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Re: lots of write slowing down searches

--On Thursday, December 09, 2004 1:32 PM -0500 Patrick Radtke <phr2101@columbia.edu> wrote:


We have some software that occasionally likes to make lots of
modifications and adds to OpenLDAP in a short amount of time (5
modification per sec for a period of 10 minutes).

When ever this happens all ldapsearches become very slow (servers handle
about 16 searches per second normally). They take upwards of 2 seconds
where previously the were taking 0.05s to answer requests. This causes us
various problems with log-ins and email lookups.

We are running 2.1.30, but I ran tests on 2.2.19 and had the same issues.
we use lbdm as our backend and our indexes are for the standard stuff for
unix accounts and groups

I understand that OpenLDAP is read optimized but I am wondering if
switching to BDB would provide significantly better search speeds when
writes are occurring (ie enough to solve the problem)?

The reasons we haven't switched to BDB so far is that it takes extra time
to build, setup and tune, and I haven't had much extra time:)

We are planning on fixing our misbehaving software but are just concerned
that the next time a program does too many writes, everything will grind
to a halt.

You might look at HDB, which is read & write optimized. I've not had any issues with heavy writes with BDB, but it is not specifically write optimized as far as I know. I do suggest dumping ldbm. ;)


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