The SQL Manager

The SQL manager, which we looked at in Chapter 3, is the driving force in much of SQL Server's query processing. You might say that it's the heart of SQL Server itself. The SQL manager deals with all of the requests to run stored procedures. It manages the procedure cache and the pseudo_system stored procedures, and it's involved in autoparameterization of ad hoc queries, which I'll discuss shortly.

Typically, the SQL manager is invoked with an RPC message when you ask SQL Server to do some work for you. However, when a SQL language statement comes in as an ad hoc SQL statement instead of as a procedure call, the SQL manager is also involved. It can be involved when a procedure or a batch has an EXEC statement in it because the EXEC is actually calling the SQL manager. If the SQL statement passes the autoparameterization template (which I'll discuss below), the SQL manager is called to parameterize the queries. It's also called when ad hoc queries need to be placed in the cache. The SQL manager really is the heart of SQL Server's query processing system.