Re: Some shared memory chunks are allocated even if related processes won't start

On 2024-Mar-05, Hayato Kuroda (Fujitsu) wrote:

> Basically sounds good. My concerns are:
>
> * GetNamedDSMSegment() does not returns a raw pointer to dsm_segment. This means
> that it may be difficult to do dsm_unpin_segment on the caller side.

Maybe we don't need a "named" DSM segment at all, and instead just use
bare dsm segments (dsm_create and friends) or a DSA -- not sure. But
see commit 31ae1638ce35, which removed use of a DSA in autovacuum/BRIN.
Maybe fixing this is just a matter of reverting that commit. At the
time, there was a belief that DSA wasn't supported everywhere so we
couldn't use it for autovacuum workitem stuff, but I think our reliance
on DSA is now past the critical point.

BTW, we should turn BRIN autosummarization to be on by default.

--
Álvaro Herrera PostgreSQL Developer — https://www.EnterpriseDB.com/
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