Обсуждение: What does RIR as in fireRIRrules stand for?

Hi,

I searched the current code, all diffs to the current code, and the
mailing list, but still haven't got an actual clue what RIR is supposed
to stand for. There's a few things that come to mind (Rewrite Instead
Rule?), but none of them seem to make too much sense.

Greetings,

Andres Freund

<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Pure speculation but the word
firemakes me think of triggers, not rule.  Fire Referential Integrity Rules (Triggers)?</div><div class="gmail_default"
style="font-family:arial,helvetica,sans-serif"><br/></div><div class="gmail_default"
style="font-family:arial,helvetica,sans-serif">DavidJ.</div><div class="gmail_default"
style="font-family:arial,helvetica,sans-serif"><br/></div></div><div class="gmail_extra"><br /><div
class="gmail_quote">OnThu, Aug 27, 2015 at 9:13 AM, Andres Freund <span dir="ltr"><<a
href="mailto:andres@anarazel.de"target="_blank">andres@anarazel.de</a>></span> wrote:<br /><blockquote
class="gmail_quote"style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi,<br /><br /> I searched the
currentcode, all diffs to the current code, and the<br /> mailing list, but still haven't got an actual clue what RIR
issupposed<br /> to stand for. There's a few things that come to mind (Rewrite Instead<br /> Rule?), but none of them
seemto make too much sense.<br /><br /> Greetings,<br /><br /> Andres Freund<br /><span class="HOEnZb"><font
color="#888888"><br/><br /> --<br /> Sent via pgsql-hackers mailing list (<a
href="mailto:pgsql-hackers@postgresql.org">pgsql-hackers@postgresql.org</a>)<br/> To make changes to your
subscription:<br/><a href="http://www.postgresql.org/mailpref/pgsql-hackers" rel="noreferrer"
target="_blank">http://www.postgresql.org/mailpref/pgsql-hackers</a><br/></font></span></blockquote></div><br /></div> 

Andres Freund <andres@anarazel.de> writes:
> I searched the current code, all diffs to the current code, and the
> mailing list, but still haven't got an actual clue what RIR is supposed
> to stand for. There's a few things that come to mind (Rewrite Instead
> Rule?), but none of them seem to make too much sense.

http://www.postgresql.org/message-id/3E887762.5B68F64B@Yahoo.com
        regards, tom lane

On 2015-08-27 15:13:52 +0200, Andres Freund wrote:
> I searched the current code, all diffs to the current code, and the
> mailing list, but still haven't got an actual clue what RIR is supposed
> to stand for. There's a few things that come to mind (Rewrite Instead
> Rule?), but none of them seem to make too much sense.

Looking over the original submission it seems to actually stand for
retrieve-instead-retrieve (as somebody on IRC guessed). Doesn't seem to
make much sense to me.

The explanation seems to have been removed way back, in f93b6974 .

Greetings,

Andres Freund

On 2015-08-27 09:43:09 -0400, Tom Lane wrote:
> Andres Freund <andres@anarazel.de> writes:
> > I searched the current code, all diffs to the current code, and the
> > mailing list, but still haven't got an actual clue what RIR is supposed
> > to stand for. There's a few things that come to mind (Rewrite Instead
> > Rule?), but none of them seem to make too much sense.
> 
> http://www.postgresql.org/message-id/3E887762.5B68F64B@Yahoo.com

Oops. I saw that message but thought, based on the subject, it'd a scam
mail...

Can we either add a comment to the effect of Jan's message, or just
renamoe the functions/variables?

Greetings,

Andres Freund


PS: The sources taught me something today:   reality is for dead birds -- glass

Andres Freund <andres@anarazel.de> writes:
> On 2015-08-27 09:43:09 -0400, Tom Lane wrote:
>> http://www.postgresql.org/message-id/3E887762.5B68F64B@Yahoo.com

> Oops. I saw that message but thought, based on the subject, it'd a scam
> mail...

> Can we either add a comment to the effect of Jan's message, or just
> renamoe the functions/variables?

Let's add a comment.
        regards, tom lane

Steve Crawford <scrawford@pinpointresearch.com> writes:
> Candidate for Appendix K?

Meh ... it's not a user-visible notation, in fact it only appears in
rewriteHandler.c AFAICS.  I think an explanation in fireRIRrules'
header comment would be fine.
        regards, tom lane

On 2015-08-27 11:12:42 -0400, Tom Lane wrote:
> Steve Crawford <scrawford@pinpointresearch.com> writes:
> > Candidate for Appendix K?
> 
> Meh ... it's not a user-visible notation, in fact it only appears in
> rewriteHandler.c AFAICS.

Agreed, I don't think we want to distribute that term any wider than
that file.

> I think an explanation in fireRIRrules' header comment would be fine.

I was thinking of adding it to the file's header like* NOTES*      Some of the terms used in this file are of historic
nature:"retrieve"*      was the PostQUEL keyword for what today is SELECT. "RIR" stands for*
"Retrieve-Instead-Retrieve",that is an ON SELECT INSTEAD rule (which*      has to be unconditional and where only one
rulecan exist on each*      relation).
 

since both retrieve and RIR are used in a bunch of places.

Andres

Andres Freund <andres@anarazel.de> writes:
> On 2015-08-27 11:12:42 -0400, Tom Lane wrote:
>> I think an explanation in fireRIRrules' header comment would be fine.

> I was thinking of adding it to the file's header like
>  * NOTES
>  *      Some of the terms used in this file are of historic nature: "retrieve"
>  *      was the PostQUEL keyword for what today is SELECT. "RIR" stands for
>  *      "Retrieve-Instead-Retrieve", that is an ON SELECT INSTEAD rule (which
>  *      has to be unconditional and where only one rule can exist on each
>  *      relation).

> since both retrieve and RIR are used in a bunch of places.

Seems reasonable.  Maybe worth writing out the modern spelling a bit
further, "an ON SELECT DO INSTEAD SELECT rule", to make the parallel
to Retrieve-Instead-Retrieve perfectly clear.
        regards, tom lane

On 2015-08-28 10:20:58 -0400, Tom Lane wrote:
> Seems reasonable.  Maybe worth writing out the modern spelling a bit
> further, "an ON SELECT DO INSTEAD SELECT rule", to make the parallel
> to Retrieve-Instead-Retrieve perfectly clear.

Makes sense. Pushed that way.

Thanks

fred yin <legendmakeryy@gmail.com> writes:
> I found this thread when trying to understand what RIR means in the source
> code. The explanation by Andres (which I find informative) is not in the
> code. Should we add it into the comment? I think it will be useful for
> readability.

There's this at the top of rewriteHandler.c:

 * NOTES
 *      Some of the terms used in this file are of historic nature: "retrieve"
 *      was the PostQUEL keyword for what today is SELECT. "RIR" stands for
 *      "Retrieve-Instead-Retrieve", that is an ON SELECT DO INSTEAD SELECT rule
 *      (which has to be unconditional and where only one rule can exist on each
 *      relation).

            regards, tom lane