Ident::new("my_schema"),
+                Ident::new("foo")
+            ])))
         )
     }
 }
diff --git a/src/sql/src/statements/describe.rs b/src/sql/src/statements/describe.rs
index a3fd0197a3..f435f628a9 100644
--- a/src/sql/src/statements/describe.rs
+++ b/src/sql/src/statements/describe.rs
@@ -12,22 +12,22 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use sqlparser::ast::ObjectName;
+
 /// SQL structure for `DESCRIBE TABLE`.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct DescribeTable {
-    pub catalog_name: String,
-    pub schema_name: String,
-    pub table_name: String,
+    name: ObjectName,
 }
 
 impl DescribeTable {
     /// Creates a statement for `DESCRIBE TABLE`
-    pub fn new(catalog_name: String, schema_name: String, table_name: String) -> Self {
-        DescribeTable {
-            catalog_name,
-            schema_name,
-            table_name,
-        }
+    pub fn new(name: ObjectName) -> Self {
+        Self { name }
+    }
+
+    pub fn name(&self) -> &ObjectName {
+        &self.name
     }
 }
 
@@ -49,7 +49,7 @@ mod tests {
         assert_matches!(&stmts[0], Statement::DescribeTable { .. });
         match &stmts[0] {
             Statement::DescribeTable(show) => {
-                assert_eq!(show.table_name.as_str(), "test");
+                assert_eq!(show.name.to_string(), "test");
             }
             _ => {
                 unreachable!();
@@ -66,8 +66,7 @@ mod tests {
         assert_matches!(&stmts[0], Statement::DescribeTable { .. });
         match &stmts[0] {
             Statement::DescribeTable(show) => {
-                assert_eq!(show.schema_name.as_str(), "test_schema");
-                assert_eq!(show.table_name.as_str(), "test");
+                assert_eq!(show.name.to_string(), "test_schema.test");
             }
             _ => {
                 unreachable!();
@@ -84,9 +83,7 @@ mod tests {
         assert_matches!(&stmts[0], Statement::DescribeTable { .. });
         match &stmts[0] {
             Statement::DescribeTable(show) => {
-                assert_eq!(show.catalog_name.as_str(), "test_catalog");
-                assert_eq!(show.schema_name.as_str(), "test_schema");
-                assert_eq!(show.table_name.as_str(), "test");
+                assert_eq!(show.name.to_string(), "test_catalog.test_schema.test");
             }
             _ => {
                 unreachable!();
diff --git a/src/sql/src/statements/drop.rs b/src/sql/src/statements/drop.rs
index 72092e08b6..b8fc0401fa 100644
--- a/src/sql/src/statements/drop.rs
+++ b/src/sql/src/statements/drop.rs
@@ -12,21 +12,21 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use sqlparser::ast::ObjectName;
+
 /// DROP TABLE statement.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct DropTable {
-    pub catalog_name: String,
-    pub schema_name: String,
-    pub table_name: String,
+    table_name: ObjectName,
 }
 
 impl DropTable {
     /// Creates a statement for `DROP TABLE`
-    pub fn new(catalog_name: String, schema_name: String, table_name: String) -> Self {
-        DropTable {
-            catalog_name,
-            schema_name,
-            table_name,
-        }
+    pub fn new(table_name: ObjectName) -> Self {
+        Self { table_name }
+    }
+
+    pub fn table_name(&self) -> &ObjectName {
+        &self.table_name
     }
 }
diff --git a/src/table/src/engine.rs b/src/table/src/engine.rs
index 75980e7d2a..0f67d69e4f 100644
--- a/src/table/src/engine.rs
+++ b/src/table/src/engine.rs
@@ -20,6 +20,7 @@ use crate::requests::{AlterTableRequest, CreateTableRequest, DropTableRequest, O
 use crate::TableRef;
 
 /// Represents a resolved path to a table of the form “catalog.schema.table”
+#[derive(Debug, PartialEq)]
 pub struct TableReference<'a> {
     pub catalog: &'a str,
     pub schema: &'a str,
diff --git a/src/table/src/requests.rs b/src/table/src/requests.rs
index 4d6a6b1b87..9de1f22777 100644
--- a/src/table/src/requests.rs
+++ b/src/table/src/requests.rs
@@ -64,8 +64,8 @@ pub struct OpenTableRequest {
 /// Alter table request
 #[derive(Debug)]
 pub struct AlterTableRequest {
-    pub catalog_name: Option<String>,
-    pub schema_name: Option<String>,
+    pub catalog_name: String,
+    pub schema_name: String,
     pub table_name: String,
     pub alter_kind: AlterKind,
 }
diff --git a/tests-integration/tests/grpc.rs b/tests-integration/tests/grpc.rs
index 88ade995fd..15e2687b42 100644
--- a/tests-integration/tests/grpc.rs
+++ b/tests-integration/tests/grpc.rs
@@ -18,7 +18,7 @@ use api::v1::{
     InsertRequest, TableId,
 };
 use client::{Client, Database};
-use common_catalog::consts::MIN_USER_TABLE_ID;
+use common_catalog::consts::{DEFAULT_CATALOG_NAME, DEFAULT_SCHEMA_NAME, MIN_USER_TABLE_ID};
 use common_query::Output;
 use servers::server::Server;
 use tests_integration::test_util::{setup_grpc_server, StorageType};
@@ -65,7 +65,7 @@ pub async fn test_auto_create_table(store_type: StorageType) {
         setup_grpc_server(store_type, "auto_create_table").await;
 
