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Posted to derby-dev@db.apache.org by "Kathey Marsden (JIRA)" <ji...@apache.org> on 2009/03/02 19:48:56 UTC

[jira] Updated: (DERBY-4055) Space may not be reclaimed if row locks are not available after three retries

     [ https://issues.apache.org/jira/browse/DERBY-4055?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Kathey Marsden updated DERBY-4055:
----------------------------------

    Derby Categories: [High Value Fix]

> Space may not be reclaimed if  row locks are not available after three retries 
> -------------------------------------------------------------------------------
>
>                 Key: DERBY-4055
>                 URL: https://issues.apache.org/jira/browse/DERBY-4055
>             Project: Derby
>          Issue Type: Bug
>          Components: Store
>    Affects Versions: 10.1.3.1, 10.2.2.0, 10.3.3.0, 10.4.2.0, 10.5.0.0
>            Reporter: Kathey Marsden
>         Attachments: derby.log.T_RawStoreFactoryWithAssert
>
>
> In a multithreaded clob update where the same row is being updated, space will not be reclaimed.  The offending code is in ReclaimSpaceHelper:
> 	RecordHandle headRecord = work.getHeadRowHandle();
> 		if (!container_rlock.lockRecordForWrite(
>                 tran, headRecord, false /* not insert */, false /* nowait */))
> 		{
> 			// cannot get the row lock, retry
> 			tran.abort();
> 			if (work.incrAttempts() < 3)
>             {
> 				return Serviceable.REQUEUE;
>             }
> 			else
>             {
>                 // If code gets here, the space will be lost forever, and
>                 // can only be reclaimed by a full offline compress of the
>                 // table/index.
>                 if (SanityManager.DEBUG)
>                 {
>                     if (SanityManager.DEBUG_ON(DaemonService.DaemonTrace))
>                     {
>                         SanityManager.DEBUG(
>                             DaemonService.DaemonTrace, 
>                             "  gave up after 3 tries to get row lock " + 
>                             work);
>                     }
>                 }
> 				return Serviceable.DONE;
>             }
> 		}
> If we cannot get the lock after three tries we give up.  The reproduction for this issue is in the test store.ClobReclamationTest.xtestMultiThreadUpdateSingleRow().
> This issue also used to reference the code below and has some references to trying to get a reproduction for that issue, but that work has moved to DERBY-4054.  Please see DERBY-4054 for work on the container lock issue.
> ContainerHandle containerHdl = 
> 			openContainerNW(tran, container_rlock, work.getContainerId());
> 		if (containerHdl == null)
> 		{
> 			tran.abort();
> 			if (SanityManager.DEBUG)
>             {
>                 if (SanityManager.DEBUG_ON(DaemonService.DaemonTrace))
>                 {
>                     SanityManager.DEBUG(
>                         DaemonService.DaemonTrace, " aborted " + work + 
>                         " because container is locked or dropped");
>                 }
>             }
> 			if (work.incrAttempts() < 3) // retry this for serveral times
>             {
> 				return Serviceable.REQUEUE;
>             }
> 			else
>             {
>                 // If code gets here, the space will be lost forever, and
>                 // can only be reclaimed by a full offline compress of the
>                 // table/index.
>                 if (SanityManager.DEBUG)
>                 {
>                     if (SanityManager.DEBUG_ON(DaemonService.DaemonTrace))
>                     {
>                         SanityManager.DEBUG(
>                             DaemonService.DaemonTrace, 
>                             "  gave up after 3 tries to get container lock " + 
>                             work);
>                     }
>                 }
> 				return Serviceable.DONE;
>             }
> 		}	

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