Limiting Traces
If a filter is not set, all events of the selected event classes are returned in the trace output. Filters limit the events collected in the trace. For example, limiting the Microsoft® Windows NT® 4.0 or Windows® 2000 user names in the trace to specific users reduces the output data to only those users in which you are interested.
Trace event criteria are parameters used to restrict (filter) the event data captured within the trace. For example, you can monitor the activity of a specific application or exclude an application from monitoring (the default trace event criteria excludes SQL Profiler from monitoring itself). For example, when monitoring queries to determine the batches that take the longest time to execute, you can set the trace event criteria to monitor (trace) only those batches that take longer than 30 seconds to execute (a CPU minimum value of 30,000 milliseconds). You can specify filters by right-clicking on the appropriate trace event criteria value and entering the information.
To filter events in a trace template