     let grpc_client = Client::with_urls(vec![addr]);
-    let db = Database::new("greptime", grpc_client);
+    let db = Database::with_client(grpc_client);
     insert_and_assert(&db).await;
     let _ = fe_grpc_server.shutdown().await;
     guard.remove_all().await;
@@ -131,8 +131,7 @@ pub async fn test_insert_and_select(store_type: StorageType) {
         setup_grpc_server(store_type, "insert_and_select").await;
 
     let grpc_client = Client::with_urls(vec![addr]);
-
-    let db = Database::new("greptime", grpc_client.clone());
+    let db = Database::with_client(grpc_client);
 
     // create
     let expr = testing_create_expr();
@@ -153,9 +152,9 @@ pub async fn test_insert_and_select(store_type: StorageType) {
         }],
     });
     let expr = AlterExpr {
+        catalog_name: DEFAULT_CATALOG_NAME.to_string(),
+        schema_name: DEFAULT_SCHEMA_NAME.to_string(),
         table_name: "demo".to_string(),
-        catalog_name: "".to_string(),
-        schema_name: "".to_string(),
         kind: Some(kind),
     };
     let result = db.alter(expr).await.unwrap();
@@ -173,7 +172,6 @@ async fn insert_and_assert(db: &Database) {
     let (expected_host_col, expected_cpu_col, expected_mem_col, expected_ts_col) = expect_data();
 
     let request = InsertRequest {
-        schema_name: "public".to_string(),
         table_name: "demo".to_string(),
         region_number: 0,
         columns: vec![
diff --git a/tests/cases/standalone/aggregate/distinct.result b/tests/cases/standalone/aggregate/distinct.result
index 3a6620fba6..2fbeb15d9d 100644
--- a/tests/cases/standalone/aggregate/distinct.result
+++ b/tests/cases/standalone/aggregate/distinct.result
@@ -1,12 +1,21 @@
-CREATE TABLE test_distinct (a INTEGER, b INTEGER, t BIGINT TIME INDEX);
+CREATE SCHEMA test_distinct;
+
+Affected Rows: 1
+
+USE test_distinct;
+
+++
+++
+
+CREATE TABLE test (a INTEGER, b INTEGER, t BIGINT TIME INDEX);
 
 Affected Rows: 0
 
-INSERT INTO test_distinct VALUES (11, 22, 1), (13, 22, 2), (11, 21, 3), (11, 22, 4);
+INSERT INTO test VALUES (11, 22, 1), (13, 22, 2), (11, 21, 3), (11, 22, 4);
 
 Affected Rows: 4
 
-SELECT DISTINCT a, b FROM test_distinct ORDER BY a, b;
+SELECT DISTINCT a, b FROM test ORDER BY a, b;
 
 +----+----+
 | a  | b  |
@@ -16,7 +25,7 @@ SELECT DISTINCT a, b FROM test_distinct ORDER BY a, b;
 | 13 | 22 |
 +----+----+
 
-SELECT DISTINCT test_distinct.a, b FROM test_distinct ORDER BY a, b;
+SELECT DISTINCT test.a, b FROM test ORDER BY a, b;
 
 +----+----+
 | a  | b  |
@@ -26,7 +35,7 @@ SELECT DISTINCT test_distinct.a, b FROM test_distinct ORDER BY a, b;
 | 13 | 22 |
 +----+----+
 
-SELECT DISTINCT a FROM test_distinct ORDER BY a;
+SELECT DISTINCT a FROM test ORDER BY a;
 
 +----+
 | a  |
@@ -35,7 +44,7 @@ SELECT DISTINCT a FROM test_distinct ORDER BY a;
 | 13 |
 +----+
 
-SELECT DISTINCT b FROM test_distinct ORDER BY b;
+SELECT DISTINCT b FROM test ORDER BY b;
 
 +----+
 | b  |
@@ -44,32 +53,32 @@ SELECT DISTINCT b FROM test_distinct ORDER BY b;
 | 22 |
 +----+
 
