RE: indices in slapd.conf

["Mike Denka" <mdenk@whidbey.net>]

Thanks, Agustin.  That makes sense.  I'll give it a try and hope it
speeds up my access times appreciably.  I'm not near as concerned about
writing (update) times.

Mike

-----Original Message-----
From: Agustin [mailto:torrest@andaluciajunta.es] 
Sent: Thursday, November 07, 2002 12:23 AM
To: Mike Denka; openldap-software@OpenLDAP.org
Subject: Re: indices in slapd.conf


 "Mike Denka" WROTE:

> I am selectively replicating data from my master ldap server to the
> slaves.  So the data the slaves receive from the master is only
partial.
> Because of this and because the master has some front end software
that
> allows us to manipulate the data via a web interface, I access data
from
> ldap in different ways on the master and slaves.  My question is
> twofold:
>
> 1) Can I use different indices on the slave servers than on the
master?
>
 yes , you can. in my system (i have one master and two slaves) i used
different index
because the master is for write operations mainly, operations via web.
And
my slaves
are used to router the mail.

>
> 2) And what are the considerations when deciding which and how many
> indices to use in slapd.conf?  Obviously you want to use the
attributes
> you search for most often as indices, but what is the penalty for
using
> more indices rather than less?  What is the order of magnitude of
memory
> usage and other penalties related to the number of indices you use?
> Does memory double as indices double, for example?  Or is it a
fourfold
> increase in memory when the number of indices doubles?  What are the
> pitfalls and caveats one should observe when customizing indices?
>

the exact penalty for use index depends of the type of db that you use.
but the problem with a lot of indexes not is at the search. the problem
is
at updates
because one lonely update require that a lot of files are updates too.

> Thanks,
>
> Mike
>