Jeff Davis writes:
> One point about the commit message: fadvise does not block to go into
> the request queue, sync_file_range does. The problem with fadvise is
> that, when the request queue is small, it fills up so fast that most of
> the requests never make it in, and fadvise is essentially a
On Fri, 2012-07-13 at 17:35 -0400, Tom Lane wrote:
> I wrote:
> > I'm picking up this patch now. What I'm inclined to do about the -N
> > business is to commit without that, so that we get a round of testing
> > in the buildfarm and find out about any portability issues, but then
> > change to use
Jeff Davis writes:
> For the case of initdb, the data needing to be fsync'd is effectively
> constant, and it's a lot of small files. If the requests don't make it
> to the io scheduler queue before fsync, the kernel doesn't have an
> opportunity to schedule them properly.
> But for larger amount
On Fri, 2012-07-13 at 15:21 -0400, Tom Lane wrote:
> No, that's incorrect: the fadvise is there, inside pg_flush_data() which
> is done during the writing phase.
Yeah, Andres pointed that out, also.
> It seems to me that if we think
> sync_file_range is a win, we ought to be using it in pg_flus
I wrote:
> I'm picking up this patch now. What I'm inclined to do about the -N
> business is to commit without that, so that we get a round of testing
> in the buildfarm and find out about any portability issues, but then
> change to use -N after a week or so. I agree that in the long run
> we do
Jeff Davis writes:
> On Mon, 2012-06-18 at 20:57 +0200, Andres Freund wrote:
>> Ok. Sensible reasons. I dislike that we know have two files using different
>> logic (copydir.c only using fadvise, initdb using sync_file_range if
>> available). Maybe we should just move the fadvise and sync_file_r
Andres Freund writes:
> On Tuesday, June 19, 2012 07:22:02 PM Jeff Davis wrote:
>> Right now I'm inclined to leave the patch as-is.
> Fine with that, I wanted to bring it up and see it documented.
> I have marked it with ready for committer. That committer needs to decide on -
> N in the regress
On mån, 2012-06-18 at 20:57 +0200, Andres Freund wrote:
> I don't think the difference in initdb cost is relevant when running
> the regression tests. Should it prove to be we can re-add -N after a
> week or two in the buildfarm machines.
Keep in mind that the regression tests are not only run on
On Fri, 2012-06-22 at 10:04 -0400, Robert Haas wrote:
> This may be a stupid question, by why is it initdb's job to fsync the
> files the server creates, rather than the server's job? Normally we
> rely on the server to make its own writes persistent.
That was my first reaction as well:
http://a
On Fri, Jun 22, 2012 at 10:04:23AM -0400, Robert Haas wrote:
> On Sat, Feb 4, 2012 at 8:18 PM, Noah Misch wrote:
> > If we add fsync calls to the initdb process, they should cover the entire
> > data
> > directory tree. ?This patch syncs files that initdb.c writes, but we ought
> > to
> > also s
On Sat, Feb 4, 2012 at 8:18 PM, Noah Misch wrote:
> On Sat, Feb 04, 2012 at 03:41:27PM -0800, Jeff Davis wrote:
>> On Sat, 2012-01-28 at 13:18 -0500, Tom Lane wrote:
>> > Yeah. Personally I would be sad if initdb got noticeably slower, and
>> > I've never seen or heard of a failure that this woul
On Tuesday, June 19, 2012 07:22:02 PM Jeff Davis wrote:
> On Mon, 2012-06-18 at 21:41 +0200, Andres Freund wrote:
> > It calls pg_flush_data inside of copy_file which does the
> > posix_fadvise... So maybe just put the sync_file_range in pg_flush_data?
>
> The functions in fd.c aren't linked to in
On Mon, 2012-06-18 at 21:41 +0200, Andres Freund wrote:
> It calls pg_flush_data inside of copy_file which does the posix_fadvise... So
> maybe just put the sync_file_range in pg_flush_data?
The functions in fd.c aren't linked to initdb, so it's a challenge to
share that code (I remember now: tha
On Mon, Jun 18, 2012 at 09:34:30PM +0300, Peter Eisentraut wrote:
> On mån, 2012-06-18 at 18:05 +0200, Andres Freund wrote:
> > - defaulting to initdb -N in the regression suite is not a good imo,
> > because that way the buildfarm won't catch problems in that area...
