pgsql: In predtest.c, install a limit on the number of branches we will

From: tgl(at)postgresql(dot)org (Tom Lane)
To: pgsql-committers(at)postgresql(dot)org
Subject: pgsql: In predtest.c, install a limit on the number of branches we will
Date: 2008-11-12 23:08:43
Message-ID: 20081112230843.0D65B7545A4@cvs.postgresql.org
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-committers

Log Message:
-----------
In predtest.c, install a limit on the number of branches we will process in
AND, OR, or equivalent clauses: if there are too many (more than 100) just
exit without proving anything. This ensures that we don't spend O(N^2) time
trying (and most likely failing) to prove anything about very long IN lists
and similar cases.

Also, install a couple of CHECK_FOR_INTERRUPTS calls to ensure that a long
proof attempt can be interrupted.

Per gripe from Sergey Konoplev.

Back-patch the whole patch to 8.2 and just the CHECK_FOR_INTERRUPTS addition
to 8.1. (The rest of the patch doesn't apply cleanly, and since 8.1 doesn't
show the complained-of behavior anyway, it doesn't seem necessary to work
hard on it.)

Tags:
----
REL8_3_STABLE

Modified Files:
--------------
pgsql/src/backend/optimizer/util:
predtest.c (r1.19 -> r1.19.2.1)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/util/predtest.c?r1=1.19&r2=1.19.2.1)

Browse pgsql-committers by date

  From Date Subject
Next Message Tom Lane 2008-11-12 23:08:50 pgsql: In predtest.c, install a limit on the number of branches we will
Previous Message Tom Lane 2008-11-12 23:08:37 pgsql: In predtest.c, install a limit on the number of branches we will