SQL Server running slow

Question

I have SQL job that runs every night which does various inserts/updates/deletes. The job contains 40 steps which mainly execute stored procedures.

It's been running fine up until a week ago when suddenly the run time went up from 2.5 hours to over 5 hours, sometimes even 8,9,10!

Could one you please give me any pointers?

Answer 1

First of all let me recommend you a valuable resource on Simple-Talk site. Is a detailed methodology of how to troubleshoot performance issues on SQL Server.

Does the insert you say was carried out was a huge bulk insert that could affect performance? Maybe if it was a huge load the query execution plans could be different and you need to re-tune your table structure, indexes, etc.

If the run time suddenlychanged and no changes where done in the queries or your database structure then I would ask myself several questions:

• first, does the process is still taking so long or it was only one time it ran so slow? maybe now is running smoothly and the issue only arised once. Nevertheless, try to find what triggered that bad performance, it can happend again and take down your server
• is the server a dedicated sql server? if not, check if some new tasks unrelated to the SQL engine had been configured, maybe a new tasks is doing some heavy I/O jobs and therefore your CRUD operations take longer
• if it is a dedicated server, then check that no new job has been added and can take down your existing jobs. Check this SO link for details on jobs settled up from the SQL Agent
• maybe low memory due to another process on same server?

And there is lot more to check, but before going deeper I would check that no external (non sql server related) was the reason of the delay on the process execution.