Multi-metrics throttler: adding InnoDB history_list_length metric

go/test/endtoend/tabletmanager/throttler_topo/throttler_test.go

@@ -175,6 +175,16 @@ func throttledApps(tablet *cluster.Vttablet) (resp *http.Response, respBody stri
 	return resp, respBody, err
 }
 
+func vitessThrottleCheck(tablet *cluster.Vttablet, skipRequestHeartbeats bool) (*vtctldatapb.CheckThrottlerResponse, error) {
+	flags := &throttle.CheckFlags{
+		Scope:                 base.ShardScope,
+		SkipRequestHeartbeats: skipRequestHeartbeats,
+		MultiMetricsEnabled:   true,
+	}
+	resp, err := throttler.CheckThrottler(clusterInstance, tablet, throttlerapp.VitessName, flags)
+	return resp, err
+}
+
 func throttleCheck(tablet *cluster.Vttablet, skipRequestHeartbeats bool) (*vtctldatapb.CheckThrottlerResponse, error) {
 	flags := &throttle.CheckFlags{
 		Scope:                 base.ShardScope,
@@ -305,6 +315,17 @@ func TestInitialThrottler(t *testing.T) {
 		waitForThrottleCheckStatus(t, primaryTablet, tabletmanagerdatapb.CheckThrottlerResponseCode_THRESHOLD_EXCEEDED)
 	})
 	t.Run("setting high threshold", func(t *testing.T) {
+		{
+			req := &vtctldatapb.UpdateThrottlerConfigRequest{MetricName: base.LoadAvgMetricName.String(), Threshold: 5555}
+			_, err := throttler.UpdateThrottlerTopoConfig(clusterInstance, req, nil, nil)
+			assert.NoError(t, err)
+		}
+		{
+			req := &vtctldatapb.UpdateThrottlerConfigRequest{MetricName: base.MysqldLoadAvgMetricName.String(), Threshold: 5555}
+			_, err := throttler.UpdateThrottlerTopoConfig(clusterInstance, req, nil, nil)
+			assert.NoError(t, err)
+		}
+
 		req := &vtctldatapb.UpdateThrottlerConfigRequest{Threshold: extremelyHighThreshold.Seconds()}
 		_, err := throttler.UpdateThrottlerTopoConfig(clusterInstance, req, nil, nil)
 		assert.NoError(t, err)
@@ -317,6 +338,19 @@ func TestInitialThrottler(t *testing.T) {
 	t.Run("validating OK response from throttler with high threshold", func(t *testing.T) {
 		waitForThrottleCheckStatus(t, primaryTablet, tabletmanagerdatapb.CheckThrottlerResponseCode_OK)
 	})
+	t.Run("validating vitess app throttler check", func(t *testing.T) {
+		resp, err := vitessThrottleCheck(primaryTablet, true)
+		require.NoError(t, err)
+		for _, metricName := range base.KnownMetricNames {
+			t.Run(metricName.String(), func(t *testing.T) {
+				assert.Contains(t, resp.Check.Metrics, metricName.String())
+				metric := resp.Check.Metrics[metricName.String()]
+				require.NotNil(t, metric)
+				assert.Equal(t, tabletmanagerdatapb.CheckThrottlerResponseCode_OK, metric.ResponseCode, "metric: %+v", metric)
+			})
+		}
+	})
+
 	t.Run("setting low threshold", func(t *testing.T) {
 		req := &vtctldatapb.UpdateThrottlerConfigRequest{Threshold: throttler.DefaultThreshold.Seconds()}
 		_, err := throttler.UpdateThrottlerTopoConfig(clusterInstance, req, nil, nil)

go/vt/vttablet/tabletserver/throttle/base/metric_name.go

@@ -65,6 +65,7 @@ const (
 	ThreadsRunningMetricName         MetricName = "threads_running"
 	CustomMetricName                 MetricName = "custom"
 	LoadAvgMetricName                MetricName = "loadavg"
+	HistoryListLengthMetricName      MetricName = "history_list_length"
 	MysqldLoadAvgMetricName          MetricName = "mysqld-loadavg"
 	MysqldDatadirUsedRatioMetricName MetricName = "mysqld-datadir-used-ratio"
 )

go/vt/vttablet/tabletserver/throttle/base/metric_name_test.go

@@ -241,15 +241,17 @@ func TestKnownMetricNames(t *testing.T) {
 	assert.Contains(t, KnownMetricNames, LoadAvgMetricName)
 	assert.Contains(t, KnownMetricNames, CustomMetricName)
 	assert.Contains(t, KnownMetricNames, DefaultMetricName)
+	assert.Contains(t, KnownMetricNames, HistoryListLengthMetricName)
 	assert.Contains(t, KnownMetricNames, MysqldLoadAvgMetricName)
 	assert.Contains(t, KnownMetricNames, MysqldDatadirUsedRatioMetricName)
 }
 
