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new a27598a487a Segregate advance and advanceUninterruptibly flow in
postJoinCursor to allow for interrupts in advance (#15222)
a27598a487a is described below
commit a27598a487a9edbe0ce7d094ccaf1bf515958a2b
Author: Vishesh Garg <[email protected]>
AuthorDate: Mon Oct 30 14:39:15 2023 +0530
Segregate advance and advanceUninterruptibly flow in postJoinCursor to
allow for interrupts in advance (#15222)
Currently advance function in postJoinCursor calls advanceUninterruptibly
which in turn keeps calling baseCursor.advanceUninterruptibly until the post
join condition matches, without checking for interrupts. This causes the CPU to
hit 100% without getting a chance for query to be cancelled.
With this change, the call flow of advance and advanceUninterruptibly is
separated out so that they call baseCursor.advance and
baseCursor.advanceUninterruptibly in them, respectively, giving a chance for
interrupts in the former case between successive calls to baseCursor.advance.
---
.../apache/druid/segment/join/PostJoinCursor.java | 33 ++-
.../druid/segment/join/PostJoinCursorTest.java | 264 +++++++++++++++++++++
2 files changed, 292 insertions(+), 5 deletions(-)
diff --git
a/processing/src/main/java/org/apache/druid/segment/join/PostJoinCursor.java
b/processing/src/main/java/org/apache/druid/segment/join/PostJoinCursor.java
index 57da128c73d..26c119bd34f 100644
--- a/processing/src/main/java/org/apache/druid/segment/join/PostJoinCursor.java
+++ b/processing/src/main/java/org/apache/druid/segment/join/PostJoinCursor.java
@@ -19,7 +19,7 @@
package org.apache.druid.segment.join;
-import org.apache.druid.query.BaseQuery;
+import com.google.common.annotations.VisibleForTesting;
import org.apache.druid.query.filter.Filter;
import org.apache.druid.query.filter.ValueMatcher;
import org.apache.druid.segment.ColumnSelectorFactory;
@@ -39,7 +39,7 @@ public class PostJoinCursor implements Cursor
private final ColumnSelectorFactory columnSelectorFactory;
@Nullable
- private final ValueMatcher valueMatcher;
+ private ValueMatcher valueMatcher;
@Nullable
private final Filter postJoinFilter;
@@ -69,7 +69,28 @@ public class PostJoinCursor implements Cursor
return postJoinCursor;
}
+ @VisibleForTesting
+ public void setValueMatcher(@Nullable ValueMatcher valueMatcher)
+ {
+ this.valueMatcher = valueMatcher;
+ }
+
private void advanceToMatch()
+ {
+ if (valueMatcher != null) {
+ while (!isDone() && !valueMatcher.matches(false)) {
+ baseCursor.advance();
+ }
+ }
+ }
+
+ /**
+ * Matches tuples coming out of a join to a post-join condition
uninterruptibly, and hence can be a long-running call.
+ * For this reason, {@link PostJoinCursor#advance()} instead calls {@link
PostJoinCursor#advanceToMatch()} (unlike
+ * other cursors) that allows interruptions, thereby resolving issues where
the
+ * <a href="https://github.com/apache/druid/issues/14514";>CPU thread running
PostJoinCursor cannot be terminated</a>
+ */
+ private void advanceToMatchUninterruptibly()
{
if (valueMatcher != null) {
while (!isDone() && !valueMatcher.matches(false)) {
@@ -99,15 +120,17 @@ public class PostJoinCursor implements Cursor
@Override
public void advance()
{
- advanceUninterruptibly();
- BaseQuery.checkInterrupted();
+ baseCursor.advance();
+ // Relies on baseCursor.advance() call inside this for
BaseQuery.checkInterrupted() checks -- unlike other cursors
+ // which call advanceInterruptibly() and hence have to explicitly
provision for interrupts.
