Re: Possible issue with expanded object infrastructure on Postgres 9.6.1

On Thu, Feb 16, 2017 at 11:45 AM, Justin Workman <justin(at)photolynx(dot)com> wrote:
>> It would help to know the data types of the columns involved in this
>> query; but just eyeballing it, it doesn't look like it involves any
>> array operations, so it's pretty hard to believe that the expanded-object
>> code could have gotten invoked intentionally. (The mere presence of
>> an array column somewhere in the vicinity would not do that; you'd
>> need to invoke an array-ish operation, or at least pass the array into
>> a plpgsql function.)
>> If I had to bet on the basis of this much info, I would bet that the
>> parallel-query infrastructure is dropping the ball somewhere and
>> transmitting a corrupted datum that accidentally looks like it is
>> an expanded-object reference.
>> If $customer wants a quick fix, I'd suggest seeing whether disabling
>> parallel query makes the problem go away. That might be a good first
>> step anyway, just to narrow down where the problem lies.
>> regards, tom lane
>
>
> Hi Tom,
>
> My name is Justin, and I am $customer as it were. As Peter explained, we
> haven't seen the segfaults anymore since disabling parallel queries. This
> works as a quick fix and is much appreciated! If you would still like to get
> to the bottom of this, I am willing to help out with more information as
> needed. My knowledge of PG internals is extremely limited so I don't know
> how much help I can be, but we'd like to see this resolved beyond the quick
> fix, or at least understand why it happened.
>

Thanks Justin for the confirmation. Is it possible for you to get a
standalone test case with which we can reproduce the problem?

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com