Tag: SQL Server Query Plans

Part III – A Look at a “Physical” Subquery Perhaps I am being a little loose in my terminology, since there really isn’t a query operator called “subquery”. When I say “physical subquery” I am referring to those correlated subqueries where the subquery portion must be executed again and again, once for every row returned […]

Part II – The Table Spool In the previous installment, we looked at a very simple logical subquery that SQL Server executed as a physical join. We shall now take a look at a somewhat more complicated query and see what SQL Server does with it. In this query, we would like to get a […]

Some Surprising Traits of SQL Server Query Caching In the previous section<link SQL Server: Some Quirks In the Cache Part 1>, we saw that it is easy to observe query execution plans being entered into the procedure cache by SQL Server. Now that the tools are in place, we will observe some unexpected behavior of […]

Monitoring the Procedure Cache Getting the best performance from SQL Server is a complex task involving virtually every aspect of the system. Memory management is one of the most important aspects, of course. The primary concern is memory for data itself, but that doesn’t mean we can ignore the procedure cache. Procedure cache is the […]