On 09/28/2011 12:26 AM, Venkat Balaji wrote:
Thanks a lot Kevin !! Yes. I intended to track full table scans first to ensure that only small tables or tables with very less pages are (as you said) getting scanned full.
It can also be best to do a full table scan of a big table for some queries. If the query needs to touch all the data in a table - for example, for an aggregate - then the query will often complete fastest and with less disk use by using a sequential scan.
I guess what you'd really want to know is to find out about queries that do seqscans to match relatively small fractions of the total tuples scanned, ie low-selectivity seqscans. I'm not sure whether or not it's possible to gather this data with PostgreSQL's current level of stats detail.
-- Craig Ringer -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
