we observed that spawning the specified number of parallel workers for every query that satisfies for parallelism is sometimes leading to performance drop compared to improvement during the peak system load with other processes. Adding more processes to the system is leading to more context switches thus it reducing the performance of other SQL operations.
In order to avoid this problem, how about adding some kind of system load consideration into account before spawning the parallel workers? This may not be a problem for some users, so instead of adding the code into the core for the system load calculation and etc, how about providing some additional hook in the code? so that user who wants to consider the system load registers the function and this hooks provides the number of parallel workers that can be started. comments? Regards, Hari Babu Fujitsu Australia -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers