Re: Convert query plan to sql query - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Convert query plan to sql query
Date
Msg-id 12359.1415253811@sss.pgh.pa.us
Whole thread Raw
In response to Re: Convert query plan to sql query  (mariem <mariem.benfadhel@gmail.com>)
Responses Re: Convert query plan to sql query  (mariem <mariem.benfadhel@gmail.com>)
List pgsql-hackers
mariem <mariem.benfadhel@gmail.com> writes:
>> I don't think SQL can express the information the plan contains. For example,
>> join methods (hash, nest loop, merge).

> I don't need the way the query will be executed, so there is no need for
> (hash, nest loop, merge).

If you don't need that, why are you insistent on extracting the
information from a plan tree?

It seems far simpler to me to make use of ruleutils.c to reverse-list
the original parsetree.  That functionality already exists and is well
tested and well maintained.  If you insist on working from a plan tree,
you will be writing a fair amount of code that you will have to maintain
yourself.  And I absolutely, positively guarantee that we will break it
in every major release, and occasionally in minor releases.  You should
read the git history of explain.c and ruleutils.c and ask yourself whether
you want to keep up with that level of churn.
        regards, tom lane



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