changefeedccl: add observability metrics into sarama code

Now that this patch (cockroachdb#117544) has been merged, sarama now acknowledges and
reacts to kafka server's throttling messages by slowing down. To provide better
observability into sarama code, this patch adds a metrics registry interceptor
and a new metrics `changefeed.kafka_throttling_hist_nanos` which tracks time (in
nanos) spent in sarama's throttling when cockroachdb exceed the kafka quota.

Fixes: cockroachdb#117618

Release note: changefeed.kafka_throttling_hist_nanos has now been added to
metrics to monitor sarama throttling behavior resulting from exceeding kafka
quota.

docs/generated/metrics/metrics.html

@@ -762,6 +762,7 @@
 <tr><td>APPLICATION</td><td>changefeed.forwarded_resolved_messages</td><td>Resolved timestamps forwarded from the change aggregator to the change frontier</td><td>Messages</td><td>COUNTER</td><td>COUNT</td><td>AVG</td><td>NON_NEGATIVE_DERIVATIVE</td></tr>
 <tr><td>APPLICATION</td><td>changefeed.frontier_updates</td><td>Number of change frontier updates across all feeds</td><td>Updates</td><td>COUNTER</td><td>COUNT</td><td>AVG</td><td>NON_NEGATIVE_DERIVATIVE</td></tr>
 <tr><td>APPLICATION</td><td>changefeed.internal_retry_message_count</td><td>Number of messages for which an attempt to retry them within an aggregator node was made</td><td>Messages</td><td>GAUGE</td><td>COUNT</td><td>AVG</td><td>NONE</td></tr>
+<tr><td>APPLICATION</td><td>changefeed.kafka_throttling_hist_nanos</td><td>Time spent in throttling due to exceeding kafka quota</td><td>Nanoseconds</td><td>HISTOGRAM</td><td>NANOSECONDS</td><td>AVG</td><td>NONE</td></tr>
 <tr><td>APPLICATION</td><td>changefeed.lagging_ranges</td><td>The number of ranges considered to be lagging behind</td><td>Ranges</td><td>GAUGE</td><td>COUNT</td><td>AVG</td><td>NONE</td></tr>
 <tr><td>APPLICATION</td><td>changefeed.max_behind_nanos</td><td>(Deprecated in favor of checkpoint_progress) The most any changefeed&#39;s persisted checkpoint is behind the present</td><td>Nanoseconds</td><td>GAUGE</td><td>NANOSECONDS</td><td>AVG</td><td>NONE</td></tr>
 <tr><td>APPLICATION</td><td>changefeed.message_size_hist</td><td>Message size histogram</td><td>Bytes</td><td>HISTOGRAM</td><td>BYTES</td><td>AVG</td><td>NONE</td></tr>

pkg/ccl/changefeedccl/BUILD.bazel

@@ -163,6 +163,7 @@ go_library(
         "@com_github_klauspost_compress//zstd",
         "@com_github_klauspost_pgzip//:pgzip",
         "@com_github_linkedin_goavro_v2//:goavro",
+        "@com_github_rcrowley_go_metrics//:go-metrics",
         "@com_github_xdg_go_scram//:scram",
         "@com_google_cloud_go_pubsub//:pubsub",
         "@com_google_cloud_go_pubsub//apiv1",

pkg/ccl/changefeedccl/metrics.go

@@ -22,10 +22,12 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/sql/pgwire/pgcode"
 	"github.com/cockroachdb/cockroach/pkg/sql/pgwire/pgerror"
 	"github.com/cockroachdb/cockroach/pkg/util/hlc"
+	"github.com/cockroachdb/cockroach/pkg/util/log"
 	"github.com/cockroachdb/cockroach/pkg/util/metric"
 	"github.com/cockroachdb/cockroach/pkg/util/metric/aggmetric"
 	"github.com/cockroachdb/cockroach/pkg/util/syncutil"
 	"github.com/cockroachdb/cockroach/pkg/util/timeutil"
+	"github.com/rcrowley/go-metrics"
 )
 
 const (
@@ -35,6 +37,7 @@ const (
 	changefeedIOQueueMaxLatency        = 5 * time.Minute
 	admitLatencyMaxValue               = 1 * time.Minute
 	commitLatencyMaxValue              = 10 * time.Minute
+	kafkaThrottlingTimeMaxValue        = 5 * time.Minute
 )
 
