[
https://issues.apache.org/jira/browse/DERBY-4055?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Kathey Marsden updated DERBY-4055:
----------------------------------
Description:
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;
}
}
was:
I don't have a reproduction for these cases but there are two places in
ReclaimSpaceHelper where reclamation will give up after three tries if it
cannot obtain the lock to reclaim the space. The first code path is:
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;
}
}
the second is:
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 working to get a reproduction for these cases, you can set
derby.debug.true=DaemonTrace and look for "gave up" in the derby.log.
Summary: Space may not be reclaimed if row locks are not available
after three retries (was: Space may not be reclaimed if locks are not
available after three retries (code inspection))
> 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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