Re: [HACKERS] WIP: Faster Expression Processing v4 - Mailing list pgsql-hackers

From Tom Lane
Subject Re: [HACKERS] WIP: Faster Expression Processing v4
Date
Msg-id 9137.1489616217@sss.pgh.pa.us
Whole thread Raw
In response to Re: [HACKERS] WIP: Faster Expression Processing v4  (Andres Freund <andres@anarazel.de>)
Responses Re: [HACKERS] WIP: Faster Expression Processing v4  (Andres Freund <andres@anarazel.de>)
List pgsql-hackers
Andres Freund <andres@anarazel.de> writes:
> On 2017-03-15 17:33:46 -0400, Tom Lane wrote:
>> We could make the planner mark each table scan node with the highest
>> column number that the plan will access, and use that to drive a
>> slot_getsomeattrs call in advance of any access to tuple contents.

> probably isn't sufficient - we build non-virtual tuples in a good number
> of places (sorts, tuplestore using stuff like nodeMaterial, nodeHash.c
> output, ...).  I suspect it'd have measurable negative consequences if
> we removed the deforming logic for all expressions/projections above
> such nodes.  I guess we could just do such a logic for every Plan node?

[ scratches head... ]  What deforming logic do you think I'm proposing
removing?
        regards, tom lane



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