Re: [HACKERS] Re: [BUGS] General Bug Report: palloc fails with lots of ANDs and ORs

Vadim B. Mikheev <vadim@sable.krasnoyarsk.su>

From: "Vadim B. Mikheev" <vadim@sable.krasnoyarsk.su>
To: Bruce Momjian <maillist@candle.pha.pa.us>
Cc: David Hartwig <daveh@insightdist.com>, PostgreSQL-development <hackers@postgreSQL.org>
Date: 1998-01-15T04:34:26Z
Lists: pgsql-hackers
Bruce Momjian wrote:
> 
> > Bruce,
> >
> > I did some homework.   Here is what I have.   The default max data segment size on our (AIX 4.1.4) box is around 130000 kbytes.
> >
> > I put together a query which put me just past the threshold of the palloc "out of memory error".  It is as follows:
> >
> > create table outlet (
> >     number int,
> >     name varchar(30),
> >     ...
> > }
> >
> > create unique index outlet_key on outlet using btree (number);
> >
> > select count(*) from outlet
> > where
> >     (number = 1 and number = 1 and number = 1) or
> >     (number = 1 and number = 1 and number = 1) or
> >     (number = 1 and number = 1 and number = 1) or
> >     (number = 1 and number = 1 and number = 1) or
> >     (number = 1 and number = 1 and number = 1) or
> >     (number = 1 and number = 1 and number = 1) or
> >     (number = 1 and number = 1 and number = 1) or
> >     (number = 1 and number = 1 and number = 1) or
> >     (number = 1 and number = 1 and number = 1);
> >
...
> >
> 
> Wow, looks like a bug.  Vadim, why would this happen?  I got the same
> palloc failure message here, and there is NO data in the table.

This is bug in optimizer - try to EXPLAIN query...
I have no time to fix it now - could return to this after Feb 1.

Vadim