Обсуждение: rule or trigger on select?

How can I update on select?

From the User's Guide, it seems triggers can only be used on INSERT,
UPDATE and DELTE events. As for rules, the guide says they can be used on
SELECT. When I actually tried updating on select using rules, here's what
I got:

test=> CREATE RULE tab_rule AS ON select
test-> TO tab
test-> DO UPDATE tab SET stats=stats+1;
ERROR:  only instead-select rules currently supported on select

My ultimate goal is to keep statistics for tab counting how many times
records are being selected. Unfortunately, I cannot simply use UPDATE
since my SELECT queries use LIMIT, which is not supported by UPDATE.

Looking forward to any suggestions,
Marc