On Tue, Feb 26, 2008 at 10:48 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> "Markus Bertheau" <mbertheau.pg@googlemail.com> writes:
> > 2008/2/27, Tom Lane <tgl@sss.pgh.pa.us>:
>
> >> No, what makes you think that? The index won't change at all in the
> >> above example. The major problem is, as Scott says, that DROP INDEX
> >> takes exclusive lock on the table so any other sessions will be locked
> >> out of it for the duration of your test query.
>
> > Why is the exclusive lock not taken later, so that this method can be
> > used reasonably risk-free on production systems?
>
> Er, later than what? Once the DROP is pending, other transactions can
> hardly safely use the index for lookups, and what should they do about
> insertions?
I see what you're saying. Sadly, my dreams of drop index concurrently
appear dashed.