On Fri, 6 Apr 2007, Takayuki Tsunakawa wrote:
could anyone evaluate O_SYNC approach again that commercial databases
use and tell me if and why PostgreSQL's fsync() approach is better than
theirs?
I noticed a big improvement switching the WAL to use O_SYNC (+O_DIRECT)
instead of fsync on my
From: Greg Smith [EMAIL PROTECTED]
If you compare how Oracle handles their writes and checkpoints to
the
Postgres code, it's obvious they have a different architecture that
enables them to support sync writing usefully. I'd recommend the
Database
Writer Process section of
On Fri, 2007-04-06 at 02:53 -0400, Greg Smith wrote:
If you compare how Oracle handles their writes and checkpoints to the
Postgres code, it's obvious they have a different architecture that
enables them to support sync writing usefully. I'd recommend the
Database
Writer Process section
On Fri, 6 Apr 2007, Takayuki Tsunakawa wrote:
Hmm... what makes you think that sync writes is useful for Oracle and
not for PostgreSQL?
They do more to push checkpoint-time work in advance, batch writes up more
efficiently, and never let clients do the writing. All of which make for
a
ITAGAKI Takahiro wrote:
Here is the latest version of Load distributed checkpoint patch.
Unfortunately because of the recent instrumentation and
CheckpointStartLock patches this patch doesn't apply cleanly to CVS HEAD
anymore. Could you fix the bitrot and send an updated patch, please?
--
On Thu, 5 Apr 2007, Heikki Linnakangas wrote:
Unfortunately because of the recent instrumentation and CheckpointStartLock
patches this patch doesn't apply cleanly to CVS HEAD anymore. Could you fix
the bitrot and send an updated patch, please?
The Logging checkpoints and other slowdown
Greg Smith wrote:
On Thu, 5 Apr 2007, Heikki Linnakangas wrote:
Bgwriter has two goals:
1. keep enough buffers clean that normal backends never need to do a
write
2. smooth checkpoints by writing buffers ahead of time
Load distributed checkpoints will do 2. in a much better way than the
Heikki Linnakangas [EMAIL PROTECTED] writes:
The number of buffers evicted by normal backends in a bgwriter_delay
period is simple to keep track of, just increase a counter in
StrategyGetBuffer and reset it when bgwriter wakes up. We can use that
as an estimate of X with some safety margin.
Tom Lane wrote:
Heikki Linnakangas [EMAIL PROTECTED] writes:
The number of buffers evicted by normal backends in a bgwriter_delay
period is simple to keep track of, just increase a counter in
StrategyGetBuffer and reset it when bgwriter wakes up. We can use that
as an estimate of X with some
Hello, long time no see.
I'm sorry to interrupt your discussion. I'm afraid the code is getting
more complicated to continue to use fsync(). Though I don't intend to
say the current approach is wrong, could anyone evaluate O_SYNC
approach again that commercial databases use and tell me if and why
On Thu, 5 Apr 2007, Heikki Linnakangas wrote:
The purpose of the bgwriter_all_* settings is to shorten the duration of
the eventual checkpoint. The reason to shorten the checkpoint duration
is to limit the damage to other I/O activity it causes. My thinking is
that assuming the LDC patch is
On Fri, 23 Mar 2007, ITAGAKI Takahiro wrote:
Here is the latest version of Load distributed checkpoint patch.
Couple of questions for you:
-Is it still possible to get the original behavior by adjusting your
tunables? It would be nice to do a before/after without having to
recompile, and
Greg Smith [EMAIL PROTECTED] wrote:
Here is the latest version of Load distributed checkpoint patch.
Couple of questions for you:
-Is it still possible to get the original behavior by adjusting your
tunables? It would be nice to do a before/after without having to
recompile, and I
On Mon, 26 Mar 2007, ITAGAKI Takahiro wrote:
I'm assuming checkpoints are triggered by timeout in normal use -- and
it's my recommended configuration whether the patch is installed or not.
I'm curious what other people running fairly serious hardware do in this
area for write-heavy loads,
Your patch has been added to the PostgreSQL unapplied patches list at:
http://momjian.postgresql.org/cgi-bin/pgpatches
It will be applied as soon as one of the PostgreSQL committers reviews
and approves it.
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