sql: add telemetry for SERIAL expansions

This adds telemetry for the SERIAL expansion strategies.

Counter format: `sql.schema.serial.<normtype>.<coltype>`

For example: `sql.schema.serial.rowid.SERIAL2`

Release note (sql change): CockroachDB will now report how the SERIAL
pseudo-type is expanded in table column definitions, when telemetry is
enabled.

pkg/server/updates_test.go

@@ -275,6 +275,12 @@ func TestReportUsage(t *testing.T) {
 		t.Fatal(err)
 	}
 
+	if _, err := db.Exec(
+		fmt.Sprintf(`CREATE TABLE %[1]s.%[1]s_s (%[1]s SERIAL2)`, elemName),
+	); err != nil {
+		t.Fatal(err)
+	}
+
 	// Run some queries so we have some query statistics collected.
 	for i := 0; i < 10; i++ {
 		// Run some sample queries. Each are passed a string and int by Exec.
@@ -388,7 +394,7 @@ func TestReportUsage(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if actual := len(tables); actual != 1 {
+	if actual := len(tables); actual != 2 {
 		t.Fatalf("unexpected table count %d", actual)
 	}
 	for _, table := range tables {
@@ -543,6 +549,9 @@ func TestReportUsage(t *testing.T) {
 		"test.b": 2,
 		"test.c": 3,
 
+		// SERIAL normalization.
+		"sql.schema.serial.rowid.SERIAL2": 1,
+
 		// Although the query is executed 10 times, due to plan caching
 		// keyed by the SQL text, the planning only occurs once.
 		"sql.plan.ops.cast.string::inet":                                            1,
@@ -693,6 +702,7 @@ func TestReportUsage(t *testing.T) {
 		`[false,false,false] SET application_name = $1`,
 		`[false,false,false] SET application_name = DEFAULT`,
 		`[false,false,false] SET application_name = _`,
+		`[true,false,false] CREATE TABLE _ (_ INT8 NOT NULL DEFAULT unique_rowid())`,
 		`[true,false,false] CREATE TABLE _ (_ INT8, CONSTRAINT _ CHECK (_ > _))`,
 		`[true,false,false] INSERT INTO _ SELECT unnest(ARRAY[_, _, __more2__])`,
 		`[true,false,false] INSERT INTO _ VALUES (_), (__more2__)`,
@@ -743,6 +753,7 @@ func TestReportUsage(t *testing.T) {
 			`ALTER TABLE _ CONFIGURE ZONE = _`,
 			`CREATE DATABASE _`,
 			`CREATE TABLE _ (_ INT8, CONSTRAINT _ CHECK (_ > _))`,
+			`CREATE TABLE _ (_ INT8 NOT NULL DEFAULT unique_rowid())`,
 			`CREATE TABLE _ (_ INT8 PRIMARY KEY, _ INT8, INDEX (_) INTERLEAVE IN PARENT _ (_))`,
 			`INSERT INTO _ VALUES (length($1::STRING)), (__more1__)`,
 			`INSERT INTO _ VALUES (_), (__more2__)`,

pkg/sql/serial.go

@@ -18,10 +18,12 @@ import (
 	"context"
 	"fmt"
 
+	"github.com/cockroachdb/cockroach/pkg/server/telemetry"
 	"github.com/cockroachdb/cockroach/pkg/sql/coltypes"
 	"github.com/cockroachdb/cockroach/pkg/sql/pgwire/pgerror"
 	"github.com/cockroachdb/cockroach/pkg/sql/sem/tree"
 	"github.com/cockroachdb/cockroach/pkg/sql/sessiondata"
+	"github.com/cockroachdb/cockroach/pkg/sql/sqltelemetry"
 	"github.com/cockroachdb/cockroach/pkg/util/log"
 )
 
@@ -83,6 +85,8 @@ func (p *planner) processSerialInColumnDef(
 		newSpec.Type = t.TInt
 	}
 
+	telemetry.Inc(sqltelemetry.SerialColumnNormalizationCounter(t.String(), serialNormalizationMode.String()))
+
 	if serialNormalizationMode == sessiondata.SerialUsesRowID {
 		// We're not constructing a sequence for this SERIAL column.
 		// Use the "old school" CockroachDB default.

pkg/sql/sqltelemetry/schema.go

@@ -0,0 +1,29 @@
+// Copyright 2019 The Cockroach Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+// implied. See the License for the specific language governing
+// permissions and limitations under the License.
+
+package sqltelemetry
+
+import (
+	"fmt"
+
+	"github.com/cockroachdb/cockroach/pkg/server/telemetry"
+)
+
+// SerialColumnNormalizationCounter is to be incremented every time
+// a SERIAL type is processed in a column definition.
+// It includes the normalization type, so we can
+// estimate usage of the various normalization strategies.
+func SerialColumnNormalizationCounter(inputType, normType string) telemetry.Counter {
+	return telemetry.GetCounter(fmt.Sprintf("sql.schema.serial.%s.%s", normType, inputType))
+}