Re: How do I fix issues of really poor performance

[Howard Chu <hyc@symas.com>]

Rob Tanner wrote:
> Hi,
>
> I'm replacing an old Netscape server running on a 296 MHz dual processor 
> Solaris 5.7 (sun4u sparc) box with OpenLDAP 2.3.27 running on a single 
> 2.4GHz processor Intel box running Fedora Core 4.  I have duplicated one 
> of my hierarchies -- approx 9000 entries.  There is an index on an 
> attribute called deptaffiliationcodes (on both systems) which I'm using  
> as a search filter to make sure everything is working.  Dumping the 
> results to /dev/null, a search on the Netscape server takes typically 35 
> milliseconds to complete.  The exact same search on the OpenLDAP server 
> takes between 2.5 to 3.5 seconds.  And that's way too slow for me to put 
> the OpenLDAP server into production.
>
> I am using the bdb backend and the example DB_CONFIG file which sets the 
> cache size to 268435456 bytes, which is bigger than the actual size of 
> dn2id.bdb and id2entry.bdb combined (about 16Mb).  What other factors 
> can affect performance?

Hard to say with just that info. If your indexes are configured to match 
the search filters you're using, and the cache is hot, there's not a lot 
else to do. It's impossible to guess what is slowing things down without 
knowing more about your setup.

  Are you using syslog, is it at a particularly verbose level, is it 
logging synchronously or asynchronously?
  What does "top" show while a search is in progress, high CPU usage or 
high I/O wait? Or nothing but idle time?

--
  -- Howard Chu
  Chief Architect, Symas Corp.  http://www.symas.com
  Director, Highland Sun        http://highlandsun.com/hyc
  OpenLDAP Core Team            http://www.openldap.org/project/