2:42 p.m.
Is there an upper limit to mdb_env_set_maxdbs()? And what's the overhead for adding
additional DBs? Can I change this number once it's set if I close and reopen the env?
Ben Johnson
ben(a)skylandlabs.com
3:04 p.m.
Ben Johnson wrote:
Is there an upper limit to mdb_env_set_maxdbs()? And what's the
overhead for
adding additional DBs? Can I change this number once it's set if I close and
reopen the env?
The upper limit is the upper limit of an unsigned int.
The overhead is about 96 bytes per DB on a 64 bit machine. Yes, you can change
the number if you close and reopen the env, it's not persisted on disk. It's
just sizing an array in your MDB_env.
Ben Johnson
ben(a)skylandlabs.com <mailto:ben@skylandlabs.com>
--
-- Howard Chu
CTO, Symas Corp. http://www.symas.com
Director, Highland Sun http://highlandsun.com/hyc/
Chief Architect, OpenLDAP http://www.openldap.org/project/
3:25 p.m.
Ben Johnson writes:
Is there an upper limit to mdb_env_set_maxdbs()?
In theory INT_MAX or memory limits (see below), not that it'd be a good
idea to go that high.
And what's the overhead for adding additional DBs?
Around 60 bytes malloc & init overhead per DB for each txn and env, or
half that on a 32-bit machine. Also time to scan some of that memory
now and then.
Can I change this number once it's set if I close and reopen the
env?
Yes. It only affects the MDB_env structure, not the database.
--
Hallvard
3592
days inactive
3592
days old
openldap-technical@openldap.org
3 comments
3 participants
participants (3)
-
Ben Johnson -
Hallvard Breien Furuseth -
Howard Chu