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Re: High volume ldap queries causing corruption in bdb backend.

--On Thursday, September 18, 2003 11:03 AM -0700 Peter Johnson <paj1@humboldt.edu> wrote:


	I'm trying to use openldap, v2.1.22 on red-hat linux AS 2.1, to support
email  routing with sendmail (8.12.6).  Our email server processes
50-100k messages  per day.  After running for a few hours, the ldap
server suddenly becomes  very slow to respond.
	I can take sendmail out of the picture and duplicate the problem easily
with  the ldapsearch command.  I setup a shell script that loops through
the  alphabet and searches the ldap server as fast as it can.  Running by
itself,  the script can do about 200k queries per hour and overnight did
over 2.7M  queries without error or slow downs and the CPU load on the
server is only  10-15%.
	The problem is that within minutes of starting a second shell script
both  scripts start experiencing very slow response times, 10
seconds/query.   Performance does not return to normal when either of the
scripts is killed.   Even after bouncing the ldap server processes the
response time is still very  slow.
	The only thing that seems to fix the problem is using db_recover -c
before  starting the server.  If I slow the scripts down to 1
query/second, both  scripts can run without causing problems.
	I don't understand running two high volume query scripts can corrupt the
bdb   database (version 4.1.25).  There are no updates being done during
the time  the scripts are running.
	I cant imagine that 100k email messages/day is to much for openldap so
something must be wrong with my installation.  I am going to rebuild the
bdb  software to enable the test scripts and diagnostics but was hoping
someone  else has seen this problem.
	I didn't see any bdb list servers on the sleepycat web site, is there a
better place to post this question?

Hi Peter,

Here at Stanford, we use 3 of our 9 replica servers for email routing. The 3 servers handle some 375,000 connections each per day. What type of settings do you have in your DB_CONFIG file for BDB?


Quanah Gibson-Mount
Principal Software Developer
ITSS/TSS/Computing Systems
Stanford University
GnuPG Public Key: http://www.stanford.edu/~quanah/pgp.html