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 sync files that bootstrap-mode backends had written. > > It doesn't make sense for initdb to take responsibility to sync files > created by the backend. If there are important files that the backend > creates, it should be the backend's responsibility to fsync them (and > their parent directory, if needed). And if they are unimportant to the > backend, then there is no reason for initdb to fsync them.
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 small handful of files and leave nearly everything else vulnerable. That being said, having each backend fsync its own writes will mean syncing certain files several times within a single initdb run. If the penalty from that proves high enough, we may do well to instead have initdb.c sync everything just once. > > 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 0.3s. So, we'd need some more convenient way to choose > the no-fsync option, like an environment variable that developers can > set. Or maybe developers don't care about 0.3s? Developers have shell aliases/functions/scripts and command history. I wouldn't object to having an environment variable control it, but I would not personally find that more convenient than a command-line switch. Thanks, nm -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