-SELECT DISTINCT a, SUM(B) FROM test_distinct GROUP BY a ORDER BY a;
+SELECT DISTINCT a, SUM(B) FROM test GROUP BY a ORDER BY a;
 
-+----+----------------------+
-| a  | SUM(test_distinct.b) |
-+----+----------------------+
-| 11 | 65                   |
-| 13 | 22                   |
-+----+----------------------+
++----+-------------+
+| a  | SUM(test.b) |
++----+-------------+
+| 11 | 65          |
+| 13 | 22          |
++----+-------------+
 
-SELECT DISTINCT MAX(b) FROM test_distinct GROUP BY a;
+SELECT DISTINCT MAX(b) FROM test GROUP BY a;
 
-+----------------------+
-| MAX(test_distinct.b) |
-+----------------------+
-| 22                   |
-+----------------------+
++-------------+
+| MAX(test.b) |
++-------------+
+| 22          |
++-------------+
 
-SELECT DISTINCT CASE WHEN a > 11 THEN 11 ELSE a END FROM test_distinct;
+SELECT DISTINCT CASE WHEN a > 11 THEN 11 ELSE a END FROM test;
 
-+-------------------------------------------------------------------------------+
-| CASE WHEN test_distinct.a > Int64(11) THEN Int64(11) ELSE test_distinct.a END |
-+-------------------------------------------------------------------------------+
-| 11                                                                            |
-+-------------------------------------------------------------------------------+
++-------------------------------------------------------------+
+| CASE WHEN test.a > Int64(11) THEN Int64(11) ELSE test.a END |
++-------------------------------------------------------------+
+| 11                                                          |
++-------------------------------------------------------------+
 
-DROP TABLE test_distinct;
+DROP TABLE test;
 
 Affected Rows: 1
 
diff --git a/tests/cases/standalone/aggregate/distinct.sql b/tests/cases/standalone/aggregate/distinct.sql
index 4fa22f5d6b..ce6617a24d 100644
--- a/tests/cases/standalone/aggregate/distinct.sql
+++ b/tests/cases/standalone/aggregate/distinct.sql
@@ -1,19 +1,23 @@
-CREATE TABLE test_distinct (a INTEGER, b INTEGER, t BIGINT TIME INDEX);
+CREATE SCHEMA test_distinct;
 
-INSERT INTO test_distinct VALUES (11, 22, 1), (13, 22, 2), (11, 21, 3), (11, 22, 4);
+USE test_distinct;
 
-SELECT DISTINCT a, b FROM test_distinct ORDER BY a, b;
+CREATE TABLE test (a INTEGER, b INTEGER, t BIGINT TIME INDEX);
 
-SELECT DISTINCT test_distinct.a, b FROM test_distinct ORDER BY a, b;
+INSERT INTO test VALUES (11, 22, 1), (13, 22, 2), (11, 21, 3), (11, 22, 4);
 
-SELECT DISTINCT a FROM test_distinct ORDER BY a;
+SELECT DISTINCT a, b FROM test ORDER BY a, b;
 
-SELECT DISTINCT b FROM test_distinct ORDER BY b;
+SELECT DISTINCT test.a, b FROM test ORDER BY a, b;
 
-SELECT DISTINCT a, SUM(B) FROM test_distinct GROUP BY a ORDER BY a;
+SELECT DISTINCT a FROM test ORDER BY a;
 
-SELECT DISTINCT MAX(b) FROM test_distinct GROUP BY a;
+SELECT DISTINCT b FROM test ORDER BY b;
 
-SELECT DISTINCT CASE WHEN a > 11 THEN 11 ELSE a END FROM test_distinct;
+SELECT DISTINCT a, SUM(B) FROM test GROUP BY a ORDER BY a;
 
-DROP TABLE test_distinct;
+SELECT DISTINCT MAX(b) FROM test GROUP BY a;
+
+SELECT DISTINCT CASE WHEN a > 11 THEN 11 ELSE a END FROM test;
+
+DROP TABLE test;
diff --git a/tests/cases/standalone/aggregate/sum.result b/tests/cases/standalone/aggregate/sum.result
index df699dccd3..eaa30a830d 100644
--- a/tests/cases/standalone/aggregate/sum.result
+++ b/tests/cases/standalone/aggregate/sum.result
@@ -1,3 +1,8 @@
+USE public;
+
+++
+++
+
 SELECT SUM(number) FROM numbers;
 
 +---------------------+
diff --git a/tests/cases/standalone/aggregate/sum.sql b/tests/cases/standalone/aggregate/sum.sql
index 929621caf1..97428c5767 100644
--- a/tests/cases/standalone/aggregate/sum.sql
+++ b/tests/cases/standalone/aggregate/sum.sql
@@ -1,3 +1,5 @@
+USE public;
+
 SELECT SUM(number) FROM numbers;
 
