Re: Revert: Remove useless self-joins *and* -DREALLOCATE_BITMAPSETS make server crash, regress test fail.

Andrew Dunstan <andrew@dunslane.net> writes:
> On 2024-05-07 Tu 06:05, Richard Guo wrote:
>> +1 to have build farm coverage of REALLOCATE_BITMAPSETS. This flag
>> seems quite useful.

> I have added it to the CPPFLAGS on prion.

... and as expected, prion fell over.

I find that Richard's proposed fix makes the core regression tests
pass, but we still fail check-world.  So I'm afraid we need something
more aggressive, like the attached which makes make_restrictinfo
copy all its input bitmapsets.  Without that, we still have sharing
of bitmapsets across different RestrictInfos, which seems pretty
scary given what we now see about the effects of 00b41463c.  This
seems annoyingly expensive, but maybe there's little choice?

Given this, we could remove ad-hoc bms_copy calls from the callers
of make_restrictinfo, distribute_quals_to_rels, etc.  I didn't go
looking for possible wins of that sort; there's unlikely to be a
lot of them.

			regards, tom lane