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

Hi,

On 2023-04-12 08:00:00 +0300, Alexander Lakhin wrote:
> 12.04.2023 02:21, Andres Freund wrote:
> > Hi,
> > 
> > On 2023-04-11 22:00:00 +0300, Alexander Lakhin wrote:
> > > A few days later I've found a new defect introduced with 31966b151.
> > That's the same issue that Tom also just reported, at
> > https://postgr.es/m/392271.1681238924%40sss.pgh.pa.us
> > 
> > Attached is my WIP fix, including a test.
> 
> Thanks for the fix. I can confirm that the issue is gone.
> ReadBuffer_common() contains an Assert(), that is similar to the fixed one,
> but it looks unreachable for the WAL replay case after 26158b852.

Good catch. I implemented it there too. As now all of the modes are supported,
I removed the assertion.

I also extended the test slightly to also test the case of dropped relations.

Greetings,

Andres Freund