Re: (ITS#7210) back-mdb endless database growth

[hyc@symas.com]

hyc@symas.com wrote:
> quanah@OpenLDAP.org wrote:
>> Full_Name: Quanah Gibson-Mount
>> Version: 2.4.30
>> OS: Linux 2.6
>> URL: ftp://ftp.openldap.org/incoming/
>> Submission from: (NULL) (75.108.184.39)
>>
>>
>> If you create a script to add&   delete the same 50,000 users, and then re-run
>> that script multiple times, the MDB database on disk continues to grow, despite
>> the fact that we are only adding and deleting the same data repeatedly.  There
>> should be zero growth to the database.
>>
>> Instead, the data.mdb file went from 108MB in size to over 1.2GB after 5-6 runs.
>>    Time to add/delete all the users went from 3 minutes 32 seconds on the first
>> run to over 90 minutes on the final run (5th or 6th, I lost count).
>
> At present, MDB is working as intended. In your test a number of overflow
> pages are being used. Currently libmdb always allocates overflow pages from
> new space, because it's not smart enough to search the free list for
> contiguous pages. Can treat this ITS as an enhancement request for that
> purpose, but this is not a new issue nor is it unexpected in the current
> version of MDB.
>
Hm, I take this back. The overflow pages are not enough to account for the 
difference. Still looking.

-- 
   -- Howard Chu
   CTO, Symas Corp.           http://www.symas.com
   Director, Highland Sun     http://highlandsun.com/hyc/
   Chief Architect, OpenLDAP  http://www.openldap.org/project/