 // max length for the scope name.
@@ -76,6 +79,7 @@ type AggMetrics struct {
 	CheckpointProgress          *aggmetric.AggGauge
 	LaggingRanges               *aggmetric.AggGauge
 	CloudstorageBufferedBytes   *aggmetric.AggGauge
+	KafkaThrottlingNanos        *aggmetric.AggHistogram
 
 	// There is always at least 1 sliMetrics created for defaultSLI scope.
 	mu struct {
@@ -106,6 +110,7 @@ type metricsRecorder interface {
 	newParallelIOMetricsRecorder() parallelIOMetricsRecorder
 	recordSinkIOInflightChange(int64)
 	makeCloudstorageFileAllocCallback() func(delta int64)
+	newKafkaMetricsGetter() KafkaMetricsGetter
 }
 
 var _ metricsRecorder = (*sliMetrics)(nil)
@@ -145,6 +150,7 @@ type sliMetrics struct {
 	CheckpointProgress          *aggmetric.Gauge
 	LaggingRanges               *aggmetric.Gauge
 	CloudstorageBufferedBytes   *aggmetric.Gauge
+	KafkaThrottlingNanos        *aggmetric.Histogram
 
 	mu struct {
 		syncutil.Mutex
@@ -325,6 +331,94 @@ func (m *sliMetrics) recordSizeBasedFlush() {
 	m.SizeBasedFlushes.Inc(1)
 }
 
+type kafkaHistogramAdapter struct {
+	wrapped *aggmetric.Histogram
+}
+
+var _ metrics.Histogram = (*kafkaHistogramAdapter)(nil)
+
+func (k *kafkaHistogramAdapter) Update(valueInMs int64) {
+	if k != nil {
+		// valueInMs is passed in from sarama with a unit of milliseconds. To
+		// convert this value to nanoseconds, valueInMs * 10^6 is recorded here.
+		k.wrapped.RecordValue(valueInMs * 1000000)
+	}
+}
+
+func (k *kafkaHistogramAdapter) Clear() {
+	log.Error(context.Background(), "clear is not expected to be called on kafkaHistogramAdapter")
+}
+
+func (k *kafkaHistogramAdapter) Count() (_ int64) {
+	log.Error(context.Background(), "count is not expected to be called on kafkaHistogramAdapter")
+	return
+}
+
+func (k *kafkaHistogramAdapter) Max() (_ int64) {
+	log.Error(context.Background(), "max is not expected to be called on kafkaHistogramAdapter")
+	return
+}
+
+func (k *kafkaHistogramAdapter) Mean() (_ float64) {
+	log.Error(context.Background(), "mean is not expected to be called on kafkaHistogramAdapter")
+	return
+}
+
+func (k *kafkaHistogramAdapter) Min() (_ int64) {
+	log.Error(context.Background(), "min is not expected to be called on kafkaHistogramAdapter")
+	return
+}
+
+func (k *kafkaHistogramAdapter) Percentile(float64) (_ float64) {
+	log.Error(context.Background(), "percentile is not expected to be called on kafkaHistogramAdapter")
+	return
+}
+
+func (k *kafkaHistogramAdapter) Percentiles([]float64) (_ []float64) {
+	log.Error(context.Background(), "percentiles is not expected to be called on kafkaHistogramAdapter")
+	return
+}
+
+func (k *kafkaHistogramAdapter) Sample() (_ metrics.Sample) {
+	log.Error(context.Background(), "sample is not expected to be called on kafkaHistogramAdapter")
+	return
+}
+
+func (k *kafkaHistogramAdapter) Snapshot() (_ metrics.Histogram) {
+	log.Error(context.Background(), "snapshot is not expected to be called on kafkaHistogramAdapter")
+	return
+}
+
+func (k *kafkaHistogramAdapter) StdDev() (_ float64) {
+	log.Error(context.Background(), "stdDev is not expected to be called on kafkaHistogramAdapter")
+	return
+}
+
+func (k *kafkaHistogramAdapter) Sum() (_ int64) {
+	log.Error(context.Background(), "sum is not expected to be called on kafkaHistogramAdapter")
+	return
+}
+
+func (k *kafkaHistogramAdapter) Variance() (_ float64) {
+	log.Error(context.Background(), "variance is not expected to be called on kafkaHistogramAdapter")
+	return
+}
+
+type KafkaMetricsGetter interface {
+	GetKafkaThrottlingNanos() *kafkaHistogramAdapter
+}
+
+type kafkaMetricsGetterImpl struct {
+	kafkaThrottlingNanos *kafkaHistogramAdapter
+}
+
+func (kg *kafkaMetricsGetterImpl) GetKafkaThrottlingNanos() *kafkaHistogramAdapter {
+	if kg == nil {
+		return (*kafkaHistogramAdapter)(nil)
+	}
+	return kg.kafkaThrottlingNanos
+}
+
 type parallelIOMetricsRecorder interface {
 	recordPendingQueuePush(numKeys int64)
 	recordPendingQueuePop(numKeys int64, latency time.Duration)
@@ -380,6 +474,17 @@ func (m *sliMetrics) newParallelIOMetricsRecorder() parallelIOMetricsRecorder {
 	}
 }
 
