sql: support EXPLAIN ANALYZE EXECUTE

We currently cannot EXPLAIN an EXECUTE statement (the syntax doesn't
even allow it). EXECUTE is handled with special code at the top-level,
so it's tricky to make it work with EXPLAIN. However, EXPLAIN ANALYZE
Is also handled at the top level, before the EXECUTE handling, so that
should just work.

This change allows the parsing of such statements so we can use
EXPLAIN ANALYZE EXECUTE. If EXPLAIN EXECUTE is attempted, we get a
"not supported" error (this is less cryptic than the parsing error
anyway).

Release note: None

docs/generated/sql/bnf/explain_analyze_stmt.bnf

@@ -1,7 +1,7 @@
 explain_stmt ::=
-	'EXPLAIN' preparable_stmt
-	| 'EXPLAIN' '(' ( 'PLAN' | 'DISTSQL' | 'DEBUG' ) ( ( ',' ( 'PLAN' | 'DISTSQL' | 'DEBUG' ) ) )* ')' preparable_stmt
-	| 'EXPLAIN' 'ANALYZE' preparable_stmt
-	| 'EXPLAIN' 'ANALYSE' preparable_stmt
-	| 'EXPLAIN' 'ANALYZE' '(' ( 'PLAN' | 'DISTSQL' | 'DEBUG' ) ( ( ',' ( 'PLAN' | 'DISTSQL' | 'DEBUG' ) ) )* ')' preparable_stmt
-	| 'EXPLAIN' 'ANALYSE' '(' ( 'PLAN' | 'DISTSQL' | 'DEBUG' ) ( ( ',' ( 'PLAN' | 'DISTSQL' | 'DEBUG' ) ) )* ')' preparable_stmt
+	'EXPLAIN' explainable_stmt
+	| 'EXPLAIN' '(' ( 'PLAN' | 'DISTSQL' | 'DEBUG' ) ( ( ',' ( 'PLAN' | 'DISTSQL' | 'DEBUG' ) ) )* ')' explainable_stmt
+	| 'EXPLAIN' 'ANALYZE' explainable_stmt
+	| 'EXPLAIN' 'ANALYSE' explainable_stmt
+	| 'EXPLAIN' 'ANALYZE' '(' ( 'PLAN' | 'DISTSQL' | 'DEBUG' ) ( ( ',' ( 'PLAN' | 'DISTSQL' | 'DEBUG' ) ) )* ')' explainable_stmt
+	| 'EXPLAIN' 'ANALYSE' '(' ( 'PLAN' | 'DISTSQL' | 'DEBUG' ) ( ( ',' ( 'PLAN' | 'DISTSQL' | 'DEBUG' ) ) )* ')' explainable_stmt

docs/generated/sql/bnf/explain_stmt.bnf

@@ -1,3 +1,3 @@
 explain_stmt ::=
-	'EXPLAIN' preparable_stmt
-	| 'EXPLAIN' '(' ( 'VERBOSE' | 'TYPES' | 'OPT' | 'DISTSQL' | 'VEC' ) ( ( ',' ( 'VERBOSE' | 'TYPES' | 'OPT' | 'DISTSQL' | 'VEC' ) ) )* ')' preparable_stmt
+	'EXPLAIN' explainable_stmt
+	| 'EXPLAIN' '(' ( 'VERBOSE' | 'TYPES' | 'OPT' | 'DISTSQL' | 'VEC' ) ( ( ',' ( 'VERBOSE' | 'TYPES' | 'OPT' | 'DISTSQL' | 'VEC' ) ) )* ')' explainable_stmt

docs/generated/sql/bnf/stmt_block.bnf

@@ -148,12 +148,12 @@ drop_stmt ::=
 	| drop_schedule_stmt
 
 explain_stmt ::=
-	'EXPLAIN' preparable_stmt
-	| 'EXPLAIN' '(' explain_option_list ')' preparable_stmt
-	| 'EXPLAIN' 'ANALYZE' preparable_stmt
-	| 'EXPLAIN' 'ANALYSE' preparable_stmt
-	| 'EXPLAIN' 'ANALYZE' '(' explain_option_list ')' preparable_stmt
-	| 'EXPLAIN' 'ANALYSE' '(' explain_option_list ')' preparable_stmt
+	'EXPLAIN' explainable_stmt
+	| 'EXPLAIN' '(' explain_option_list ')' explainable_stmt
+	| 'EXPLAIN' 'ANALYZE' explainable_stmt
+	| 'EXPLAIN' 'ANALYSE' explainable_stmt
+	| 'EXPLAIN' 'ANALYZE' '(' explain_option_list ')' explainable_stmt
+	| 'EXPLAIN' 'ANALYSE' '(' explain_option_list ')' explainable_stmt
 
 import_stmt ::=
 	'IMPORT' import_format string_or_placeholder opt_with_options
@@ -492,6 +492,10 @@ drop_schedule_stmt ::=
 	'DROP' 'SCHEDULE' a_expr
 	| 'DROP' 'SCHEDULES' select_stmt
 
