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

Re: [HACKERS] Sun Donated a Sun Fire T2000 to the PostgreSQL

From: "Jim C(dot) Nasby" <jnasby(at)pervasive(dot)com>
To: Robert Lor <Robert(dot)Lor(at)Sun(dot)COM>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Tatsuo Ishii <ishii(at)sraoss(dot)co(dot)jp>,pgsql-hackers(at)postgresql(dot)org, pgsql-performance(at)postgresql(dot)org
Subject: Re: [HACKERS] Sun Donated a Sun Fire T2000 to the PostgreSQL
Date: 2006-07-21 13:56:53
Message-ID: 20060721135653.GC83250@pervasive.com (view raw or flat)
Thread:
Lists: pgsql-hackerspgsql-performance
On Fri, Jul 21, 2006 at 12:56:56AM -0700, Robert Lor wrote:
> I ran pgbench and fired up a DTrace script using the lwlock probes we've 
> added, and it looks like BufMappingLock is the most contended lock, but  
> CheckpointStartLocks are held for longer duration!
 
Not terribly surprising given that that lock can generate a substantial
amount of IO (though looking at the numbers, you might want to make
bgwriter more aggressive). Also, that's a shared lock, so it won't have
nearly the impact that BufMappingLock does.

>             Lock Id            Mode           Count
>     ControlFileLock       Exclusive               1
> SubtransControlLock       Exclusive               1
>    BgWriterCommLock       Exclusive               6
>       FreeSpaceLock       Exclusive               6
>    FirstLockMgrLock       Exclusive              48
>     BufFreelistLock       Exclusive              74
>      BufMappingLock       Exclusive              74
>     CLogControlLock       Exclusive             184
>          XidGenLock       Exclusive             184
> CheckpointStartLock          Shared             185
>        WALWriteLock       Exclusive             185
>       ProcArrayLock       Exclusive             368
>     CLogControlLock          Shared             552
> SubtransControlLock          Shared            1273
>       WALInsertLock       Exclusive            1476
>          XidGenLock          Shared            1842
>       ProcArrayLock          Shared            3160
>          SInvalLock          Shared            3684
>      BufMappingLock          Shared           14578
> 
>             Lock Id   Combined Time (ns)
>     ControlFileLock                 7915
>    BgWriterCommLock                43438
>       FreeSpaceLock               111139
>     BufFreelistLock               448530
>    FirstLockMgrLock              2879957
>     CLogControlLock              4237750
> SubtransControlLock              6378042
>          XidGenLock              9500422
>       WALInsertLock             16372040
>          SInvalLock             23284554
>       ProcArrayLock             32188638
>      BufMappingLock            113128512
>        WALWriteLock            142391501
> CheckpointStartLock           4171106665
> 
> 
> Regards,
> -Robert
> 
>      
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Have you searched our list archives?
> 
>               http://archives.postgresql.org
> 

-- 
Jim C. Nasby, Sr. Engineering Consultant      jnasby(at)pervasive(dot)com
Pervasive Software      http://pervasive.com    work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf       cell: 512-569-9461

In response to

pgsql-performance by date

Next:From: Sven GeislerDate: 2006-07-21 14:59:49
Subject: Re: [HACKERS] Sun Donated a Sun Fire T2000 to the PostgreSQL
Previous:From: Tom LaneDate: 2006-07-21 13:42:45
Subject: Re: Sun Donated a Sun Fire T2000 to the PostgreSQL

pgsql-hackers by date

Next:From: Tom LaneDate: 2006-07-21 14:03:33
Subject: Re: Freezing tuples on pages dirtied by vacuum
Previous:From: Tom LaneDate: 2006-07-21 13:55:31
Subject: Re: How does the planner deal with multiple possible indexes?

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