| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Tobias Brox <tobias(at)nordicbet(dot)com> |
| Cc: | John A Meinel <john(at)arbash-meinel(dot)com>, Yves Vindevogel <yves(dot)vindevogel(at)implements(dot)be>, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Limit clause not using index |
| Date: | 2005-06-21 21:20:07 |
| Message-ID: | 17468.1119388807@sss.pgh.pa.us |
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| Lists: | pgsql-performance |
Tobias Brox <tobias(at)nordicbet(dot)com> writes:
> [John A Meinel - Tue at 10:14:24AM -0500]
>> I believe if you drop the indexes inside a transaction, they will still
>> be there for other queries, and if you rollback instead of commit, you
>> won't lose anything.
> Has anyone tested this?
Certainly. Bear in mind though that DROP INDEX will acquire exclusive
lock on the index's table, so until you roll back, no other transaction
will be able to touch the table at all. So the whole thing may be a
nonstarter in a production database anyway :-(. You can probably get
away with
BEGIN;
DROP INDEX ...
EXPLAIN ...
ROLLBACK;
if you fire it from a script rather than by hand --- but EXPLAIN
ANALYZE might be a bad idea ...
regards, tom lane
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