Re: refactoring relation extension and BufferAlloc(), faster COPY

Hi,

On 2023-04-05 18:46:16 -0700, Andres Freund wrote:
> On 2023-04-04 17:39:45 -0700, Andres Freund wrote:
> > After that I'm planning to wait for a buildfarm cycle, and push the changes
> > necessary to use bulk extension in hio.c (the main win).
>
> Working on that. Might end up being tomorrow.

It did. So far no complaints from the buildfarm. Although I pushed the last
piece just now...

Besides editing the commit message, not a lot of changes between what I posted
last and what I pushed. A few typos and awkward sentences, code formatting,
etc. I did change the API of RelationAddBlocks() to set *did_unlock = false,
if it didn't unlock (and thus removed setting it in the caller).

> > I might split the patch to use ExtendBufferedRelTo() into two, one for
> > vm_extend() and fsm_extend(), and one for xlogutils.c. The latter is more
> > complicated and has more of a complicated history (see [1]).
>
> I've pushed the vm_extend() and fsm_extend() piece, and did split out the
> xlogutils.c case.

Which I pushed, just now. I did perform manual testing with creating
disconnected segments on the standby, and checking that everything behaves
well in that case.

I think it might be worth having a C test for some of the bufmgr.c API. Things
like testing that retrying a failed relation extension works the second time
round.

Greetings,

Andres Freund