 SELECT SUM(1) FROM numbers;
diff --git a/tests/cases/standalone/alter/add_col.result b/tests/cases/standalone/alter/add_col.result
index d3b0be78f2..989e13ce97 100644
--- a/tests/cases/standalone/alter/add_col.result
+++ b/tests/cases/standalone/alter/add_col.result
@@ -1,16 +1,25 @@
-CREATE TABLE test_add_col(i INTEGER, j BIGINT TIME INDEX);
+CREATE SCHEMA test_add_col;
+
+Affected Rows: 1
+
+USE test_add_col;
+
+++
+++
+
+CREATE TABLE test(i INTEGER, j BIGINT TIME INDEX);
 
 Affected Rows: 0
 
-INSERT INTO test_add_col VALUES (1, 1), (2, 2);
+INSERT INTO test VALUES (1, 1), (2, 2);
 
 Affected Rows: 2
 
-ALTER TABLE test_add_col ADD COLUMN k INTEGER;
+ALTER TABLE test ADD COLUMN k INTEGER;
 
 Affected Rows: 0
 
-SELECT * FROM test_add_col;
+SELECT * FROM test;
 
 +---+---+---+
 | i | j | k |
@@ -19,7 +28,7 @@ SELECT * FROM test_add_col;
 | 2 | 2 |   |
 +---+---+---+
 
-DROP TABLE test_add_col;
+DROP TABLE test;
 
 Affected Rows: 1
 
diff --git a/tests/cases/standalone/alter/add_col.sql b/tests/cases/standalone/alter/add_col.sql
index d15e789c45..b961263ba9 100644
--- a/tests/cases/standalone/alter/add_col.sql
+++ b/tests/cases/standalone/alter/add_col.sql
@@ -1,9 +1,13 @@
-CREATE TABLE test_add_col(i INTEGER, j BIGINT TIME INDEX);
+CREATE SCHEMA test_add_col;
 
-INSERT INTO test_add_col VALUES (1, 1), (2, 2);
+USE test_add_col;
 
-ALTER TABLE test_add_col ADD COLUMN k INTEGER;
+CREATE TABLE test(i INTEGER, j BIGINT TIME INDEX);
 
-SELECT * FROM test_add_col;
+INSERT INTO test VALUES (1, 1), (2, 2);
 
-DROP TABLE test_add_col;
+ALTER TABLE test ADD COLUMN k INTEGER;
+
+SELECT * FROM test;
+
+DROP TABLE test;
diff --git a/tests/cases/standalone/alter/rename_table.result b/tests/cases/standalone/alter/rename_table.result
index f05f6523a3..551d571259 100644
--- a/tests/cases/standalone/alter/rename_table.result
+++ b/tests/cases/standalone/alter/rename_table.result
@@ -1,3 +1,12 @@
+CREATE SCHEMA test_rename_table;
+
+Affected Rows: 1
+
+USE test_rename_table;
+
+++
+++
+
 CREATE TABLE t(i INTEGER, j BIGINT TIME INDEX);
 
 Affected Rows: 0
@@ -31,11 +40,11 @@ Affected Rows: 0
 
 DESC TABLE t;
 
-Error: 1004(InvalidArguments), Table not found: t
+Error: 4001(TableNotFound), Table not found: t
 
 SELECT * FROM t;
 
-Error: 3000(PlanQuery), Error during planning: table 'greptime.public.t' not found
+Error: 3000(PlanQuery), Error during planning: table 'greptime.test_rename_table.t' not found
 
 CREATE TABLE t(i INTEGER, j BIGINT TIME INDEX);
 
@@ -62,11 +71,11 @@ SELECT * FROM new_table;
 
 ALTER TABLE new_table RENAME new_table;
 
-Error: 1004(InvalidArguments), Table already exists: greptime.public.new_table
+Error: 1004(InvalidArguments), Table already exists: greptime.test_rename_table.new_table
 
 ALTER TABLE new_table RENAME t;
 
-Error: 1004(InvalidArguments), Table already exists: greptime.public.t
+Error: 1004(InvalidArguments), Table already exists: greptime.test_rename_table.t
 
 DROP TABLE t;
 
diff --git a/tests/cases/standalone/alter/rename_table.sql b/tests/cases/standalone/alter/rename_table.sql
index af4de9ca87..3b91cf07e6 100644
--- a/tests/cases/standalone/alter/rename_table.sql
+++ b/tests/cases/standalone/alter/rename_table.sql
@@ -1,3 +1,7 @@
+CREATE SCHEMA test_rename_table;
+
+USE test_rename_table;
+
 CREATE TABLE t(i INTEGER, j BIGINT TIME INDEX);
 
