TSQL Tuning

TSQL Tuning

My favourite wait state– ASYNC_NETWORK_IO

Sometimes it does feel that a problem is a database problem until proven otherwise.  When this does occur I have had to put a lot of time and effort into demonstrating the hows and whys.  One of the easiest ( and most common ) scenarios of this is related to ASYNC_NETWORK_IO waits. Simply put ASYNC_NETWORK_IO […]

Please please tell me now…

.. Is there something I should know,  sang Duran Duran many moons ago when I was young and before I knew that query optimization was even a thing.  But,  it is quite a handy little line to keep in mind when you are tuning queries,  giving SQL server a little bit more explicit information about […]

Reasons why your plans suck : No 56,536

I have been working with SQL server for more years than I really care to mention and like to think that I am now quite comfortable with the internals, specifically the Query Optimizer. Every so often though a new problem gets thrown into the mix, just to keep me on my toes ( or so […]

Reading a snapshot – Are there performance implications ?

My present role is to look at the performance of a large datawarehouse load.  This is right up my alley,  and I have be playing with all manner of performance tuning fun, indexing, execution plans, filtered statistics etc, all good stuff. However,  during QA testing some of my suggestions actually made things worse.  Not a little worse, but a […]