Ask Why My Query So Slow?

Working with SQL Server for many years, I have rescued a number of organizations from degrading database performance back to outstanding production database. I often see incorrect configuration and settings, inefficient T-SQL code execution.

In this session, I will elaborate on the following topics by presenting real-world examples, and why they are bad and the remedy to improve performance.

Configuration:

1.      RAM (Memory)

2.      RAID (IO), ....

3.      Concurrency, Isolation level –

·         Dirty Read

·         Phantom Read

·         Non-repeatable Read

·         Select blocking update

·         Update blocking select

T-SQL Code:

         First, an in-a-nutshell Query Tuning example

  1. inline function (and expression)
  2. select *, order by, group by
  3. compiled to incorrect plan 
  4. recompile plan
  5. union (union all)
  6. missing  join
  7. type implicit conversion 
  8. unfiltered delete (truncate table instead)
  9. like operator (and execution plan and index)
  10. missing, unused, redundant indexes
  11. query hint
  12. database version compatibility
  13. locking, blocking (isolation level)
  14. not in, in, exists, not exists
  15. schema naming convention

What you can expect to take away from this session:

  1. Learn the efficient T-SQL programming syntax.
  2. Understand the intertwined server configuration and code execution, such as between query and index, between cache and IO, between isolation level and locking etc.
  3. Best practice principles based on real world scenarios
  4. Learn how to re-factor old code to improve performance
  5. Leverage the SQL Server 2008 new features to solve performance issues.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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