 DESC TABLE t;
diff --git a/tests/cases/standalone/catalog/schema.result b/tests/cases/standalone/catalog/schema.result
index ff0bb3ca39..51fdb1322e 100644
--- a/tests/cases/standalone/catalog/schema.result
+++ b/tests/cases/standalone/catalog/schema.result
@@ -1,41 +1,42 @@
-CREATE SCHEMA test_schema;
+CREATE SCHEMA test_public_schema;
 
 Affected Rows: 1
 
-SHOW DATABASES;
+CREATE SCHEMA test_public_schema;
 
-+-------------+
-| Schemas     |
-+-------------+
-| public      |
-| test_schema |
-+-------------+
+Error: 1003(Internal), Schema test_public_schema already exists
 
-CREATE TABLE test_schema.hello(i BIGINT TIME INDEX);
+SHOW DATABASES LIKE '%public%';
+
++--------------------+
+| Schemas            |
++--------------------+
+| public             |
+| test_public_schema |
++--------------------+
+
+USE test_public_schema;
+
+++
+++
+
+CREATE TABLE hello(i BIGINT TIME INDEX);
 
 Affected Rows: 0
 
-DROP TABLE test_schema.hello;
+DROP TABLE hello;
 
 Affected Rows: 1
 
-DROP SCHEMA test_schema;
-
-Error: 1001(Unsupported), SQL statement is not supported:  DROP SCHEMA test_schema;, keyword: SCHEMA
-
-CREATE SCHEMA test_schema;
-
-Error: 1003(Internal), Schema test_schema already exists
-
-CREATE TABLE test_schema.hello(i BIGINT TIME INDEX);
+CREATE TABLE hello(i BIGINT TIME INDEX);
 
 Affected Rows: 0
 
-INSERT INTO test_schema.hello VALUES (2), (3), (4);
+INSERT INTO hello VALUES (2), (3), (4);
 
 Affected Rows: 3
 
-SELECT * FROM test_schema.hello;
+SELECT * FROM hello;
 
 +---+
 | i |
@@ -47,6 +48,29 @@ SELECT * FROM test_schema.hello;
 
 SHOW TABLES;
 
++--------+
+| Tables |
++--------+
+| hello  |
++--------+
+
+DROP TABLE hello;
+
+Affected Rows: 1
+
+DROP TABLE hello;
+
+Error: 4001(TableNotFound), Table `greptime.test_public_schema.hello` not exist
+
+SHOW TABLES FROM test_public_schema;
+
++--------+
+| Tables |
++--------+
++--------+
+
+SHOW TABLES FROM public;
+
 +---------+
 | Tables  |
 +---------+
@@ -54,34 +78,11 @@ SHOW TABLES;
 | scripts |
 +---------+
 
-SHOW TABLES FROM test_schema;
+DROP SCHEMA test_public_schema;
 
-+--------+
-| Tables |
-+--------+
-| hello  |
-+--------+
+Error: 1001(Unsupported), SQL statement is not supported:  DROP SCHEMA test_public_schema;, keyword: SCHEMA
 
-DROP TABLE test_schema.hello;
+SELECT * FROM test_public_schema.hello;
 
-Affected Rows: 1
-
-DROP TABLE test_schema.hello;
-
-Error: 4001(TableNotFound), Table `greptime.test_schema.hello` not exist
-
-SHOW TABLES FROM test_schema;
-
-+--------+
-| Tables |
-+--------+
-+--------+
-
-DROP SCHEMA test_schema;
-
-Error: 1001(Unsupported), SQL statement is not supported:  DROP SCHEMA test_schema;, keyword: SCHEMA
-
-SELECT * FROM test_schema.hello;
-
-Error: 3000(PlanQuery), Error during planning: table 'greptime.test_schema.hello' not found
+Error: 3000(PlanQuery), Error during planning: table 'greptime.test_public_schema.hello' not found
 
diff --git a/tests/cases/standalone/catalog/schema.sql b/tests/cases/standalone/catalog/schema.sql
index 208fc1b725..5ca617f5fc 100644
--- a/tests/cases/standalone/catalog/schema.sql
+++ b/tests/cases/standalone/catalog/schema.sql
@@ -1,31 +1,31 @@
-CREATE SCHEMA test_schema;
+CREATE SCHEMA test_public_schema;
 
-SHOW DATABASES;
+CREATE SCHEMA test_public_schema;
 
-CREATE TABLE test_schema.hello(i BIGINT TIME INDEX);
+SHOW DATABASES LIKE '%public%';
 
-DROP TABLE test_schema.hello;
+USE test_public_schema;
 
-DROP SCHEMA test_schema;
+CREATE TABLE hello(i BIGINT TIME INDEX);
 
-CREATE SCHEMA test_schema;
+DROP TABLE hello;
 
-CREATE TABLE test_schema.hello(i BIGINT TIME INDEX);
+CREATE TABLE hello(i BIGINT TIME INDEX);
 