> >
> The regression test sui
On Mon, 2012-06-18 at 21:41 +0200, Andres Freund wrote:
> It calls pg_flush_data inside of copy_file which does the posix_fadvise... So
> maybe just put the sync_file_range in pg_flush_data?
Oh, I didn't notice that, thank you.
In that case, it may be good to combine them if possible. I will loo
Excerpts from Jeff Davis's message of lun jun 18 15:32:25 -0400 2012:
> On Mon, 2012-06-18 at 20:57 +0200, Andres Freund wrote:
> > Btw, I just want to have said this, although I don't think its particularly
> > relevant as it doesn't affect correctness: Its possible to have a system
> > where
On Monday, June 18, 2012 09:32:25 PM Jeff Davis wrote:
> > > > - could the copydir.c and initdb.c versions of walkdir/sync_fname et
> > > > al be unified?
> > >
> > > There's a lot of backend-specific code in the copydir versions, like
> > > using ereport() and CHECK_FOR_INTERRUPTS(). I gave a bri
On Mon, 2012-06-18 at 20:57 +0200, Andres Freund wrote:
> > > - defaulting to initdb -N in the regression suite is not a good imo,
> > > because that way the buildfarm won't catch problems in that area...
> > I removed the -N as you suggest. How much does performance matter on the
> > buildfarm?
>
On Monday, June 18, 2012 08:39:47 PM Jeff Davis wrote:
> On Mon, 2012-06-18 at 18:05 +0200, Andres Freund wrote:
> > Quick review:
> > - defaulting to initdb -N in the regression suite is not a good imo,
> > because that way the buildfarm won't catch problems in that area...
> I removed the -N as y
On Mon, 2012-06-18 at 21:34 +0300, Peter Eisentraut wrote:
> On mån, 2012-06-18 at 18:05 +0200, Andres Freund wrote:
> > - defaulting to initdb -N in the regression suite is not a good imo,
> > because that way the buildfarm won't catch problems in that area...
> >
> The regression test suite also
On Mon, 2012-06-18 at 18:05 +0200, Andres Freund wrote:
> Quick review:
> - defaulting to initdb -N in the regression suite is not a good imo, because
> that way the buildfarm won't catch problems in that area...
I removed the -N as you suggest. How much does performance matter on the
buildfarm?
On mån, 2012-06-18 at 18:05 +0200, Andres Freund wrote:
> - defaulting to initdb -N in the regression suite is not a good imo,
> because that way the buildfarm won't catch problems in that area...
>
The regression test suite also starts postgres with fsync off. This is
good, and I don't want to h
On Wednesday, June 13, 2012 06:53:17 PM Jeff Davis wrote:
> On Wed, 2012-06-13 at 13:53 +0300, Peter Eisentraut wrote:
> > The --help output for the -N option was copy-and-pasted wrongly.
> >
> > The message issued when using -N is also a bit content-free. Maybe
> > something like
> >
> > "Runni
On Wed, 2012-06-13 at 13:53 +0300, Peter Eisentraut wrote:
> The --help output for the -N option was copy-and-pasted wrongly.
>
> The message issued when using -N is also a bit content-free. Maybe
> something like
>
> "Running in nosync mode. The data directory might become corrupt if the
> ope
On tis, 2012-06-12 at 21:09 -0700, Jeff Davis wrote:
> On Sun, 2012-03-25 at 19:59 -0700, Jeff Davis wrote:
> > On Sat, 2012-03-17 at 17:48 +0100, Cédric Villemain wrote:
> > > I agree with Andres.
> > >
> > >
> > > I believe we should use sync_file_range (_before?) with linux.
> > >
> > > And w
On Sun, 2012-03-25 at 19:59 -0700, Jeff Davis wrote:
> On Sat, 2012-03-17 at 17:48 +0100, Cédric Villemain wrote:
> > I agree with Andres.
> >
> >
> > I believe we should use sync_file_range (_before?) with linux.
> >
> > And we can use posix_fadvise_dontneed on other kernels.
> >
> OK, updated
On Sat, 2012-03-17 at 17:48 +0100, Cédric Villemain wrote:
> I agree with Andres.
>
>
> I believe we should use sync_file_range (_before?) with linux.
>
> And we can use posix_fadvise_dontneed on other kernels.
