From: | "John Li" <john(dot)li(at)earthlink(dot)net> |
---|---|
To: | "Rod Taylor" <pg(at)rbt(dot)ca>, "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | "PostgreSQL Development" <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Slow DROP INDEX |
Date: | 2004-02-16 19:08:49 |
Message-ID: | EBECLIDIJCMMAPENHIFLIEFACEAA.john.li@earthlink.net |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
Based on my experience, "drop index" is waiting for a chance to place the
lock. If all those queries are within the same connection, "drop index" has
to wait until that connection disconnected.
John Li
-----Original Message-----
From: pgsql-hackers-owner(at)postgresql(dot)org
[mailto:pgsql-hackers-owner(at)postgresql(dot)org]On Behalf Of Rod Taylor
Sent: Monday, February 16, 2004 10:56 AM
To: Tom Lane
Cc: PostgreSQL Development
Subject: Re: [HACKERS] Slow DROP INDEX
On Mon, 2004-02-16 at 13:03, Tom Lane wrote:
> Rod Taylor <pg(at)rbt(dot)ca> writes:
> > The real question is why does DROP INDEX take more than a couple of
> > seconds to complete? It is not held up by locked.
>
> AFAICS it shouldn't take any time to complete. I think you're mistaken
> and it is blocking on a lock (it will want exclusive lock on the table).
> Everyone else will then queue up behind it.
I not convinced it is waiting on a lock. The queries on that table are
very short (couple of milliseconds) -- but there are a ton of them. All
backends appear to be idle (pg_stat_activity with command shown) when we
start the drop and shortly after huge backups occur.
---------------------------(end of broadcast)---------------------------
TIP 7: don't forget to increase your free space map settings
From | Date | Subject | |
---|---|---|---|
Next Message | Tom Lane | 2004-02-16 19:23:42 | Re: Proposed Query Planner TODO items |
Previous Message | Tom Lane | 2004-02-16 19:05:04 | Re: Slow DROP INDEX |