i started out with a normal installation where the PGDATA dir was
/usr/local/pgsql/data
the database grew, so i created /data/pgsql/data, moved the data and symlinked
/usr/local/pgsql/data to point to /data/pgsql/data.
at some point, i changed the PGDATA env var in ~pgsql/.profile to be
/data/pgsql/data, hence when the postmaster started up, the PGDATA env var
supposedly overrode the -D flag.
(my pgsql.sh rc startup file sources ~pgsql/.profile)
time moves on, and i jiggled the disk around, and actually mounted a RAID
array as /usr/local/pgsql/data.
in that process, i added a symlink pointing /data/pgsql/data back to
/usr/local/pgsql/data.
i then updated ~pgsql/.profile to have PGDATA using /usr/local/pgsql/data
once again.
i nuked the /data/pgsql/data symlink, figuring that both PGDATA and -D
both pointed to /usr/local/pgsql/data.
my applications, which insert piles of records into several tables went fine.
for about 6 hours.
then the nightly job fired up, halted the insert processes, and attempted to
vacuum the database.
well, things got highly unpleasant.
the normal vacuum on the main table crashed with a message saying the backend
was gone.
i killed and restarted the postmaster, and couldn't even do a "\dt".
i recompiled and installed (maybe the binaries somehow got icked??).
still vacuum crashed.
figuring something got icky, i su'd to pgsql and attempted to vacuum template1.
crash again.
i thought about what i had done, and thought i'd put back the symlink, pointing
/data/pgsql/data to /usr/local/pgsql/data.
whamo, the vacuums worked fine.
now, it just gets more strange, after vacuuming several tables (but not all
of them), decided to do some dignostics.
i nuked the symlink, and the vacuums worked fine.
so, my questions are:
does something somewhere records the absolute pathname?
does vacuum update this item using PGDATA?
why are absolute pathnames stored?
--
[ Jim Mercer jim@reptiles.org +1 416 506-0654 ]
[ Reptilian Research -- Longer Life through Colder Blood ]
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