strange memory-consumming psql ...

just a moment ago friend sent me strange log.
it is partial output of ps auxww on linux system:
---
root      1308  0.0  0.1  4744  248 ?        S    Nov29 0:01 /usr/lib/postfix/master
postgres  8095  0.0  0.6  7816  784 pts/21   S    Nov30 2:07 /usr/bin/postmaster -i -D /var/lib/pgsql -o -Q
postgres 29739  0.2  2.4  7392 3152 pts/21   S    Dec03 5:14 /usr/bin/postgres localhost agaran test001 idle
agaran   25448  0.0  0.7  1984  992 pts/14   S    16:51 0:00 grep -i post
agaran   27789  0.0 58.8 77392 74416 pts/13  S    Dec03 1:00 psql
---

as you can see the psql process is >77 megabytes !
actually this process was nto doing anything - jsut waiting for another query.
it looks like it was caching some query results or something like that.
i don't know what was the queries run on the psql, but ... it just looks werid.

any ideas on what could have been wrong?

depesz

--
hubert depesz lubaczewski
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     najwspanialszą rzeczą jaką dało nam nowoczesne społeczeństwo,
      jest niesamowita wręcz łatwość unikania kontaktów z nim ...