So my first question: Does mdb have limitations like bdb it have aka BDB_IDL_LOGN?
Yes. back-mdb is ~60% the same code as back-bdb/hdb, its indexing functions are basically identical.
However, I never got mdb to work successfully by modifying these values.
Does this mean, it's not possible at moment to get running the mdb with BDB_IDL_LOGN = 2^17?
I can guarantee that would never work, as the variable with MDB is MDB_IDL_LOGN. I don't recall exactly the issues I hit when changing it to 17 from 16. Also, MDB has changed substantially since I did that testing. ;) I was ok with not modifying it given the read speed improvements in mdb vs bdb.
Thank for sharing, so I'll do test regarding this with the unmodified slapd and mdb, if it is fast enough in our environment! Have a nice weekend!
Meike
--On Friday, January 18, 2013 6:43 PM +0100 Meike Stone meike.stone@googlemail.com wrote:
I can guarantee that would never work, as the variable with MDB is MDB_IDL_LOGN. I don't recall exactly the issues I hit when changing it to 17 from 16. Also, MDB has changed substantially since I did that testing. ;) I was ok with not modifying it given the read speed improvements in mdb vs bdb.
Thank for sharing, so I'll do test regarding this with the unmodified slapd and mdb, if it is fast enough in our environment! Have a nice weekend!
I would note I set the following bits in my back-mdb configuration:
olcDbEnvFlags: writemap olcDbEnvFlags: nometasync
Also, I would advise using current RE24 for your testing. Keep in mind too that there is a database format change coming for mdb to fix ITS#7473.
--Quanah
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Quanah Gibson-Mount Sr. Member of Technical Staff Zimbra, Inc A Division of VMware, Inc. -------------------- Zimbra :: the leader in open source messaging and collaboration
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