Re: Let's make PostgreSQL multi-threaded

On 05/06/2023 13:10, Bruce Momjian wrote:
> nOn Mon, Jun 5, 2023 at 05:51:57PM +0300, Heikki Linnakangas wrote:
>> # Restart on crash
>>
>> If a backend process crashes, postmaster terminates all other backends and
>> restarts the system. That's hard (impossible?) to do safely if everything
>> runs in one process. We can continue have a separate postmaster process that
>> just monitors the main process and restarts it on crash.
>
> It would be good to know what new class of errors would cause server
> restarts, e.g., memory allocation failures?

You mean "out of memory"? No, that would be horrible.

I don't think there would be any new class of errors that would cause
server restarts. In theory, having a separate address space for each
backend gives you some protection. In practice, there are a lot of
shared memory structures anyway that you can stomp over, and a segfault
or unexpected exit of any backend process causes postmaster to restart
the whole system anyway.

--
Heikki Linnakangas
Neon (https://neon.tech)