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Re: openldap.git branch mdb updated. a4c38efe297e6b40f968c0ec45f1008ec338c80a

openldap-commit2devel@OpenLDAP.org wrote:
A ref change was pushed to the OpenLDAP (openldap.git) repository.
It will be available in the public mirror shortly.

The branch, mdb has been updated
        via  a4c38efe297e6b40f968c0ec45f1008ec338c80a (commit)
       from  874fe18ad97511c8564f4e6930c5df1f0aacfa7e (commit)

I've now got rudimentary slapadd/slapcat support built around MDB. This is
just with dn2id and id2entry, no attribute indexing supported yet. Comparing
to back-hdb on ada. Loading a 250K entry database, 147MB LDIF file

MDB time to slapadd was real 0m34.345s user 0m25.366s sys 0m2.492s
BDB time to slapadd was real 0m42.284s user 0m35.646s sys 0m2.424s

MDB uses significantly less CPU time and is significantly faster overall. The
resulting MDB database was around 561MB. The resulting BDB database was around
436MB, with another ~460MB or so occupied on disk by the BDB cache files.

Repeating the same test using a 1M entry database, 589MB LDIF file

MDB time to slapadd was real 2m8.615s  user 1m42.074s sys 0m5.504s
BDB time to slapadd was real 2m49.811s user 2m41.874s sys 0m8.969s

The MDB database size was 2.2GB. The BDB database size was about 1.7GB plus
again as much for its BDB cache so total 3.5GB on disk.

All of these tests were run with slapadd -q, so BDB was only doing database
writes, no transaction logging. With fully synchronous writes, MDB is about twice as slow as BDB. I'm not sure there's much we can do about this, since generally any MDB write dirties more pages than a single BDB write.

At the moment back-mdb is functionally identical to back-hdb - all of the
dn2id layout is the same, etc. so this is a pretty apples-to-apples comparison.

The mdb library itself is now pretty much complete; at least I believe it supports everything that back-mdb needs. I'll be porting the rest of the back-mdb code over now.

Those revisions listed above that are new to this repository have
not appeared on any other notification email; so we list those
revisions in full, below.

- Log -----------------------------------------------------------------
commit a4c38efe297e6b40f968c0ec45f1008ec338c80a
Author: Howard Chu<highlandsun@gmail.com>
Date:   Fri Aug 19 18:20:06 2011 -0700

     Fix config typo, tweak slapadd -q


Summary of changes:
  servers/slapd/back-mdb/config.c |    4 ++--
  servers/slapd/back-mdb/libmdb   |    2 +-
  servers/slapd/back-mdb/tools.c  |    4 ++--
  3 files changed, 5 insertions(+), 5 deletions(-)


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