hbase-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Hiroshi Ikeda (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-6651) Thread safety of HTablePool is doubtful
Date Thu, 18 Oct 2012 02:00:03 GMT

    [ https://issues.apache.org/jira/browse/HBASE-6651?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13478592#comment-13478592
] 

Hiroshi Ikeda commented on HBASE-6651:
--------------------------------------

bq. Can you explain why calling clear() followed by returnObject() would result in return
value of false ? There is space in SharedMap at this moment, right ?

SharedMap holds a collection of registered objects independent of whether the objects are
pooled or borrowed, and SharedMap.invalidateObject() and SharedMap.clear() remove the specified
object(s) from the collection. SharedMap.returnObject() always does nothing and returns false
if the given object is not found in the collection. Filling a space of the registered objects
is done by SharedMap.registerObject(), not SharedMap.returnObject(). 

                
> Thread safety of HTablePool is doubtful
> ---------------------------------------
>
>                 Key: HBASE-6651
>                 URL: https://issues.apache.org/jira/browse/HBASE-6651
>             Project: HBase
>          Issue Type: Bug
>          Components: Client
>    Affects Versions: 0.94.1
>            Reporter: Hiroshi Ikeda
>            Priority: Minor
>         Attachments: HBASE-6651.patch, HBASE-6651-V2.patch, sample.zip, sample.zip, sharedmap_for_hbaseclient.zip
>
>
> There are some operations in HTablePool to access to PoolMap in multiple times without
any explict synchronization. 
> For example HTablePool.closeTablePool() calles PoolMap.values(), and calles PoolMap.remove().
If other threads add new instances to the pool in the middle of the calls, the new added instances
might be dropped. (HTablePool.closeTablePool() also has another problem that calling it by
multple threads causes accessing HTable by multiple threads.)
> Moreover, PoolMap is not thread safe for the same reason.
> For example PoolMap.put() calles ConcurrentMap.get() and calles ConcurrentMap.put().
If other threads add a new instance to the concurent map in the middle of the calls, the new
instance might be dropped.
> And also implementations of Pool have the same problems.

--
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