When in doubt - test. Why not remove index in MySQL (or create index in PostgreSQL) and see what happens. Why trying compare "apples and oranges"? Igor Neyman > -----Original Message----- > From: Yang Zhang [mailto:yanghatespam@xxxxxxxxx] > Sent: Monday, February 22, 2010 1:37 PM > To: Richard Broersma > Cc: Frank Heikens; pgsql-general@xxxxxxxxxxxxxx > Subject: Re: Sorting performance vs. MySQL > > On Mon, Feb 22, 2010 at 1:30 PM, Richard Broersma > <richard.broersma@xxxxxxxxx> wrote: > > On Mon, Feb 22, 2010 at 10:17 AM, Frank Heikens > <frankheikens@xxxxxxx> wrote: > > > >> There is no index on the column transactionid in your > >> PostgreSQL-table, as there is in your MySQL-table. This > explains the difference. > >> > >> CREATE INDEX i_transactionid ON public.metarelcloud_transactionlog > >> (transactionid); > > > > Does an index help a sort operation in PostgreSQL? > > I also share the same doubt. An external merge-sort needs to > make complete passes over the entire dataset, with no > index-directed accesses. > -- > Yang Zhang > http://www.mit.edu/~y_z/ > -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
