SQL Server error log is a standard text file that holds SQL Server information and error messages. This file can provide meaningful information for handling SQL Server-related issues. This information can either be used for tracking down problems or alert to potential or existing problems.
Execution contexts, also known as executable plan, are created when, during the execution of a compiled plan, SQL Server keeps track of information about the state of execution and stores this information in the plan cache.
A SQL Server object that dynamically loads and executes a function within a dynamic-link library (DLL) in a manner similar to a stored procedure. Actions outside SQL Server can be triggered, and external information returned to SQL Server. SQL Server comes pre-installed with a large number of extended stored procedures. In addition, SQL Server includes system-stored procedures that allow adding and dropping extended stored procedures, or provide information about such procedures.