Re: Postresql 8.0 Beta 3 - SELECT ... FOR UPDATE

Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> Rod Taylor wrote:
>> Anyway, it shows a situation where it would be nice to differentiate
>> between statement_timeout and lock_timeout OR it demonstrates that I
>> should be using userlocks...

> Wouldn't a LOCK NOWAIT be a better solution? That is new in 8.0.

LOCK NOWAIT is only helpful if you can express your problem as not
wanting to wait for a table-level lock. When you're trying to grab a
row-level lock via SELECT FOR UPDATE, there isn't any provision for
NOWAIT.

The notion of a global lock_timeout setting is bogus IMHO, because
every proposed application of it has failed to consider the locks taken
internally by the system. But that objection wouldn't apply to a SELECT
FOR UPDATE NOWAIT command where the "no wait" behavior only applied to
the row lock being explicitly grabbed.

I thought I remembered someone working on such a thing just recently.

regards, tom lane