hbase-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Devin Bayer (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-7035) thrift server closes HTable of open Scanners
Date Mon, 15 Jul 2013 09:04:56 GMT

    [ https://issues.apache.org/jira/browse/HBASE-7035?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13708328#comment-13708328
] 

Devin Bayer commented on HBASE-7035:
------------------------------------

Hi Lars - what about this:

If the pool is full, table.close() may be called by HTablePool. This calls connection.close(),
but ResultScanner calls table.getConnection().

OK, maybe it will happen to work due to various coincidences, but it's not obvious it will
work 100% of the time. For sure we must not change implementations of HTable, HConnection
or HTablePool. We must also set the pool size greater than the thrift thread size.

ClientScanner is an inner class and does retain a reference to the HTable instance.

I think it's just asking for trouble.
                
> thrift server closes HTable of open Scanners
> --------------------------------------------
>
>                 Key: HBASE-7035
>                 URL: https://issues.apache.org/jira/browse/HBASE-7035
>             Project: HBase
>          Issue Type: Sub-task
>          Components: Thrift
>    Affects Versions: 0.94.4
>            Reporter: Devin Bayer
>              Labels: thrift2
>         Attachments: old-hbase-thrift-v1.patch
>
>   Original Estimate: 4h
>  Remaining Estimate: 4h
>
> ThriftHBaseServiceHandler.openScanner() does this:
> 1. table = pool.getTable()
> 2. scanner = table.getScanner()
> 3. table.close()
> 4. return scanner
> While back porting the thrift server to 0.92.6, I found that table.close() calls connection.close().
Further calls to scanner.next() raise a ConnectionClosed exception. The unit tests do not
catch this since they reuse an open HConnection instance.
> This might work on trunk, but depends on the implementations of HTablePool, HTable and
HConnectionManager. Even with the pool wrapper, if the pool is full, table.close() may be
called, which may invalidate the table. Also,  HTable is not thread-safe, but they are being
reused since they go back in the pool.
> I suggest storing the table handle along with the scanner.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira

Mime
View raw message