As far as i know if you created the indexes properly and postgres sees that it will give some improvement he will use those. - Look at the page of index creation that we may be forgeting some thing.
http://www.postgresql.org/docs/8.3/static/indexes.html I have to go to the hospital know. Tomorrow i will take a look at the manual and try to understand all the necessary for the postgresql use an index. Regards On Thu, Nov 6, 2008 at 2:33 PM, Віталій Тимчишин <[EMAIL PROTECTED]> wrote: > > > 2008/11/6 Helio Campos Mello de Andrade <[EMAIL PROTECTED]> > >> For what i see in four OR-plan.txt tou are doing too much "sequencial >> scan" . Create some indexes for those tables using the fields that you use >> an it may help you. >> >> OBS: If you already have lots of indexes in your tables it may be a good >> time for you re-think your strategy because it´s ot working. >> Tips: >> 1 - create indexes for the tables with the fields that you will use in >> the query if it is your most important query. If you have others querys that >> are used please post those here and we can help you to desing a better plan. > > > As you can see from other plans, it do have all the indexes to perform it's > work fast (when given part by part). It simply do not wish to use them. My > question: Is this a configuration problem or postgresql optimizer simply > can't do such a query rewrite? > > Actually I did rewrite the query to work properly as you can see from > union-plan.txt. My question is if postgresql can do this automatically > because such a rewrite is not always easy/possible (esp. for generated > queries)? > > -- Helio Campos Mello de Andrade
