On Tue, Nov 29, 2011 at 11:15 AM, Craig James
<craig_james@emolecules.com> wrote:
> Several times recently one of our databases has gotten stuck with the
> following situation:
>
> postgres=# select datname, procpid, usename, current_query from
> pg_stat_activity where current_query != '<IDLE>';
> datname | procpid | usename |
> current_query
>
------------+---------+----------+--------------------------------------------------------------------------------------------------------
> emolecules | 13503 | customerdb | select tableid from hitlist_table_pool
> where hitlistid <= 0 for update
> emolecules | 32082 | customerdb | select tableid from hitlist_table_pool
> where hitlistid <= 0 for update
> emolecules | 17974 | customerdb | select tableid from hitlist_table_pool
> where hitlistid <= 0 for update
> emolecules | 31299 | customerdb | select tableid from hitlist_table_pool
> where hitlistid = 0 limit 1 for update
> emolecules | 30247 | customerdb | select tableid from hitlist_table_pool
> where hitlistid = 0 limit 1 for update
> postgres | 1705 | postgres | select datname, procpid, usename,
> current_query from pg_stat_activity where current_query != '<IDLE>';
> emolecules | 28866 | customerdb | <IDLE> in transaction
> emolecules | 21394 | customerdb | select tableid from hitlist_table_pool
> where hitlistid = 0 limit 1 for update
> emolecules | 22237 | customerdb | select tableid from hitlist_table_pool
> where hitlistid = 0 limit 1 for update
> (9 rows)
>
> It's obvious that they're all waiting ... but for what? The "<IDLE>"
> process looks like the culprit, but how do I figure out what it's doing?
> The next time this happens, what queries can I run to help diagnose what's
> going on?
> This is PG 8.4.4 on Ubuntu 10.
Does this help?
http://wiki.postgresql.org/wiki/Lock_Monitoring