topic Re: Syncsort Process - SEM Wait State in Operating System - HP-UX

Syncsort Process - SEM Wait State

Alzhy — Fri, 18 Feb 2011 14:35:24 GMT

Trying my luck if someone else had encountered this issue:

A Warehouse system, running for many years started encountering delays in large sorts. On one Sort of a 10GB file with 18 million lines - it used to take only less than 1 hour to perform. But in the last few, it's been taking 4+ hours.

Observation in glance shows the Syncsort process is waitig on SEM.

Any clues as to what can be done to recifty this issues? Server has been static with patches, configuration for many years now and we've no I/O issues at all.

Also, the end process of the job which does a "wc -l" takes much longer to perform with CACHE waits.

TIA!

Re: Syncsort Process - SEM Wait State

James R. Ferguson — Mon, 08 Aug 2011 18:34:33 GMT

Hi Alzhy:

This would appear to be a continuation of your earlier thread:

http://h30499.www3.hp.com/t5/System-Administration/HP-UX-11-11-wc-l-on-a-BIG-ASCII-File-is-slow-and-is-in-quot/m-p/4753730#M388452

...which should bear mention.

Regards!

...JRF...

Re: Syncsort Process - SEM Wait State

Alzhy — Wed, 23 Feb 2011 14:51:32 GMT

Yes bos.. and I am still dumbfounded.

HP insists a "Change" happened and I am still trying to find out.

Re: Syncsort Process - SEM Wait State

Jose Mosquera — Wed, 23 Feb 2011 15:21:46 GMT

Hi,

Have you considered the possibility that the input data have experienced a slight change of content (language or character type, field definition, length, etc)?

Rgds.

Re: Syncsort Process - SEM Wait State

Alzhy — Wed, 23 Feb 2011 15:46:55 GMT

That's our (Admins) immediate train of thought. But they've been doing this kind of processsing for the last 3 to 4 years at or near the current filesizes

Re: Syncsort Process - SEM Wait State

Jose Mosquera — Wed, 23 Feb 2011 16:09:14 GMT

Ok, if there is a change of field position, this wouldn't change the filesize but it could affect performance if one of the fields involved belonged to a key index. The symptoms that you explain are very similar to cases of index loss.

Rgds.