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  1. HBase
  2. HBASE-8806

Row locks are acquired repeatedly in HRegion.doMiniBatchMutation for duplicate rows.

    Details

    • Type: Improvement
    • Status: Closed
    • Priority: Critical
    • Resolution: Fixed
    • Affects Version/s: 0.94.5
    • Fix Version/s: 0.94.10
    • Component/s: regionserver
    • Labels:
      None

      Description

      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.

      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);
        }
      
      

        Attachments

        1. row_lock_perf_results.txt
          6 kB
          churro morales
        2. HBASE-8806-threadBasedRowLocks-v2.patch
          43 kB
          Dave Latham
        3. HBASE-8806-threadBasedRowLocks.patch
          44 kB
          Dave Latham
        4. hbase-8806-0.94-microbenchmarks-dupe-rows.txt
          6 kB
          Dave Latham
        5. hbase-8806-0.94-microbenchmark-no-dupe-rows.txt
          5 kB
          Dave Latham
        6. HBASE-8806-0.94.10-v3.patch
          14 kB
          churro morales
        7. HBASE-8806-0.94.10-v2.patch
          8 kB
          churro morales
        8. HBASE-8806-0.94.10.patch
          8 kB
          churro morales
        9. HBASE-8806.patch
          3 kB
          Anoop Sam John
        10. 8806-0.94-v7.txt
          11 kB
          Lars Hofhansl
        11. 8806-0.94-v6.txt
          5 kB
          Lars Hofhansl
        12. 8806-0.94-v5.txt
          5 kB
          Lars Hofhansl
        13. 8806-0.94-v4.txt
          5 kB
          Lars Hofhansl

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              • Assignee:
                churromorales churro morales
                Reporter:
                churromorales churro morales
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                Dates

                • Created:
                  Updated:
                  Resolved: