Re: Parallel Seq Scan - Mailing list pgsql-hackers

From Amit Langote
Subject Re: Parallel Seq Scan
Date
Msg-id 55026D14.2090604@lab.ntt.co.jp
Whole thread Raw
In response to Re: Parallel Seq Scan  (Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>)
List pgsql-hackers
On 13-03-2015 PM 01:37, Amit Langote wrote:
> By the way, is it right that TupleQueueFunnel.queue has one shm_mq_handle per
> initialized parallel worker? If so, how does TupleQueueFunnel.maxqueues relate
> to ParallelContext.nworkers (of the corresponding parallel context)?
> 
> Why I asked this is because in CreateTupleQueueFunnel():
> 
>     funnel->maxqueues = 8;
>     funnel->queue = palloc(funnel->maxqueues * sizeof(shm_mq_handle *));
> 
> So, is the hardcoded "8" intentional or an oversight?
> 

Oh, I see that in RegisterTupleQueueOnFunnel(), the TupleQueueFunnel.queue is
expanded (repalloc'd) if needed as per corresponding pcxt->nworkers.

Thanks,
Amit




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