Re: PostgreSQL Query Speed Issues
От | Joseph Pravato |
---|---|
Тема | Re: PostgreSQL Query Speed Issues |
Дата | |
Msg-id | 5134D36C.2030209@nomagic.com обсуждение исходный текст |
Ответ на | Re: PostgreSQL Query Speed Issues (Joseph Pravato <joseph.pravato@nomagic.com>) |
Ответы |
Re: PostgreSQL Query Speed Issues
|
Список | pgsql-novice |
Thanks again to everyone that has been assisting us with our query speed issue. We have possibly found a reason why our views are running slow, does anyone know if that could be our problem?
Please read below.
Please read below.
We've started to test more of our queries that involve the view and we believe we may have come across a possible reason for the poor performance in our views. The view is pulling data from many tables as said before, one of them has a varchar(255) column (ColA) that is copied over into the view. However, in the view column definition, it is a varchar(2147483647). In the query we tested, we are running an equivalence check against this column, along with another varchar column of size 1 (ColB). When we remove the check against ColA the query returns in 2.5 seconds. When included it talks 200 seconds. There is almost no difference when the ColB check is removed (2.5s vs 2.3s). It is of our belief that this varchar(2147483647) could be causing performance problems. ColA might be defaulting to 2147483647 because it is being union-ed with the same column a couple of times in different circumstances. So we are wondering if there a way to set the column's varchar size in a view definition?
Thanks!
В списке pgsql-novice по дате отправления: