Using logging to diagnose errors
Logging is an effective means of generating diagnostic information. When writing log entries, consider the overhead of string allocation, garbage collection, and writing data to disk. Use conditional tests to reduce this overhead and minimize unnecessary logging.
The EPL
log statement is a simple means of generating logging output. The EPL
log statement writes to the correlator log file by default so any messages your program sends to the log file are mixed in with all other correlator logging messages. However, you can configure the correlator to send your EPL logging to a separate file. See
Setting EPL log files and log levels dynamically. The logging attributes you can specify include a particular target log file and a particular log level for any number of individual packages, monitors and events.
When sending messages to the correlator log file, consider the following:
Log messages can be lost if the correlator is logging to
stdout.
Using the correlator log is relatively expensive if there are many
log statements in the critical path.
Anything you send to the log might be lost if the correlator log level is
OFF.