error 57014

Hello.

The next query runs into error 57014 in about 50 % of the cases. We
certainly have not aborted the request. In the other 50 % it runs OK. The
statement is executed
in pgsql 7.4.8

Statement:
------------
SELECT pst.typ_stay, SUM(pst.nr_rooms), SUM(pst.nr_trans), SUM(pst.pst_amnt)
from pst where pst.companyc = 'H' AND pst.pst_date >= (date '2006-01-01')
AND pst.pst_date <= (date '2006-06-08') AND pst.pst_type IN (1,7) AND
pst.typ_stay IS NOT NULL AND pst.dpt_code = 'FO' GROUP BY pst.typ_stay ;

Extract logfile
----------------
2006-06-09 03:55:06 LOG: 00000: database system is ready
LOCATION: StartupXLOG, xlog.c:2946
2006-06-09 03:55:37 ERROR: 57014: canceling query due to user request
LOCATION: ProcessInterrupts, postgres.c:1964
STATEMENT: SELECT pst.typ_stay, SUM(pst.nr_rooms), SUM(pst.nr_trans),
SUM(pst.pst_amnt) from pst where pst.companyc = 'H' AND pst.pst_date >=
(date '2006-01-01') AND pst.pst_date <= (date '2006-06-08') AND pst.pst_type
IN (1,7) AND pst.typ_stay IS NOT NULL AND pst.dpt_code = 'FO' GROUP BY
pst.typ_stay ;
2006-06-09 03:56:07 LOG: 08P01: unexpected EOF on client connection

Anyone any idea?

Many thanks

Henk Sanders