The INFORMATION_SCHEMA PARAMETERS Table The  OPTIMIZER_TRACE  table provides information produced by the optimizer tracing capability for traced statements. To enable tracking, use the  optimizer_trace  system variable. For details, see MySQL Internals: Tracing the Optimizer. The  OPTIMIZER_TRACE  table has these columns: The text of the traced statement. The trace, in  JSON  format. Each remembered trace is a string that is extended as optimization progresses and appends data to it. The  optimizer_trace_max_mem_size  variable sets a limit on the total amount of memory used by all currently remembered traces. If this limit is reached, the current trace is not extended (and thus is incomplete), and the  MISSING_BYTES_BEYOND_MAX_MEM_SIZE  column shows the number of bytes missing from the trace. If a traced query uses views or stored routines that have  SQL SECURITY  with a value of  DEFINER , it may be that a user other than the definer is denied from seeing the trace of the query. In that case, the trace is shown as empty and  INSUFFICIENT_PRIVILEGES  has a value of 1. Otherwise, the value is 0. 26.3.20 The INFORMATION_SCHEMA PARAMETERS Table The  PARAMETERS  table provides information about parameters for stored routines (stored procedures and stored functions), and about return values for stored functions. The  PARAMETERS  table does not include built-in (native) functions or loadable functions. The  PARAMETERS  table has these columns: The name of the catalog to which the routine containing the parameter belongs. This value is always def . The name of the schema (database) to which the routine containing the parameter belongs. The name of the routine containing the parameter. For successive parameters of a stored procedure or function, the  ORDINAL_POSITION  values are 1, 2, 3, and so forth. For a stored function, there is also a row that applies to the function return value (as described by the  RETURNS  clause). The return value is not a true parameter, so the row that describes it has these unique characteristics: 4803 •The  ORDINAL_POSITION  value is 0. • ORDINAL_POSITION • SPECIFIC_NAME • SPECIFIC_SCHEMA • SPECIFIC_CATALOG • INSUFFICIENT_PRIVILEGES • MISSING_BYTES_BEYOND_MAX_MEM_SIZE • TRACE • QUERY