PostgreSQL-Slony error?

Hi all,

We have a master and a slave DB server (both PostgreSQL 8.3, Slony 2.0.1).
Maybe we were hasty, because we delete ~18 million rows from a table on
master with one SQL command. Slony log and transfer jobs/transactions to
the slave node, but on the slave node the slony can't do this job. Slony
starts the transaction, but after ~7 million delete commands the server
close the connection.

We found this in the Slony log:
2011-11-15 11:39:25 CET DEBUG4 remoteHelperThread_1_1: fetch from cursor
2011-11-15 11:39:25 CET ERROR remoteHelperThread_1_1: "fetch 500 from LOG;
" server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
2011-11-15 11:39:25 CET DEBUG4 remoteHelperThread_1_1: return 50 unused
line buffers
2011-11-15 11:39:25 CET ERROR remoteWorkerThread_1: "close LOG; "
PGRES_FATAL_ERROR 2011-11-15 11:39:25 CET ERROR remoteWorkerThread_1:
"rollback transaction; set enable_seqsca
n = default; set enable_indexscan = default; " PGRES_FATAL_ERROR 2011-11-15
11:39:25 CET DEBUG1 remoteHelperThread_1_1: 2850.992 seconds until close
cursor
2011-11-15 11:39:25 CET INFO remoteHelperThread_1_1: inserts=0 updates=0
deletes=7220000

We tried to tuning the PostgreSQL and now two times faster, but every
transaction stop after ~ 7 million rows. We couldn't find error message in
the PostgreSQL log.

Why stop the transaction? What should we do?

Thank you in advance,
Kyp