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Re: mdb_stat question

Frank Swasey wrote:
Today at 4:42am, Howard Chu wrote:
Huh? I'm wondering what you're looking for when you run mdb_stat. What did
you expect to see?

I guess I was expecting to see something more like the output of
db_stat, which I ran looking for deadlocks and evidence that any limits
were starting to be hit so I should tweak the DB_CONFIG file and

Since mdb doesn't have any of those issues, then I guess I'm just really
looking for guidance about the use of mdb_stat and what I should be
monitoring to be sure that I'm not on the brink of something breaking.

Right. Since MDB is deadlock proof there's no information of that sort to show.

Perhaps I have read the existing documentation too quickly.  However, so
far, I don't think I've found any guidance about how to monitor the
back_mdb to stay on top of possible issues.

There are only two settings to worry about: mapsize and maxreaders. If your maxreaders is greater than the number of slapd threads, you probably don't have to worry about it. For the mapsize, you can just use "du" on the MDB directory to see how much space is in use.

There's really not much more to tell.

These tools are definitely immature though. In the source tree you'll also find mdb_stata.c and mfree.c; their functionality is intended to be merged into a more useful mdb_stat command at some point in the future.

We'll likely also add some function to dump out the contents of the readers table. But the need for these things is pretty low.
  -- Howard Chu
  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/