feat: support "use" stmt part 1 (#672)

* feat: a bare sketch of session; support "use" in MySQL server; modify insertion and selection related codes in Datanode

src/script/Cargo.toml

@@ -48,6 +48,7 @@ rustpython-vm = { git = "https://github.com/RustPython/RustPython", optional = t
   "default",
   "freeze-stdlib",
 ] }
+session = { path = "../session" }
 snafu = { version = "0.7", features = ["backtraces"] }
 sql = { path = "../sql" }
 table = { path = "../table" }

src/script/src/python/engine.rs

@@ -26,6 +26,7 @@ use common_recordbatch::{RecordBatch, RecordBatchStream, SendableRecordBatchStre
 use datatypes::schema::SchemaRef;
 use futures::Stream;
 use query::QueryEngineRef;
+use session::context::QueryContext;
 use snafu::{ensure, ResultExt};
 use sql::statements::statement::Statement;
 
@@ -93,7 +94,9 @@ impl Script for PyScript {
                 matches!(stmt, Statement::Query { .. }),
                 error::UnsupportedSqlSnafu { sql }
             );
-            let plan = self.query_engine.statement_to_plan(stmt)?;
+            let plan = self
+                .query_engine
+                .statement_to_plan(stmt, Arc::new(QueryContext::new()))?;
             let res = self.query_engine.execute(&plan).await?;
             let copr = self.copr.clone();
             match res {

src/script/src/table.rs

@@ -28,6 +28,7 @@ use datatypes::prelude::{ConcreteDataType, ScalarVector};
 use datatypes::schema::{ColumnSchema, Schema, SchemaBuilder};
 use datatypes::vectors::{StringVector, TimestampVector, VectorRef};
 use query::QueryEngineRef;
+use session::context::QueryContext;
 use snafu::{ensure, OptionExt, ResultExt};
 use table::requests::{CreateTableRequest, InsertRequest};
 
@@ -151,7 +152,7 @@ impl ScriptsTable {
 
         let plan = self
             .query_engine
-            .sql_to_plan(&sql)
+            .sql_to_plan(&sql, Arc::new(QueryContext::new()))
             .context(FindScriptSnafu { name })?;
 
         let stream = match self