>
OK, updated patch attached. sync_file_range() is preferred,
posix_fadvise() is a f
Le vendredi 16 mars 2012 16:51:04, Andres Freund a écrit :
> On Friday, March 16, 2012 04:47:06 PM Robert Haas wrote:
> > On Fri, Mar 16, 2012 at 6:25 AM, Andres Freund wrote:
> > >> > How are the results with sync_file_range(fd, 0, 0,
> > >> > SYNC_FILE_RANGE_WRITE)?
> > >>
> > >> That is much f
On Fri, 2012-03-16 at 11:25 +0100, Andres Freund wrote:
> > I take that back. There was something wrong with my test -- fadvise
> > helps, but it only takes it from ~10s to ~6.5s. Not quite as good as I
> > hoped.
> Thats surprising. I wouldn't expect such a big difference between fadvise +
> sync
On Friday, March 16, 2012 04:47:06 PM Robert Haas wrote:
> On Fri, Mar 16, 2012 at 6:25 AM, Andres Freund wrote:
> >> > How are the results with sync_file_range(fd, 0, 0,
> >> > SYNC_FILE_RANGE_WRITE)?
> >>
> >> That is much faster than using fadvise. It goes down to ~2s.
> >>
> >> Unfortunately
On Fri, Mar 16, 2012 at 6:25 AM, Andres Freund wrote:
>> > How are the results with sync_file_range(fd, 0, 0,
>> > SYNC_FILE_RANGE_WRITE)?
>> That is much faster than using fadvise. It goes down to ~2s.
>
>> Unfortunately, that's non-portable. Any other ideas? 6.5s a little on
>> the annoying side
On Thursday, March 15, 2012 07:38:38 AM Jeff Davis wrote:
> On Wed, 2012-03-14 at 10:26 +0100, Andres Freund wrote:
> > On Wednesday, March 14, 2012 05:23:03 AM Jeff Davis wrote:
> > > On Tue, 2012-03-13 at 09:42 +0100, Andres Freund wrote:
> > > > for recursively everything in dir:
> > > >posi
On Wed, 2012-03-14 at 10:26 +0100, Andres Freund wrote:
> On Wednesday, March 14, 2012 05:23:03 AM Jeff Davis wrote:
> > On Tue, 2012-03-13 at 09:42 +0100, Andres Freund wrote:
> > > for recursively everything in dir:
> > >posix_fadvise(fd, POSIX_FADV_DONTNEED);
> > >
> > > for recursively eve
On Wednesday, March 14, 2012 05:23:03 AM Jeff Davis wrote:
> On Tue, 2012-03-13 at 09:42 +0100, Andres Freund wrote:
> > for recursively everything in dir:
> >posix_fadvise(fd, POSIX_FADV_DONTNEED);
> >
> > for recursively everything in dir:
> >fsync(fd);
>
> Wow, that made a huge differe
On Tue, 2012-03-13 at 09:42 +0100, Andres Freund wrote:
> for recursively everything in dir:
>posix_fadvise(fd, POSIX_FADV_DONTNEED);
>
> for recursively everything in dir:
>fsync(fd);
Wow, that made a huge difference!
no sync: ~ 1.0s
sync: ~10.0s
fadvise+sync: ~ 1.3s
On Tuesday, March 13, 2012 04:49:40 AM Jeff Davis wrote:
> On Sun, 2012-02-05 at 17:56 -0500, Noah Misch wrote:
> > I meant primarily to illustrate the need to be comprehensive, not comment
> > on which executable should fsync a particular file. Bootstrap-mode
> > backends do not sync anything dur
On Sun, 2012-02-05 at 17:56 -0500, Noah Misch wrote:
> I meant primarily to illustrate the need to be comprehensive, not comment on
> which executable should fsync a particular file. Bootstrap-mode backends do
> not sync anything during an initdb run on my system. With your patch, we'll
> fsync a
On Fri, Feb 10, 2012 at 3:57 PM, Peter Eisentraut wrote:
> On sön, 2012-02-05 at 10:53 -0800, Jeff Davis wrote:
>> > initdb should do these syncs by default and offer an option to
>> disable them.
>>
>> For test frameworks that run initdb often, that makes sense.
>>
>> But for developers, it doesn
On sön, 2012-02-05 at 10:53 -0800, Jeff Davis wrote:
> > initdb should do these syncs by default and offer an option to
> disable them.
>
> For test frameworks that run initdb often, that makes sense.
