Memory grows without bounds in aggregates!

Hello,

I have downloaded the latest snapshot-version from 27th, compiled and
installed it onto a Linux 2.1.131, libc6 I have the following table:

CREATE TABLE "west0" (
"lfnr" int8,
"kdnr" int8,
"artnr" int8,
"eknumsatz" float8,
"ekumsatz" float8,
"vkumsatz" float8,
"lvkumsatz" float8,
"menge" float8,
"anz" int2,
"datum" date);

Doing the following is quite fast and memory usage of the postmaster is
ok (abt 3MB).

stamm=> select count(*) from west0;
count
--------
12290703
(1 row)

But doing the following aggregate on the same table will crash the
backend:

stamm=> select sum(ekumsatz), sum(vkumsatz),sum(lvkumsatz),count(*) from
west0;
pqReadData() -- backend closed the channel unexpectedly.
This probably means the backend terminated abnormally
before or while processing the request.
We have lost the connection to the backend, so further processing is
impossible. Terminating.

Take a look at the output of top after about 2 minutes:

6:43pm up 25 days, 10:19, 1 user, load average: 1.97, 0.71, 0.42
70 processes: 68 sleeping, 2 running, 0 zombie, 0 stopped
CPU states: 25.6% user, 11.1% system, 1.5% nice, 63.4% idle
Mem: 257244K av, 254048K used, 3196K free, 6116K shrd, 13100K buff

Swap: 130748K av, 122264K used, 8484K free 18812K
cached

PID USER PRI NI SIZE RSS SHARE STAT LIB %CPU %MEM TIME
COMMAND
12253 postgres 16 0 304M 205M 1148 R 0 33.8 81.7 2:00
postmaster
^^^^^^^^^^

Any idea?

Kind regards

Michael Contzen

Dohle Handelsgruppe Systemberatung GmbH, Germany
E-Mail mcontzen(at)dohle(dot)com