Robert Haas escribió:
> Just for fun, I implemented a toy background worker tonight using the
> new bgworker framework. Generally, it went well, and I'm pleased with
> the design of the new facility.
Thanks.
> However, I did notice one oddity. I initialized the worker flags like
> this:
>
> worker.bgw_flags = BGWORKER_SHMEM_ACCESS;
>
> And... latches didn't work. It turns out that if you request database
> access, then the SIGUSR1 handler is set to procsignal_sigusr1_handler,
> which is fine. But if you don't, it gets set to SIG_IGN. And the
> result of *that* is that if someone sets a latch for which the
> background process is waiting, the background process fails to notice.
>
> Now, once you understand what's going on here, it's not hard to work
> around. But it seems to me that it would be a saner default to set
> the signal handler to something like the bgwriter handler, which just
> calls latch_sigusr1_handler.
Sounds sensible -- done that way.
--
Álvaro Herrera http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services