Re: probs with postgres

> "Christopher Kings-Lynne" <chriskl(at)familyhealth(dot)com(dot)au> writes:
> > I keep getting this:
> > 2003-03-20 08:15:49 WARNING: Rel users_sessions: Uninitialized page
3195 -
> > fixing
>
> Hmm. In 7.2.* I'd have said this was a known problem, but in 7.3.* it's
> not. Want to dig into it? This is what I know about the 7.2 problem:
>
> http://fts.postgresql.org/db/mw/msg.html?mid=1357214

OK, well I can tell you this at the moment:

1. We're running 7.3.2
2. We do an hourly VACUUM ANALYZE. I do the odd VACUUM FULL (not on that
table) when I do large changes to tables.
3. users_sessions has heaps and heaps of reads and updates regular scan
deletes. There are lots of SELECT..FOR UPDATEs done on the table
4. Table def:

usa=# \d users_sessions
Table "public.users_sessions"
Column | Type | Modifiers
---------+--------------------------+------------------------
sid | character varying(32) | not null
name | character varying(32) | not null
val | text |
changed | timestamp with time zone | not null default 'now'
uid | integer | not null
Indexes: users_sessions_pkey primary key btree (sid, name),
users_sessions_cha_name_idx btree (changed, name),
users_sessions_uid_idx btree (uid)

5. We have been having load and stability problems with our Postgres since
we released a massive upgrade to our website. We did actually have one time
when Postgres crashed and the whole server rebooted when we got a bunch of
these:

Mar 20 09:25:54 serendipity /kernel: pmap_collect: collecting pv entries --
suggest increasing PMAP_SHPGPERPROC
Mar 20 09:27:09 serendipity /kernel: pmap_collect: collecting pv entries --
suggest increasing PMAP_SHPGPERPROC
Mar 20 09:28:29 serendipity last message repeated 2 times
Mar 20 09:29:42 serendipity /kernel: pmap_collect: collecting pv entries --
suggest increasing PMAP_SHPGPERPROC

So I reduced our shared buffers by a few thousand and I'm waiting on our
sysadmin to up the max pages per proc in the kernel.

Any ideas on anything I can look into?

Chris