Question

I have a query that runs on a data warehouse. I ran the report last month. It gave me some results in say x minutes. The same report when run on the same database without any modifications to the database returns the same results but in y minutes now.

y>x. The difference between the time is so large.

The amount of data and the indexes are also the same. There is no difference in them.

Now clients ask for me for a reason for this. What are the possible reasons for this?

Answer 1

You leave a lot of questions open

• is the database running on a dedicated server.
• do you run the reports from clients or directly on the server.
• have there been changes to the phyisical network, have some settings been changed.
• did they (by accident) change the protocol to communicate with the server (tcp, named-pipes, …)
• have you tried defragmenting
• have you rebooted the server
• do you have an execution plan before and after