On 2014-09-29 14:09:01 +0530, Abhijit Menon-Sen wrote:
> Hi.
>
> I just noticed that initdb -S ("Safely write all database files to disk
> and exit") does (only) the following in perform_fsync:
>
> pre_sync_fname(pdir, true);
> walkdir(pg_data, pre_sync_fname);
>
> fsync_fname(pdir, true);
> walkdir(pg_data, fsync_fname);
>
> walkdir() reads the directory and calls itself recursively for S_ISDIR
> entries, or calls the function for S_ISREG entries… which means it
> doesn't follow links.
>
> Which means it doesn't fsync the contents of tablespaces.
Which means at least pg_upgrade is unsafe right
now... c.f. 630cd14426dc1daf85163ad417f3a224eb4ac7b0.
Note that the perform_fsync() *was* ok for its original purpose in
initdb. At the end of initdb there's no relevant tablespaces. But if
used *after* pg_upgrade, that's not necessarily the case.
Greetings,
Andres Freund
-- Andres Freund http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
Services