Skip site navigation (1) Skip section navigation (2)

Re: Wierd context-switching issue on Xeon

From: "Anjan Dave" <adave(at)vantage(dot)com>
To: "Josh Berkus" <josh(at)agliodbs(dot)com>, Dirk Lutzeb├Ąck <lutzeb(at)aeccom(dot)com>,"Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: <pgsql-performance(at)postgreSQL(dot)org>,"Neil Conway" <neilc(at)samurai(dot)com>
Subject: Re: Wierd context-switching issue on Xeon
Date: 2004-04-23 02:27:55
Message-ID: 4BAFBB6B9CC46F41B2AD7D9F4BBAF785098157@vt-pe2550-001.vantage.vantage.com (view raw or flat)
Thread:
Lists: pgsql-performance
Tested the sql on Quad 2.0GHz XEON/8GB RAM:
 
During the first run, the CS shooted up more than 100k, and was randomly high/low
Second process made it consistently high 100k+
Third brought it down to anaverage 80-90k
Fourth brought it down to an average of 50-60k/s
 
By cancelling the queries one-by-one, the CS started going up again.
 
8 logical CPUs in 'top', all of them not at all too busy, load average stood around 2 all the time.
 
Thanks.
Anjan
 
-----Original Message----- 
From: Josh Berkus [mailto:josh(at)agliodbs(dot)com] 
Sent: Tue 4/20/2004 12:59 PM 
To: Anjan Dave; Dirk Lutzeb├Ąck; Tom Lane 
Cc: pgsql-performance(at)postgreSQL(dot)org; Neil Conway 
Subject: Re: [PERFORM] Wierd context-switching issue on Xeon



	Anjan,
	
	> Quad 2.0GHz XEON with highest load we have seen on the applications, DB
	> performing great -
	
	Can you run Tom's test?   It takes a particular pattern of data access to
	reproduce the issue.
	
	--
	Josh Berkus
	Aglio Database Solutions
	San Francisco
	
	---------------------------(end of broadcast)---------------------------
	TIP 9: the planner will ignore your desire to choose an index scan if your
	      joining column's datatypes do not match
	


Attachment: Context-Switching.rtf
Description: text/richtext (8.9 KB)

pgsql-performance by date

Next:From: Joe ConwayDate: 2004-04-23 04:38:05
Subject: Re: Looking for ideas on how to speed up warehouse loading
Previous:From: Tom LaneDate: 2004-04-23 02:03:12
Subject: Re: Looking for ideas on how to speed up warehouse loading

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group