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Fix flaky DefaultCacheStatsHolderTests (opensearch-project#14462)
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Signed-off-by: Peter Alfonsi <[email protected]>
Co-authored-by: Peter Alfonsi <[email protected]>
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peteralfonsi and Peter Alfonsi authored Jun 25, 2024
1 parent d320f36 commit 0eb39ae
Showing 1 changed file with 42 additions and 33 deletions.
Original file line number Diff line number Diff line change
Expand Up @@ -127,49 +127,58 @@ public void testCount() throws Exception {
}

public void testConcurrentRemoval() throws Exception {
List<String> dimensionNames = List.of("dim1", "dim2");
List<String> dimensionNames = List.of("A", "B");
DefaultCacheStatsHolder cacheStatsHolder = new DefaultCacheStatsHolder(dimensionNames, storeName);

// Create stats for the following dimension sets
List<List<String>> populatedStats = List.of(List.of("A1", "B1"), List.of("A2", "B2"), List.of("A2", "B3"));
List<List<String>> populatedStats = new ArrayList<>();
int numAValues = 10;
int numBValues = 2;
for (int indexA = 0; indexA < numAValues; indexA++) {
for (int indexB = 0; indexB < numBValues; indexB++) {
populatedStats.add(List.of("A" + indexA, "B" + indexB));
}
}
for (List<String> dims : populatedStats) {
cacheStatsHolder.incrementHits(dims);
}

// Remove (A2, B2) and (A1, B1), before re-adding (A2, B2). At the end we should have stats for (A2, B2) but not (A1, B1).

Thread[] threads = new Thread[3];
CountDownLatch countDownLatch = new CountDownLatch(3);
threads[0] = new Thread(() -> {
cacheStatsHolder.removeDimensions(List.of("A2", "B2"));
countDownLatch.countDown();
});
threads[1] = new Thread(() -> {
cacheStatsHolder.removeDimensions(List.of("A1", "B1"));
countDownLatch.countDown();
});
threads[2] = new Thread(() -> {
cacheStatsHolder.incrementMisses(List.of("A2", "B2"));
cacheStatsHolder.incrementMisses(List.of("A2", "B3"));
countDownLatch.countDown();
});
// Remove a subset of the dimensions concurrently.
// Remove both (A0, B0), and (A0, B1), so we expect the intermediate node for A0 to be null afterwards.
// For all the others, remove only the B0 value. Then we expect the intermediate nodes for A1 through A9 to be present
// and reflect only the stats for their B1 child.

Thread[] threads = new Thread[numAValues + 1];
for (int i = 0; i < numAValues; i++) {
int finalI = i;
threads[i] = new Thread(() -> { cacheStatsHolder.removeDimensions(List.of("A" + finalI, "B0")); });
}
threads[numAValues] = new Thread(() -> { cacheStatsHolder.removeDimensions(List.of("A0", "B1")); });
for (Thread thread : threads) {
thread.start();
// Add short sleep to ensure threads start their functions in order (so that incrementing doesn't happen before removal)
Thread.sleep(1);
}
countDownLatch.await();
assertNull(getNode(List.of("A1", "B1"), cacheStatsHolder.getStatsRoot()));
assertNull(getNode(List.of("A1"), cacheStatsHolder.getStatsRoot()));
assertNotNull(getNode(List.of("A2", "B2"), cacheStatsHolder.getStatsRoot()));
assertEquals(
new ImmutableCacheStats(0, 1, 0, 0, 0),
getNode(List.of("A2", "B2"), cacheStatsHolder.getStatsRoot()).getImmutableStats()
);
assertEquals(
new ImmutableCacheStats(1, 1, 0, 0, 0),
getNode(List.of("A2", "B3"), cacheStatsHolder.getStatsRoot()).getImmutableStats()
);
for (Thread thread : threads) {
thread.join();
}

// intermediate node for A0 should be null
assertNull(getNode(List.of("A0"), cacheStatsHolder.getStatsRoot()));

// leaf nodes for all B0 values should be null since they were removed
for (int indexA = 0; indexA < numAValues; indexA++) {
assertNull(getNode(List.of("A" + indexA, "B0"), cacheStatsHolder.getStatsRoot()));
}

// leaf nodes for all B1 values, except (A0, B1), should not be null as they weren't removed,
// and the intermediate nodes A1 through A9 shouldn't be null as they have remaining children
for (int indexA = 1; indexA < numAValues; indexA++) {
DefaultCacheStatsHolder.Node b1LeafNode = getNode(List.of("A" + indexA, "B1"), cacheStatsHolder.getStatsRoot());
assertNotNull(b1LeafNode);
assertEquals(new ImmutableCacheStats(1, 0, 0, 0, 0), b1LeafNode.getImmutableStats());
DefaultCacheStatsHolder.Node intermediateLevelNode = getNode(List.of("A" + indexA), cacheStatsHolder.getStatsRoot());
assertNotNull(intermediateLevelNode);
assertEquals(b1LeafNode.getImmutableStats(), intermediateLevelNode.getImmutableStats());
}
}

/**
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