sql: reduce allocations for unsupported type checker

Release note: None

Author: mgartner

pkg/sql/planner.go

@@ -930,12 +930,15 @@ func (p *planner) resetPlanner(
 
 	p.cancelChecker.Reset(ctx)
 
+	utc := p.semaCtx.UnsupportedTypeChecker
 	p.semaCtx = tree.MakeSemaContext(p)
 	p.semaCtx.SearchPath = &sd.SearchPath
 	p.semaCtx.Annotations = nil
 	p.semaCtx.DateStyle = sd.GetDateStyle()
 	p.semaCtx.IntervalStyle = sd.GetIntervalStyle()
-	p.semaCtx.UnsupportedTypeChecker = eval.NewUnsupportedTypeChecker(p.execCfg.Settings.Version)
+	p.semaCtx.UnsupportedTypeChecker = eval.ResetUnsupportedTypeChecker(
+		p.execCfg.Settings.Version, utc,
+	)
 	p.semaCtx.UsePre_25_2VariadicBuiltins = sd.UsePre_25_2VariadicBuiltins
 
 	p.autoCommit = false

pkg/sql/sem/eval/unsupported_types.go

@@ -24,10 +24,22 @@ type unsupportedTypeChecker struct {
 // NewUnsupportedTypeChecker returns a new tree.UnsupportedTypeChecker that can
 // be used to check whether a type is allowed by the current cluster version.
 func NewUnsupportedTypeChecker(handle clusterversion.Handle) tree.UnsupportedTypeChecker {
-	// There are currently no types to check. Uncomment this code if a new type is introduced.
 	return &unsupportedTypeChecker{version: handle}
 }
 
+// ResetUnsupportedTypeChecker is similar to NewUnsupportedTypeChecker, but
+// reuses an existing, non-nil tree.UnsupportedTypeChecker if one is given,
+// instead of allocating a new one.
+func ResetUnsupportedTypeChecker(
+	handle clusterversion.Handle, existing tree.UnsupportedTypeChecker,
+) tree.UnsupportedTypeChecker {
+	if u, ok := existing.(*unsupportedTypeChecker); ok && u != nil {
+		u.version = handle
+		return existing
+	}
+	return NewUnsupportedTypeChecker(handle)
+}
+
 var _ tree.UnsupportedTypeChecker = (*unsupportedTypeChecker)(nil)
 
 // CheckType implements the tree.UnsupportedTypeChecker interface.