-INSERT INTO test_schema.hello VALUES (2), (3), (4);
+INSERT INTO hello VALUES (2), (3), (4);
 
-SELECT * FROM test_schema.hello;
+SELECT * FROM hello;
 
 SHOW TABLES;
 
-SHOW TABLES FROM test_schema;
+DROP TABLE hello;
 
-DROP TABLE test_schema.hello;
+DROP TABLE hello;
 
-DROP TABLE test_schema.hello;
+SHOW TABLES FROM test_public_schema;
 
-SHOW TABLES FROM test_schema;
+SHOW TABLES FROM public;
 
-DROP SCHEMA test_schema;
+DROP SCHEMA test_public_schema;
 
-SELECT * FROM test_schema.hello;
+SELECT * FROM test_public_schema.hello;
diff --git a/tests/cases/standalone/insert/insert_invalid.result b/tests/cases/standalone/insert/insert_invalid.result
index 0037e9ce99..8e96feaa81 100644
--- a/tests/cases/standalone/insert/insert_invalid.result
+++ b/tests/cases/standalone/insert/insert_invalid.result
@@ -1,16 +1,25 @@
-CREATE TABLE insert_invalid_strings(i STRING, t BIGINT, time index(t));
-
-Affected Rows: 0
-
-INSERT INTO insert_invalid_strings VALUES ('â‚(', 1);
+CREATE SCHEMA insert_invalid;
 
 Affected Rows: 1
 
-INSERT INTO insert_invalid_strings VALUES (3, 4);
+USE insert_invalid;
+
+++
+++
+
+CREATE TABLE strings(i STRING, t BIGINT, time index(t));
+
+Affected Rows: 0
+
+INSERT INTO strings VALUES ('â‚(', 1);
+
+Affected Rows: 1
+
+INSERT INTO strings VALUES (3, 4);
 
 Error: 2000(InvalidSyntax), Failed to parse value: Fail to parse number 3, invalid column type: String(StringType)
 
-SELECT * FROM insert_invalid_strings WHERE i = 'â‚(';
+SELECT * FROM strings WHERE i = 'â‚(';
 
 +-----+---+
 | i   | t |
diff --git a/tests/cases/standalone/insert/insert_invalid.sql b/tests/cases/standalone/insert/insert_invalid.sql
index 58b22858c8..e9be3ff671 100644
--- a/tests/cases/standalone/insert/insert_invalid.sql
+++ b/tests/cases/standalone/insert/insert_invalid.sql
@@ -1,10 +1,14 @@
-CREATE TABLE insert_invalid_strings(i STRING, t BIGINT, time index(t));
+CREATE SCHEMA insert_invalid;
 
-INSERT INTO insert_invalid_strings VALUES ('â‚(', 1);
+USE insert_invalid;
 
-INSERT INTO insert_invalid_strings VALUES (3, 4);
+CREATE TABLE strings(i STRING, t BIGINT, time index(t));
 
-SELECT * FROM insert_invalid_strings WHERE i = 'â‚(';
+INSERT INTO strings VALUES ('â‚(', 1);
+
+INSERT INTO strings VALUES (3, 4);
+
+SELECT * FROM strings WHERE i = 'â‚(';
 
 CREATE TABLE a(i integer, j BIGINT, time index(j));
 
diff --git a/tests/cases/standalone/limit/limit.result b/tests/cases/standalone/limit/limit.result
index 0f58f3c0bf..096d2c7c0d 100644
--- a/tests/cases/standalone/limit/limit.result
+++ b/tests/cases/standalone/limit/limit.result
@@ -1,3 +1,8 @@
+USE public;
+
+++
+++
+
 SELECT * FROM (SELECT SUM(number) FROM numbers LIMIT 100000000000) LIMIT 0;
 
 ++
diff --git a/tests/cases/standalone/limit/limit.sql b/tests/cases/standalone/limit/limit.sql
index 1a3f42380f..86e4326652 100644
--- a/tests/cases/standalone/limit/limit.sql
+++ b/tests/cases/standalone/limit/limit.sql
@@ -1,3 +1,5 @@
+USE public;
+
 SELECT * FROM (SELECT SUM(number) FROM numbers LIMIT 100000000000) LIMIT 0;
 
 EXPLAIN SELECT * FROM (SELECT SUM(number) FROM numbers LIMIT 100000000000) LIMIT 0;
diff --git a/tests/cases/standalone/order/order_variable_size_payload.result b/tests/cases/standalone/order/order_variable_size_payload.result
index 28f63c800e..0f746f2047 100644
--- a/tests/cases/standalone/order/order_variable_size_payload.result
+++ b/tests/cases/standalone/order/order_variable_size_payload.result
@@ -1,3 +1,12 @@
+CREATE SCHEMA order_variable_size_payload;
+
+Affected Rows: 1
+
+USE order_variable_size_payload;
+
+++
+++
+
 create table t0 (c0 varchar, t BIGINT TIME INDEX);
 
