On Thu, Aug 26, 2010 at 6:03 PM, Ozer, Pam <pozer@xxxxxxxxxxxxxx> wrote: > > I am new to Postgres and I am trying to understand the Explain Analyze so I can tune the following query. I run the same query using mysql and it takes less than 50ms. I run it on postgres and it takes 10 seconds. I feel like I am missing something very obvious. (VehicleUsed is a big table over 750,000records) and datasetgroupyearmakemodel has 150000 records. > > It looks like the cost is highest in the Hash Join on Postalcode. Am I reading this correctly.? I do have indexes on the lower(postalcode) in both tables. Why wouldn’t be using the index? No, it's spending most of its time here: > " -> Nested Loop (cost=101.81..37776.78 rows=11887 width=10) (actual time=1.172..9876.586 rows=382528 loops=1)" Note that it expects 11,887 rows but gets 382k rows. Try turning up default stats target and running analyze again and see how it runs. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
