Обсуждение: pgsql: Re-allow DISTINCT in pl/pgsql expressions.
Re-allow DISTINCT in pl/pgsql expressions. I'd omitted this from the grammar in commit c9d529848, figuring that it wasn't worth supporting. However we already have one complaint, so it seems that judgment was wrong. It doesn't require a huge amount of code, so add it back. (I'm still drawing the line at UNION/INTERSECT/EXCEPT though: those'd require an unreasonable amount of grammar refactoring, and the single-result-row restriction makes them near useless anyway.) Also rethink the documentation: this behavior is a property of all pl/pgsql expressions, not just assignments. Discussion: https://postgr.es/m/20210122134106.e94c5cd7@mail.verfriemelt.org Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/7cd9765f9bd3397b8d4d0f507021ef848b6d48d2 Modified Files -------------- doc/src/sgml/plpgsql.sgml | 32 ++++++++++++++++++-------------- src/backend/parser/analyze.c | 29 ++++++++++++++++++++++++----- src/backend/parser/gram.y | 44 ++++++++++++++++++++++++++++---------------- 3 files changed, 70 insertions(+), 35 deletions(-)
On Fri, Jan 22, 2021 at 09:26:29PM +0000, Tom Lane wrote: > Re-allow DISTINCT in pl/pgsql expressions. > > I'd omitted this from the grammar in commit c9d529848, figuring that > it wasn't worth supporting. However we already have one complaint, > so it seems that judgment was wrong. It doesn't require a huge > amount of code, so add it back. (I'm still drawing the line at > UNION/INTERSECT/EXCEPT though: those'd require an unreasonable > amount of grammar refactoring, and the single-result-row restriction > makes them near useless anyway.) > > Also rethink the documentation: this behavior is a property of > all pl/pgsql expressions, not just assignments. > > Discussion: https://postgr.es/m/20210122134106.e94c5cd7@mail.verfriemelt.org I am seeing a warning generated by preproc.y, which is generated via Perl from gram.y, which was modified by this commit. The bison output is: $ /usr/bin/bison -Wno-deprecated -d -o preproc.c preproc.y preproc.y: warning: 1 nonterminal useless in grammar [-Wother] preproc.y: warning: 2 rules useless in grammar [-Wother] preproc.y:10134.2-20: warning: nonterminal useless in grammar: opt_distinct_clause [-Wother] opt_distinct_clause: ^~~~~~~~~~~~~~~~~~~ I only see it when I do a "make maintainer-clean" before the make because "make clean" does not remove preproc.y. -- Bruce Momjian <bruce@momjian.us> https://momjian.us EDB https://enterprisedb.com The usefulness of a cup is in its emptiness, Bruce Lee
On Fri, Jan 22, 2021 at 07:04:20PM -0500, Bruce Momjian wrote: > On Fri, Jan 22, 2021 at 09:26:29PM +0000, Tom Lane wrote: > > Re-allow DISTINCT in pl/pgsql expressions. > > > > I'd omitted this from the grammar in commit c9d529848, figuring that > > it wasn't worth supporting. However we already have one complaint, > > so it seems that judgment was wrong. It doesn't require a huge > > amount of code, so add it back. (I'm still drawing the line at > > UNION/INTERSECT/EXCEPT though: those'd require an unreasonable > > amount of grammar refactoring, and the single-result-row restriction > > makes them near useless anyway.) > > > > Also rethink the documentation: this behavior is a property of > > all pl/pgsql expressions, not just assignments. > > > > Discussion: https://postgr.es/m/20210122134106.e94c5cd7@mail.verfriemelt.org > > I am seeing a warning generated by preproc.y, which is generated via > Perl from gram.y, which was modified by this commit. The bison output > is: > > $ /usr/bin/bison -Wno-deprecated -d -o preproc.c preproc.y > preproc.y: warning: 1 nonterminal useless in grammar [-Wother] > preproc.y: warning: 2 rules useless in grammar [-Wother] > preproc.y:10134.2-20: warning: nonterminal useless in grammar: opt_distinct_clause [-Wother] > opt_distinct_clause: > ^~~~~~~~~~~~~~~~~~~ > > I only see it when I do a "make maintainer-clean" before the make > because "make clean" does not remove preproc.y. Sorry, this is Bison version 3.3.2, included in Debian 10. -- Bruce Momjian <bruce@momjian.us> https://momjian.us EDB https://enterprisedb.com The usefulness of a cup is in its emptiness, Bruce Lee
Bruce Momjian <bruce@momjian.us> writes:
> On Fri, Jan 22, 2021 at 09:26:29PM +0000, Tom Lane wrote:
>> Re-allow DISTINCT in pl/pgsql expressions.
> I am seeing a warning generated by preproc.y, which is generated via
> Perl from gram.y, which was modified by this commit.
Mea culpa, didn't think to try the ecpg tests.
regards, tom lane
On Fri, Jan 22, 2021 at 07:16:34PM -0500, Tom Lane wrote: > Bruce Momjian <bruce@momjian.us> writes: > > On Fri, Jan 22, 2021 at 09:26:29PM +0000, Tom Lane wrote: > >> Re-allow DISTINCT in pl/pgsql expressions. > > > I am seeing a warning generated by preproc.y, which is generated via > > Perl from gram.y, which was modified by this commit. > > Mea culpa, didn't think to try the ecpg tests. I only found it because of the private test harness I use which checks for anything unusual in the compile logs. -- Bruce Momjian <bruce@momjian.us> https://momjian.us EDB https://enterprisedb.com The usefulness of a cup is in its emptiness, Bruce Lee
Bruce Momjian <bruce@momjian.us> writes:
> On Fri, Jan 22, 2021 at 07:16:34PM -0500, Tom Lane wrote:
>> Mea culpa, didn't think to try the ecpg tests.
> I only found it because of the private test harness I use which checks
> for anything unusual in the compile logs.
Actually, I *did* run check-world before committing, so I'm not sure
how I missed the warning. Oh well.
regards, tom lane
On Fri, Jan 22, 2021 at 07:32:07PM -0500, Tom Lane wrote: > Bruce Momjian <bruce@momjian.us> writes: > > On Fri, Jan 22, 2021 at 07:16:34PM -0500, Tom Lane wrote: > >> Mea culpa, didn't think to try the ecpg tests. > > > I only found it because of the private test harness I use which checks > > for anything unusual in the compile logs. > > Actually, I *did* run check-world before committing, so I'm not sure > how I missed the warning. Oh well. I can confirm the fix, thanks. -- Bruce Momjian <bruce@momjian.us> https://momjian.us EDB https://enterprisedb.com The usefulness of a cup is in its emptiness, Bruce Lee