[Bizgres-general] Transactional Statement Queuing

[Mark Kirkwood]

Mark Kirkwood wrote:
> Jim C. Nasby wrote:
> 
>> Another possibility is bringing query plan cost into the picture. For
>> example, it seems silly to hold off on a query that we know will be very
>> fast just because there's a bunch of monster queries ahead of it.
>>
> 
> Yeah - I'm thinking some sort of minimum cost threshold might be a good 
> idea,  so that (for instance) the other users' OLAP session don't freeze 
> simply because they are looking up values in the time dimension while 
> setting up their main query to run...

Altho this sounds good, on reflection I might have fallen straight
into the deadlock trap (c.f. from the original mail):


> Request for Active Slots will be made at start of a transaction and
> will
> be held until *end of transaction*. Holding an active slot is possible
> even if nothing is being executed while "Idle in Transaction". This
> behaviour ensures that we do not get resource deadlocks caused by
> statements holding resources not being able to execute. [Discuss]
>

So - I'm not sure the threshold idea is workable.

regards

Mark