Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-14 Thread Greg Stark
On Sun, Feb 14, 2010 at 8:57 PM, Robert Haas wrote: > On a pragmatic note, if this does turn out to be a problem, it's a > bug: and we can and do fix bugs whenever we discover them.  But the > other part of this patch - to speed up createdb - is a feature - and > we are very rapidly running out of

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-14 Thread Andres Freund
On Sunday 14 February 2010 21:57:08 Robert Haas wrote: > On Sun, Feb 14, 2010 at 10:31 AM, Greg Stark wrote: > > On Sun, Feb 14, 2010 at 2:03 PM, Greg Stark wrote: > >> On Fri, Feb 12, 2010 at 3:49 PM, Robert Haas wrote: > >>> Greg Stark, have you managed to get your access issues sorted out?

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-14 Thread Robert Haas
On Sun, Feb 14, 2010 at 10:31 AM, Greg Stark wrote: > On Sun, Feb 14, 2010 at 2:03 PM, Greg Stark wrote: >> On Fri, Feb 12, 2010 at 3:49 PM, Robert Haas wrote: >>> Greg Stark, have you managed to get your access issues sorted out?  If >> >> Yep, will look at this today. > > So I think we have a

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-14 Thread Tom Lane
Andres Freund writes: > On Sunday 14 February 2010 18:11:39 Tom Lane wrote: >> It seems to me that we're talking about a huge hit in both code >> complexity and performance to deal with a problem that doesn't actually >> occur in the field; and which furthermore is trivially solved on any >> moder

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-14 Thread Andres Freund
On Sunday 14 February 2010 18:11:39 Tom Lane wrote: > Greg Stark writes: > > So I think we have a bigger problem than just copydir.c. It seems to > > me we should be fsyncing the table space data directories on every > > checkpoint. > > Is there any evidence that anyone anywhere has ever lost dat

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-14 Thread Tom Lane
Greg Stark writes: > So I think we have a bigger problem than just copydir.c. It seems to > me we should be fsyncing the table space data directories on every > checkpoint. Is there any evidence that anyone anywhere has ever lost data because of a lack of directory fsyncs? I sure don't recall an

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-14 Thread Greg Stark
On Sun, Feb 14, 2010 at 2:03 PM, Greg Stark wrote: > On Fri, Feb 12, 2010 at 3:49 PM, Robert Haas wrote: >> Greg Stark, have you managed to get your access issues sorted out?  If > > Yep, will look at this today. So I think we have a bigger problem than just copydir.c. It seems to me we should b

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-14 Thread Greg Stark
On Fri, Feb 12, 2010 at 3:49 PM, Robert Haas wrote: > Greg Stark, have you managed to get your access issues sorted out?  If Yep, will look at this today. -- greg -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-12 Thread Robert Haas
On Wed, Feb 10, 2010 at 9:27 PM, Andres Freund wrote: > On Monday 08 February 2010 05:53:23 Robert Haas wrote: >> On Sun, Feb 7, 2010 at 10:09 PM, Alvaro Herrera >> >> wrote: >> > Andres Freund escribió: >> >> I personally think the fsync on the directory should be added to the >> >> stable branc

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-10 Thread Andres Freund
On Monday 08 February 2010 05:53:23 Robert Haas wrote: > On Sun, Feb 7, 2010 at 10:09 PM, Alvaro Herrera > > wrote: > > Andres Freund escribió: > >> I personally think the fsync on the directory should be added to the > >> stable branches - other opinions? > >> If wanted I can prepare patches for

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-08 Thread Andres Freund
On Monday 08 February 2010 19:34:01 Greg Stark wrote: > On Mon, Feb 8, 2010 at 4:53 AM, Robert Haas wrote: > > On Sun, Feb 7, 2010 at 10:09 PM, Alvaro Herrera > > > >> Yeah, it seems there are two patches here -- one is the addition of > >> fsync_fname() and the other is the fsync_prepare stuff.

