Re: Suggestions on message transfer among backends

Andy Fan  wrote:

> I just don't know why shm_mq is designed to single-reader & single-writer. 

shm_mq was implemented as a part of infrastructure for parallel query
processing. The leader backend launches multiple parallel workers and sets up
a few queues to communicate with each. One queue is used to send request
(query plan) to the worker, one queue is there to receive data from it, and I
think there's one more queue to receive error messages.

-- 
Antonin Houska
https://www.cybertec-postgresql.com