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Add contains method to LocalCheckpointTracker #33871

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Merged
merged 3 commits into from
Sep 20, 2018
Merged

Add contains method to LocalCheckpointTracker #33871

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a5302e1
Add contains method to LocalCheckpointTracker
dnhatn Sep 19, 2018
d22f136
remove synchronization
dnhatn Sep 19, 2018
d57cb77
make it final
dnhatn Sep 19, 2018
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15 changes: 15 additions & 0 deletions server/src/main/java/org/elasticsearch/index/seqno/LocalCheckpointTracker.java
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Original file line number Diff line number Diff line change
Expand Up @@ -158,6 +158,21 @@ public synchronized void waitForOpsToComplete(final long seqNo) throws Interrupt
}
}

/**
* Checks if the given sequence number was marked as completed in this tracker.
*/
public synchronized boolean contains(long seqNo) {
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@jasontedor jasontedor Sep 19, 2018 •
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I don't think we need to be fully synchronized here (and so can save ourselves from locking for the quick returns). I think that we only need to lock on this on access to processedSeqNo. I see that we have asserts that we have a lock on this in getBitSetKey and seqNoToBitSetOffset but I think that neither of those are necessary.

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Good suggestion. I pushed d22f136.

if (seqNo >= nextSeqNo) {
return false;
}
if (seqNo <= checkpoint) {
return true;
}
final long bitSetKey = getBitSetKey(seqNo);
final CountedBitSet bitSet = processedSeqNo.get(bitSetKey);
return bitSet != null && bitSet.get(seqNoToBitSetOffset(seqNo));
}

/**
* Moves the checkpoint to the last consecutively processed sequence number. This method assumes that the sequence number following the
* current checkpoint is processed.
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31 changes: 27 additions & 4 deletions server/src/test/java/org/elasticsearch/index/seqno/LocalCheckpointTrackerTests.java
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Expand Up @@ -65,52 +65,71 @@ public void testSimplePrimary() {
assertThat(seqNo1, equalTo(0L));
tracker.markSeqNoAsCompleted(seqNo1);
assertThat(tracker.getCheckpoint(), equalTo(0L));
assertThat(tracker.contains(0L), equalTo(true));
assertThat(tracker.contains(atLeast(1)), equalTo(false));
seqNo1 = tracker.generateSeqNo();
seqNo2 = tracker.generateSeqNo();
assertThat(seqNo1, equalTo(1L));
assertThat(seqNo2, equalTo(2L));
tracker.markSeqNoAsCompleted(seqNo2);
assertThat(tracker.getCheckpoint(), equalTo(0L));
assertThat(tracker.contains(seqNo1), equalTo(false));
assertThat(tracker.contains(seqNo2), equalTo(true));
tracker.markSeqNoAsCompleted(seqNo1);
assertThat(tracker.getCheckpoint(), equalTo(2L));
assertThat(tracker.contains(between(0, 2)), equalTo(true));
assertThat(tracker.contains(atLeast(3)), equalTo(false));
}

public void testSimpleReplica() {
assertThat(tracker.getCheckpoint(), equalTo(SequenceNumbers.NO_OPS_PERFORMED));
assertThat(tracker.contains(randomNonNegativeLong()), equalTo(false));
tracker.markSeqNoAsCompleted(0L);
assertThat(tracker.getCheckpoint(), equalTo(0L));
assertThat(tracker.contains(0), equalTo(true));
tracker.markSeqNoAsCompleted(2L);
assertThat(tracker.getCheckpoint(), equalTo(0L));
assertThat(tracker.contains(1L), equalTo(false));
assertThat(tracker.contains(2L), equalTo(true));
tracker.markSeqNoAsCompleted(1L);
assertThat(tracker.getCheckpoint(), equalTo(2L));
assertThat(tracker.contains(between(0, 2)), equalTo(true));
assertThat(tracker.contains(atLeast(3)), equalTo(false));
}

public void testLazyInitialization() {
/*
* Previously this would allocate the entire chain of bit sets to the one for the sequence number being marked; for very large
* sequence numbers this could lead to excessive memory usage resulting in out of memory errors.
*/
tracker.markSeqNoAsCompleted(randomNonNegativeLong());
long seqNo = randomNonNegativeLong();
tracker.markSeqNoAsCompleted(seqNo);
assertThat(tracker.processedSeqNo.size(), equalTo(1));
assertThat(tracker.contains(seqNo), equalTo(true));
assertThat(tracker.contains(randomValueOtherThan(seqNo, ESTestCase::randomNonNegativeLong)), equalTo(false));
assertThat(tracker.processedSeqNo.size(), equalTo(1));
}

public void testSimpleOverFlow() {
List<Integer> seqNoList = new ArrayList<>();
List<Long> seqNoList = new ArrayList<>();
final boolean aligned = randomBoolean();
final int maxOps = BIT_SET_SIZE * randomIntBetween(1, 5) + (aligned ? 0 : randomIntBetween(1, BIT_SET_SIZE - 1));

for (int i = 0; i < maxOps; i++) {
for (long i = 0; i < maxOps; i++) {
seqNoList.add(i);
}
Collections.shuffle(seqNoList, random());
for (Integer seqNo : seqNoList) {
for (Long seqNo : seqNoList) {
tracker.markSeqNoAsCompleted(seqNo);
}
assertThat(tracker.checkpoint, equalTo(maxOps - 1L));
assertThat(tracker.processedSeqNo.size(), equalTo(aligned ? 0 : 1));
if (aligned == false) {
assertThat(tracker.processedSeqNo.keys().iterator().next().value, equalTo(tracker.checkpoint / BIT_SET_SIZE));
}
assertThat(tracker.contains(randomFrom(seqNoList)), equalTo(true));
final long notCompletedSeqNo = randomValueOtherThanMany(seqNoList::contains, ESTestCase::randomNonNegativeLong);
assertThat(tracker.contains(notCompletedSeqNo), equalTo(false));
}

public void testConcurrentPrimary() throws InterruptedException {
Expand Down Expand Up @@ -199,8 +218,12 @@ protected void doRun() throws Exception {
}
assertThat(tracker.getMaxSeqNo(), equalTo(maxOps - 1L));
assertThat(tracker.getCheckpoint(), equalTo(unFinishedSeq - 1L));
assertThat(tracker.contains(randomValueOtherThan(unFinishedSeq, () -> (long) randomFrom(seqNos))), equalTo(true));
assertThat(tracker.contains(unFinishedSeq), equalTo(false));
tracker.markSeqNoAsCompleted(unFinishedSeq);
assertThat(tracker.getCheckpoint(), equalTo(maxOps - 1L));
assertThat(tracker.contains(unFinishedSeq), equalTo(true));
assertThat(tracker.contains(randomLongBetween(maxOps, Long.MAX_VALUE)), equalTo(false));
assertThat(tracker.processedSeqNo.size(), isOneOf(0, 1));
if (tracker.processedSeqNo.size() == 1) {
assertThat(tracker.processedSeqNo.keys().iterator().next().value, equalTo(tracker.checkpoint / BIT_SET_SIZE));
Expand Down