Re: journaled FS and and WAL

On Fri, Oct 14, 2016 at 11:27 PM, Albe Laurenz <laurenz.albe@wien.gv.at> wrote:
> After a successful commit, the WAL file and its metadata are on disk.
> Moreover, the file metadata won't change (except for the write and access
> timestamps) because WAL files are created with their full size and never
> extended, so no WAL file should ever get "lost" because of partial metadata
> writes.

This behavior depends as well on the value of wal_sync_method. For
example with fdatasync the metadata is not flushed. It does not matter
any for for WAL segments as Albe has already mentioned, but the choice
here impacts performance.
--
Michael