+ advanceToMatch();
}
@Override
public void advanceUninterruptibly()
{
baseCursor.advanceUninterruptibly();
- advanceToMatch();
+ advanceToMatchUninterruptibly();
}
@Override
diff --git
a/processing/src/test/java/org/apache/druid/segment/join/PostJoinCursorTest.java
b/processing/src/test/java/org/apache/druid/segment/join/PostJoinCursorTest.java
new file mode 100644
index 00000000000..6813c04bb10
--- /dev/null
+++
b/processing/src/test/java/org/apache/druid/segment/join/PostJoinCursorTest.java
@@ -0,0 +1,264 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you 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 org.apache.druid.segment.join;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Iterables;
+import org.apache.druid.java.util.common.Intervals;
+import org.apache.druid.java.util.common.granularity.Granularities;
+import org.apache.druid.java.util.common.granularity.Granularity;
+import org.apache.druid.java.util.common.guava.Sequence;
+import org.apache.druid.query.QueryInterruptedException;
+import org.apache.druid.query.QueryMetrics;
+import org.apache.druid.query.filter.Filter;
+import org.apache.druid.query.filter.ValueMatcher;
+import org.apache.druid.query.monomorphicprocessing.RuntimeShapeInspector;
+import org.apache.druid.segment.ColumnSelectorFactory;
+import org.apache.druid.segment.Cursor;
+import org.apache.druid.segment.QueryableIndex;
+import org.apache.druid.segment.QueryableIndexSegment;
+import org.apache.druid.segment.QueryableIndexStorageAdapter;
+import org.apache.druid.segment.StorageAdapter;
+import org.apache.druid.segment.VirtualColumns;
+import org.apache.druid.segment.join.filter.JoinFilterPreAnalysis;
+import org.apache.druid.timeline.SegmentId;
+import org.joda.time.DateTime;
+import org.joda.time.Interval;
+import org.junit.Test;
+
+import javax.annotation.Nullable;
+import java.io.IOException;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+import static java.lang.Thread.sleep;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+public class PostJoinCursorTest extends BaseHashJoinSegmentStorageAdapterTest
+{
+
+ public QueryableIndexSegment infiniteFactSegment;
+
+ /**
+ * Simulates infinite segment by using a base cursor with advance() and
advanceInterruptibly()
+ * reduced to a no-op.
+ */
+ private static class TestInfiniteQueryableIndexSegment extends
QueryableIndexSegment
+ {
+
+ private static class InfiniteQueryableIndexStorageAdapter extends
QueryableIndexStorageAdapter
+ {
+ CountDownLatch countDownLatch;
+
+ public InfiniteQueryableIndexStorageAdapter(QueryableIndex index,
CountDownLatch countDownLatch)
+ {
+ super(index);
+ this.countDownLatch = countDownLatch;
+ }
+
+ @Override
+ public Sequence<Cursor> makeCursors(
+ @Nullable Filter filter,
+ Interval interval,
+ VirtualColumns virtualColumns,
+ Granularity gran,
+ boolean descending,
+ @Nullable QueryMetrics<?> queryMetrics
+ )
+ {
+ return super.makeCursors(filter, interval, virtualColumns, gran,
descending, queryMetrics)
+ .map(cursor -> new CursorNoAdvance(cursor,
countDownLatch));
+ }
+
+ private static class CursorNoAdvance implements Cursor
+ {
+ Cursor cursor;
+ CountDownLatch countDownLatch;
+
+ public CursorNoAdvance(Cursor cursor, CountDownLatch countDownLatch)
+ {
+ this.cursor = cursor;
+ this.countDownLatch = countDownLatch;
+ }
+
+ @Override
+ public ColumnSelectorFactory getColumnSelectorFactory()
