Re: BTMaxItemSize seems to be subtly incorrect

On Thu, Aug 4, 2022 at 10:40 PM Peter Geoghegan <pg@bowt.ie> wrote:
> This very likely has something to do with the way nbtdedup.c uses
> BTMaxItemSize(), which apparently won't work on these 32-bit systems
> now.

Update: I discovered that I can get the regression tests to fail (even
on mainstream 64-bit platforms) by MAXALIGN()'ing the expression that
we assign to state->maxpostingsize at the top of _bt_dedup_pass().
This is surprising; it contradicts existing comments that explain that
the existing max is 1/6 of a page by choice, to get better space
utilization than the more natural cap of 1/3 of a page. It now looks
like that might have actually been strictly necessary, all along.

-- 
Peter Geoghegan