Log4j logs decreases application performance?

java, log4j, logging

Solution

Does logging decreases application performance?

Yes. How much it does depends on a number of factors; see below.

and how to restrict display-tags logs to be printed in log files?

By changing the ConversionPattern in the logging properties

why the above is in log file?

Because:

- somewhere in the code is a call to a Logger method (probably `debug(String)`) with that message, and

- your logging properties set the logging Threshold to DEBUG for the appender.

To improve performance:

- change the ConversionPattern to use less expensive date/time formatting, and (more importantly) avoid 'C', 'F', 'L' and 'M' because they are particularly expensive.

- change the logging Threshold to INFO or WARNING or ERROR to reduce the amount of logging,

- put the `Logger.debug(...)` call inside an `if` statement that checks that debug logging is enabled. This saves the cost of assembling the log message in cases where it won't be needed; see In log4j, does checking isDebugEnabled before logging improve performance?.

- with log4j version 2 (log4j2), there are overloads that on the logging methods that take a format and parameters. These reduce the overhead when a logging at a level that is disabled.

- look also at logback and log4j 2.0.

You can also throttle logging at the `Logger` level ... as described in the log4j documentation. In fact, the documentation answers most of the questions that you asked, and has a lot of detail on the topics of logging performance and logging configuration.

Problem

Original source

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