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

[hyc@symas.com]

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.

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