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From "ChiaPing Tsai (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HBASE-17510) DefaultMemStore gets the wrong heap size after rollback
Date Mon, 23 Jan 2017 09:24:26 GMT

     [ https://issues.apache.org/jira/browse/HBASE-17510?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

ChiaPing Tsai updated HBASE-17510:
----------------------------------
    Assignee: ChiaPing Tsai
      Status: Patch Available  (was: Open)

> 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
>            Assignee: ChiaPing Tsai
>             Fix For: 1.4.0
>
>         Attachments: HBASE-17510.branch-1.v0.patch
>
>
> 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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