+func (m *sliMetrics) newKafkaMetricsGetter() KafkaMetricsGetter {
+	if m == nil {
+		return (*kafkaMetricsGetterImpl)(nil)
+	}
+	return &kafkaMetricsGetterImpl{
+		kafkaThrottlingNanos: &kafkaHistogramAdapter{
+			wrapped: m.KafkaThrottlingNanos,
+		},
+	}
+}
+
 func (m *sliMetrics) recordSinkIOInflightChange(delta int64) {
 	if m == nil {
 		return
@@ -470,6 +575,10 @@ func (w *wrappingCostController) newParallelIOMetricsRecorder() parallelIOMetric
 	return w.inner.newParallelIOMetricsRecorder()
 }
 
+func (w *wrappingCostController) newKafkaMetricsGetter() KafkaMetricsGetter {
+	return w.inner.newKafkaMetricsGetter()
+}
+
 var (
 	metaChangefeedForwardedResolvedMessages = metric.Metadata{
 		Name:        "changefeed.forwarded_resolved_messages",
@@ -721,6 +830,12 @@ func newAggregateMetrics(histogramWindow time.Duration) *AggMetrics {
 		Measurement: "Bytes",
 		Unit:        metric.Unit_COUNT,
 	}
+	metaChangefeedKafkaThrottlingNanos := metric.Metadata{
+		Name:        "changefeed.kafka_throttling_hist_nanos",
+		Help:        "Time spent in throttling due to exceeding kafka quota",
+		Measurement: "Nanoseconds",
+		Unit:        metric.Unit_NANOSECONDS,
+	}
 
 	functionalGaugeMinFn := func(childValues []int64) int64 {
 		var min int64
@@ -813,6 +928,13 @@ func newAggregateMetrics(histogramWindow time.Duration) *AggMetrics {
 		CheckpointProgress:        b.FunctionalGauge(metaCheckpointProgress, functionalGaugeMinFn),
 		LaggingRanges:             b.Gauge(metaLaggingRangePercentage),
 		CloudstorageBufferedBytes: b.Gauge(metaCloudstorageBufferedBytes),
+		KafkaThrottlingNanos: b.Histogram(metric.HistogramOptions{
+			Metadata:     metaChangefeedKafkaThrottlingNanos,
+			Duration:     histogramWindow,
+			MaxVal:       kafkaThrottlingTimeMaxValue.Nanoseconds(),
+			SigFigs:      2,
+			BucketConfig: metric.BatchProcessLatencyBuckets,
+		}),
 	}
 	a.mu.sliMetrics = make(map[string]*sliMetrics)
 	_, err := a.getOrCreateScope(defaultSLIScope)
@@ -878,6 +1000,7 @@ func (a *AggMetrics) getOrCreateScope(scope string) (*sliMetrics, error) {
 		SchemaRegistrations:         a.SchemaRegistrations.AddChild(scope),
 		LaggingRanges:               a.LaggingRanges.AddChild(scope),
 		CloudstorageBufferedBytes:   a.CloudstorageBufferedBytes.AddChild(scope),
+		KafkaThrottlingNanos:        a.KafkaThrottlingNanos.AddChild(scope),
 	}
 	sm.mu.resolved = make(map[int64]hlc.Timestamp)
 	sm.mu.checkpoint = make(map[int64]hlc.Timestamp)

