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Revert "Add indexing throttle on merge pressure for DataFormatAwareEngine (#22319) #22335

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Merged
mgodwan merged 1 commit into from
Jun 28, 2026
Merged

Revert "Add indexing throttle on merge pressure for DataFormatAwareEngine (#22319) #22335

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8 changes: 1 addition & 7 deletions server/src/main/java/org/opensearch/index/engine/DataFormatAwareEngine.java
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Original file line number Diff line number Diff line change
Expand Up @@ -500,13 +500,7 @@ public DataFormatAwareEngine(EngineConfig engineConfig) {
refreshLock.unlock();
}
}
},
this::activateThrottling,
this::deactivateThrottling,
shardId,
engineConfig.getIndexSettings(),
engineConfig.getThreadPool()
);
}, shardId, engineConfig.getIndexSettings(), engineConfig.getThreadPool());
success = true;
logger.trace("created new DataFormatBasedEngine");
} catch (IOException | TranslogCorruptedException e) {
Expand Down
34 changes: 0 additions & 34 deletions server/src/main/java/org/opensearch/index/engine/dataformat/merge/MergeScheduler.java
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Original file line number Diff line number Diff line change
Expand Up @@ -48,11 +48,8 @@ public class MergeScheduler {
private final MergeHandler mergeHandler;
private final BiConsumer<MergeResult, OneMerge> applyMergeChanges;
private final Runnable onMergeFailureCleanup;
private final Runnable activateThrottling;
private final Runnable deactivateThrottling;
private final ThreadPool threadPool;
private final AtomicInteger activeMerges = new AtomicInteger(0);
private final AtomicBoolean isThrottling = new AtomicBoolean(false);
private final AtomicBoolean isShutdown = new AtomicBoolean(false);
private final Semaphore forceMergeLock = new Semaphore(1);
private final AtomicBoolean frozen = new AtomicBoolean(false);
Expand All @@ -78,8 +75,6 @@ public class MergeScheduler {
* @param mergeHandler the handler that selects and executes merges
* @param applyMergeChanges callback to apply merge results (e.g., update the catalog)
* @param onMergeFailureCleanup callback invoked when a merge fails and cleanup is performed
* @param activateThrottling callback to activate indexing throttle when merge pressure is high
* @param deactivateThrottling callback to deactivate indexing throttle when merge pressure subsides
* @param shardId the shard this scheduler is associated with
* @param indexSettings the index settings providing merge scheduler configuration
* @param threadPool the OpenSearch thread pool for executing merge tasks
Expand All @@ -88,17 +83,13 @@ public MergeScheduler(
MergeHandler mergeHandler,
BiConsumer<MergeResult, OneMerge> applyMergeChanges,
Runnable onMergeFailureCleanup,
Runnable activateThrottling,
Runnable deactivateThrottling,
ShardId shardId,
IndexSettings indexSettings,
ThreadPool threadPool
) {
this.mergeHandler = mergeHandler;
this.applyMergeChanges = applyMergeChanges;
this.onMergeFailureCleanup = onMergeFailureCleanup;
this.activateThrottling = activateThrottling;
this.deactivateThrottling = deactivateThrottling;
this.threadPool = threadPool;
logger = Loggers.getLogger(getClass(), shardId);
this.indexSettings = indexSettings;
Expand Down Expand Up @@ -147,7 +138,6 @@ public void triggerMerges() {
if (!isFrozen()) {
mergeHandler.findAndRegisterMerges();
}
evaluateThrottle();
executeMerge();
}

Expand Down Expand Up @@ -353,7 +343,6 @@ private void submitMergeTask(OneMerge oneMerge) {
// uncaught exception on the merge thread pool.
} finally {
activeMerges.decrementAndGet();
evaluateThrottle();
// Fire all drain listeners if all merges completed and none pending
if (isFrozen() && activeMerges.get() == 0 && !mergeHandler.hasPendingMerges() && !onDrainedListeners.isEmpty()) {
List<Runnable> listeners = List.copyOf(onDrainedListeners);
Expand Down Expand Up @@ -405,27 +394,4 @@ private void runMerge(OneMerge oneMerge) throws IOException {
mergeStatsTracker.afterMerge(tookMS, totalNumDocs, totalSizeInBytes);
}
}