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-08 Thread Greg Stark
On Mon, Feb 8, 2010 at 4:53 AM, Robert Haas wrote: > On Sun, Feb 7, 2010 at 10:09 PM, Alvaro Herrera >> Yeah, it seems there are two patches here -- one is the addition of >> fsync_fname() and the other is the fsync_prepare stuff. Sorry, I'm just catching up on my mail from FOSDEM this past weeke

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-07 Thread Andres Freund
On Monday 08 February 2010 05:53:23 Robert Haas wrote: > On Sun, Feb 7, 2010 at 10:09 PM, Alvaro Herrera > > wrote: > > Andres Freund escribió: > >> I personally think the fsync on the directory should be added to the > >> stable branches - other opinions? > >> If wanted I can prepare patches for

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-07 Thread Robert Haas
On Sun, Feb 7, 2010 at 10:09 PM, Alvaro Herrera wrote: > Andres Freund escribió: >> I personally think the fsync on the directory should be added to the stable >> branches - other opinions? >> If wanted I can prepare patches for that. > > Yeah, it seems there are two patches here -- one is the add

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-07 Thread Alvaro Herrera
Andres Freund escribió: > I personally think the fsync on the directory should be added to the stable > branches - other opinions? > If wanted I can prepare patches for that. Yeah, it seems there are two patches here -- one is the addition of fsync_fname() and the other is the fsync_prepare stuf

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-07 Thread Andres Freund
On Sunday 07 February 2010 19:27:02 Andres Freund wrote: > On Sunday 07 February 2010 19:23:10 Robert Haas wrote: > > On Sun, Feb 7, 2010 at 11:24 AM, Tom Lane wrote: > > > Greg Smith writes: > > >> This is turning into yet another one of those situations where > > >> something simple and useful

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-07 Thread Andres Freund
On Sunday 07 February 2010 19:23:10 Robert Haas wrote: > On Sun, Feb 7, 2010 at 11:24 AM, Tom Lane wrote: > > Greg Smith writes: > >> This is turning into yet another one of those situations where something > >> simple and useful is being killed by trying to generalize it way more > >> than it ne

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-07 Thread Robert Haas
On Sun, Feb 7, 2010 at 11:24 AM, Tom Lane wrote: > Greg Smith writes: >> This is turning into yet another one of those situations where something >> simple and useful is being killed by trying to generalize it way more >> than it needs to be, given its current goals and its lack of external >> in

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-07 Thread Tom Lane
Greg Smith writes: > This is turning into yet another one of those situations where something > simple and useful is being killed by trying to generalize it way more > than it needs to be, given its current goals and its lack of external > interfaces. There's no catversion bump or API breakage

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-07 Thread Greg Smith
Robert Haas wrote: Well it seems that what we're trying to implement is more like it_would_be_nice_if_you_would_start_syncing_this_file_range_but_its_ok_if_you_dont(), so maybe that would work. Anyway, is there something that we can agree on and get committed here for 9.0, or should we postpone

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-06 Thread Robert Haas
On Sat, Feb 6, 2010 at 7:03 AM, Andres Freund wrote: > On Saturday 06 February 2010 06:03:30 Greg Smith wrote: >> Andres Freund wrote: >> > On 02/03/10 14:42, Robert Haas wrote: >> >> Well, maybe we should start with a discussion of what kernel calls >> >> you're aware of on different platforms an

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-06 Thread Andres Freund
On Saturday 06 February 2010 06:03:30 Greg Smith wrote: > Andres Freund wrote: > > On 02/03/10 14:42, Robert Haas wrote: > >> Well, maybe we should start with a discussion of what kernel calls > >> you're aware of on different platforms and then we could try to put an > >> API around it. > > > > I

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-05 Thread Greg Smith
Andres Freund wrote: On 02/03/10 14:42, Robert Haas wrote: Well, maybe we should start with a discussion of what kernel calls you're aware of on different platforms and then we could try to put an API around it. In linux there is sync_file_range. On newer Posixish systems one can emulate that w