pkg/ccl/changefeedccl/sink_kafka.go

@@ -36,6 +36,7 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/util/timeutil"
 	"github.com/cockroachdb/errors"
 	"github.com/cockroachdb/logtags"
+	"github.com/rcrowley/go-metrics"
 	"golang.org/x/oauth2"
 	"golang.org/x/oauth2/clientcredentials"
 )
@@ -1078,7 +1079,10 @@ func buildConfluentKafkaConfig(u sinkURL) (kafkaDialConfig, error) {
 }
 
 func buildKafkaConfig(
-	ctx context.Context, u sinkURL, jsonStr changefeedbase.SinkSpecificJSONConfig,
+	ctx context.Context,
+	u sinkURL,
+	jsonStr changefeedbase.SinkSpecificJSONConfig,
+	kafkaMetricsGetter KafkaMetricsGetter,
 ) (*sarama.Config, error) {
 	dialConfig, err := buildDialConfig(u)
 	if err != nil {
@@ -1090,6 +1094,7 @@ func buildKafkaConfig(
 	config.Producer.Partitioner = newChangefeedPartitioner
 	// Do not fetch metadata for all topics but just for the necessary ones.
 	config.Metadata.Full = false
+	config.MetricRegistry = newMetricsRegistryInterceptor(kafkaMetricsGetter)
 
 	if dialConfig.tlsEnabled {
 		config.Net.TLS.Enable = true
@@ -1176,7 +1181,8 @@ func makeKafkaSink(
 		return nil, errors.Errorf(`%s is not yet supported`, changefeedbase.SinkParamSchemaTopic)
 	}
 
-	config, err := buildKafkaConfig(ctx, u, jsonStr)
+	m := mb(requiresResourceAccounting)
+	config, err := buildKafkaConfig(ctx, u, jsonStr, m.newKafkaMetricsGetter())
 	if err != nil {
 		return nil, err
 	}
@@ -1195,7 +1201,7 @@ func makeKafkaSink(
 		ctx:                  ctx,
 		kafkaCfg:             config,
 		bootstrapAddrs:       u.Host,
-		metrics:              mb(requiresResourceAccounting),
+		metrics:              m,
 		topics:               topics,
 		disableInternalRetry: !internalRetryEnabled,
 	}
@@ -1234,3 +1240,26 @@ func (s *kafkaStats) String() string {
 		atomic.LoadInt64(&s.largestMessageSize),
 	)
 }
+
+type metricsRegistryInterceptor struct {
+	metrics.Registry
+	kafkaThrottlingNanos metrics.Histogram
+}
+
+var _ metrics.Registry = (*metricsRegistryInterceptor)(nil)
+
+func newMetricsRegistryInterceptor(kafkaMetrics KafkaMetricsGetter) *metricsRegistryInterceptor {
+	return &metricsRegistryInterceptor{
+		Registry:             metrics.NewRegistry(),
+		kafkaThrottlingNanos: kafkaMetrics.GetKafkaThrottlingNanos(),
+	}
+}
+
+func (mri *metricsRegistryInterceptor) GetOrRegister(name string, i interface{}) interface{} {
+	const throttleTimeMsMetricsPrefix = "throttle-time-in-ms"
+	if strings.HasPrefix(name, throttleTimeMsMetricsPrefix) {
+		return mri.kafkaThrottlingNanos
+	} else {
+		return mri.Registry.GetOrRegister(name, i)
+	}
+}

pkg/ccl/changefeedccl/telemetry.go

@@ -216,6 +216,10 @@ func (r *telemetryMetricsRecorder) newParallelIOMetricsRecorder() parallelIOMetr
 	return r.inner.newParallelIOMetricsRecorder()
 }
 
+func (r *telemetryMetricsRecorder) newKafkaMetricsGetter() KafkaMetricsGetter {
+	return r.inner.newKafkaMetricsGetter()
+}
+
 // continuousTelemetryInterval determines the interval at which each node emits telemetry events
 // during the lifespan of each enterprise changefeed.
 var continuousTelemetryInterval = settings.RegisterDurationSetting(