private synchronized void evaluateThrottle() {
int numMergesInFlight = activeMerges.get() + mergeHandler.getPendingMergeCount();
if (numMergesInFlight > maxMergeCount) {
if (isThrottling.getAndSet(true) == false) {
logger.info("now throttling indexing: numMergesInFlight={}, maxMergeCount={}", numMergesInFlight, maxMergeCount);
try {
activateThrottling.run();
} catch (Exception e) {
logger.warn("exception in activateThrottling callback", e);
}
}
} else if (numMergesInFlight < maxMergeCount) {
if (isThrottling.getAndSet(false)) {
logger.info("stop throttling indexing: numMergesInFlight={}, maxMergeCount={}", numMergesInFlight, maxMergeCount);
try {
deactivateThrottling.run();
} catch (Exception e) {
logger.warn("exception in deactivateThrottling callback", e);
}
}
}
}
}
101 changes: 10 additions & 91 deletions .../test/java/org/opensearch/index/engine/dataformat/merge/MergeSchedulerOnDrainedTests.java
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Expand Up @@ -67,16 +67,7 @@ public void testOnDrained_AlreadyDrained_FiresListenerImmediately() {

IndexSettings indexSettings = IndexSettingsModule.newIndexSettings("test", Settings.EMPTY);
ShardId testShardId = new ShardId(indexSettings.getIndex(), 0);
MergeScheduler scheduler = new MergeScheduler(
mockHandler,
(result, merge) -> {},
() -> {},
() -> {},
() -> {},
testShardId,
indexSettings,
threadPool
);
MergeScheduler scheduler = new MergeScheduler(mockHandler, (result, merge) -> {}, () -> {}, testShardId, indexSettings, threadPool);

AtomicBoolean listenerCalled = new AtomicBoolean(false);
scheduler.onDrained(() -> listenerCalled.set(true));
Expand All @@ -93,16 +84,7 @@ public void testOnDrained_MergesPending_RegistersListener() {

IndexSettings indexSettings = IndexSettingsModule.newIndexSettings("test", Settings.EMPTY);
ShardId testShardId = new ShardId(indexSettings.getIndex(), 0);
MergeScheduler scheduler = new MergeScheduler(
mockHandler,
(result, merge) -> {},
() -> {},
() -> {},
() -> {},
testShardId,
indexSettings,
threadPool
);
MergeScheduler scheduler = new MergeScheduler(mockHandler, (result, merge) -> {}, () -> {}, testShardId, indexSettings, threadPool);

AtomicBoolean listenerCalled = new AtomicBoolean(false);
scheduler.onDrained(() -> listenerCalled.set(true));
Expand All @@ -119,16 +101,7 @@ public void testOnDrained_MultipleListeners_AllFire() {

IndexSettings indexSettings = IndexSettingsModule.newIndexSettings("test", Settings.EMPTY);
ShardId testShardId = new ShardId(indexSettings.getIndex(), 0);
MergeScheduler scheduler = new MergeScheduler(
mockHandler,
(result, merge) -> {},
() -> {},
() -> {},
() -> {},
testShardId,
indexSettings,
threadPool
);
MergeScheduler scheduler = new MergeScheduler(mockHandler, (result, merge) -> {}, () -> {}, testShardId, indexSettings, threadPool);

AtomicInteger callCount = new AtomicInteger(0);

Expand Down Expand Up @@ -204,16 +177,7 @@ public void testOnDrained_ListenersFire_WhenMergesGoFromNToZero() throws Excepti

IndexSettings indexSettings = IndexSettingsModule.newIndexSettings("test", Settings.EMPTY);
ShardId testShardId = new ShardId(indexSettings.getIndex(), 0);
MergeScheduler scheduler = new MergeScheduler(
mockHandler,
(result, merge) -> {},
() -> {},
() -> {},
() -> {},
testShardId,
indexSettings,
threadPool
);
MergeScheduler scheduler = new MergeScheduler(mockHandler, (result, merge) -> {}, () -> {}, testShardId, indexSettings, threadPool);

CountDownLatch latch = new CountDownLatch(3);
AtomicInteger callCount = new AtomicInteger(0);
Expand Down Expand Up @@ -259,16 +223,7 @@ public void testOnDrained_DoubleCheckRace_ListenerFiresImmediately() throws Exce

IndexSettings indexSettings = IndexSettingsModule.newIndexSettings("test", Settings.EMPTY);
ShardId testShardId = new ShardId(indexSettings.getIndex(), 0);
MergeScheduler scheduler = new MergeScheduler(
mockHandler,
(result, merge) -> {},
() -> {},
() -> {},
() -> {},
testShardId,
indexSettings,
threadPool
);
MergeScheduler scheduler = new MergeScheduler(mockHandler, (result, merge) -> {}, () -> {}, testShardId, indexSettings, threadPool);

