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Re: Window Functions: v07 APIs and buffering strateties

From: "Hitoshi Harada" <umi(dot)tanuki(at)gmail(dot)com>
To: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: "ITAGAKI Takahiro" <itagaki(dot)takahiro(at)oss(dot)ntt(dot)co(dot)jp>, "PostgreSQL Hackers" <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Window Functions: v07 APIs and buffering strateties
Date: 2008-10-28 17:23:41
Message-ID: e08cc0400810281023k157681d0p4d44a7cfeedac033@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-hackers
2008/10/29 Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>:
> "Hitoshi Harada" <umi(dot)tanuki(at)gmail(dot)com> writes:
>> Can "ROWS" be reserved_keyword?
>
>> In window specifications, we have
>
>> OVER (ORDER BY expr_list [(ROWS|RANGE) ... ])
>
>> and currently "ROWS" is not reserved so bison is confused with cases
>> of "ROWS" included in expr_list and in FRAME clause. Because there is
>> no delimiter between ORDER BY clause and FRAME (that is (ROWS |
>> RANGE)) clause, "ROWS" can be in expr_list as a_expr.
>
> Right offhand, I don't see any alternative but to make both ROWS and
> RANGE reserved.  It's pretty annoying since that might break existing
> applications that have been using these as identifiers, but the SQL
> committee seems to care little about that :-(
>
> BTW, finding this sort of problem is exactly why ignoring shift/reduce
> conflicts is a bad idea.  You would've ended up with unexpected
> behaviors given the wrong input.
>

I see it now. This is so good study to me, though it spent me much
time. Thanks anyway.

Regards,


-- 
Hitoshi Harada

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