Re: es_query_dsa is broken

Amit Kapila <amit.kapila16@gmail.com>

From: Amit Kapila <amit.kapila16@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Thomas Munro <thomas.munro@enterprisedb.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2017-12-06T09:16:16Z
Lists: pgsql-hackers
On Wed, Dec 6, 2017 at 1:14 AM, Robert Haas <robertmhaas@gmail.com> wrote:
> On Tue, Dec 5, 2017 at 7:24 AM, Amit Kapila <amit.kapila16@gmail.com> wrote:
>> + EState *estate = gatherstate->ps.state;
>> +
>> + /* Install our DSA area while executing the plan. */
>> + estate->es_query_dsa = gatherstate->pei->area;
>>   outerTupleSlot = ExecProcNode(outerPlan);
>> + estate->es_query_dsa = NULL;
>>
>> Won't the above coding pattern create a problem, if ExecProcNode
>> throws an error and outer block catches it and continues execution
>> (consider the case of execution inside PL blocks)?
>
> I don't see what the problem is.  The query that got aborted by the
> error wouldn't be sharing an EState with one that didn't.
>

That's right.  Ignore my comment, I got confused.   Other than that, I
don't see any problem with the code as such apart from that it looks
slightly hacky.  I think Thomas or someone needs to develop a patch on
the lines you have mentioned or what Thomas was trying to describe in
his email and see how it comes out.

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


Commits

  1. Fix crashes on plans with multiple Gather (Merge) nodes.

  2. Teach bitmap heap scan to cope with absence of a DSA.

  3. Provide a DSA area for all parallel queries.