On Oct 29, 2010, at 7:38 AM, Igor Neyman wrote: >> is my intuition completely off on this? >> >> best regards, ben >> > > If your SELECT retrieves substantial amount of records, table scan could > be more efficient than index access. > > Now, if while retrieving large amount of records "WHERE clause" of this > SELECT still satisfies constraints on some partition(s), then obviously > one (or few) partition scans will be more efficient than full table scan > of non-partitioned table. > > So, yes partitioning provides performance improvements, not only > maintenance convenience. my impression was that a *clustered* index would give a lot of the same I/O benefits, in a more flexible way. if you're clustered on the column in question, then an index scan for a range is much like a sequential scan over a partition (as far as i understand.) b -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
