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https://issues.apache.org/jira/browse/HBASE-7035?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13708288#comment-13708288
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Devin Bayer commented on HBASE-7035:
------------------------------------
If you read
[HTable|http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/HTable.html]
is says:
{quote}
This class is not thread safe for reads nor write.
...
In case of reads, some fields used by a Scan are shared among all threads. The
HTable implementation can either not contract to be safe in case of a Get
{quote}
That does not inspire confidence that scanners are or will remain threadsafe -
in fact it suggests the opposite.
> 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.
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