[PATCH] CTDB vacuuming updates

Michael Adam obnox at samba.org
Thu Nov 6 10:44:18 MST 2014


Hi Amitay,

the commit messages look promising...
...but where are the patches? :-)

Cheers - Michael

On 2014-11-06 at 23:28 +1100, Amitay Isaacs wrote:
> Hi,
> 
> Here are some CTDB vacuuming changes to improve performance.
> 
> [PATCH 1/6] ctdb-vacuum: Track time for vacuuming in database
> 
> Add vacuuming latency to database statistics.
> 
> [PATCH 2/6] ctdb-vacuum: Stagger vacuuming child processes
> 
> On a highly loaded system, forking multiple vacuuming child processes
> simultaneously can be expensive.  So delay vacuuming event till there are
> no active vacuuming child processes.
> 
> [PATCH 3/6] ctdb-vacuum: Use non-blocking lock when traversing delete
> [PATCH 4/6] ctdb-vacuum: Use non-blocking lock when traversing delete
> 
> These change tdb_chainlock() to tdb_chainlock_nonblock().  Vacuuming needs
> more work to re-add skipped records back into scheduled delete list.
> However, these patches still prevent vacuuming getting in the way of ctdb
> daemon.
> 
> [PATCH 5/6] ctdb-vacuum: Do not delete VACUUM MIGRATED records
> 
> While processing records scheduled for deletion, any record for which the
> current node is not lmaster, is migrated to the lmaster node.  For this
> migration recovery deamon creates a call_request with
> CTDB_CALL_FLAG_VACUUM_MIGRATION flag.  When such a record is stored on
> lmaster, the record is marked with CTDB_REC_FLAG_VACUUM_MIGRATED.  such
> records must be stored locally and scheduled for deletion locally.
> 
> [PATCH 6/6] ctdb-recoverd: Process all the records for vacuum fetch
> 
> Recovery daemon sends migration call requests one after another only after
> receiving reply.  This is very slow and can take longer than the
> VacuumInterval.  Any subsequent migration request sent to recovery daemon
> will be ignored if the previous run has not completed.
> 
> 
> Please review and push if ok.
> 
> Amitay.
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