On Oct 16, 2012, at 20:01 , Evgeny Shishkin <itparanoia@xxxxxxxxx> wrote: > Selecting 5 yours of data is not selective at all, so postgres decides it is cheaper to do seqscan. > > Do you have an index on patient.dnsortpersonnumber? Can you post a result from > select count(*) from patient where dnsortpersonnumber = '347450'; ? > Yes, there is an index: "Aggregate (cost=6427.06..6427.07 rows=1 width=0)" " -> Index Scan using patient_pracsortpatientnumber on patient (cost=0.00..6427.06 rows=1 width=0)" " Index Cond: (dnsortpersonnumber = '347450'::text)" In fact, all the other criteria is picked using an index. I fear that the >= and <= on the timestamp is causing the issue. If I do a "=" of just one of them, I get an index scan. But I need to scan the entire range. I get queries like "give me everything that was entered into the system for this patient between these two dates". A single date wouldn't work. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
