Rushabh Shah created HBASE-25932:
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Summary: TestWALEntryStream#testCleanClosedWALs test is failing.
Key: HBASE-25932
URL: https://issues.apache.org/jira/browse/HBASE-25932
Project: HBase
Issue Type: Bug
Components: Replication
Affects Versions: 3.0.0-alpha-1, 2.5.0, 2.3.6, 2.4.4
Reporter: Rushabh Shah
Assignee: Rushabh Shah
We are seeing the following test failure. TestWALEntryStream#testCleanClosedWALs
This test was added in HBASE-25924. I don't think the test failure has
anything to do with the patch in HBASE-25924.
Before HBASE-25924, we were *not* monitoring _uncleanlyClosedWAL_ metric. In
all the branches, we were not parsing the wal trailer when we close the wal
reader inside ReplicationSourceWALReader thread. The root cause was when we add
active WAL to ReplicationSourceWALReader, we cache the file size when the wal
was being actively written and once the wal was closed and replicated and
removed from WALEntryStream, we did reset the ProtobufLogReader object but we
didn't update the length of the wal and that was causing EOF errors since it
can't find the WALTrailer with the stale wal file length.
The fix applied nicely to branch-1 since we use FSHlog implementation which
closes the WAL file sychronously.
But in branch-2 and master, we use _AsyncFSWAL_ implementation and the closing
of wal file is done asynchronously (as the name suggests). This is causing the
test to fail. Below is the test.
{code:java}
@Test
public void testCleanClosedWALs() throws Exception {
try (WALEntryStream entryStream = new WALEntryStream(
logQueue, CONF, 0, log, null, logQueue.getMetrics(), fakeWalGroupId)) {
assertEquals(0, logQueue.getMetrics().getUncleanlyClosedWALs());
appendToLogAndSync();
assertNotNull(entryStream.next());
log.rollWriter(); =======> This does an asynchronous close of wal.
appendToLogAndSync();
assertNotNull(entryStream.next());
assertEquals(0, logQueue.getMetrics().getUncleanlyClosedWALs());
}
}
{code}
In the above code, when we roll writer, we don't close the old wal file
immediately so the ReplicationReader thread is not able to get the updated wal
file size and that is throwing EOF errors.
If I added a sleep of few milliseconds (1 ms in my local env) between
rollWriter and appendToLogAndSync statement then the test passes but this is
*not* a proper fix since we are working around the race between
ReplicationSourceWALReaderThread and closing of WAL file.
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