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-03 Thread Andres Freund
On 02/03/10 14:42, Robert Haas wrote: On Wed, Feb 3, 2010 at 6:53 AM, Greg Stark wrote: On Tue, Feb 2, 2010 at 7:45 PM, Robert Haas wrote: I think you're probably right, but it's not clear what the new name should be until we have a comment explaining what the function is responsible for. S

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-03 Thread Robert Haas
On Wed, Feb 3, 2010 at 6:53 AM, Greg Stark wrote: > On Tue, Feb 2, 2010 at 7:45 PM, Robert Haas wrote: >> I think you're probably right, but it's not clear what the new name >> should be until we have a comment explaining what the function is >> responsible for. > > So I wrote some comments but w

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-03 Thread Andres Freund
On 02/03/10 12:53, Greg Stark wrote: On Tue, Feb 2, 2010 at 7:45 PM, Robert Haas wrote: I think you're probably right, but it's not clear what the new name should be until we have a comment explaining what the function is responsible for. So I wrote some comments but wasn't going to repost th

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-03 Thread Greg Stark
On Tue, Feb 2, 2010 at 7:45 PM, Robert Haas wrote: > I think you're probably right, but it's not clear what the new name > should be until we have a comment explaining what the function is > responsible for. So I wrote some comments but wasn't going to repost the patch with the unchanged name wit

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-02 Thread Robert Haas
On Tue, Feb 2, 2010 at 2:33 PM, Tom Lane wrote: > Robert Haas writes: >> Hmm, in that case, I think the problem is that this function has no >> comment explaining its intended charter. > > That's certainly a big problem, but a comment won't fix the fact that > the name is misleading.  We need bot

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-02 Thread Tom Lane
Robert Haas writes: > Hmm, in that case, I think the problem is that this function has no > comment explaining its intended charter. That's certainly a big problem, but a comment won't fix the fact that the name is misleading. We need both a comment and a name change. re

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-02 Thread Robert Haas
On Fri, Jan 29, 2010 at 1:56 PM, Greg Stark wrote: > On Tue, Jan 19, 2010 at 3:25 PM, Tom Lane wrote: >> That function *seriously* needs documentation, in particular the fact >> that it's a no-op on machines without the right kernel call.  The name >> you've chosen is very bad for those semantics

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-02 Thread Andres Freund
On Tuesday 02 February 2010 20:06:32 Robert Haas wrote: > On Tue, Feb 2, 2010 at 1:34 PM, Andres Freund wrote: > > For now it could - but it very well might be converted to sync_file_range > > or similar, which would have different "sideeffects". > > > > As the potential code duplication is rathe

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-02 Thread Robert Haas
On Tue, Feb 2, 2010 at 1:34 PM, Andres Freund wrote: > For now it could - but it very well might be converted to sync_file_range or > similar, which would have different "sideeffects". > > As the potential code duplication is rather small I would prefer to describe > the prime effect not the sidee

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-02 Thread Andres Freund
On Tuesday 02 February 2010 19:14:40 Robert Haas wrote: > On Tue, Feb 2, 2010 at 12:50 PM, Tom Lane wrote: > > Andres Freund writes: > >> On Tuesday 02 February 2010 18:36:12 Robert Haas wrote: > >>> I took a look at this patch today and I agree with Tom that > >>> pg_fsync_start() is a very conf

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-02 Thread Robert Haas
On Tue, Feb 2, 2010 at 12:50 PM, Tom Lane wrote: > Andres Freund writes: >> On Tuesday 02 February 2010 18:36:12 Robert Haas wrote: >>> I took a look at this patch today and I agree with Tom that >>> pg_fsync_start() is a very confusing name.  I don't know what the >>> right name is, but this doe

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-02 Thread Andres Freund
On Tuesday 02 February 2010 18:36:12 Robert Haas wrote: > On Fri, Jan 29, 2010 at 1:56 PM, Greg Stark wrote: > > On Tue, Jan 19, 2010 at 3:25 PM, Tom Lane wrote: > >> That function *seriously* needs documentation, in particular the fact > >> that it's a no-op on machines without the right kernel

