Re: Sanity Check?

Lists: pgsql-hackers
From: "Larry Rosenman" <ler(at)lerctr(dot)org>
To: "'pgsql-hackers list'" <pgsql-hackers(at)postgresql(dot)org>
Cc: "'Tom Lane'" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Subject: Sanity Check?
Date: 2005-07-27 22:38:46
Message-ID: E1DxuYx-0002Ml-Af@lerami.lerctr.org
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SCO is seeing the following failure without -O, but no failure with -O:

The sanity_check diffs show:
*** ./expected/sanity_check.out Wed Jul 27 17:58:12 2005
--- ./results/sanity_check.out Wed Jul 27 18:09:41 2005
***************
*** 17,22 ****
--- 17,24 ----
circle_tbl | t
fast_emp4000 | t
func_index_heap | t
+ gcircle_tbl | t
+ gpolygon_tbl | t
hash_f8_heap | t
hash_i4_heap | t
hash_name_heap | t
***************
*** 67,73 ****
shighway | t
tenk1 | t
tenk2 | t
! (57 rows)

--
-- another sanity check: every system catalog that has OIDs should have
--- 69,75 ----
shighway | t
tenk1 | t
tenk2 | t
! (59 rows)

--
-- another sanity check: every system catalog that has OIDs should have

Any ideas? I'm **NOT** seeing this on my box, but.

LER

--
Larry Rosenman http://www.lerctr.org/~ler
Phone: +1 972-414-9812 E-Mail: ler(at)lerctr(dot)org
US Mail: 3535 Gaspar Drive, Dallas, TX 75220-3611 US


From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: "Larry Rosenman" <ler(at)lerctr(dot)org>
Cc: "'pgsql-hackers list'" <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Sanity Check?
Date: 2005-07-27 22:52:08
Message-ID: 12507.1122504728@sss.pgh.pa.us
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"Larry Rosenman" <ler(at)lerctr(dot)org> writes:
> SCO is seeing the following failure without -O, but no failure with -O:

> *** ./expected/sanity_check.out Wed Jul 27 17:58:12 2005
> --- ./results/sanity_check.out Wed Jul 27 18:09:41 2005
> ***************
> *** 17,22 ****
> --- 17,24 ----
> circle_tbl | t
> fast_emp4000 | t
> func_index_heap | t
> + gcircle_tbl | t
> + gpolygon_tbl | t
> hash_f8_heap | t
> hash_i4_heap | t
> hash_name_heap | t

Hmm. This looks like a race condition in the test to me. gcircle_tbl
and gpolygon_tbl are temp tables created during the create_index test.
They do have indexes, so if the backend that ran create_index hadn't
managed to delete 'em yet, it'd make sense that they show up in
sanity_check's query. And in the parallel regression schedule,
create_index does run directly before sanity_check.

Those temp tables are recently introduced, I believe, so the fact that
this hasn't been reported before doesn't mean it can't happen elsewhere
than SCO machines.

It's pretty surprising though that sanity_check manages to execute
a complete database-wide VACUUM before the create_index backend has
managed to drop its couple of temp tables. So there may be something
wrong with this explanation; or there might be something weird about
the kernel scheduling policy on their machine.

regards, tom lane


From: Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>
To: Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Sanity Check?
Date: 2005-07-27 23:12:24
Message-ID: 20050727231224.GN1832@alvh.no-ip.org
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Why does the sanity check test start with a VACUUM? Why not a VACUUM
FULL?

--
Alvaro Herrera (<alvherre[a]alvh.no-ip.org>)
"Los románticos son seres que mueren de deseos de vida"


From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>
Cc: Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Sanity Check?
Date: 2005-07-28 00:12:10
Message-ID: 13285.1122509530@sss.pgh.pa.us
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Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> writes:
> Why does the sanity check test start with a VACUUM? Why not a VACUUM
> FULL?

The test predates the existence of VACUUM FULL ;-); so that's what it
did originally. I think I deliberately left it as-is during the 7.2
devel cycle, so that the new lazy-vacuum code would get exercised.

I don't see any strong reason to change it now ...

regards, tom lane