On Wed, Aug 7, 2013 at 07:04:43PM +0100, Thom Brown wrote: > On 7 August 2013 18:49, Jon Nelson <jnelson+pg...@jamponi.net> wrote: > > On Wed, Aug 7, 2013 at 12:42 PM, Thom Brown <t...@linux.com> wrote: > >> for i in 1 2 5 10 100; do ./test_fallocate foo $i 1; done > >> method: classic. 1 open/close iterations, 1 rewrite in 0.6380s > >> method: posix_fallocate. 1 open/close iterations, 1 rewrite in 0.3204s > >> method: glibc emulation. 1 open/close iterations, 1 rewrite in 0.6274s > >> method: classic. 2 open/close iterations, 1 rewrite in 1.2908s > >> method: posix_fallocate. 2 open/close iterations, 1 rewrite in 0.6596s > >> method: glibc emulation. 2 open/close iterations, 1 rewrite in 1.2666s > >> method: classic. 5 open/close iterations, 1 rewrite in 3.1419s > >> method: posix_fallocate. 5 open/close iterations, 1 rewrite in 1.5930s > >> method: glibc emulation. 5 open/close iterations, 1 rewrite in 3.1516s > >> method: classic. 10 open/close iterations, 1 rewrite in 6.2912s > >> method: posix_fallocate. 10 open/close iterations, 1 rewrite in 3.2626s > >> method: glibc emulation. 10 open/close iterations, 1 rewrite in 6.3667s > >> method: classic. 100 open/close iterations, 1 rewrite in 67.4174s > >> method: posix_fallocate. 100 open/close iterations, 1 rewrite in 37.8788s > >> method: glibc emulation. 100 open/close iterations, 1 rewrite in 55.0714s > > > > OK. That's interesting, and a good data point. > > > > One thing you could try manually disabling the use of posix_fallocate in > > 269e78. > > After running ./configure --stuff-here > > edit src/include/pg_config.h and comment out the following line (on or > > around line 374) > > #define HAVE_POSIX_FALLOCATE 1 > > > > *then* build postgresql and see if the performance hit is still there. > > Okay, done that. The TPS increases again: > > 2308.807568 / 2554.264572 / 2563.190204 > > And I did run ./configure... before removing the line, and built it > after the change.
Where are we on this issue? -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + It's impossible for everything to be true. + -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers