feat: allow multiple sql statements in query string (#699)

* feat: allow multiple sql statement in query string

* test: add a test for multiple statement call

* feat: add temprary workaround for standalone mode

* fix: resolve sql parser issue temporarily

* Update src/datanode/src/instance/sql.rs

Co-authored-by: Yingwen <realevenyag@gmail.com>

* fix: adopt new sql handler

* refactor: revert changes in query engine

* refactor: assume sql-statement 1-1 on datanode

* test: use frontend for integration test

* refactor: add statement execution api for explicit single statement call

* fix: typo

* refactor: rename query method

* test: add test case for error

* test: data type change adoption

* chore: add todo from review

* chore: remove obsolete comments

* fix: resolve resolve issues

Co-authored-by: Yingwen <realevenyag@gmail.com>

src/query/src/datafusion.rs

@@ -33,7 +33,7 @@ use common_telemetry::timer;
 use datafusion::physical_plan::coalesce_partitions::CoalescePartitionsExec;
 use datafusion::physical_plan::ExecutionPlan;
 use session::context::QueryContextRef;
-use snafu::{OptionExt, ResultExt};
+use snafu::{ensure, OptionExt, ResultExt};
 use sql::dialect::GenericDialect;
 use sql::parser::ParserContext;
 use sql::statements::statement::Statement;
@@ -72,8 +72,7 @@ impl QueryEngine for DatafusionQueryEngine {
     fn sql_to_statement(&self, sql: &str) -> Result<Statement> {
         let mut statement = ParserContext::create_with_dialect(sql, &GenericDialect {})
             .context(error::ParseSqlSnafu)?;
-        // TODO(dennis): supports multi statement in one sql?
-        assert!(1 == statement.len());
+        ensure!(1 == statement.len(), error::MultipleStatementsSnafu { sql });
         Ok(statement.remove(0))
     }
 
@@ -280,6 +279,7 @@ mod tests {
             .sql_to_plan(sql, Arc::new(QueryContext::new()))
             .unwrap();
 
+        // TODO(sunng87): do not rely on to_string for compare
         assert_eq!(
             format!("{:?}", plan),
             r#"DfPlan(Limit: skip=0, fetch=20
@@ -297,6 +297,7 @@ mod tests {
         let plan = engine
             .sql_to_plan(sql, Arc::new(QueryContext::new()))
             .unwrap();
+
         let output = engine.execute(&plan).await.unwrap();
 
         match output {

src/query/src/datafusion/error.rs

@@ -40,6 +40,9 @@ pub enum InnerError {
         source: sql::error::Error,
     },
 
+    #[snafu(display("The SQL string has multiple statements, sql: {}", sql))]
+    MultipleStatements { sql: String, backtrace: Backtrace },
+
     #[snafu(display("Cannot plan SQL: {}, source: {}", sql, source))]
     PlanSql {
         sql: String,
@@ -90,6 +93,7 @@ impl ErrorExt for InnerError {
             PlanSql { .. } => StatusCode::PlanQuery,
             ConvertDfRecordBatchStream { source } => source.status_code(),
             ExecutePhysicalPlan { source } => source.status_code(),
+            MultipleStatements { .. } => StatusCode::InvalidArguments,
         }
     }