Ok. But that means I need a trigger on the original column to update the new column on each insert/update and that overhead. -----Original Message----- From: Ruben Rubio Rey [mailto:ruben@xxxxxxxxxxxx] Sent: Thursday, April 20, 2006 12:49 PM To: Doron Baranes; pgsql-performance@xxxxxxxxxxxxxx Subject: Re: [PERFORM] Perfrmance Problems (7.4.6) I think that the problem is the GROUP BY (datetime) that is date_trunc('hour'::text, i.entry_time) You should create an indexe with this expression (if its possible). http://www.postgresql.org/docs/7.4/interactive/indexes-expressional.html If is not possible, I would create a column with value date_trunc('hour'::text, i.entry_time) of each row and then index it. Hope this helps :) Doron Baranes wrote: >Hi, > >I am running on postgres 7.4.6. >I did a vacuum analyze on the database but there was no change. >I Attached here a file with details about the tables, the queries and >the Explain analyze plans. >Hope this can be helpful to analyze my problem > >10x >Doron > > >----------------------------------------------------------------------- - > > >---------------------------(end of broadcast)--------------------------- >TIP 9: In versions below 8.0, the planner will ignore your desire to > choose an index scan if your joining column's datatypes do not > match > >