// First call to hasPendingMerges returns true (first check fails, goes to add),
// second call returns false (double-check succeeds, fires the listener)
Expand All @@ -293,16 +248,7 @@ public void testOnDrained_ListenerExceptionIsolation_OtherListenersStillFire() t

IndexSettings indexSettings = IndexSettingsModule.newIndexSettings("test", Settings.EMPTY);
ShardId testShardId = new ShardId(indexSettings.getIndex(), 0);
MergeScheduler scheduler = new MergeScheduler(
mockHandler,
(result, merge) -> {},
() -> {},
() -> {},
() -> {},
testShardId,
indexSettings,
threadPool
);
MergeScheduler scheduler = new MergeScheduler(mockHandler, (result, merge) -> {}, () -> {}, testShardId, indexSettings, threadPool);

// Register listeners individually via the double-check path.
// Each onDrained call is independent — if one listener throws during its own
Expand Down Expand Up @@ -339,16 +285,7 @@ public void testHasPendingMerges_DelegatesToMergeHandler() {

IndexSettings indexSettings = IndexSettingsModule.newIndexSettings("test", Settings.EMPTY);
ShardId testShardId = new ShardId(indexSettings.getIndex(), 0);
MergeScheduler scheduler = new MergeScheduler(
mockHandler,
(result, merge) -> {},
() -> {},
() -> {},
() -> {},
testShardId,
indexSettings,
threadPool
);
MergeScheduler scheduler = new MergeScheduler(mockHandler, (result, merge) -> {}, () -> {}, testShardId, indexSettings, threadPool);

assertTrue("hasPendingMerges should delegate to handler when handler reports true", scheduler.hasPendingMerges());

Expand All @@ -365,16 +302,7 @@ public void testGetActiveMergeCount_InitiallyZero() {

IndexSettings indexSettings = IndexSettingsModule.newIndexSettings("test", Settings.EMPTY);
ShardId testShardId = new ShardId(indexSettings.getIndex(), 0);
MergeScheduler scheduler = new MergeScheduler(
mockHandler,
(result, merge) -> {},
() -> {},
() -> {},
() -> {},
testShardId,
indexSettings,
threadPool
);
MergeScheduler scheduler = new MergeScheduler(mockHandler, (result, merge) -> {}, () -> {}, testShardId, indexSettings, threadPool);

assertEquals("Active merge count should be 0 initially", 0, scheduler.getActiveMergeCount());
}
Expand Down Expand Up @@ -408,16 +336,7 @@ public void testSubmitMergeTask_FinallyBlock_FiresListenersWhenLastMergeComplete

IndexSettings indexSettings = IndexSettingsModule.newIndexSettings("test", Settings.EMPTY);
ShardId testShardId = new ShardId(indexSettings.getIndex(), 0);
MergeScheduler scheduler = new MergeScheduler(
mockHandler,
(result, merge) -> {},
() -> {},
() -> {},
() -> {},
testShardId,
indexSettings,
threadPool
);
MergeScheduler scheduler = new MergeScheduler(mockHandler, (result, merge) -> {}, () -> {}, testShardId, indexSettings, threadPool);

// Register an onDrained listener BEFORE triggering merges.
// Reset hasPendingMerges stub for the full flow:
Expand Down Expand Up @@ -497,7 +416,7 @@ private MergeScheduler newIdleScheduler(MergeHandler mockHandler) {
when(mockHandler.hasPendingMerges()).thenReturn(false);
IndexSettings indexSettings = IndexSettingsModule.newIndexSettings("test", Settings.EMPTY);
ShardId testShardId = new ShardId(indexSettings.getIndex(), 0);
return new MergeScheduler(mockHandler, (result, merge) -> {}, () -> {}, () -> {}, () -> {}, testShardId, indexSettings, threadPool);
return new MergeScheduler(mockHandler, (result, merge) -> {}, () -> {}, testShardId, indexSettings, threadPool);
}

/**
Expand Down
94 changes: 1 addition & 93 deletions server/src/test/java/org/opensearch/index/engine/dataformat/merge/MergeSchedulerTests.java
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Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,6 @@
import org.opensearch.core.index.shard.ShardId;
import org.opensearch.index.IndexModule;
import org.opensearch.index.IndexSettings;
import org.opensearch.index.MergeSchedulerConfig;
import org.opensearch.index.engine.dataformat.MergeResult;
import org.opensearch.index.engine.exec.Segment;
import org.opensearch.test.IndexSettingsModule;
Expand All @@ -26,9 +25,7 @@
import java.io.IOException;
import java.util.List;
import java.util.Map;
import java.util.concurrent.atomic.AtomicInteger;

