pgadmin sneaks a REINDEX into the SQL when you specify a change to the
fillfactor of an index.
That's not very handy because the Postgres manual says specifically that
ALTER INDEX doesn't issue a REINDEX. It's a perfectly valid thing to run
on its own, since it will affect the future growth of the index.
Issuing the REINDEX can lock the table for hours and shouldn't be issued
quietly on production systems. There should be a REINDEX immediate
option, or a reminder prompt.
It would be even better if there was an option to do that CONCURRENTLY,
i.e. add the new index and then drop the old one afterwards. (It's
unfortunate that there isn't a REINDEX concurrently, but there isn't
yet).
--
Simon Riggs
2ndQuadrant http://www.2ndQuadrant.com