From: Tom Lane <tgl@sss.pgh.pa.us>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: Simon Riggs <simon@2ndquadrant.com>
Cc: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
Cc: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Cc: Dean Rasheed <dean.a.rasheed@gmail.com>
Subject: Re: WITH clause in CREATE STATISTICS
Date: Thu, 11 May 2017 15:50:19 -0400
Message-ID: <26396.1494532219@sss.pgh.pa.us> (raw)
In-Reply-To: <20170511193236.ecuwhixts7y3s7u5@alvherre.pgsql>
References: <20170511193236.ecuwhixts7y3s7u5@alvherre.pgsql>
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Alvaro Herrera <alvherre@2ndquadrant.com> writes:
> Tom Lane wrote:
>> Have you thought further about the upthread suggestion to just borrow
>> SELECT's syntax lock stock and barrel?
> Bison seems to like the productions below. Is this what you had in
> mind? These mostly mimic joined_table and table_ref, stripping out the
> rules that we don't need.
I'd suggest just using the from_list production and then complaining
at runtime if what you get is too complicated. Otherwise, you have
to maintain a duplicate set of productions, and you're going to be
unable to throw anything more informative than "syntax error" when
somebody tries to exceed the implementation limits.
> Note that I had to put back the FOR keyword in there; without the FOR,
> that is "CREATE STATS any_name opt_name_list expr_list FROM" there was
> one shift/reduce conflict, which I tried to solve by splitting
> opt_name_list using two rules (one with "'(' name_list ')'" and one
> without), but that gave rise to two reduce/reduce conflicts, and I didn't
> see any way to deal with them.
That's fine. I was going to suggest using ON after the stats type list
just because it seemed to read better. FOR is about as good.
> (Note that I ended up realizing that stats_type_list is unnecessary
> since we can use name_list.)
Check.
regards, tom lane
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To: pgsql-hackers@postgresql.org
Cc: tgl@sss.pgh.pa.us, alvherre@2ndquadrant.com, simon@2ndquadrant.com, andrew.dunstan@2ndquadrant.com, tomas.vondra@2ndquadrant.com, dean.a.rasheed@gmail.com
Subject: Re: WITH clause in CREATE STATISTICS
In-Reply-To: <26396.1494532219@sss.pgh.pa.us>
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