Added to TODO: * Add temporal versions of generate_series()
http://archives.postgresql.org/pgsql-hackers/2007-04/msg01180.php --------------------------------------------------------------------------- Jim Nasby wrote: > On May 6, 2007, at 8:07 PM, Tom Lane wrote: > > Jim Nasby <[EMAIL PROTECTED]> writes: > >> Also, what would be the appropriate way to put this into initdb? > > You seem to have missed a step here, which is to convince people that > > these belong in core at all. So far I've not even seen an argument > > that > > would justify putting them in contrib. > > These are all examples of using generate series plus additional math > to generate a series of dates/timestamps: > http://archives.postgresql.org/pgsql-general/2007-01/msg01292.php > http://archives.postgresql.org/pgsql-sql/2006-02/msg00249.php > http://archives.postgresql.org/pgsql-general/2005-06/msg01254.php > http://archives.postgresql.org/pgsql-sql/2007-03/msg00093.php > http://archives.postgresql.org/pgsql-novice/2007-01/msg00002.php > http://archives.postgresql.org/pgsql-sql/2006-03/msg00391.php > http://archives.postgresql.org/pgsql-hackers/2006-09/msg00330.php > > That's from the first page of search results for 'generate_series > timestamp'. > > FWIW, I could also make use of this in some of my code. > > > If they *were* of sufficiently > > wide use to justify putting them into core, a more efficient > > implementation would probably be expected. > > Ok, I'll look into a C version, but why do SQL functions have such a > high overhead? I'm seeing an SQL function taking ~2.6x longer than > the equivalent code run directly in a query. With 100 days, the > difference drops a bit to ~2.4x. (this is on HEAD from a few months ago) > > This is on my MacBook Pro with the Jean-Pierre's version of > generate_series: > > decibel=# select count(*) from generate_series(now(),now()+'10 > days'::interval,'1'::interval); > Time: 1851.407 ms > decibel=# select count(*) from generate_series(1,86400*10); > Time: 657.894 ms > decibel=# select count(*) from (select now() + (generate_series > (1,86400*10) * '1 second'::interval)) a; > Time: 733.592 ms > decibel=# select count(*) from (select 'epoch'::timestamptz + s.i * > '1 second'::interval AS "generate_series" from generate_series(extract > ('epoch' from now())::bigint, extract('epoch' from now()+'10 > days'::interval)::bigint, extract('epoch' from > '1'::interval)::bigint) s(i)) a; > Time: 699.606 ms > -- > Jim Nasby [EMAIL PROTECTED] > EnterpriseDB http://enterprisedb.com 512.569.9461 (cell) > > > > ---------------------------(end of broadcast)--------------------------- > TIP 1: if posting/reading through Usenet, please send an appropriate > subscribe-nomail command to [EMAIL PROTECTED] so that your > message can get through to the mailing list cleanly -- Bruce Momjian <[EMAIL PROTECTED]> http://momjian.us EnterpriseDB http://postgres.enterprisedb.com + If your life is a hard drive, Christ can be your backup. + -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