+ {
+ return cursor.getColumnSelectorFactory();
+ }
+
+ @Override
+ public DateTime getTime()
+ {
+ return cursor.getTime();
+ }
+
+ @Override
+ public void advance()
+ {
+ // Do nothing to simulate infinite rows
+ countDownLatch.countDown();
+ }
+
+ @Override
+ public void advanceUninterruptibly()
+ {
+ // Do nothing to simulate infinite rows
+ countDownLatch.countDown();
+
+ }
+
+ @Override
+ public boolean isDone()
+ {
+ return false;
+ }
+
+ @Override
+ public boolean isDoneOrInterrupted()
+ {
+ return cursor.isDoneOrInterrupted();
+ }
+
+ @Override
+ public void reset()
+ {
+
+ }
+ }
+ }
+
+ private final StorageAdapter testStorageAdaptor;
+
+ public TestInfiniteQueryableIndexSegment(QueryableIndex index, SegmentId
segmentId, CountDownLatch countDownLatch)
+ {
+ super(index, segmentId);
+ testStorageAdaptor = new InfiniteQueryableIndexStorageAdapter(index,
countDownLatch);
+ }
+
+ @Override
+ public StorageAdapter asStorageAdapter()
+ {
+ return testStorageAdaptor;
+ }
+ }
+
+
+ private static class ExceptionHandler implements
Thread.UncaughtExceptionHandler
+ {
+
+ Throwable exception;
+
+ @Override
+ public void uncaughtException(Thread t, Throwable e)
+ {
+ exception = e;
+ }
+
+ public Throwable getException()
+ {
+ return exception;
+ }
+ }
+
+ @Test
+ public void testAdvanceWithInterruption() throws IOException,
InterruptedException
+ {
+
+ final int rowsBeforeInterrupt = 1000;
+
+ CountDownLatch countDownLatch = new CountDownLatch(rowsBeforeInterrupt);
+
+ infiniteFactSegment = new TestInfiniteQueryableIndexSegment(
+
JoinTestHelper.createFactIndexBuilder(temporaryFolder.newFolder()).buildMMappedIndex(),
+ SegmentId.dummy("facts"),
+ countDownLatch
+ );
+
+ countriesTable = JoinTestHelper.createCountriesIndexedTable();
+
+ Thread joinCursorThread = new Thread(() -> makeCursorAndAdvance());
+ ExceptionHandler exceptionHandler = new ExceptionHandler();
+ joinCursorThread.setUncaughtExceptionHandler(exceptionHandler);
+ joinCursorThread.start();
+
+ countDownLatch.await(1, TimeUnit.SECONDS);
+ joinCursorThread.interrupt();
+
+ // Wait for a max of 1 sec for the exception to be set.
+ for (int i = 0; i < 1000; i++) {
+ if (exceptionHandler.getException() == null) {
+ sleep(1);
+ } else {
+ assertTrue(exceptionHandler.getException() instanceof
QueryInterruptedException);
+ return;
+ }
+ }
+ fail();
+ }
+
+ public void makeCursorAndAdvance()
+ {
+
+ List<JoinableClause> joinableClauses = ImmutableList.of(
+ factToCountryOnIsoCode(JoinType.LEFT)
+ );
+
+ JoinFilterPreAnalysis joinFilterPreAnalysis = makeDefaultConfigPreAnalysis(
+ null,
+ joinableClauses,
+ VirtualColumns.EMPTY
+ );
+
+ HashJoinSegmentStorageAdapter hashJoinSegmentStorageAdapter = new
HashJoinSegmentStorageAdapter(
+ infiniteFactSegment.asStorageAdapter(),
+ joinableClauses,
+ joinFilterPreAnalysis
+ );
+
+ Cursor cursor =
Iterables.getOnlyElement(hashJoinSegmentStorageAdapter.makeCursors(
+ null,
+ Intervals.ETERNITY,
+ VirtualColumns.EMPTY,
+ Granularities.ALL,
+ false,
+ null
+ ).toList());
+
+ ((PostJoinCursor) cursor).setValueMatcher(new ValueMatcher()
+ {
+ @Override
+ public boolean matches(boolean includeUnknown)
+ {
+ return false;
+ }
+
+ @Override
+ public void inspectRuntimeShape(RuntimeShapeInspector inspector)
+ {
+
+ }
+ });
+
+ cursor.advance();
+ }
+}
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