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

On 09-08-2021 18:43, Mark Reynolds wrote:
> 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".

Somehow I doubt that this will do anything.

The first entry in cn=changelog is more than two months old. (May 26th is about
the time I installed this server as a FreeIPA replica.)

dn: changenumber=1,cn=changelog
objectClass: top
objectClass: changelogentry
objectClass: extensibleObject
targetuniqueid: 1e89ebcb-e20111e8-8820f96e-fc0c60a4
changeNumber: 1
targetDn: idnsname=_ldap._tcp,idnsname=example.com.,cn=dns,dc=example,dc=com
changeTime: 20210526122901Z
changeType: modify
changes:: YWRkOiBzUlZSZWNvc...gplbnRyeXVzbjogMTEyCi0KAA==

Is there a way to see trimming in action? I'm afraid it is not doing anything.

>
>>
>>
>>>
>>> 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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