 Affected Rows: 0
@@ -137,7 +146,7 @@ SELECT * FROM tpch_q1_agg ORDER BY l_returnflag, l_linestatus;
 | R            | F            | 3785523 | 5337950526.47  | 5071818532.942  | 5274405503.049367  | 25.5259438574251   | 35994.029214030925 | 0.04998927856184382 | 148301      | 2 |
 +--------------+--------------+---------+----------------+-----------------+--------------------+--------------------+--------------------+---------------------+-------------+---+
 
-create table order_variable_size_payload_test5 (i int, s varchar, t BIGINT TIME INDEX);
+create table test5 (i int, s varchar, t BIGINT TIME INDEX);
 
 Affected Rows: 0
 
diff --git a/tests/cases/standalone/order/order_variable_size_payload.sql b/tests/cases/standalone/order/order_variable_size_payload.sql
index 672f403703..5ec272eb87 100644
--- a/tests/cases/standalone/order/order_variable_size_payload.sql
+++ b/tests/cases/standalone/order/order_variable_size_payload.sql
@@ -1,3 +1,7 @@
+CREATE SCHEMA order_variable_size_payload;
+
+USE order_variable_size_payload;
+
 create table t0 (c0 varchar, t BIGINT TIME INDEX);
 
 insert into t0 values ('a', 1), (NULL,2), (NULL, 3), (NULL, 4), (NULL, 5), (NULL,6), (NULL,7);
@@ -35,7 +39,7 @@ INSERT INTO tpch_q1_agg VALUES ('N', 'O', 7459297, 10512270008.90, 9986238338.38
 
 SELECT * FROM tpch_q1_agg ORDER BY l_returnflag, l_linestatus;
 
-create table order_variable_size_payload_test5 (i int, s varchar, t BIGINT TIME INDEX);
+create table test5 (i int, s varchar, t BIGINT TIME INDEX);
 
 CREATE TABLE test6 (i1 INT, s1 VARCHAR, i2 int, s2 VARCHAR, t BIGINT TIME INDEX);
 
diff --git a/tests/conf/standalone-test.toml.template b/tests/conf/standalone-test.toml.template
new file mode 100644
index 0000000000..b27c6d050b
--- /dev/null
+++ b/tests/conf/standalone-test.toml.template
@@ -0,0 +1,18 @@
+mode = 'standalone'
+enable_memory_catalog = false
+
+[wal]
+dir = '{wal_dir}'
+file_size = '1GB'
+purge_interval = '10m'
+purge_threshold = '50GB'
+read_batch_size = 128
+sync_write = false
+
+[storage]
+type = 'File'
+data_dir = '{data_dir}'
+
+[grpc_options]
+addr = '127.0.0.1:4001'
+runtime_size = 8
diff --git a/tests/runner/Cargo.toml b/tests/runner/Cargo.toml
index 8945d12896..3a3bf48ce0 100644
--- a/tests/runner/Cargo.toml
+++ b/tests/runner/Cargo.toml
@@ -11,5 +11,8 @@ common-base = { path = "../../src/common/base" }
 common-error = { path = "../../src/common/error" }
 common-grpc = { path = "../../src/common/grpc" }
 common-query = { path = "../../src/common/query" }
-sqlness = "0.1"
+common-time = { path = "../../src/common/time" }
+serde.workspace = true
+sqlness = "0.2"
+tinytemplate = "1.2"
 tokio.workspace = true
diff --git a/tests/runner/src/env.rs b/tests/runner/src/env.rs
index 038d3aad8d..a7769b5a5d 100644
--- a/tests/runner/src/env.rs
+++ b/tests/runner/src/env.rs
@@ -14,7 +14,7 @@
 
 use std::fmt::Display;
 use std::fs::OpenOptions;
-use std::path::Path;
+use std::path::{Path, PathBuf};
 use std::process::Stdio;
 use std::time::Duration;
 
@@ -23,8 +23,11 @@ use client::{Client, Database as DB, Error as ClientError};
 use common_error::ext::ErrorExt;
 use common_error::snafu::ErrorCompat;
 use common_query::Output;
+use serde::Serialize;
 use sqlness::{Database, EnvController};
+use tinytemplate::TinyTemplate;
 use tokio::process::{Child, Command};
+use tokio::sync::Mutex;
 
 use crate::util;
 
@@ -38,6 +41,7 @@ const DATANODE_LOG_FILE: &str = "/tmp/greptime-sqlness-datanode.log";
 
 pub struct Env {}
 
+#[allow(clippy::print_stdout)]
 #[async_trait]
 impl EnvController for Env {
     type DB = GreptimeDB;
@@ -51,7 +55,6 @@ impl EnvController for Env {
     }
 
