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Re: 2.2.15 MASSIVE performance problems with proxycache enabled

Howard Chu wrote:
Andre Konopka wrote:


with the help of this list I configured a LDAP Proxy Server with overlay proxycache. My aim is to speed up Netscape/Outlook Address Book access.

First I was really impressed about the increasing performance...
But I found that if you query the LDAP-Server with just a few parallel queries slapd is only updating his cache and doesn't answer any further questions.

How to reproduce...

Just open Netscape Addressbook and enter a single character in the search field. Normally you get back around 100 entries.
The next time you enter the same letter, say 'a', you can see how fast the answer is available. Now try the same with 'b', 'c' and so on. Very soon you will see that slapd gives you no answer anymore. If you are patient enough you will see that slapd comes back after 5-10 minutes or so...

Here ist the slapd.conf

allow bind_v2 database ldap lastmod off suffix "c=de" uri "ldap://x3se.presse-data.de:389/"; rootdn "cn=root,c=de" overlay proxycache

proxyCache bdb 1000000 2 1000 100

cachesize 500
checkpoint 64 5
directory /opt/pdldap/openldap/var/openldap-data
index objectClass eq
index cn,sn,givenName,mail pres,eq,sub

What's wrong?

You have configured the proxycache to use back-bdb but you have not properly configured the back-bdb parameters. You've chosen 1000000 entries for the size of the proxycache but only 500 entries for the back-bdb entry cache. Most likely you haven't set up a proper DB_CONFIG either. You're probably also checkpointing too frequently, which is also slowing down the server because you're flushing the BDB cache all the time.

Thank you for your hints...

I tried out with

proxyCache bdb 1000000 2 1000 100
cachesize 1000000
checkpoint 4096 15

same behaviour.

Mmh, now I tried searching with the same character. I frequently typed 'a'. I have noticed that for every request a new slapd process is forked. At 20 it comes to an end and slapd answers anymore...

If you disable the 'overlay proxycache' the behaviour of slapd is different. Only one slapd process is forked...

I think that's the problem...

Any idea

Best regards