# Query Profiling Collect XQuery Performance Statistics

Enable tracing to start collecting statistics. Run queries as usual (through any eXist interface), then press "Refresh" to see statistics.
Enable Tracing Clear Tare Refresh

Source | Calls | Timing
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No statistics available or tracing not enabled.

Function | Source | Calls | Timing
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No statistics available or tracing not enabled.

Source | Index | Optimization | Calls | Timing
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No statistics available or tracing not enabled.

Optimization = Optimized means: the query optimizer could use the index to execute the expression in the best possible way. Basic: an index was available but could only be used to speed up the lookup, no further optimization was applied. None : no index was found, no optimization possible.