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stack commented on HBASE-6322: ------------------------------ Thanks Ted. I reverted the patch for now. Thank your time Ryan. Patch looks worth it if you can figure the test fail. Thanks. > Unnecessary creation of finalizers in HTablePool > ------------------------------------------------ > > Key: HBASE-6322 > URL: https://issues.apache.org/jira/browse/HBASE-6322 > Project: HBase > Issue Type: Bug > Components: client > Affects Versions: 0.92.0, 0.92.1, 0.94.0 > Reporter: Ryan Brush > Fix For: 0.92.2 > > Attachments: HBASE-6322-0.92.1.patch, HBASE-6322-trunk.1.patch > > > From a mailing list question: > While generating some load against a library that makes extensive use of > HTablePool in 0.92, I noticed that the largest heap consumer was > java.lang.ref.Finalizer. Digging in, I discovered that HTablePool's internal > PooledHTable extends HTable, which instantiates a ThreadPoolExecutor and > supporting objects every time a pooled HTable is retrieved. Since > ThreadPoolExecutor has a finalizer, it and its dependencies can't get garbage > collected until the finalizer runs. The result is by using HTablePool, we're > creating a ton of objects to be finalized that are stuck on the heap longer > than they should be, creating our largest source of pressure on the garbage > collector. It looks like this will also be a problem in 0.94 and trunk. > The easy fix is just to have PooledHTable implement HTableInterface (rather > than subclass HTable), but this does break a unit test that explicitly checks > that PooledHTable implements HTable -- I can only assume this test is there > for some historical passivity reason. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira