Re: Deleting older versions in unique indexes to avoid page splits

On Wed, Oct 7, 2020 at 7:48 PM Peter Geoghegan <pg@bowt.ie> wrote:
> To be blunt: It may be controversial that we're accessing multiple
> heap pages while holding an exclusive lock on a leaf page, in the
> hopes that we can avoid a page split, but without any certainty that
> it'll work out.

That certainly isn't great. I mean, it might be not be too terrible,
because it's a leaf index page isn't nearly as potentially hot as a VM
page or a clog page, but it hurts interruptibility and risks hurting
concurrency, but if it were possible to arrange to hold only a pin on
the page during all this rather than a lock, it would be better. I'm
not sure how realistic that is, though.

-- 
Robert Haas
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