Bruce Momjian wrote:
Yes. If you were doing multiple WAL writes before transaction fsync,
you would be fsyncing every write, rather than doing two writes and
fsync'ing them both. I wonder if larger transactions would find
open_sync slower?
No hard numbers, but I remember testing fsync vs open_sy
On Tue, 14 Oct 2003, Tom Lane wrote:
> "scott.marlowe" <[EMAIL PROTECTED]> writes:
> > open_sync was WAY faster at this than the other two methods.
>
> Do you not have open_datasync? That's the preferred method if
> available.
Nope, when I try to start postgresql with it set to that, I get this
"scott.marlowe" <[EMAIL PROTECTED]> writes:
> open_sync was WAY faster at this than the other two methods.
Do you not have open_datasync? That's the preferred method if
available.
regards, tom lane
---(end of broadcast)---
> "BM" == Bruce Momjian <[EMAIL PROTECTED]> writes:
BM> COPY only does fsync on COPY completion, so I am not sure there are
BM> enough fsync's there to make a difference.
Perhaps then it is part of the indexing that takes so much time with
the WAL. When I applied Marc's WAL disabling patch,
On Fri, 10 Oct 2003, Josh Berkus wrote:
> Bruce,
>
> > Yes. If you were doing multiple WAL writes before transaction fsync,
> > you would be fsyncing every write, rather than doing two writes and
> > fsync'ing them both. I wonder if larger transactions would find
> > open_sync slower?
>
> Want
Vivek Khera wrote:
> > "BM" == Bruce Momjian <[EMAIL PROTECTED]> writes:
>
> >> Sounds reasonable to me. Are there many / any scenarios where a plain
> >> fsync would be faster than open_sync?
>
> BM> Yes. If you were doing multiple WAL writes before transaction fsync,
> BM> you would be f
> "BM" == Bruce Momjian <[EMAIL PROTECTED]> writes:
>> Sounds reasonable to me. Are there many / any scenarios where a plain
>> fsync would be faster than open_sync?
BM> Yes. If you were doing multiple WAL writes before transaction fsync,
BM> you would be fsyncing every write, rather than
Bruce,
> I would be interested to see if wal_sync_method = fsync is slower than
> wal_sync_method = open_sync. How often are we doing more then one write
> before a fsync anyway?
OK. I'll see if I can get to it around my other stuff I have to do this
weekend.
--
Josh Berkus
Aglio Database S
Josh Berkus wrote:
> Bruce,
>
> > Yes. If you were doing multiple WAL writes before transaction fsync,
> > you would be fsyncing every write, rather than doing two writes and
> > fsync'ing them both. I wonder if larger transactions would find
> > open_sync slower?
>
> Want me to test? I've go
On Fri, 10 Oct 2003, Josh Berkus wrote:
> Bruce,
>
> > Yes. If you were doing multiple WAL writes before transaction fsync,
> > you would be fsyncing every write, rather than doing two writes and
> > fsync'ing them both. I wonder if larger transactions would find
> > open_sync slower?
>
> Want
Bruce,
> Yes. If you were doing multiple WAL writes before transaction fsync,
> you would be fsyncing every write, rather than doing two writes and
> fsync'ing them both. I wonder if larger transactions would find
> open_sync slower?
Want me to test? I've got an ide-based test machine here, a
scott.marlowe wrote:
> On Thu, 9 Oct 2003, Bruce Momjian wrote:
>
> > scott.marlowe wrote:
> > > I was testing to get some idea of how to speed up the speed of pgbench
> > > with IDE drives and the write caching turned off in Linux (i.e. hdparm -W0
> > > /dev/hdx).
> > >
> > > The only paramete
On Thu, 9 Oct 2003, Bruce Momjian wrote:
> scott.marlowe wrote:
> > I was testing to get some idea of how to speed up the speed of pgbench
> > with IDE drives and the write caching turned off in Linux (i.e. hdparm -W0
> > /dev/hdx).
> >
> > The only parameter that seems to make a noticeable dif
Nope, write-cache enabled by default.
On Thu, 9 Oct 2003, Bruce Momjian wrote:
>
> How did this drive come by default? Write-cache disabled?
>
> ---
>
> scott.marlowe wrote:
> > On Thu, 2 Oct 2003, scott.marlowe wrote:
>
How did this drive come by default? Write-cache disabled?
---
scott.marlowe wrote:
> On Thu, 2 Oct 2003, scott.marlowe wrote:
>
> > I was testing to get some idea of how to speed up the speed of pgbench
> > with IDE drive
scott.marlowe wrote:
> I was testing to get some idea of how to speed up the speed of pgbench
> with IDE drives and the write caching turned off in Linux (i.e. hdparm -W0
> /dev/hdx).
>
> The only parameter that seems to make a noticeable difference was setting
> wal_sync_method = open_sync. W
On Thu, 2 Oct 2003, scott.marlowe wrote:
> I was testing to get some idea of how to speed up the speed of pgbench
> with IDE drives and the write caching turned off in Linux (i.e. hdparm -W0
> /dev/hdx).
>
> The only parameter that seems to make a noticeable difference was setting
> wal_sync_m
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