Skip to content

[improve][broker] Implemets PIP-487: add event count metrics for InflightReadsLimiter acquire and release operations #26093

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
poorbarcode wants to merge 2 commits into
base: master
Choose a base branch
from
Open

[improve][broker] Implemets PIP-487: add event count metrics for InflightReadsLimiter acquire and release operations #26093

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
244be83
add metrics: pulsar.broker.managed_ledger.inflight.read.acquire.count
poorbarcode Jun 25, 2026
e327d43
add tests
poorbarcode Jun 25, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
27 changes: 27 additions & 0 deletions ...d-ledger/src/main/java/org/apache/bookkeeper/mledger/impl/cache/InflightReadsLimiter.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,7 @@

import com.google.common.annotations.VisibleForTesting;
import io.opentelemetry.api.OpenTelemetry;
import io.opentelemetry.api.metrics.LongCounter;
import io.opentelemetry.api.metrics.ObservableLongCounter;
import io.prometheus.client.Gauge;
import java.util.ArrayDeque;
Expand Down Expand Up @@ -52,6 +53,15 @@ public class InflightReadsLimiter implements AutoCloseable {
public static final String INFLIGHT_READS_LIMITER_USAGE_METRIC_NAME =
"pulsar.broker.managed_ledger.inflight.read.usage";
private final ObservableLongCounter inflightReadsUsageCounter;

public static final String INFLIGHT_READS_LIMITER_ACQUIRE_COUNT_METRIC_NAME =
"pulsar.broker.managed_ledger.inflight.read.acquire.count";
private final LongCounter inflightReadsAcquireCountCounter;

public static final String INFLIGHT_READS_LIMITER_RELEASE_COUNT_METRIC_NAME =
"pulsar.broker.managed_ledger.inflight.read.release.count";
private final LongCounter inflightReadsReleaseCountCounter;

private final int maxReadsInFlightAcquireQueueSize;

@PulsarDeprecatedMetric(newMetricName = INFLIGHT_READS_LIMITER_USAGE_METRIC_NAME)
Expand Down Expand Up @@ -118,6 +128,18 @@ public InflightReadsLimiter(long maxReadsInFlightSize, int maxReadsInFlightAcqui
measurement.record(usedBytes, InflightReadLimiterUtilization.USED.attributes);
}
});
inflightReadsAcquireCountCounter = meter
.counterBuilder(INFLIGHT_READS_LIMITER_ACQUIRE_COUNT_METRIC_NAME)
.setDescription("The number of times inflight read permits were acquired, "
+ "decreasing the remaining bytes.")
.setUnit("{event}")
.build();
inflightReadsReleaseCountCounter = meter
.counterBuilder(INFLIGHT_READS_LIMITER_RELEASE_COUNT_METRIC_NAME)
.setDescription("The number of times inflight read permits were released, "
+ "increasing the remaining bytes.")
.setUnit("{event}")
.build();
}

@VisibleForTesting
Expand Down Expand Up @@ -163,13 +185,15 @@ private synchronized Optional<Handle> internalAcquire(long permits, Consumer<Han
Handle handle = new Handle(permits, System.currentTimeMillis(), true);
if (remainingBytes >= permits) {
remainingBytes -= permits;
inflightReadsAcquireCountCounter.add(1);
log.debug().attr("permits", permits)
.attr("creationTime", handle.creationTime)
.attr("remainingBytes", remainingBytes).log("Acquired permits");
updateMetrics();
return Optional.of(handle);
} else if (permits > maxReadsInFlightSize && remainingBytes == maxReadsInFlightSize) {
remainingBytes = 0;
inflightReadsAcquireCountCounter.add(1);
log.info().attr("permits", permits)
.attr("maxReadsInFlightSize", maxReadsInFlightSize)
.attr("creationTime", handle.creationTime)
Expand Down Expand Up @@ -266,6 +290,7 @@ private synchronized void internalRelease(Handle handle) {
.attr("remainingBytes", getRemainingBytes())
.log("Release permits");
remainingBytes += handle.permits;
inflightReadsReleaseCountCounter.add(1);
while (true) {
QueuedHandle queuedHandle = queuedHandles.peek();
if (queuedHandle != null) {
Expand Down Expand Up @@ -296,6 +321,7 @@ private void handleQueuedHandle(QueuedHandle queuedHandle) {
Handle handleForCallback = queuedHandle.handle;
if (permits > maxReadsInFlightSize && remainingBytes == maxReadsInFlightSize) {
remainingBytes = 0;
inflightReadsAcquireCountCounter.add(1);
log.info().attr("permits", permits)
.attr("maxReadsInFlightSize", maxReadsInFlightSize)
.attr("creationTime", queuedHandle.handle.creationTime)
Expand All @@ -306,6 +332,7 @@ private void handleQueuedHandle(QueuedHandle queuedHandle) {
handleForCallback = new Handle(maxReadsInFlightSize, queuedHandle.handle.creationTime, true);
} else {
remainingBytes -= permits;
inflightReadsAcquireCountCounter.add(1);
log.debug().attr("permits", permits)
.attr("creationTime", queuedHandle.handle.creationTime)
.attr("remainingBytes", remainingBytes)
Expand Down
100 changes: 100 additions & 0 deletions ...dger/src/test/java/org/apache/bookkeeper/mledger/impl/cache/InflightReadsLimiterTest.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -25,12 +25,15 @@
import io.opentelemetry.api.OpenTelemetry;
import io.opentelemetry.sdk.OpenTelemetrySdk;
import io.opentelemetry.sdk.autoconfigure.AutoConfiguredOpenTelemetrySdk;
import io.opentelemetry.sdk.metrics.data.MetricData;
import io.opentelemetry.sdk.testing.exporter.InMemoryMetricReader;
import java.util.Collection;
import java.util.Map;
import java.util.Optional;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.atomic.AtomicReference;
import java.util.stream.Collectors;
import lombok.Cleanup;
import lombok.CustomLog;
import org.apache.commons.lang3.tuple.Pair;
Expand Down Expand Up @@ -551,6 +554,81 @@ public void testPrometheusMetrics() throws Exception {
.isEqualTo(maxReadsInFlightSize);
}

