On 8/29/13 9:22 PM, Bastiaan Olij wrote:
Work well enough.. But as I'm using the same data in different reports and I though a view might be smart. So I created a view: ---- create view v_costs as select dcjobid as costjobid, sum(dcamount) as costamount from directcosts group by dcjobid union all select invjobid as costjobid, sum(detamount) as costamount from invoiceheader join finvoicedetail on detinvid = invid group by invjobid ---- And rewrote my report to: ---- select jobid, jobdesc, sum(costamount) from jobs join v_costs on costjobid = jobid where <some filter for my jobs> group by jobid, jobdesc ---- Now what I was hoping for was that postgres would start at my jobs table, find the records I'm trying to report on and then index scan on the related tables and start aggregating the amounts. What it seems to do is to first execute the view to get totals for all the jobs in the database and join that result set with my 2 or 3 jobs that match my filter. What is it about my view that prevents postgres to effectively use it? The group bys? the union?
It's probably either the GROUP BY or the UNION. Try stripping those out one at a time and see if it helps. If it doesn't, please post EXPLAIN ANALYZE (or at least EXPLAIN) output. -- Jim C. Nasby, Data Architect jim@xxxxxxxxx 512.569.9461 (cell) http://jim.nasby.net -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
