From: Alex Turner <armtuk@gmail.com>
To: Kelly Burkhart <kelly@tradebotsystems.com>
Cc: Ron <rjpeace@earthlink.net>
Cc: pgsql-performance@postgresql.org
Subject: Re: Need for speed 2
Date: Tue, 20 Sep 2005 11:35:58 -0400
Message-ID: <33c6269f05092008357973a651@mail.gmail.com> (raw)
In-Reply-To: <1124996422.6969.47.camel@krb06.tradebot.com>
References: <6.2.3.4.0.20050817140116.05d317b0@pop.earthlink.net>
<f3c0b408050817133325dfa491@mail.gmail.com>
<430D6EED.10603@relevanttraffic.se>
<6.2.3.4.0.20050825094630.05e6b160@pop.earthlink.net>
<1124996422.6969.47.camel@krb06.tradebot.com>
I have found that while the OS may flush to the controller fast with
fsync=true, the controller does as it pleases (it has BBU, so I'm not too
worried), so you get great performance because your controller is determine
read/write sequence outside of what is being demanded by an fsync.
Alex Turner
NetEconomist
On 8/25/05, Kelly Burkhart <kelly@tradebotsystems.com> wrote:
>
> On Thu, 2005-08-25 at 11:16 -0400, Ron wrote:
> > ># - Settings -
> > >
> > >fsync = false # turns forced synchronization on or off
> > >#wal_sync_method = fsync # the default varies across platforms:
> > > # fsync, fdatasync, open_sync, or
> >
> > I hope you have a battery backed write buffer!
>
> Battery backed write buffer will do nothing here, because the OS is
> taking it's sweet time flushing to the controller's battery backed write
> buffer!
>
> Isn't the reason for batter backed controller cache to make fsync()s
> fast?
>
> -K
>
> ---------------------------(end of broadcast)---------------------------
> TIP 9: In versions below 8.0, the planner will ignore your desire to
> choose an index scan if your joining column's datatypes do not
> match
>
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To: pgsql-performance@postgresql.org
Cc: armtuk@gmail.com, kelly@tradebotsystems.com, rjpeace@earthlink.net
Subject: Re: Need for speed 2
In-Reply-To: <33c6269f05092008357973a651@mail.gmail.com>
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