[PERFORM] 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 t...@sss.pgh.pa.us 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.  

[PERFORM] 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 gsst...@mit.edu 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

[PERFORM] 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 gsst...@mit.edu 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-performance mailing

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

2010-01-19 Thread Andres Freund
Hi Greg, On Monday 18 January 2010 17:35:59 Greg Stark wrote: 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 would be much more natural to just loop through the files in the new directory. But I suppose it

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

2010-01-19 Thread Greg Smith
Greg Stark wrote: On Tue, Jan 19, 2010 at 2:52 PM, Greg Stark gsst...@mit.edu 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? I think the final

[PERFORM] 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

[PERFORM] 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 and...@anarazel.de 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

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

2009-12-28 Thread david
On Tue, 29 Dec 2009, Greg Stark wrote: On Mon, Dec 28, 2009 at 10:54 PM, Andres Freund and...@anarazel.de 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