BUG #1186: Broken Index?

The following bug has been logged online:

Bug reference: 1186
Logged by: Gosen, Hitoshi

Email address: mic-gosen(at)ns(dot)inter-mic(dot)co(dot)jp

PostgreSQL version: 7.4

Operating system: linux 2.4.18

Description: Broken Index?

Details:

Hello All,
We are using PostgreSQL 7.4.2 for our website that handles over 200,000
transactions a day.
About a month ago, the responses from the SELECT queries on the database
became terribly slow.
We tried to anaylze the cause of the problem, searching throught the system
logs and all, but nothing appeared to be out of the ordinary.

What we did to resolve this was to dump the database, delete the database,
recreate the database, and finally restore it. After that, things were back
to normal.

From the above experience, we were able to hypothesize that the fault of the
slow responses was not from a broken data or hardware failures, but from a
broken index, since we were able to recover 100% of the data on the same
machine.

Today, the same problem occured, and the same actions are going to be taken
to temporary resolve it.

Final note: we will also experiment with the 'vacuum full' command to see
if it counters this problem.