>
> But for developers, it doesn't make sense to spend 0.5s typing an
> option
> that saves you
On Sun, Feb 05, 2012 at 10:53:20AM -0800, Jeff Davis wrote:
> On Sat, 2012-02-04 at 20:18 -0500, Noah Misch wrote:
> > If we add fsync calls to the initdb process, they should cover the entire
> > data
> > directory tree. This patch syncs files that initdb.c writes, but we ought
> > to
> > also
Jeff Davis writes:
> On Sat, 2012-02-04 at 20:18 -0500, Noah Misch wrote:
>> If we add fsync calls to the initdb process, they should cover the entire
>> data
>> directory tree. This patch syncs files that initdb.c writes, but we ought to
>> also sync files that bootstrap-mode backends had writt
On Sat, 2012-02-04 at 20:18 -0500, Noah Misch wrote:
> If we add fsync calls to the initdb process, they should cover the entire data
> directory tree. This patch syncs files that initdb.c writes, but we ought to
> also sync files that bootstrap-mode backends had written.
It doesn't make sense fo
On Sat, Feb 04, 2012 at 03:41:27PM -0800, Jeff Davis wrote:
> On Sat, 2012-01-28 at 13:18 -0500, Tom Lane wrote:
> > Yeah. Personally I would be sad if initdb got noticeably slower, and
> > I've never seen or heard of a failure that this would fix.
>
> I worked up a patch, and it looks like it do
On Sat, 2012-01-28 at 13:18 -0500, Tom Lane wrote:
> Yeah. Personally I would be sad if initdb got noticeably slower, and
> I've never seen or heard of a failure that this would fix.
I worked up a patch, and it looks like it does about 6 file fsync's and
a 7th for the PGDATA directory. That degra
* Tom Lane:
> I wonder whether it wouldn't be sufficient to call sync(2) at the end,
> anyway, rather than cluttering the entire initdb codebase with fsync
> calls.
We tried to do this in the Debian package mananger. It works as
expected on Linux systems, but it can cause a lot of data to hit th
On 01/28/2012 01:46 PM, Jeff Davis wrote:
On Sat, 2012-01-28 at 13:18 -0500, Tom Lane wrote:
Andrew Dunstan writes:
I'm curious what problem we're actually solving here, though. I've run
the buildfarm countless thousands of times on different VMs, and five of
my seven current animals run in
On Sat, Jan 28, 2012 at 10:18 AM, Tom Lane wrote:
> Andrew Dunstan writes:
>> I'm curious what problem we're actually solving here, though. I've run
>> the buildfarm countless thousands of times on different VMs, and five of
>> my seven current animals run in VMs, and I don't think I've ever seen
On Sat, 2012-01-28 at 13:18 -0500, Tom Lane wrote:
> Andrew Dunstan writes:
> > I'm curious what problem we're actually solving here, though. I've run
> > the buildfarm countless thousands of times on different VMs, and five of
> > my seven current animals run in VMs, and I don't think I've ever
On Sat, Jan 28, 2012 at 7:31 AM, Andrew Dunstan wrote:
>
>
> On 01/27/2012 11:52 PM, Noah Misch wrote:
>>>
>>> Is a platform-independent fsync be available at initdb time?
>>
>> Not sure.
>>
>
> It's a macro on Windows that calls _commit(fd), so it should be portable
> enough.
>
> I'm curious what
Andrew Dunstan writes:
> I'm curious what problem we're actually solving here, though. I've run
> the buildfarm countless thousands of times on different VMs, and five of
> my seven current animals run in VMs, and I don't think I've ever seen a
> failure ascribable to inadequately synced files
On Sat, 2012-01-28 at 10:31 -0500, Andrew Dunstan wrote:
> I'm curious what problem we're actually solving here, though. I've run
> the buildfarm countless thousands of times on different VMs, and five of
> my seven current animals run in VMs, and I don't think I've ever seen a
> failure ascriba
On 01/27/2012 11:52 PM, Noah Misch wrote:
Is a platform-independent fsync be available at initdb time?
Not sure.
It's a macro on Windows that calls _commit(fd), so it should be portable
enough.
I'm curious what problem we're actually solving here, though. I've run
the buildfarm countles
On Fri, Jan 27, 2012 at 04:19:41PM -0800, Jeff Davis wrote:
> It looks like initdb doesn't fsync all the files it creates, e.g. the
> PG_VERSION file.
>
> While it's unlikely that it would cause any real data loss, it can be
> inconvenient in some testing scenarios involving VMs.
>
> Thoughts? Wo
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