--On Tuesday, March 20, 2012 2:16 PM +0000 hyc@symas.com wrote:

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.

If this were truly the expected behavior, it would make using back-mdb with delta-syncrepl useless, as the accesslog would simply grow without bound. ;) Even back-bdb/hdb don't do that. While the DB will never be smaller than the maximum size ever reached without reloading, it won't unnecessarily grow past that either. :P

--Quanah

--

Quanah Gibson-Mount Sr. Member of Technical Staff Zimbra, Inc A Division of VMware, Inc. -------------------- Zimbra :: the leader in open source messaging and collaboration