too short string for SQL in pg_stat_backend_activity

Hello

I my work I have problem with some ugly SQL. Processing some query takes 2 
days and more (problem is in queries not in PostgreSQL). I can't wait on 
end of query and can't take text of query from serverlog. Text of queries 
has about 2 - 7 Kb. I have problem identifi queries in our is, becouse I 
can see only begin of queries in pg_stat_activity, and in this view is 
text of query cut on 1Kb. 

Can I set somewhere an long for text, which is in current_query in 
"pg_catalog.pg_stat_activity"?

Regards
Pavel Stehule