Re: [HACKERS] Restructuring Paths to allow per-Path targetlist info

[Tom Lane]

Alvaro Herrera  writes:
>> So, the attached patch just bites the bullet and adds explicit output
>> tlist information to struct Path.

> Hmm, I wonder if this can be used to attack the problem here in a more
> sensible manner:
> https://github.com/2ndQuadrant/postgres/commit/e7c5df6b614b542d55588a483dd2ddba3892a0f6

As far as I gather from that commit message, it wouldn't help much, because
everything discussed there happens before any Paths have been built.

regards, tom lane


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Re: [HACKERS] Restructuring Paths to allow per-Path targetlist info

[Alvaro Herrera]

Tom Lane wrote:

> So, the attached patch just bites the bullet and adds explicit output
> tlist information to struct Path.  I did set things up so that the cost
> is only one pointer in each Path in the typical case where Paths emit
> the set of Vars needed from their relation; in that case, they just
> point to a default PathTarget struct embedded in the parent RelOptInfo.
> A Path emitting something else will need its own PathTarget struct.

Hmm, I wonder if this can be used to attack the problem here in a more
sensible manner:
https://github.com/2ndQuadrant/postgres/commit/e7c5df6b614b542d55588a483dd2ddba3892a0f6

-- 
Álvaro Herrerahttp://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services


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