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From "ChiaPing Tsai (JIRA)" <j...@apache.org>
Subject [jira] [Created] (HBASE-17510) DefaultMemStore gets the wrong heap size after rollback
Date Mon, 23 Jan 2017 09:19:26 GMT
ChiaPing Tsai created HBASE-17510:
-------------------------------------

             Summary: DefaultMemStore gets the wrong heap size after rollback
                 Key: HBASE-17510
                 URL: https://issues.apache.org/jira/browse/HBASE-17510
             Project: HBase
          Issue Type: Bug
            Reporter: ChiaPing Tsai
             Fix For: 1.4.0


We should calculate the size of “found” rather than “cell” because the offset value
may cause the difference heap size between “cell” and “found”.
{code:title=DefaultMemStore.java|borderStyle=solid}
  @Override
  public void rollback(Cell cell) {
    // If the key is in the memstore, delete it. Update this.size.
    found = this.cellSet.get(cell);
    if (found != null && found.getSequenceId() == cell.getSequenceId()) {
      removeFromCellSet(cell);
      long s = heapSizeChange(cell, true);
      this.size.addAndGet(-s);
    }
  }
{code}

{code:title=KeyValue.java|borderStyle=solid}
  @Override
  public long heapSize() {
    return ClassSize.align(sum) +
        (offset == 0
          ? ClassSize.sizeOf(bytes, length) // count both length and object overhead
          : length);                        // only count the number of bytes
  }
{code}

The wrong heap size of store will block the HRegion#doClose because the HRegion#memstoreSize
will always be bigger than zero even if we flush the store.
{code:title=HRegion.java|borderStyle=solid}
        while (this.memstoreSize.get() > 0) {
          try {
            if (flushCount++ > 0) {
              int actualFlushes = flushCount - 1;
              if (actualFlushes > 5) {
                // If we tried 5 times and are unable to clear memory, abort
                // so we do not lose data
                throw new DroppedSnapshotException("Failed clearing memory after " +
                  actualFlushes + " attempts on region: " +
                    Bytes.toStringBinary(getRegionInfo().getRegionName()));
              }
              LOG.info("Running extra flush, " + actualFlushes +
                " (carrying snapshot?) " + this);
            }
            internalFlushcache(status);
          } catch (IOException ioe) {
            status.setStatus("Failed flush " + this + ", putting online again");
            synchronized (writestate) {
              writestate.writesEnabled = true;
            }
            // Have to throw to upper layers.  I can't abort server from here.
            throw ioe;
          }
        }
{code}



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