sp_trace_getdata is used by SQL Profiler to read it's trace and return the results to the SQL Profiler GUI/application;
SQL Profiler is definitely known to have an impact on SQL server...it potentially can have a very severe performance impact if the trace is catching lots of events.
the way to deactivate it is to not allow anyone to run SQL Profiler;
you can see who's running it by running sp_who2, and find any thing that has ProgramName like SQL Profiler.
For that row(s) , look at the username and the hostname, so you know who is using Profiler, and at what machine, and make them stop using profiler.
if you need to trace something , make a server side trace and use that instead; SQL Profiler can make the trace definition for you.
a server side trace has a much much lighter impact on the server.
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