Troubleshooting Performance Issues in SQL Server

There are many reasons for SQL Server slowdown. They can be broadly classified into three types to start our investigation.

1. Resource Bottleneck – CPU, Memory, I/O.  Check tools used for troubleshooting
2. Tempdb Bottlenck – There is only one tempdb for a SQL Server instance. If there is an application that overloads tempdb through excessive DML/DDL operations it can affect other processes on the server.
3. Slow running User Query – Performance of existing queries can degrade or a new query can be taking longer than expected to complete. Statistics/ Indexes / Locking / Blocking / Deadlocks/ Schema design / Isolation Level are factors that can affect the slowdown.