2010/11/18 Pavel Stehule <pavel.steh...@gmail.com>: > 2010/11/18 Cédric Villemain <cedric.villemain.deb...@gmail.com>: >> 2010/11/18 Robert Haas <robertmh...@gmail.com>: >>> On Thu, Nov 18, 2010 at 10:24 AM, Merlin Moncure <mmonc...@gmail.com> wrote: >>>> On Thu, Nov 18, 2010 at 12:47 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: >>>>> Merlin Moncure <mmonc...@gmail.com> writes: >>>>>> On Wed, Nov 17, 2010 at 7:08 PM, Jaime Casanova <ja...@2ndquadrant.com> >>>>>> wrote: >>>>>>> i will start the review of this one... but before that sorry for >>>>>>> suggesting this a bit later but about using UNNEST as part of the >>>>>>> sintax? >>>>> >>>>>> Does for-in-array do what unnset does? >>>>> >>>>> Yes, which begs the question of why bother at all. AFAICS this patch >>>>> simply allows you to replace >>>>> >>>>> for x in select unnest(array_value) loop >>>>> >>>>> with >>>>> >>>>> for x in unnest array_value loop >>>>> >>>>> (plus or minus a parenthesis or so). I do not think we need to add a >>>>> bunch of code and create even more syntactic ambiguity (FOR loops are >>>>> already on the hairy edge of unparsability) to save people from writing >>>>> "select". >>>> >>>> Pavel's performance argument is imnsho valid. arrays at present are >>>> the best way to pass data around functions and any optimizations here >>>> are very welcome. Given that, is there any way to mitigate your >>>> concerns on the syntax side? >>> >>> Can we get the performance benefit any other way? I hate to think >>> that it will still be slow for people using the already-supported >>> syntax. >> >> If you are able to make unnest() outputting 1st row without detoasting >> last field. >> >> I think if we have : >> #define DatumGetTextPSlice(X,m,n) ((text *) PG_DETOAST_DATUM_SLICE(X,m,n)) >> but for array, most is done >> >> Pavel, am I correct ? > > yes, it can help, but still if you iterate over complete array, you > have to do n - detoast ops.
sure. > > Pavel > >> >>> >>> -- >>> Robert Haas >>> EnterpriseDB: http://www.enterprisedb.com >>> The Enterprise PostgreSQL Company >>> >>> -- >>> Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) >>> To make changes to your subscription: >>> http://www.postgresql.org/mailpref/pgsql-hackers >>> >> >> >> >> -- >> Cédric Villemain 2ndQuadrant >> http://2ndQuadrant.fr/ PostgreSQL : Expertise, Formation et Support >> > -- Cédric Villemain 2ndQuadrant http://2ndQuadrant.fr/ PostgreSQL : Expertise, Formation et Support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
