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

Re: User concurrency thresholding: where do I look?

From: "Simon Riggs" <simon(at)2ndquadrant(dot)com>
To: "Jignesh K(dot) Shah" <J(dot)K(dot)Shah(at)Sun(dot)COM>
Cc: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>,"Josh Berkus" <josh(at)agliodbs(dot)com>,<pgsql-performance(at)postgresql(dot)org>,"Alvaro Herrera" <alvherre(at)commandprompt(dot)com>
Subject: Re: User concurrency thresholding: where do I look?
Date: 2007-07-26 20:04:50
Message-ID: 1185480291.5510.22.camel@ebony.site (view raw or flat)
Thread:
Lists: pgsql-performance
On Thu, 2007-07-26 at 15:44 -0400, Jignesh K. Shah wrote:
> BEAUTIFUL!!!
> 
> Using the Patch I can now go upto 1300 users without dropping.. But now 
> it still repeats at 1300-1350 users..

OK, can you try again with 16 and 32 buffers please?  We need to know
how many is enough and whether this number needs to be variable via a
parameter, or just slightly larger by default. Thanks.

> I corrected the Lock Descriptions based on what I got from lwlock.h and 
> retried the whole scalability again with profiling again.. This time it 
> looks like the ProcArrayLock

That's what I would expect with that many users.

>              Lock Id            Mode           Count
>           XidGenLock       Exclusive               1
>      CLogControlLock          Shared               2
>           XidGenLock          Shared               2
>         WALWriteLock       Exclusive               4
>        WALInsertLock       Exclusive               8
>      CLogControlLock       Exclusive               9
>        ProcArrayLock       Exclusive               9

...but as Tom mentioned, we need to do longer runs now so these counts
get to somewhere in the hundreds so we have some statistical validity.

-- 
  Simon Riggs
  EnterpriseDB  http://www.enterprisedb.com


In response to

Responses

pgsql-performance by date

Next:From: Jignesh K. ShahDate: 2007-07-26 21:17:55
Subject: Re: User concurrency thresholding: where do I look?
Previous:From: Robert LorDate: 2007-07-26 19:56:08
Subject: Re: User concurrency thresholding: where do I look?

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