Performance Schema Status Variables The number of prepared statements that could not be instrumented in the prepared_statements_instances  table. This can be nonzero if the value of performance_schema_max_prepared_statements_instances  is too small. The number of stored programs for which statistics were lost. This can be nonzero if the value of performance_schema_max_program_instances  is too small. How many rwlock instruments could not be loaded. How many rwlock instrument instances could not be created. In addition to the connection attribute size-limit check performed by the Performance Schema against the value of the  performance_schema_session_connect_attrs_size  system variable, the server performs a preliminary check, imposing a limit of 64KB on the aggregate size of connection attribute data it accepts. If a client attempts to send more than 64KB of attribute data, the server rejects the connection. Otherwise, the server considers the attribute buffer valid and tracks the size of the longest such buffer in the  Performance_schema_session_connect_attrs_longest_seen status variable. If this value is larger than  performance_schema_session_connect_attrs_size , DBAs may wish to increase the latter value, or, alternatively, investigate which clients are sending large amounts of attribute data. For more information about connection attributes, see Section 27.12.9, “Performance Schema Connection Attribute Tables” . The number of connections for which connection attribute truncation has occurred. For a given connection, if the client sends connection attribute key-value pairs for which the aggregate size is larger than the reserved storage permitted by the value of the  performance_schema_session_connect_attrs_size  system variable, the Performance Schema truncates the attribute data and increments Performance_schema_session_connect_attrs_lost . If this value is nonzero, you may wish to set  performance_schema_session_connect_attrs_size  to a larger value. For more information about connection attributes, see Section 27.12.9, “Performance Schema Connection Attribute Tables” . How many socket instruments could not be loaded. How many socket instrument instances could not be created. How many stage instruments could not be loaded. 5121 • Performance_schema_program_lost • Performance_schema_rwlock_classes_lost • Performance_schema_rwlock_instances_lost • Performance_schema_session_connect_attrs_longest_seen • Performance_schema_session_connect_attrs_lost • Performance_schema_socket_classes_lost • Performance_schema_socket_instances_lost • Performance_schema_stage_classes_lost