     /// Stop one [`Database`].
-    #[allow(clippy::print_stdout)]
     async fn stop(&self, _mode: &str, mut database: Self::DB) {
         let mut server = database.server_process;
         Env::stop_server(&mut server).await;
@@ -65,8 +68,8 @@ impl EnvController for Env {
     }
 }
 
+#[allow(clippy::print_stdout)]
 impl Env {
-    #[allow(clippy::print_stdout)]
     pub async fn start_standalone() -> GreptimeDB {
         // Build the DB with `cargo build --bin greptime`
         println!("Going to build the DB...");
@@ -90,10 +93,12 @@ impl Env {
             .truncate(true)
             .open(SERVER_LOG_FILE)
             .unwrap_or_else(|_| panic!("Cannot open log file at {SERVER_LOG_FILE}"));
+
+        let conf = Self::generate_standalone_config_file();
         // Start the DB
         let server_process = Command::new("./greptime")
             .current_dir(util::get_binary_dir("debug"))
-            .args(["standalone", "start"])
+            .args(["--log-level=debug", "standalone", "start", "-c", &conf])
             .stdout(log_file)
             .spawn()
             .expect("Failed to start the DB");
@@ -105,17 +110,47 @@ impl Env {
         println!("Started, going to test. Log will be write to {SERVER_LOG_FILE}");
 
         let client = Client::with_urls(vec![SERVER_ADDR]);
-        let db = DB::new("greptime", client.clone());
+        let db = DB::with_client(client);
 
         GreptimeDB {
             server_process,
             metasrv_process: None,
             datanode_process: None,
-            client,
-            db,
+            client: Mutex::new(db),
         }
     }
 
+    fn generate_standalone_config_file() -> String {
+        let mut tt = TinyTemplate::new();
+
+        let mut template_file = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
+        template_file.push("../conf/standalone-test.toml.template");
+        let path = template_file.as_path();
+        let template = std::fs::read_to_string(path)
+            .unwrap_or_else(|_| panic!("Failed to read template config file: {}", path.display()));
+        tt.add_template("standalone", &template).unwrap();
+
+        #[derive(Serialize)]
+        struct Context {
+            wal_dir: String,
+            data_dir: String,
+        }
+
+        let current_time = common_time::util::current_time_millis();
+        let greptimedb_dir = format!("/tmp/greptimedb-{current_time}");
+        let ctx = Context {
+            wal_dir: format!("{greptimedb_dir}/wal/"),
+            data_dir: format!("{greptimedb_dir}/data/"),
+        };
+        let rendered = tt.render("standalone", &ctx).unwrap();
+
+        let conf_file = format!("/tmp/standalone-{current_time}.toml");
+        println!("Generating standalone config file in {conf_file}, full content:\n{rendered}");
+        std::fs::write(&conf_file, rendered).unwrap();
+
+        conf_file
+    }
+
     pub async fn start_distributed() -> GreptimeDB {
         let cargo_build_result = Command::new("cargo")
             .current_dir(util::get_workspace_root())
@@ -147,14 +182,13 @@ impl Env {
         }
 
         let client = Client::with_urls(vec![SERVER_ADDR]);
-        let db = DB::new("greptime", client.clone());
+        let db = DB::with_client(client);
 
         GreptimeDB {
             server_process: frontend,
             metasrv_process: Some(meta_server),
             datanode_process: Some(datanode),
-            client,
-            db,
+            client: Mutex::new(db),
         }
     }
 
@@ -186,6 +220,8 @@ impl Env {
             args.push("--node-id=1");
             args.push("--data-dir=/tmp/greptimedb_node_1/data");
             args.push("--wal-dir=/tmp/greptimedb_node_1/wal");
+        } else if subcommand == "metasrv" {
+            args.push("--use-memory-store");
         }
 
         let process = Command::new("./greptime")
@@ -202,15 +238,23 @@ pub struct GreptimeDB {
     server_process: Child,
     metasrv_process: Option<Child>,
     datanode_process: Option<Child>,
-    #[allow(dead_code)]
-    client: Client,
-    db: DB,
+    client: Mutex<DB>,
 }
 
 #[async_trait]
 impl Database for GreptimeDB {
     async fn query(&self, query: String) -> Box<dyn Display> {
-        let result = self.db.sql(&query).await;
+        let mut client = self.client.lock().await;
+        if query.trim().starts_with("USE ") {
+            let database = query
+                .split_ascii_whitespace()
+                .nth(1)
+                .expect("Illegal `USE` statement: expecting a database.")
+                .trim_end_matches(';');
+            client.set_schema(database);
+        }
+
+        let result = client.sql(&query).await;
         Box::new(ResultDisplayer { result }) as _
     }
 }