1
vote
1answer
58 views

Reading a SQL Server Execution plan

I am very new to any type of tuning but have been learning more.. One of my specific databases one of the problems identified with slow queries are a number of Implicit conversions. It is my ...
0
votes
1answer
47 views

Access and filter in oracle plan

I came to a execution plan where oracle choose to access the index but instead of using the columns as predicate it only filter by them. My question is what are the reasons that can cause that(all ...
2
votes
1answer
217 views

How do you figure out what planner cost constants to use in Postgres?

I'm using Postgres 8.4 right now. Performance has started to become an issue as our tables have grown in size and our queries in complexity, so I've started to look into some performance tuning, but I ...