PostgreSQL version:


The application_name can be any string of less than NAMEDATALEN characters (64 characters in a standard build). It is typically set by an application upon connection to the server. The name will be displayed in the pg_stat_activity view and included in CSV log entries. It can also be included in regular log entries via the guc-log-line-prefix parameter. Only printable ASCII characters may be used in the application_name value. Other characters will be replaced with question marks (?).


Set this to a reasonable default for most user sessions; if in the middle of working over your application to support application names, this might be “unknown”.