You create a bookmark and insert it into your log file to indicate the exact point from which the log file monitor is reading data. To accurately monitor and manage a log file, the log file monitor must know its exact position within the file and have a dependable means to reset its file position if it loses its place within the file due to truncation. If you opt not to set a bookmark, you choose which truncation action OpenEdge Management follows: searching only new data, or searching the entire file.
You are urged to use bookmarks with monitors you create for OpenEdge log files. However, using the bookmark feature in non-OpenEdge log files might cause problems using the log. If you have an application that parses out its own log file, it could get tripped up by information it considers foreign.
You might detect a small performance gain in running the log file resource monitor when the log file is truncated. However, you will sacrifice accuracy within your log file data, exposing the data and monitoring operations to an unnecessarily high level of risk and unpredictable accuracy in your log file reads.
