| From: | Surafel Temesgen <surafel3000(at)gmail(dot)com> |
|---|---|
| To: | Ryan Lambert <ryan(at)rustprooflabs(dot)com> |
| Cc: | Thomas Munro <thomas(dot)munro(at)gmail(dot)com>, Andres Freund <andres(at)anarazel(dot)de>, Kyotaro HORIGUCHI <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp>, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>, Vik Fearing <vik(dot)fearing(at)2ndquadrant(dot)com>, Mark Dilger <hornschnorter(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>, Andrew Gierth <andrew(at)tao11(dot)riddles(dot)org(dot)uk> |
| Subject: | Re: FETCH FIRST clause PERCENT option |
| Date: | 2019-08-01 12:54:11 |
| Message-ID: | CALAY4q_icXPTcAVxnPckpLGrZgER9-FWM0VPFvvOsPiJrnK6Dg@mail.gmail.com |
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| Lists: | pgsql-hackers |
Hi Ryan,
sorry for not be fast to replay
> I was suggesting a warning in the documentation so users aren't caught
> unaware about the performance characteristics. My first version was very
> rough, how about adding this in doc/src/sgml/ref/select.sgml?
>
> "Using <literal>PERCENT</literal> is best suited to returning single-digit
> percentages of the query's total row count."
>
>
> The following paragraphs in that same section give suggestions and
> warnings regarding LIMIT and OFFSET usage, I think this is more in line
> with the wording of those existing warnings.
>
>
Agreed and done
> Other than that, we can rip the clause if it is 100%
>
>
> You mean if PERCENT=100 it should short circuit and run the query
> normally? I like that.
>
The patch did not did it automatically. Its query writer obligation to do
that currently
regards
Surafel
| Attachment | Content-Type | Size |
|---|---|---|
| percent-incremental-v6.patch | text/x-patch | 48.7 KB |
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