[389-users] Re: Lock table is out of available lock entries

On 8/9/21 11:20 AM, Kees Bakker wrote:
> On 09-08-2021 16:00, Mark Reynolds wrote:
>> On 8/9/21 8:09 AM, Kees Bakker wrote:
>>> Hi,
>>>
>>> When my dirsrv was trying to compact the databases I was getting this
>>> error
>>>
>>> [07/Aug/2021:23:59:02.715984489 +0200] - NOTICE - bdb_compact -
>>> Compacting databases ...
>>> [07/Aug/2021:23:59:02.765932397 +0200] - NOTICE - bdb_compact -
>>> Compacting DB start: userRoot
>>> [07/Aug/2021:23:59:03.518175414 +0200] - NOTICE - bdb_compact -
>>> compactdb: compact userRoot - 417 pages freed
>>> [07/Aug/2021:23:59:03.576427786 +0200] - NOTICE - bdb_compact -
>>> Compacting DB start: ipaca
>>> [07/Aug/2021:23:59:03.659941533 +0200] - NOTICE - bdb_compact -
>>> compactdb: compact ipaca - 419 pages freed
>>> [07/Aug/2021:23:59:03.718445310 +0200] - NOTICE - bdb_compact -
>>> Compacting DB start: changelog
>>> [08/Aug/2021:00:00:40.807571334 +0200] - NOTICE -
>>> NSMMReplicationPlugin - changelog program - cl5CompactDBs - compacting
>>> replication changelogs...
>>> [08/Aug/2021:00:00:54.309357211 +0200] - ERR - libdb - BDB2055 Lock
>>> table is out of available lock entries
>>> [08/Aug/2021:00:00:54.726504736 +0200] - ERR - bdb_compact -
>>> compactdb: failed to compact changelog; db error - 12 Cannot allocate
>>> memory
>>> [08/Aug/2021:00:00:54.801571421 +0200] - ERR - libdb - BDB2055 Lock
>>> table is out of available lock entries
>>> [08/Aug/2021:00:00:54.876618702 +0200] - ERR - NSMMReplicationPlugin -
>>> changelog program - cl5CompactDBs - Failed to compact
>>> a797bb0b-be1d11eb-88c0b677-613aa2ad; db error - 12 Cannot allocate
>>> memory
>>> [08/Aug/2021:00:00:57.253006449 +0200] - NOTICE - bdb_compact -
>>> Compacting databases finished.
>>>
>>> There are about 402k entries in cn=changelog.
>>>
>>> I have a few questions
>>> 1) is it normal to have so many entries in cn=changelog? On another
>>> replica I have almost 3M entries Isn't this cleaned up?
>>> 2) the number of locks is 50000 (there are two config items). Should I
>>> increase that number? If so, increase to what?
>>> 3) is there maybe something else going on, causing the exhaustion of
>>> the locks?
>>
>> Ok, so by default there is no changelog trimming enabled.  So the
>> changelog will grow without bounds, which is bad.
>
> How much of this [1] applies? Indeed it says "By default the
> Replication Changelog does not use any trimming by default."
> So, how is the trimming actually enabled? I have these entries
>
> dn: cn=changelog5,cn=config
> cn: changelog5
> nsslapd-changelogdir: /var/lib/dirsrv/slapd-EXAMPLE-COM/cldb
> nsslapd-changelogmaxage: 30d
> objectClass: top
> objectClass: extensibleobject

So trimming is set, but it's set to 30 days (30d), that could/should be
shortened to "7d".

>
>
>>
>> I recommend setting up the changelog max age to 7 days:
>>
>> https://access.redhat.com/documentation/en-us/red_hat_directory_server/11/html/administration_guide/trimming_the_replication_changelog
>>
>>
>> Once that the trimming cleans up the changelog the database compaction
>> should work without issue.  You can also increase the database locks to
>> 1 million (that does require a restart of the server to take effect).
>
> Let's hope that 1 million is enough :-)

It might not be, you can keep bumping it up if needed.  There is no
limit, or negative impact on db performance.

Mark

>
>>
>> HTH,
>>
>> Mark
>>
> [1]
> https://directory.fedoraproject.org/docs/389ds/FAQ/changelog-trimming.html

--
Directory Server Development Team
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