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Re: Searches with dereferncing causing high CPU load.



Hi Andrew,

Thanks for getting back. I saw your report for mdb actually. I can
confirm that I've got "olcDBIndex objectlass eq" set on my servers.

Everyone keeps telling me that about aliases but unfortunately we've got
a group of users who require them to act in lieu of groups to support
their application i.e. they have OUs filled with aliases back to user
accounts in the main user OU.

We've started deleting old/hanging OUs and it's made a small improvement
but it's still taking 20-30s per query rather than returning almost
instantly like it was before.



On 16/11/15 18:10, Andrew Findlay wrote:
> On Mon, Nov 16, 2015 at 03:13:11PM +0000, Mark Cairney wrote:
> 
>> We're having severe performance issues for any query with alias
>> dereferencing set to "always".
>>
>> Any query with this causes the CPU to spin up to 100% and if we have a
>> number of these concurrently the machine will become unresponsive.
> 
> I hit something similar a while ago using mdb:
> 
> http://www.openldap.org/its/index.cgi/Software%20Bugs?id=8146
> 
>> We're using OpenLDAP 2.4.42 with the old hdb backend.
>>
>> We do have a large number of aliases (~63,000). Could this be the cause?
> 
> It would be worth checking that you have indexed the objectclass attribute.
> 
> I prefer to avoid aliases...
> 
> Andrew
> 

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Mark Cairney
ITI UNIX Section
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Tel: 0131 650 6565
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