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https://issues.apache.org/jira/browse/HBASE-8806?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Dave Latham updated HBASE-8806:
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Attachment: (was: hbase-8806-0.94-v6-microbenchmark.txt)
> Row locks are acquired repeatedly in HRegion.doMiniBatchMutation for
> duplicate rows.
> ------------------------------------------------------------------------------------
>
> Key: HBASE-8806
> URL: https://issues.apache.org/jira/browse/HBASE-8806
> Project: HBase
> Issue Type: Bug
> Components: regionserver
> Affects Versions: 0.94.5
> Reporter: rahul gidwani
> Priority: Critical
> Fix For: 0.98.0, 0.95.2, 0.94.10
>
> Attachments: 8806-0.94-v4.txt, 8806-0.94-v5.txt, 8806-0.94-v6.txt,
> HBASE-8806-0.94.10.patch, HBASE-8806-0.94.10-v2.patch,
> HBASE-8806-0.94.10-v3.patch, hbase-8806-0.94-microbenchmark-no-dupe-rows.txt,
> hbase-8806-0.94-microbenchmarks-dupe-rows.txt, HBASE-8806.patch,
> HBASE-8806-threadBasedRowLocks.patch,
> HBASE-8806-threadBasedRowLocks-v2.patch, row_lock_perf_results.txt
>
>
> If we already have the lock in the doMiniBatchMutation we don't need to
> re-acquire it. The solution would be to keep a cache of the rowKeys already
> locked for a miniBatchMutation and If we already have the
> rowKey in the cache, we don't repeatedly try and acquire the lock. A fix to
> this problem would be to keep a set of rows we already locked and not try to
> acquire the lock for these rows.
> We have tested this fix in our production environment and has improved
> replication performance quite a bit. We saw a replication batch go from 3+
> minutes to less than 10 seconds for batches with duplicate row keys.
> {code}
> static final int ACQUIRE_LOCK_COUNT = 0;
> @Test
> public void testRedundantRowKeys() throws Exception {
> final int batchSize = 100000;
>
> String tableName = getClass().getSimpleName();
> Configuration conf = HBaseConfiguration.create();
> conf.setClass(HConstants.REGION_IMPL, MockHRegion.class, HeapSize.class);
> MockHRegion region = (MockHRegion)
> TestHRegion.initHRegion(Bytes.toBytes(tableName), tableName, conf,
> Bytes.toBytes("a"));
> List<Pair<Mutation, Integer>> someBatch = Lists.newArrayList();
> int i = 0;
> while (i < batchSize) {
> if (i % 2 == 0) {
> someBatch.add(new Pair<Mutation, Integer>(new Put(Bytes.toBytes(0)),
> null));
> } else {
> someBatch.add(new Pair<Mutation, Integer>(new Put(Bytes.toBytes(1)),
> null));
> }
> i++;
> }
> long startTime = System.currentTimeMillis();
> region.batchMutate(someBatch.toArray(new Pair[0]));
> long endTime = System.currentTimeMillis();
> long duration = endTime - startTime;
> System.out.println("duration: " + duration + " ms");
> assertEquals(2, ACQUIRE_LOCK_COUNT);
> }
> @Override
> public Integer getLock(Integer lockid, byte[] row, boolean waitForLock)
> throws IOException {
> ACQUIRE_LOCK_COUNT++;
> return super.getLock(lockid, row, waitForLock);
> }
> {code}
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