Re: rapid degradation after postmaster restart - Mailing list pgsql-performance

Joe Conway wrote:

> Yeah, I'm sure. Snippets from the log:
>
> [...lots-o-tables...]
> [2004-03-14 12:44:48 PM] added table: specdb."public"."parametric_states"
> [2004-03-14 12:49:48 PM] Performing: VACUUM ANALYZE
> "public"."transaction_data"
> [2004-03-14 01:29:59 PM] Performing: VACUUM ANALYZE
> "public"."transaction_data"
> [2004-03-14 02:08:26 PM] Performing: ANALYZE "public"."out_of_spec"
> [2004-03-14 02:08:26 PM] Performing: VACUUM ANALYZE
> "public"."transaction_data"
> [2004-03-14 02:22:44 PM] Performing: VACUUM ANALYZE "public"."spc_graphs"
> [2004-03-14 03:06:45 PM] Performing: VACUUM ANALYZE
> "public"."out_of_spec"
> [2004-03-14 03:06:45 PM] Performing: VACUUM ANALYZE
> "public"."transaction_data"
> [2004-03-14 03:19:51 PM] Performing: VACUUM ANALYZE "public"."spc_graphs"
> [2004-03-14 03:21:09 PM] Performing: ANALYZE "public"."parametric_states"
> [2004-03-14 03:54:57 PM] Performing: ANALYZE "public"."out_of_spec"
> [2004-03-14 03:54:57 PM] Performing: VACUUM ANALYZE
> "public"."transaction_data"
> [2004-03-14 04:07:52 PM] Performing: VACUUM ANALYZE "public"."spc_graphs"
> [2004-03-14 04:09:33 PM] Performing: ANALYZE
> "public"."equip_status_history"
> [2004-03-14 04:09:33 PM] Performing: VACUUM ANALYZE
> "public"."parametric_states"
> [2004-03-14 04:43:46 PM] Performing: VACUUM ANALYZE
> "public"."out_of_spec"
> [2004-03-14 04:43:46 PM] Performing: VACUUM ANALYZE
> "public"."transaction_data"
> [2004-03-14 04:56:35 PM] Performing: VACUUM ANALYZE "public"."spc_graphs"
> [2004-03-14 04:58:32 PM] Performing: ANALYZE "public"."parametric_states"
> [2004-03-14 05:28:58 PM] added database: specdb


Yeah, you're right.....

> This is the entire period of the first test, with default autovac
> settings. The table "public"."transaction_data" is the one with 28
> million active rows. The entire test run inserts about 600 x 600 =
> 360,000 rows, out of which roughly two-thirds are later deleted.


Strange... I wonder if this is some integer overflow problem.  There was
one reported recently and fixed as of CVS head yesterday, you might try
that, however without the -d2 output I'm only guessing at why
pg_autovacuum is vacuuming so much / so often.

> I can try. The server belongs to another department, and they are
> under the gun to get back on track with their testing. Also, they
> compiled without debug symbols, so I need to get permission to recompile.


Good luck, I hope you can get permission.  Would e nice to fix this
little crash.

>> Yes I would be very curious to see the results with the vacuum delay
>> patch installed (is that patch applied to HEAD?)
>
>
> Any idea where I can get my hands on the latest version. I found the
> original post from Tom, but I thought there was a later version with
> both number of pages and time to sleep as knobs.


I think Jan posted one a while back....  [searches archives...]  But I
must say I'm at a loss to find it in the archives.  Anyone know where a
good delay patch is for 7.4?   If we can't find one, any chance you can
do some testing with CVS HEAD just to see if that works any better.  I
know there has been a fair amount of work done to improve this situation
(not just vacuum delay, but ARC etc...)
.