The Error Log Field References in log_filter_dragnet Rules log_filter_dragnet  rules support references to core, optional, and user-defined fields in error events. •Core Field References •Optional Field References •User-Defined Field References • prio Core Field References The  log_filter_dragnet  grammar at Grammar for log_filter_dragnet Rule Language names the core fields that filter rules recognize. For general descriptions of these fields, see Section 5.4.2.3, “Error Event Fields” , with which you are assumed to be familiar. The following remarks provide additional information only as it pertains specifically to core field references as used within  log_filter_dragnet  rules. The event priority, to indicate an error, warning, or note/information event. In comparisons, each priority can be specified as a symbolic priority name or an integer literal. Priority symbols are recognized only in comparisons with the  prio  field. These comparisons are equivalent: IF prio == INFORMATION THEN ... IF prio == 3 THEN ... The following table shows the permitted priority levels. There is also a message priority of  SYSTEM , but system messages cannot be filtered and are always written to the error log. Priority values follow the principle that higher priorities have lower values, and vice versa. Priority values begin at 1 for the most severe events (errors) and increase for events with decreasing priority. For example, to discard events with priority lower than warnings, test for priority values higher than Event Type Priority Symbol Numeric Priority Error event ERROR 1 Warning event WARNING 2 Note/information event INFORMATION 3 WARNING : IF prio > WARNING THEN drop. The following examples show the  log_filter_dragnet  rules to achieve an effect similar to each log_error_verbosity  value permitted by the  log_filter_internal  filter: IF prio > ERROR THEN drop. IF prio > WARNING THEN drop. IF prio > INFORMATION THEN drop. •Errors only ( log_error_verbosity=1 ): •Errors and warnings ( log_error_verbosity=2 ): •Errors, warnings, and notes ( log_error_verbosity=3 ): 1039