sql: add support for re-using lease cache for audit logging

Previously, when a query needed to resolve table names for
audit we would always take the hit of reading the descriptor KV.
This was problematic and incur round trips, which are expensive
on multi-region clusters. To address this, this patch
will add support for using the lease cache for these
looks up and eliminate any extra round trips.

Fixes: #99475

Release note (performance improvement): audit logging could
incur extra latency when resolving table/view/sequence names.

pkg/bench/rttanalysis/BUILD.bazel

@@ -36,6 +36,7 @@ go_test(
     size = "large",
     srcs = [
         "alter_table_bench_test.go",
+        "audit_bench_test.go",
         "bench_test.go",
         "create_alter_role_bench_test.go",
         "discard_bench_test.go",

pkg/bench/rttanalysis/audit_bench_test.go

@@ -0,0 +1,25 @@
+// Copyright 2020 The Cockroach Authors.
+//
+// Use of this software is governed by the Business Source License
+// included in the file licenses/BSL.txt.
+//
+// As of the Change Date specified in that file, in accordance with
+// the Business Source License, use of this software will be governed
+// by the Apache License, Version 2.0, included in the file
+// licenses/APL.txt.
+
+package rttanalysis
+
+import "testing"
+
+func BenchmarkAudit(b *testing.B) { reg.Run(b) }
+func init() {
+	reg.Register("Audit", []RoundTripBenchTestCase{
+		{
+			Name: "select from an audit table",
+			Setup: `CREATE TABLE audit_table(a INT);
+							ALTER TABLE audit_table EXPERIMENTAL_AUDIT SET READ WRITE;`,
+			Stmt: "SELECT * from audit_table",
+		},
+	})
+}

pkg/bench/rttanalysis/testdata/benchmark_expectations

@@ -27,6 +27,7 @@ exp,benchmark
 7,AlterTableUnsplit/alter_table_unsplit_at_1_value
 9,AlterTableUnsplit/alter_table_unsplit_at_2_values
 11,AlterTableUnsplit/alter_table_unsplit_at_3_values
+5,Audit/select_from_an_audit_table
 20,CreateRole/create_role_with_1_option
 23,CreateRole/create_role_with_2_options
 26,CreateRole/create_role_with_3_options

pkg/sql/schema_resolver.go

@@ -223,7 +223,10 @@ func (sr *schemaResolver) GetQualifiedTableNameByID(
 func (sr *schemaResolver) getQualifiedTableName(
 	ctx context.Context, desc catalog.TableDescriptor,
 ) (*tree.TableName, error) {
-	dbDesc, err := sr.descCollection.ByID(sr.txn).Get().Database(ctx, desc.GetParentID())
+	// When getting the fully qualified name allow use of leased descriptors,
+	// since these will not involve any round trip.
+	descGetter := sr.descCollection.ByIDWithLeased(sr.txn)
+	dbDesc, err := descGetter.Get().Database(ctx, desc.GetParentID())
 	if err != nil {
 		return nil, err
 	}
@@ -237,7 +240,7 @@ func (sr *schemaResolver) getQualifiedTableName(
 	// information from the namespace table.
 	var schemaName tree.Name
 	schemaID := desc.GetParentSchemaID()
-	scDesc, err := sr.descCollection.ByID(sr.txn).Get().Schema(ctx, schemaID)
+	scDesc, err := descGetter.Get().Schema(ctx, schemaID)
 	switch {
 	case scDesc != nil:
 		schemaName = tree.Name(scDesc.GetName())