| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Alvaro Herrera <alvherre(at)commandprompt(dot)com> |
| Cc: | "Michael P(dot) Soulier" <michael_soulier(at)mitel(dot)com>, pgsql-general <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: Misunderstanding transactions and locks |
| Date: | 2010-06-16 20:37:17 |
| Message-ID: | 14198.1276720637@sss.pgh.pa.us |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-general |
Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes:
> Excerpts from Michael P. Soulier's message of mi jun 16 12:21:16 -0400 2010:
>> I'm trying to figure out why locking isn't working as I'm expecting. I have a
>> an operation wrapped in a transaction where I explicitely grab an exclusive
>> lock on my table. When another process concurrently runs to do the same, it
>> should block on attempting to acquire the exclusive lock, no?
>> 2010-06-16 12:14:31.913008500 LOG: statement: LOCK TABLE instances IN ROW
>> EXCLUSIVE MODE
> "row exclusive mode" does not block itself.
Specifically, see the table in
http://www.postgresql.org/docs/8.3/static/explicit-locking.html#LOCKING-TABLES
Exclusive lock modes are those that conflict with themselves; to wit,
SHARE ROW EXCLUSIVE mode or higher. The mode names are, um, historical.
regards, tom lane
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Adrian Klaver | 2010-06-16 22:14:12 | Re: Dynamic triggers |
| Previous Message | Alvaro Herrera | 2010-06-16 20:01:04 | Re: Misunderstanding transactions and locks |