Recording Query Information
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Warning:

  This feature is intended for debugging only.

Flask-SQLAlchemy can record some information about every query that
executes during a request. This information can then be retrieved to
aid in debugging performance. For example, it can reveal that a
relationship performed too many individual selects, or reveal a query
that took a long time.

To enable this feature, set "SQLALCHEMY_RECORD_QUERIES" to "True" in
the Flask app config. Use "get_recorded_queries()" to get a list of
query info objects. Each object has the following attributes:

"statement"
   The string of SQL generated by SQLAlchemy with parameter
   placeholders.

"parameters"
   The parameters sent with the SQL statement.

"start_time" / "end_time"
   Timing info about when the query started execution and when the
   results where returned. Accuracy and value depends on the operating
   system.

"duration"
   The time the query took in seconds.

"location"
   A string description of where in your application code the query
   was executed. This may be unknown in certain cases.
