chia7712 commented on code in PR #19972:
URL: https://github.com/apache/kafka/pull/19972#discussion_r2160412721
##########
storage/src/test/java/org/apache/kafka/storage/internals/log/LogSegmentTest.java:
##########
@@ -856,6 +865,48 @@ public void
testNonMonotonicTimestampForMultipleBatchesInMemoryRecords() throws
assertEquals(new TimestampOffset(2, 2), segment.timeIndex().entry(1));
}
+ @Test
+ @Timeout(30)
+ public void testConcurrentAccessToMaxTimestampSoFar() throws Exception {
+ int numThreads = 16;
+ ExecutorService executor = Executors.newFixedThreadPool(numThreads);
+ TimeIndex mockTimeIndex = mock(TimeIndex.class);
+ when(mockTimeIndex.lastEntry()).thenReturn(new
TimestampOffset(RecordBatch.NO_TIMESTAMP, 0L));
+
+ try {
+ // to reproduce race, we iterate test for certain duration
+ long remainingDurationNanos = Duration.ofSeconds(1).toNanos();
+ while (remainingDurationNanos > 0) {
+ long t0 = System.nanoTime();
+ clearInvocations(mockTimeIndex);
+ try (LogSegment seg = spy(LogTestUtils.createSegment(0,
logDir, 10, Time.SYSTEM))) {
+ when(seg.timeIndex()).thenReturn(mockTimeIndex);
+ List<Future<?>> futures = new ArrayList<>();
+ for (int i = 0; i < numThreads; i++) {
+ futures.add(executor.submit(() -> {
Review Comment:
```java
futures.add(executor.submit(() ->
assertDoesNotThrow(seg::maxTimestampSoFar)));
```
##########
storage/src/main/java/org/apache/kafka/storage/internals/log/LogSegment.java:
##########
@@ -192,8 +192,13 @@ public void sanityCheck(boolean timeIndexFileNewlyCreated)
throws IOException {
* the time index).
*/
public TimestampOffset readMaxTimestampAndOffsetSoFar() throws IOException
{
- if (maxTimestampAndOffsetSoFar == TimestampOffset.UNKNOWN)
- maxTimestampAndOffsetSoFar = timeIndex().lastEntry();
+ if (maxTimestampAndOffsetSoFar == TimestampOffset.UNKNOWN) {
+ synchronized (this) {
Review Comment:
The monitor lock of `LogSegment` may be used by external code. Perhaps it
would be safer to use the monitor lock of an internal `Object` instead?
```java
private final Object maxTimestampAndOffsetLock = new Object();
synchronized (maxTimestampAndOffsetLock) {
}
```
##########
storage/src/test/java/org/apache/kafka/storage/internals/log/LogSegmentTest.java:
##########
@@ -856,6 +865,48 @@ public void
testNonMonotonicTimestampForMultipleBatchesInMemoryRecords() throws
assertEquals(new TimestampOffset(2, 2), segment.timeIndex().entry(1));
}
+ @Test
+ @Timeout(30)
+ public void testConcurrentAccessToMaxTimestampSoFar() throws Exception {
+ int numThreads = 16;
+ ExecutorService executor = Executors.newFixedThreadPool(numThreads);
+ TimeIndex mockTimeIndex = mock(TimeIndex.class);
+ when(mockTimeIndex.lastEntry()).thenReturn(new
TimestampOffset(RecordBatch.NO_TIMESTAMP, 0L));
+
+ try {
+ // to reproduce race, we iterate test for certain duration
+ long remainingDurationNanos = Duration.ofSeconds(1).toNanos();
+ while (remainingDurationNanos > 0) {
+ long t0 = System.nanoTime();
+ clearInvocations(mockTimeIndex);
+ try (LogSegment seg = spy(LogTestUtils.createSegment(0,
logDir, 10, Time.SYSTEM))) {
+ when(seg.timeIndex()).thenReturn(mockTimeIndex);
+ List<Future<?>> futures = new ArrayList<>();
+ for (int i = 0; i < numThreads; i++) {
+ futures.add(executor.submit(() -> {
Review Comment:
or we can use `CompletableFuture` to streamline the code.
```java
long remainingDurationNanos = Duration.ofSeconds(1).toNanos();
while (remainingDurationNanos > 0) {
long t0 = System.nanoTime();
clearInvocations(mockTimeIndex);
try (LogSegment seg = spy(LogTestUtils.createSegment(0, logDir,
10, Time.SYSTEM))) {
when(seg.timeIndex()).thenReturn(mockTimeIndex);
var futures = IntStream.range(0,
numThreads).mapToObj(ignored -> CompletableFuture.runAsync(() ->
assertDoesNotThrow(seg::maxTimestampSoFar))).toList();
futures.forEach(CompletableFuture::join);
// timeIndex.lastEntry should be called once if no race
verify(mockTimeIndex, times(1)).lastEntry();
long elapsedNanos = System.nanoTime() - t0;
remainingDurationNanos -= elapsedNanos;
}
}
```
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