Re: BUG #14169: Incorrect merge join result in 9.5

Kevin Grittner <kgrittn(at)gmail(dot)com> writes:
> On Wed, Jun 1, 2016 at 11:15 AM, Kevin Grittner <kgrittn(at)gmail(dot)com> wrote:
>> On Wed, Jun 1, 2016 at 11:10 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>> In short: Kevin, you broke mark/restore. Please fix.

>> I'm on it.

> Fix pushed.

I confirm this fixes the submitted test case.

> Basically, I reverted an attempt to optimize repeated
> restores to the same page. I had a rather bad thinko there where I
> essentially assumed that it was also to the same mark, so advancing
> marks on the same page caused the bug. There's probably room to
> optimize that with more refined logic, but for now I just reverted
> the problem code.

Sounds reasonable. The comments in that removed hunk of code had made
me suspicious as heck the moment I saw them ...

> I reduced the test case supplied by the OP to something smaller
> which still failed the assertion without the patch, but am having
> trouble getting it to run in the regression test environment with a
> stable plan.

Best bet might be to use a temp table, so that autoanalyze won't touch it.

regards, tom lane