Re: FETCH FIRST clause PERCENT option

From: Surafel Temesgen <surafel3000(at)gmail(dot)com>
To: Andres Freund <andres(at)anarazel(dot)de>
Cc: PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: FETCH FIRST clause PERCENT option
Date: 2018-08-21 12:47:07
Message-ID: CALAY4q8mr_uVgY5UaFh-iZWDvUZpQ2YduCJUKZ3d5dpUQHR1fA@mail.gmail.com
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On Thu, Aug 16, 2018 at 5:34 PM, Andres Freund <andres(at)anarazel(dot)de> wrote:

>
> Won't that have rather massive issues with multiple evaluations of
> clauses in the query? Besides being really expensive?
>
The plan re-scane after first execution I can’t see issue for multiple
execution of a clause in this case

>
> I think you'd have to instead spill the query results into a tuplestore
>
> The downside of it is all the result have to be stored even if needed
tuple is a fraction of it and also store it for longer so the choice became
memory or cpu utilization

>
> - Andres
>
Regards
Surafel

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