import static org.mockito.ArgumentMatchers.any;
import static org.mockito.ArgumentMatchers.anyInt;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.never;
Expand Down Expand Up @@ -70,16 +67,7 @@ private IndexSettings indexSettings(IndexModule.TieringState tieringState) {
}

private MergeScheduler newScheduler(MergeHandler mergeHandler, IndexModule.TieringState tieringState) {
return new MergeScheduler(
mergeHandler,
(result, merge) -> {},
() -> {},
() -> {},
() -> {},
shardId,
indexSettings(tieringState),
threadPool
);
return new MergeScheduler(mergeHandler, (result, merge) -> {}, () -> {}, shardId, indexSettings(tieringState), threadPool);
}

public void testFreezeBlocksTriggerMerges() {
Expand Down Expand Up @@ -169,8 +157,6 @@ public void testForceMergeAbortsRemainingMergesOnShutdown() throws Exception {
mergeHandler,
(result, merge) -> { schedulerRef.get().shutdown(); },
() -> {},
() -> {},
() -> {},
shardId,
indexSettings(IndexModule.TieringState.HOT),
threadPool
Expand All @@ -188,82 +174,4 @@ public void testForceMergeAbortsRemainingMergesOnShutdown() throws Exception {
verify(mergeHandler).doMerge(merge1);
verify(mergeHandler, never()).doMerge(merge2);
}

public void testThrottlingActivatesWhenMergesExceedMaxCount() throws Exception {
AtomicInteger activateCount = new AtomicInteger();
AtomicInteger deactivateCount = new AtomicInteger();

IndexSettings idxSettings = IndexSettingsModule.newIndexSettings(
"test",
Settings.builder()
.put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
.put(MergeSchedulerConfig.MAX_THREAD_COUNT_SETTING.getKey(), "1")
.put(MergeSchedulerConfig.MAX_MERGE_COUNT_SETTING.getKey(), "2")
.build()
);

MergeHandler mergeHandler = mock(MergeHandler.class);
OneMerge merge1 = mock(OneMerge.class);
OneMerge merge2 = mock(OneMerge.class);
OneMerge merge3 = mock(OneMerge.class);
when(merge1.getSegmentsToMerge()).thenReturn(List.of());
when(merge2.getSegmentsToMerge()).thenReturn(List.of());
when(merge3.getSegmentsToMerge()).thenReturn(List.of());

when(mergeHandler.getPendingMergeCount()).thenReturn(3, 3, 2, 1, 0);
when(mergeHandler.hasPendingMerges()).thenReturn(true, true, true, false);
when(mergeHandler.getNextMerge()).thenReturn(merge1).thenReturn(merge2).thenReturn(merge3).thenReturn(null);
when(mergeHandler.doMerge(any())).thenReturn(new MergeResult(Map.of()));

MergeScheduler scheduler = new MergeScheduler(
mergeHandler,
(result, merge) -> {},
() -> {},
activateCount::incrementAndGet,
deactivateCount::incrementAndGet,
shardId,
idxSettings,
threadPool
);

scheduler.triggerMerges();
assertBusy(() -> assertTrue("throttle should have activated", activateCount.get() > 0));
assertBusy(() -> assertTrue("throttle should have deactivated", deactivateCount.get() > 0));
}

public void testThrottlingNotActivatedWhenMergesWithinLimit() throws Exception {
AtomicInteger activateCount = new AtomicInteger();

IndexSettings idxSettings = IndexSettingsModule.newIndexSettings(
"test",
Settings.builder()
.put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT)
.put(MergeSchedulerConfig.MAX_THREAD_COUNT_SETTING.getKey(), "1")
.put(MergeSchedulerConfig.MAX_MERGE_COUNT_SETTING.getKey(), "6")
.build()
);

MergeHandler mergeHandler = mock(MergeHandler.class);
OneMerge merge1 = mock(OneMerge.class);
when(merge1.getSegmentsToMerge()).thenReturn(List.of());
when(mergeHandler.getPendingMergeCount()).thenReturn(1, 0);
when(mergeHandler.hasPendingMerges()).thenReturn(true, false);
when(mergeHandler.getNextMerge()).thenReturn(merge1).thenReturn(null);
when(mergeHandler.doMerge(any())).thenReturn(new MergeResult(Map.of()));

MergeScheduler scheduler = new MergeScheduler(
mergeHandler,
(result, merge) -> {},
() -> {},
activateCount::incrementAndGet,
() -> {},
shardId,
idxSettings,
threadPool
);

scheduler.triggerMerges();
Thread.sleep(200);
assertEquals("throttle should not activate when merges within limit", 0, activateCount.get());
}
}
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