Re: PG 12 beta 1 segfault during analyze

Andres Freund <andres@anarazel.de> writes:

> Hi,
>
> On 2019-06-17 21:46:02 -0400, Steve Singer wrote:
>> On 6/15/19 10:18 PM, Tom Lane wrote:
>> > Steve Singer <steve@ssinger.info> writes:
>> > > I encountered the following segfault when running against a  PG 12 beta1
>> > > during a analyze against a table.
>> > Nobody else has reported this, so you're going to have to work on
>> > producing a self-contained test case, or else debugging it yourself.
>> > 
>> >             regards, tom lane
>> > 
>> > 
>> > 
>> The attached patch fixes the issue.
>
> Thanks for the bug report, diagnosis and patch. Pushed.

I was going to suggest trying to prevent similar bugs by declaring these
and other output parameters as `double *const foo` in tableam.h, but
doing that without adding the corresponding `const` in heapam_handler.c
doesn't even raise a warning.

Still, declaring them as *const in both places might serve as an
example/reminder for people writing their own table AMs.

- ilmari
-- 
"I use RMS as a guide in the same way that a boat captain would use
 a lighthouse.  It's good to know where it is, but you generally
 don't want to find yourself in the same spot." - Tollef Fog Heen