sql: fix statement bundle creation when memo isn't detached

pkg/sql/explain_bundle.go

@@ -36,6 +36,8 @@ import (
 	"github.com/cockroachdb/errors"
 )
 
+const noPlan = "no plan"
+
 // setExplainBundleResult sets the result of an EXPLAIN ANALYZE (DEBUG)
 // statement. warnings will be printed out as is in the CLI.
 //
@@ -242,9 +244,9 @@ func (b *stmtBundleBuilder) addStatement() {
 func (b *stmtBundleBuilder) addOptPlans(ctx context.Context) {
 	if b.plan.mem == nil || b.plan.mem.RootExpr() == nil {
 		// No optimizer plans; an error must have occurred during planning.
-		b.z.AddFile("opt.txt", "no plan")
-		b.z.AddFile("opt-v.txt", "no plan")
-		b.z.AddFile("opt-vv.txt", "no plan")
+		b.z.AddFile("opt.txt", noPlan)
+		b.z.AddFile("opt-v.txt", noPlan)
+		b.z.AddFile("opt-vv.txt", noPlan)
 		return
 	}
 

pkg/sql/explain_bundle_test.go

@@ -101,6 +101,19 @@ CREATE TABLE s.a (a INT PRIMARY KEY);`)
 		checkBundle(t, fmt.Sprintf("%+v", pqErr.Detail), "", nil, base, plans, "distsql.html")
 	})
 
+	// #92920 Make sure schema and opt files are created.
+	t.Run("memo-reset", func(t *testing.T) {
+		rows := r.QueryStr(t, "EXPLAIN ANALYZE (DEBUG) CREATE TABLE t (i int)")
+		checkBundle(t, fmt.Sprint(rows), "", func(name, contents string) error {
+			if name == "opt.txt" {
+				if contents == noPlan {
+					return errors.Errorf("opt.txt empty")
+				}
+			}
+			return nil
+		}, base, plans, "distsql.html vec.txt vec-v.txt")
+	})
+
 	// Verify that we can issue the statement with prepare (which can happen
 	// depending on the client).
 	t.Run("prepare", func(t *testing.T) {

pkg/sql/opt/norm/factory.go

@@ -170,6 +170,15 @@ func (f *Factory) DetachMemo() *memo.Memo {
 	return m
 }
 
+// ReleaseMemo is just like DetachMemo but it doesn't call Detach on the memo
+// preserving any statistics information for explain purposes (distinct, null
+// count etc).
+func (f *Factory) ReleaseMemo() *memo.Memo {
+	m := f.mem
+	f.mem = nil
+	return m
+}
+
 // DisableOptimizations disables all transformation rules. The unaltered input
 // expression tree becomes the output expression tree (because no transforms
 // are applied).

pkg/sql/plan_opt.go

@@ -601,7 +601,7 @@ func (opc *optPlanningCtx) buildExecMemo(ctx context.Context) (_ *memo.Memo, _ e
 		return memo, nil
 	}
 
-	return f.Memo(), nil
+	return f.ReleaseMemo(), nil
 }
 
 // runExecBuilder execbuilds a plan using the given factory and stores the