Re: Parallel Seq Scan

On Sat, Jan 10, 2015 at 11:14 PM, Amit Kapila <amit.kapila16@gmail.com> wrote:
>> I don't think you should be "switching" queues.  The tuples should be
>> sent to the tuple queue, and errors and notices to the error queue.
> To achieve what you said (The tuples should be sent to the tuple
> queue, and errors and notices to the error queue.), we need to
> switch the queues.
> The difficulty here is that once we set the queue (using
> pq_redirect_to_shm_mq()) through which the communication has to
> happen, it will use the same unless we change again the queue
> using pq_redirect_to_shm_mq().  For example, assume we have
> initially set error queue (using pq_redirect_to_shm_mq()) then to
> send tuples, we need to call pq_redirect_to_shm_mq() to
> set the tuple queue as the queue that needs to be used for communication
> and again if error happens then we need to do the same for error
> queue.
> Do you have any other idea to achieve the same?

Yeah, you need two separate global variables pointing to shm_mq
objects, one of which gets used by pqmq.c for errors and the other of
which gets used by printtup.c for tuples.

-- 
Robert Haas
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