-func TestSingleWordCamelKnownMetricNames(t *testing.T) {
+func TestKnownMetricNamesPascalCase(t *testing.T) {
 	expectCases := map[MetricName]string{
 		LagMetricName:                    "Lag",
 		ThreadsRunningMetricName:         "ThreadsRunning",
 		LoadAvgMetricName:                "Loadavg",
+		HistoryListLengthMetricName:      "HistoryListLength",
 		CustomMetricName:                 "Custom",
 		DefaultMetricName:                "Default",
 		MysqldLoadAvgMetricName:          "MysqldLoadavg",

go/vt/vttablet/tabletserver/throttle/base/self_metric_innodb_history_list_length.go

@@ -0,0 +1,68 @@
+/*
+Copyright 2024 The Vitess 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 base
+
+import (
+	"context"
+	"math"
+	"sync/atomic"
+	"time"
+)
+
+var (
+	historyListLengthQuery = "select count as history_len from information_schema.INNODB_METRICS where name = 'trx_rseg_history_len'"
+
+	cachedHistoryListLengthMetric     atomic.Pointer[ThrottleMetric]
+	historyListLengthCacheDuration    = 5 * time.Second
+	historyListLengthDefaultThreshold = math.Pow10(9)
+)
+
+var _ SelfMetric = registerSelfMetric(&HistoryListLengthSelfMetric{})
+
+type HistoryListLengthSelfMetric struct {
+}
+
+func (m *HistoryListLengthSelfMetric) Name() MetricName {
+	return HistoryListLengthMetricName
+}
+
+func (m *HistoryListLengthSelfMetric) DefaultScope() Scope {
+	return SelfScope
+}
+
+func (m *HistoryListLengthSelfMetric) DefaultThreshold() float64 {
+	return historyListLengthDefaultThreshold
+}
+
+func (m *HistoryListLengthSelfMetric) RequiresConn() bool {
+	return true
+}
+
+func (m *HistoryListLengthSelfMetric) Read(ctx context.Context, params *SelfMetricReadParams) *ThrottleMetric {
+	// This function will be called sequentially, and therefore does not need strong mutex protection. Still, we use atomics
+	// to ensure correctness in case an external goroutine tries to read the metric concurrently.
+	metric := cachedHistoryListLengthMetric.Load()
+	if metric != nil {
+		return metric
+	}
+	metric = ReadSelfMySQLThrottleMetric(ctx, params.Conn, historyListLengthQuery)
+	cachedHistoryListLengthMetric.Store(metric)
+	time.AfterFunc(historyListLengthCacheDuration, func() {
+		cachedHistoryListLengthMetric.Store(nil)
+	})
+	return metric
+}

