| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | David Rowley <dgrowleyml(at)gmail(dot)com> |
| Cc: | Andrew Dunstan <andrew(at)dunslane(dot)net>, Richard Guo <guofenglinux(at)gmail(dot)com>, jian he <jian(dot)universality(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: Revert: Remove useless self-joins *and* -DREALLOCATE_BITMAPSETS make server crash, regress test fail. |
| Date: | 2024-05-08 22:40:33 |
| Message-ID: | 936562.1715208033@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
David Rowley <dgrowleyml(at)gmail(dot)com> writes:
> I'm fine with this one as it's the same as what I already mentioned
> earlier. I had imagined doing bms_del_member(bms_copy ... but maybe
> the compiler is able to optimise away the additional store. Likely, it
> does not matter much as pallocing memory likely adds far more overhead
> anyway.
I actually wrote it that way to start with, but undid it after
noticing that the existing code in remove_rel_from_restrictinfo
does it in separate steps, and thinking that that was good for
both separation of concerns and a cleaner git history. I too
can't believe that an extra fetch will be noticeable compared
to the cost of the adjacent bms_xxx operations.
regards, tom lane
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