@Test
public void testAcquireReleaseCountMetrics() throws Exception {
var otel = buildOpenTelemetryAndReader();
@Cleanup var openTelemetry = otel.getLeft();
@Cleanup var metricReader = otel.getRight();

InflightReadsLimiter limiter =
new InflightReadsLimiter(100, ACQUIRE_QUEUE_SIZE, ACQUIRE_TIMEOUT_MILLIS,
mock(ScheduledExecutorService.class), openTelemetry);

// Normal acquire: remainingBytes decreases -> acquire count +1
Optional<InflightReadsLimiter.Handle> h1 = limiter.acquire(50, null);
assertThat(h1).isPresent();
assertCountMetrics(metricReader, 1, 0);

// Normal acquire again
Optional<InflightReadsLimiter.Handle> h2 = limiter.acquire(50, null);
assertThat(h2).isPresent();
assertCountMetrics(metricReader, 2, 0);

// Queue a request (not yet acquired, so count unchanged)
AtomicReference<InflightReadsLimiter.Handle> h3Ref = new AtomicReference<>();
limiter.acquire(50, h3Ref::set);
assertCountMetrics(metricReader, 2, 0);

// Release h1: release count +1, queued h3 gets processed -> acquire count +1
limiter.release(h1.get());
assertThat(h3Ref).hasValueSatisfying(h -> assertThat(h.success()).isTrue());
assertCountMetrics(metricReader, 3, 1);

// Release h2
limiter.release(h2.get());
assertCountMetrics(metricReader, 3, 2);

// Release h3
limiter.release(h3Ref.get());
assertCountMetrics(metricReader, 3, 3);
}

@Test
public void testAcquireCountMetricsExceedingMax() throws Exception {
var otel = buildOpenTelemetryAndReader();
@Cleanup var openTelemetry = otel.getLeft();
@Cleanup var metricReader = otel.getRight();

InflightReadsLimiter limiter =
new InflightReadsLimiter(100, ACQUIRE_QUEUE_SIZE, ACQUIRE_TIMEOUT_MILLIS,
mock(ScheduledExecutorService.class), openTelemetry);

// Acquire > maxReadsInFlightSize from internalAcquire (remainingBytes == maxReadsInFlightSize)
Optional<InflightReadsLimiter.Handle> h1 = limiter.acquire(200, null);
assertThat(h1).hasValueSatisfying(h -> {
assertThat(h.success()).isTrue();
assertThat(h.permits()).isEqualTo(100);
});
assertCountMetrics(metricReader, 1, 0);

// Queue another request > maxReadsInFlightSize (will be handled by handleQueuedHandle)
AtomicReference<InflightReadsLimiter.Handle> h2Ref = new AtomicReference<>();
limiter.acquire(200, h2Ref::set);
assertCountMetrics(metricReader, 1, 0);

// Release h1 -> triggers h2 queued handle processing -> acquire count +1
limiter.release(h1.get());
assertThat(h2Ref).hasValueSatisfying(h -> {
assertThat(h.success()).isTrue();
assertThat(h.permits()).isEqualTo(100);
});
assertCountMetrics(metricReader, 2, 1);

// Release h2
limiter.release(h2Ref.get());
assertCountMetrics(metricReader, 2, 2);
}

private Pair<OpenTelemetrySdk, InMemoryMetricReader> buildOpenTelemetryAndReader() {
var metricReader = InMemoryMetricReader.create();
var openTelemetry = AutoConfiguredOpenTelemetrySdk.builder()
Expand All @@ -564,6 +642,28 @@ private Pair<OpenTelemetrySdk, InMemoryMetricReader> buildOpenTelemetryAndReader
return Pair.of(openTelemetry, metricReader);
}

private void assertCountMetrics(InMemoryMetricReader metricReader,
long expectedAcquireCount, long expectedReleaseCount) {
var metrics = metricReader.collectAllMetrics();
assertMetricCount(metrics, InflightReadsLimiter.INFLIGHT_READS_LIMITER_ACQUIRE_COUNT_METRIC_NAME,
expectedAcquireCount);
assertMetricCount(metrics, InflightReadsLimiter.INFLIGHT_READS_LIMITER_RELEASE_COUNT_METRIC_NAME,
expectedReleaseCount);
}

private static void assertMetricCount(Collection<MetricData> metrics, String metricName, long expectedValue) {
var matches = metrics.stream()
.filter(m -> m.getName().equals(metricName))
.collect(Collectors.toList());
if (expectedValue == 0 && matches.isEmpty()) {
return;
}
assertThat(matches).hasSize(1);
assertThat(matches.get(0))
.hasLongSumSatisfying(longSum -> longSum.hasPointsSatisfying(
point -> point.hasValue(expectedValue)));
}

private void assertLimiterMetrics(InMemoryMetricReader metricReader,
long expectedLimit, long expectedUsed, long expectedFree) {
var metrics = metricReader.collectAllMetrics();
Expand Down
Loading