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From "stack (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HBASE-674) memcache size unreliable
Date Mon, 09 Jun 2008 21:20:45 GMT

    [ https://issues.apache.org/jira/browse/HBASE-674?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12603691#action_12603691
] 

stack commented on HBASE-674:
-----------------------------

For example:

{code}
  public void testSizeCount() throws Exception {
    HStoreKey hsk = new HStoreKey(new Text(getName()),
      new Text(getName()), System.currentTimeMillis());
    for (int i = 0; i < 3; i++) {
      this.hmemcache.add(hsk, HStoreKey.getBytes(hsk));
    }
    this.hmemcache.snapshot();
    System.out.println(this.hmemcache.getSnapshot().size());
  }
{code}

The out.println in above says only one entry in the memcache though adding we added 3 items
to the memcache size.

Other issues here are that exceptions adding/deleting, etc., items can cause count to be off.
 We add to stuff to the memcache size before successful add of item.

> memcache size unreliable
> ------------------------
>
>                 Key: HBASE-674
>                 URL: https://issues.apache.org/jira/browse/HBASE-674
>             Project: Hadoop HBase
>          Issue Type: Bug
>    Affects Versions: 0.1.2
>            Reporter: stack
>            Priority: Blocker
>             Fix For: 0.2.0
>
>
> Multiple updates against same row/column/ts will be seen as increments to cache size
on insert but when we then play the memcache at flush time, we'll only see the most recent
entry and decrement the memcache size by whatever its size; memcache will be off.

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