Re: Vacuum as "easily obtained" locks

Michael Graham <mgraham(at)bloxx(dot)com> writes:

> On Wed, 2011-08-03 at 10:17 -0400, Tom Lane wrote:
>
>> Michael Graham <mgraham(at)bloxx(dot)com> writes:
>> > Would my applications
>> > constant polling of the queue mean that the lock could not be easily
>> > obtained?
>>
>> Very possible, depending on what duty cycle is involved there.
>
> Hmm. The clients aren't that aggressive, especially when they failed to
> find data on a previous select, there are 4 clients, they each poll
> every 10 seconds and the select runs in <1ms.
>
> It might be worth noting that they don't ever disconnect from the
> server, but I assume that is not an issue for getting the
> AccessExclusiveLock on the table?

You are certain that those clients do these quick select as
auto-commit?

What does select current_query from pg_stat_activity say?

--
Jerry Sievers
Postgres DBA/Development Consulting
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