go/vt/vttablet/tabletserver/throttle/throttler_test.go

@@ -71,6 +71,12 @@ var (
 			Value: 2.718,
 			Err:   nil,
 		},
+		base.HistoryListLengthMetricName: &base.ThrottleMetric{
+			Scope: base.SelfScope,
+			Alias: "",
+			Value: 5,
+			Err:   nil,
+		},
 		base.MysqldLoadAvgMetricName: &base.ThrottleMetric{
 			Scope: base.SelfScope,
 			Alias: "",
@@ -105,6 +111,11 @@ var (
 			ResponseCode: tabletmanagerdatapb.CheckThrottlerResponseCode_OK,
 			Value:        5.1,
 		},
+		base.HistoryListLengthMetricName.String(): {
+			StatusCode:   http.StatusOK,
+			ResponseCode: tabletmanagerdatapb.CheckThrottlerResponseCode_OK,
+			Value:        6,
+		},
 		base.MysqldLoadAvgMetricName.String(): {
 			StatusCode:   http.StatusOK,
 			ResponseCode: tabletmanagerdatapb.CheckThrottlerResponseCode_OK,
@@ -1853,6 +1864,7 @@ func TestChecks(t *testing.T) {
 				assert.EqualValues(t, 26, checkResult.Metrics[base.ThreadsRunningMetricName.String()].Value)           // self value, because flags.Scope is set
 				assert.EqualValues(t, 17, checkResult.Metrics[base.CustomMetricName.String()].Value)                   // self value, because flags.Scope is set
 				assert.EqualValues(t, 2.718, checkResult.Metrics[base.LoadAvgMetricName.String()].Value)               // self value, because flags.Scope is set
+				assert.EqualValues(t, 5, checkResult.Metrics[base.HistoryListLengthMetricName.String()].Value)         // self value, because flags.Scope is set
 				assert.EqualValues(t, 0.3311, checkResult.Metrics[base.MysqldLoadAvgMetricName.String()].Value)        // self value, because flags.Scope is set
 				assert.EqualValues(t, 0.85, checkResult.Metrics[base.MysqldDatadirUsedRatioMetricName.String()].Value) // self value, because flags.Scope is set
 				for _, metric := range checkResult.Metrics {
@@ -1914,6 +1926,7 @@ func TestChecks(t *testing.T) {
 				assert.EqualValues(t, 26, checkResult.Metrics[base.ThreadsRunningMetricName.String()].Value)           // shard value, because flags.Scope is set
 				assert.EqualValues(t, 17, checkResult.Metrics[base.CustomMetricName.String()].Value)                   // shard value, because flags.Scope is set
 				assert.EqualValues(t, 5.1, checkResult.Metrics[base.LoadAvgMetricName.String()].Value)                 // shard value, because flags.Scope is set
+				assert.EqualValues(t, 6, checkResult.Metrics[base.HistoryListLengthMetricName.String()].Value)         // shard value, because flags.Scope is set
 				assert.EqualValues(t, 0.3311, checkResult.Metrics[base.MysqldLoadAvgMetricName.String()].Value)        // shard value, because flags.Scope is set
 				assert.EqualValues(t, 0.87, checkResult.Metrics[base.MysqldDatadirUsedRatioMetricName.String()].Value) // shard value, because flags.Scope is set
 				for _, metric := range checkResult.Metrics {
@@ -1948,6 +1961,7 @@ func TestChecks(t *testing.T) {
 				assert.EqualValues(t, 26, checkResult.Metrics[base.ThreadsRunningMetricName.String()].Value)           // self value, because "self" is the default scope for threads_running
 				assert.EqualValues(t, 17, checkResult.Metrics[base.CustomMetricName.String()].Value)                   // self value, because "self" is the default scope for custom
 				assert.EqualValues(t, 2.718, checkResult.Metrics[base.LoadAvgMetricName.String()].Value)               // self value, because "self" is the default scope for loadavg
+				assert.EqualValues(t, 5, checkResult.Metrics[base.HistoryListLengthMetricName.String()].Value)         // self value, because "self" is the default scope for loadavg
 				assert.EqualValues(t, 0.3311, checkResult.Metrics[base.MysqldLoadAvgMetricName.String()].Value)        // self value, because "self" is the default scope for loadavg
 				assert.EqualValues(t, 0.85, checkResult.Metrics[base.MysqldDatadirUsedRatioMetricName.String()].Value) // self value, because "self" is the default scope for loadavg
 				assert.EqualValues(t, base.ShardScope.String(), checkResult.Metrics[base.LagMetricName.String()].Scope)
@@ -1970,6 +1984,7 @@ func TestChecks(t *testing.T) {
 					base.MetricName("custom"),
 					base.MetricName("shard/loadavg"),
 					base.MetricName("shard/mysqld-loadavg"),
+					base.MetricName("self/history_list_length"),
 					base.MetricName("self/mysqld-datadir-used-ratio"),
 					base.MetricName("default"),
 				}
@@ -1986,6 +2001,7 @@ func TestChecks(t *testing.T) {
 				assert.EqualValues(t, 26, checkResult.Metrics[base.ThreadsRunningMetricName.String()].Value)           // shard value, even though scope name is in metric name
 				assert.EqualValues(t, 17, checkResult.Metrics[base.CustomMetricName.String()].Value)                   // shard value because flags.Scope is set
 				assert.EqualValues(t, 5.1, checkResult.Metrics[base.LoadAvgMetricName.String()].Value)                 // shard value, not because scope name is in metric name but because flags.Scope is set
+				assert.EqualValues(t, 6, checkResult.Metrics[base.HistoryListLengthMetricName.String()].Value)         // shard value, even though scope name is in metric name
 				assert.EqualValues(t, 0.3311, checkResult.Metrics[base.MysqldLoadAvgMetricName.String()].Value)        // shard value, not because scope name is in metric name but because flags.Scope is set
 				assert.EqualValues(t, 0.87, checkResult.Metrics[base.MysqldDatadirUsedRatioMetricName.String()].Value) // shard value, even though scope name is in metric name
 				for _, metric := range checkResult.Metrics {
@@ -2257,6 +2273,7 @@ func TestReplica(t *testing.T) {
 						assert.Error(t, metricResult.Error, "metricName=%v, value=%v, threshold=%v", metricName, metricResult.Value, metricResult.Threshold)
 						assert.ErrorIs(t, metricResult.Error, base.ErrThresholdExceeded)
 					case base.ThreadsRunningMetricName,
+						base.HistoryListLengthMetricName,
 						base.MysqldLoadAvgMetricName,
 						base.MysqldDatadirUsedRatioMetricName:
 						assert.NoError(t, metricResult.Error, "metricName=%v, value=%v, threshold=%v", metricName, metricResult.Value, metricResult.Threshold)