+explainable_stmt ::=
+	preparable_stmt
+	| execute_stmt
+
 explain_option_list ::=
 	( explain_option_name ) ( ( ',' explain_option_name ) )*
 

pkg/sql/opt/exec/execbuilder/testdata/explain

@@ -1567,3 +1567,27 @@ vectorized: true
 • insert fast path
   into: t2(x)
   auto commit
+
+statement ok
+PREPARE prep AS SELECT $1 + 1
+
+statement error EXPLAIN EXECUTE is not supported
+EXPLAIN EXECUTE prep(1)
+
+statement error EXPLAIN EXECUTE is not supported
+SELECT 1 FROM [ EXPLAIN EXECUTE prep(1) ]
+
+query T
+EXPLAIN ANALYZE EXECUTE prep(1)
+----
+planning time: 10µs
+execution time: 100µs
+distribution: <hidden>
+vectorized: <hidden>
+maximum memory usage: <hidden>
+network usage: <hidden>
+·
+• values
+  cluster nodes: <hidden>
+  actual row count: 1
+  size: 1 column, 1 row

pkg/sql/opt/optbuilder/explain.go

@@ -14,12 +14,20 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/server/telemetry"
 	"github.com/cockroachdb/cockroach/pkg/sql/catalog/colinfo"
 	"github.com/cockroachdb/cockroach/pkg/sql/opt/memo"
+	"github.com/cockroachdb/cockroach/pkg/sql/pgwire/pgcode"
+	"github.com/cockroachdb/cockroach/pkg/sql/pgwire/pgerror"
 	"github.com/cockroachdb/cockroach/pkg/sql/sem/tree"
 	"github.com/cockroachdb/cockroach/pkg/sql/sqltelemetry"
 	"github.com/cockroachdb/errors"
 )
 
 func (b *Builder) buildExplain(explain *tree.Explain, inScope *scope) (outScope *scope) {
+	if _, ok := explain.Statement.(*tree.Execute); ok {
+		panic(pgerror.New(
+			pgcode.FeatureNotSupported, "EXPLAIN EXECUTE is not supported; use EXPLAIN ANALYZE",
+		))
+	}
+
 	stmtScope := b.buildStmtAtRoot(explain.Statement, nil /* desiredTypes */)
 
 	outScope = inScope.push()

pkg/sql/parser/sql.y

@@ -854,6 +854,7 @@ func (u *sqlSymUnion) objectNamePrefixList() tree.ObjectNamePrefixList {
 %type <tree.Statement> explain_stmt
 %type <tree.Statement> prepare_stmt
 %type <tree.Statement> preparable_stmt
+%type <tree.Statement> explainable_stmt
 %type <tree.Statement> row_source_extension_stmt
 %type <tree.Statement> export_stmt
 %type <tree.Statement> execute_stmt
@@ -3801,7 +3802,7 @@ analyze_target:
 //
 // %SeeAlso: WEBDOCS/explain.html
 explain_stmt:
-  EXPLAIN preparable_stmt
+  EXPLAIN explainable_stmt
   {
     var err error
     $$.val, err = tree.MakeExplain(nil /* options */, $2.stmt())
@@ -3810,39 +3811,39 @@ explain_stmt:
     }
   }
 | EXPLAIN error // SHOW HELP: EXPLAIN
-| EXPLAIN '(' explain_option_list ')' preparable_stmt
+| EXPLAIN '(' explain_option_list ')' explainable_stmt
   {
     var err error
     $$.val, err = tree.MakeExplain($3.strs(), $5.stmt())
     if err != nil {
       return setErr(sqllex, err)
     }
   }
-| EXPLAIN ANALYZE preparable_stmt
+| EXPLAIN ANALYZE explainable_stmt
   {
     var err error
     $$.val, err = tree.MakeExplain([]string{"ANALYZE"}, $3.stmt())
     if err != nil {
       return setErr(sqllex, err)
     }
   }
-| EXPLAIN ANALYSE preparable_stmt
+| EXPLAIN ANALYSE explainable_stmt
   {
     var err error
     $$.val, err = tree.MakeExplain([]string{"ANALYZE"}, $3.stmt())
     if err != nil {
       return setErr(sqllex, err)
     }
   }
-| EXPLAIN ANALYZE '(' explain_option_list ')' preparable_stmt
+| EXPLAIN ANALYZE '(' explain_option_list ')' explainable_stmt
   {
     var err error
     $$.val, err = tree.MakeExplain(append($4.strs(), "ANALYZE"), $6.stmt())
     if err != nil {
       return setErr(sqllex, err)
     }
   }
-| EXPLAIN ANALYSE '(' explain_option_list ')' preparable_stmt
+| EXPLAIN ANALYSE '(' explain_option_list ')' explainable_stmt
   {
     var err error
     $$.val, err = tree.MakeExplain(append($4.strs(), "ANALYZE"), $6.stmt())
@@ -3856,6 +3857,10 @@ explain_stmt:
 // the context of EXPLAIN.
 | EXPLAIN '(' error // SHOW HELP: EXPLAIN
 
+explainable_stmt:
+  preparable_stmt
+| execute_stmt
+
 preparable_stmt:
   alter_stmt     // help texts in sub-rule
 | backup_stmt    // EXTEND WITH HELP: BACKUP

pkg/sql/parser/testdata/errors

@@ -515,15 +515,6 @@ DETAIL: source SQL:
 e'\xad'::string
 ^
 
-error
-EXPLAIN EXECUTE a
-----
-at or near "execute": syntax error
-DETAIL: source SQL:
-EXPLAIN EXECUTE a
-        ^
-HINT: try \h EXPLAIN
-
 error
 EXPLAIN (ANALYZE, PLAN) SELECT 1
 ----