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Re: 8192 BLCKSZ ?

From: "Mitch Vincent" <mitch(at)venux(dot)net>
To: "Christopher Kings-Lynne" <chriskl(at)familyhealth(dot)com(dot)au>
Cc: <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: 8192 BLCKSZ ?
Date: 2000-11-28 02:39:15
Message-ID: 018901c058e4$66588940$0200000a@windows (view raw or flat)
Thread:
Lists: pgsql-hackers
If it breaks anything in PostgreSQL I sure haven't seen any evidence -- the
box this database is running on gets hit pretty hard and I haven't had a
single ounce of trouble since I went to 7.0.X

-Mitch

----- Original Message -----
From: "Christopher Kings-Lynne" <chriskl(at)familyhealth(dot)com(dot)au>
To: "Hackers List" <pgsql-hackers(at)postgresql(dot)org>
Sent: Monday, November 27, 2000 5:14 PM
Subject: RE: [HACKERS] 8192 BLCKSZ ?


> I don't believe it's a performance issue, I believe it's that writes to
> blocks greater than 8k cannot be guaranteed 'atomic' by the operating
> system.  Hence, 32k blocks would break the transactions system.  (Or
> something like that - am I correct?)
>
> Chris
>
> > -----Original Message-----
> > From: pgsql-hackers-owner(at)postgresql(dot)org
> > [mailto:pgsql-hackers-owner(at)postgresql(dot)org]On Behalf Of Mitch Vincent
> > Sent: Tuesday, November 28, 2000 8:40 AM
> > To: mlw; Hackers List
> > Subject: Re: [HACKERS] 8192 BLCKSZ ?
> >
> >
> > I've been using a 32k BLCKSZ for months now without any trouble,
> > though I've
> > not benchmarked it to see if it's any faster than one with a
> > BLCKSZ of 8k..
> >
> > -Mitch
> >
> > > This is just a curiosity.
> > >
> > > Why is the default postgres block size 8192? These days, with caching
> > > file systems, high speed DMA disks, hundreds of megabytes of RAM,
maybe
> > > even gigabytes. Surely, 8K is inefficient.
> > >
> > > Has anyone done any tests to see if a default 32K block would provide
a
> > > better overall performance? 8K seems so small, and 32K looks to be
where
> > > most x86 operating systems seem to have a sweet spot.
> > >
> > > If someone has the answer off the top of their head, and I'm just
being
> > > stupid, let me have it. However, I have needed to up the block size to
> > > 32K for a text management system and have seen no  performance
problems.
> > > (It has not been a scientific experiment, admittedly.)
> > >
> > > This isn't a rant, but my gut tells me that a 32k block size as defaul
t
> > > would be better, and that smaller deployments should adjust down as
> > > needed.
> > >
> >
>
>


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Subject: Re: 8192 BLCKSZ ?
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