SYS_LOG_PARSE parses the standard syslog format:
Mon DD HH:MM:SS server message
SYS_LOG_PARSE processes entries commonly found in UNIX/Linux system logs. System log entries start with a timestamp and are followed with a free form text field. SYS_LOG_PARSE output consists of two columns. The first column is named “COLUMN1” and is SQL data type TIMESTAMP. The second column is named “COLUMN2” and is SQL type VARCHAR().
Detailed information on SYSLOG can be found in IETF RFC3164.
Other information about date-time patterns and matching can be found in Date and Time Patterns.