Understanding Governor Limits
Governor limits are imposed on your running Apex code based on the type of resource consumed. When a governor limit is encountered, your code is immediately terminated with an exception indicating the type of limit reached. Examples of resource types are heap (memory used during execution) and SOQL queries.
Table 4.4 lists a few of the most important governor limits. Additional governor limits are introduced later in the book.
Note
Namespaces are used to separate and isolate Apex code and database objects developed by different vendors so that they can coexist and interoperate in a single Force.com organization. Governor limits are applied independently to each namespace. For example, if you install a package from Force.com AppExchange, the resources consumed by code running inside that package do not count against the limits applied to your code.