On Wed, Jul 16, 2014 at 02:39:03PM -0700, Jeff Janes wrote: > On Wed, Jul 16, 2014 at 1:21 PM, Thomas Kellerer <spam_eater@xxxxxxx> wrote: > > Hi, > > I was reading trough the ToDo list in the Postgres Wiki and noticed that > one item for Fsync[1] seems to be obsolete: > > Determine optimal fdatasync/fsync, O_SYNC/O_DSYNC options and whether > fsync does anything > Ideally this requires a separate test program like /contrib/ > pg_test_fsync that can be run at initdb time or optionally later. > > This was added with 9.1[2] , so I guess that item can be removed from the > Wiki page? > > > The to-do item is not for pg_test_fsync to be created, but rather for initdb to > automatically invoke pg_test_fsync and then analyze the results and use that > analysis to set up the fsync method. > > But I do think this entry is obsolete. If a certain method is "too fast", is > that because the operating system lies and is not really syncing the data, or > is it because you have a BBU/NVRAM in front of the disk? Or because you aren't > using spinning disk at all? I don't think that there is any way for initdb to > safely figure out what is going on just based on the outcome of some timing > tests. The person who purchased the hardware has to apply their knowledge. TODO item removed. -- Bruce Momjian <bruce@xxxxxxxxxx> http://momjian.us EnterpriseDB http://enterprisedb.com + Everyone has their own god. +