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-02-02 Thread Tom Lane
Andres Freund writes: > On Tuesday 02 February 2010 18:36:12 Robert Haas wrote: >> I took a look at this patch today and I agree with Tom that >> pg_fsync_start() is a very confusing name. I don't know what the >> right name is, but this doesn't fsync so I don't think it shuld have >> fsync in th

[HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-01-29 Thread Greg Stark
On Tue, Jan 19, 2010 at 3:25 PM, Tom Lane wrote: > That function *seriously* needs documentation, in particular the fact > that it's a no-op on machines without the right kernel call.  The name > you've chosen is very bad for those semantics.  I'd pick something > else myself.  Maybe "pg_start_dat

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-01-26 Thread Greg Smith
Greg Stark wrote: Actually before we get there could someone who demonstrated the speedup verify that this patch still gets that same speedup? Let's step back a second and get to the bottom of why some people are seeing this and others aren't. The original report here suggested this was a

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-01-19 Thread Andres Freund
On Tuesday 19 January 2010 15:57:14 Greg Stark wrote: > On Tue, Jan 19, 2010 at 2:52 PM, Greg Stark wrote: > > Barring any objections shall I commit it like this? > > Actually before we get there could someone who demonstrated the > speedup verify that this patch still gets that same speedup? At

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-01-19 Thread Tom Lane
Greg Stark writes: > 1) moved the posix_fadvise call to a new fd.c function > pg_fsync_start(fd,offset,nbytes) which initiates an fsync without > waiting on it. Currently it's only implemented with > posix_fadvise(DONT_NEED) but I want to look into using sync_file_range > in the future -- it looks

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-01-19 Thread Andres Freund
On Tuesday 19 January 2010 15:52:25 Greg Stark wrote: > On Mon, Jan 18, 2010 at 4:35 PM, Greg Stark wrote: > > Looking at this patch for the commitfest I have a few questions. > > So I've touched this patch up a bit: > > 1) moved the posix_fadvise call to a new fd.c function > pg_fsync_start(fd,

[HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-01-19 Thread Greg Stark
On Tue, Jan 19, 2010 at 2:52 PM, Greg Stark wrote: > Barring any objections shall I commit it like this? Actually before we get there could someone who demonstrated the speedup verify that this patch still gets that same speedup? -- greg -- Sent via pgsql-hackers mailing list (pgsql-hackers@p

[HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-01-19 Thread Greg Stark
On Mon, Jan 18, 2010 at 4:35 PM, Greg Stark wrote: > Looking at this patch for the commitfest I have a few questions. So I've touched this patch up a bit: 1) moved the posix_fadvise call to a new fd.c function pg_fsync_start(fd,offset,nbytes) which initiates an fsync without waiting on it. Curre

[HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2010-01-18 Thread Greg Stark
Looking at this patch for the commitfest I have a few questions. 1) You said you added an fsync of the new directory -- where is that I don't see it anywhere. 2) Why does the second pass to do the fsyncs read through fromdir to find all the filenames. I find that odd and counterintuitive. It woul

Re: [HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2009-12-28 Thread Andres Freund
On Tuesday 29 December 2009 01:27:29 Greg Stark wrote: > On Mon, Dec 28, 2009 at 10:54 PM, Andres Freund wrote: > > fsync everything in that pass. > > Including the directory - which was not done before and actually might be > > necessary in some cases. > > Er. Yes. At least on ext4 this is prett

[HACKERS] Re: Faster CREATE DATABASE by delaying fsync (was 8.4.1 ubuntu karmic slow createdb)

2009-12-28 Thread Greg Stark
On Mon, Dec 28, 2009 at 10:54 PM, Andres Freund wrote: > fsync everything in that pass. > Including the directory - which was not done before and actually might be > necessary in some cases. Er. Yes. At least on ext4 this is pretty important. I wish it weren't, but it doesn't look like we're goin