Re: Need for speed 2 - Mailing list pgsql-performance

From Alex Turner
Subject Re: Need for speed 2
Date
Msg-id 33c6269f05092008357973a651@mail.gmail.com
Whole thread Raw
In response to Re: Need for speed 2  (Kelly Burkhart <kelly@tradebotsystems.com>)
List pgsql-performance
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

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