Re: strange perf regression with data checksums

Hi,

We had a RMT meeting yesterday, and we briefly discussed whether the v2
patch should go into PG18. And we concluded we probably should try to do
that.

On the one hand, it's not a PG18-specific bug, in the sense that older
releases are affected the same way. But it requires data checksums to be
enabled, and a lot of systems runs with checksums=off, simply because
that's the default. But 18 will (likely) change that.

We didn't get any complaints about this (at least I'm not aware of any),
but I suppose that's simply because people didn't have a comparison, and
treated it as "normal". But with the default changes, it'll be easier to
spot once they upgrade to PG18.

So better to get this in now, otherwise we may have to wait until PG19,
because of ABI (the patch adds a field into BTScanPosData, but maybe
it'd be possible to add it into padding, not sure).


regards

-- 
Tomas Vondra