BUG #6365: Memory leak in insert and update

The following bug has been logged on the website:

Bug reference: 6365
Logged by: Otto Havasvölgyi
Email address: havasvolgyi(dot)otto(at)gmail(dot)com
PostgreSQL version: 9.1.2
Operating system: Win XP SP2 x86; Linux Debian 2.6.32 kernel x64
Description:

The bug can be reproduced with pgbench:

Insert script:

\set nbranches 1*:scale
\set ntellers 10*:scale
\set naccounts 100000*:scale
\setrandom aid 1 :naccounts
\setrandom bid 1 :nbranches
\setrandom tid 1 :ntellers
\setrandom delta -5000 5000
insert into pgbench_history (tid, bid, aid, delta, mtime) values (:tid,
:bid, :aid, :delta, current_timestamp);

Update script:

\set nbranches 1*:scale
\set ntellers 10*:scale
\set naccounts 100000*:scale
\setrandom aid 1 :naccounts
\setrandom bid 1 :nbranches
\setrandom tid 1 :ntellers
\setrandom delta -5000 5000
update pgbench_accounts set abalance = abalance + :delta where aid = :aid;

Steps:

./pgbench -i -Uotto test

./pgbench -c1 -j1 -T200 -Msimple -N -r -v -f insert.sql -Uotto testdb

./pgbench -c1 -j1 -T200 -Msimple -N -r -v -f update.sql -Uotto testdb

During this test a continuous increase of the backend memory comsumption can
be observed. During the insert test the increase is quite bigger than
during update.