SQL compatibility reminder: MySQL vs PostgreSQL
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From: "Pierre C" on 8 Mar 2010 05:06 > Oh, this is what I believe MySQL calls "loose index scans". I'm Exactly : http://dev.mysql.com/doc/refman/5.0/en/loose-index-scan.html > actually looking into this as we speak, Great ! Will it support the famous "top-n by category" ? > but there seems to be a > non-trivial amount of work to be done in order for this to work. > > > Regards, > Marko Tiikkaja -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
From: Robert Haas on 8 Mar 2010 09:44 On Mon, Mar 8, 2010 at 4:58 AM, Marko Tiikkaja <marko.tiikkaja(a)cs.helsinki.fi> wrote: > On 2010-03-08 11:47 +0200, Pierre C wrote: >>> As far as I can tell, we already do index skip scans: >> >> This feature is great but I was thinking about something else, like SELECT >> DISTINCT, which currently does a seq scan, even if x is indexed. >> >> Here is an example. In both cases it could use the index to skip all >> non-interesting rows, pulling only 69 rows from the heap instead of 120K. > > Oh, this is what I believe MySQL calls "loose index scans". I'm > actually looking into this as we speak, but there seems to be a > non-trivial amount of work to be done in order for this to work. We should probably have a TODO for this, if we don't already. ....Robert -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
From: Robert Haas on 8 Mar 2010 10:00 On Mon, Mar 8, 2010 at 9:48 AM, Wolfgang Wilhelm <wolfgang20121964(a)yahoo.de> wrote: > +1 > > Isn´t that a good time to think to put that question into the list of things > PostgreSQL doesn´t want to do? Yes. ....Robert > Von: Andrew Dunstan <andrew(a)dunslane.net> > François Pérou wrote: >> >> My opinion is that PostgreSQL should accept any MySQL syntax and return >> warnings. I believe that we should access even innodb syntax and turn it >> immediately into PostgreSQL tables. This would allow people with no >> interest in SQL to migrate from MySQL to PostgreSQL without any harm. >> > > This is just fantasy. Doing this will destabilize Postgres, cost us hugely > in maintenance effort and LOSE us users. -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
From: "Kevin Grittner" on 8 Mar 2010 10:16 Robert Haas <robertmhaas(a)gmail.com> wrote: > Wolfgang Wilhelm <wolfgang20121964(a)yahoo.de> wrote: >> Isn*t that a good time to think to put that question into the >> list of things PostgreSQL doesn*t want to do? > > Yes. Done. http://wiki.postgresql.org/wiki/Todo#Features_We_Do_Not_Want -Kevin -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
From: David Christensen on 8 Mar 2010 10:24
On Mar 8, 2010, at 9:16 AM, Kevin Grittner wrote: > Robert Haas <robertmhaas(a)gmail.com> wrote: >> Wolfgang Wilhelm <wolfgang20121964(a)yahoo.de> wrote: > >>> Isn*t that a good time to think to put that question into the >>> list of things PostgreSQL doesn*t want to do? >> >> Yes. > > Done. > > http://wiki.postgresql.org/wiki/Todo#Features_We_Do_Not_Want Does this conflict conceptually with the item from "Exotic Features" on the same page?: * Add pre-parsing phase that converts non-ISO syntax to supported syntax This could allow SQL written for other databases to run without modification. Regards, David -- David Christensen End Point Corporation david(a)endpoint.com -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers |