Log4j logs reduce application performance?

Question

Does logging increase application performance? and how to limit tag log logs to be printed in log files?

eg. my log file has below logs

[2012-06-20 15:52:06,290] org.displaytag.tags.TableTag isFirstIteration 684 - [data] first iteration=true (row number=1) [2012-06-20 15:52:06,290] org.displaytag.tags.TableTag isFirstIteration 684 - [data] first iteration=true (row number=1) [2012-06-20 15:52:06,290] org.displaytag.tags.TableTag isFirstIteration 684 - [data] first iteration=true (row number=1) [2012-06-20 15:52:06,290] org.displaytag.tags.TableTag isFirstIteration 684 - [data] first iteration=true (row number=1) 

why is the above in the log file?

log.properties file

 # Log4j configuration file. log4j.rootCategory=DEBUG, A1 # Available levels are DEBUG, INFO, WARN, ERROR, FATAL # # A1 is a ConsoleAppender # log4j.appender.A1 = org.apache.log4j.RollingFileAppender log4j.appender.A1.File = C:/LogInfo/logfile.log log4j.appender.A1.MaxFileSize = 100MB log4j.appender.A1.MaxBackupIndex=50 log4j.appender.A1.layout = org.apache.log4j.PatternLayout log4j.appender.A1.append = true log4j.appender.A1.layout.ConversionPattern = [%d] %C %M %L - %m%n log4j.appender.A1.Threshold = DEBUG 

how to stop (org.displaytag.tags.TableTag) such logs that will be printed in the log files

Answer 1

Does logging affect application performance?

Yes. How much this does depends on a number of factors; See below.

and how to limit the display of logs with display tags in log files?

Changing ConversionPattern in Logging Properties

why is the above in the log file?

Because:

1. somewhere in the code there is a call to the Logger method (probably debug(String) ) with this message, and
2. in your logging properties for the threshold, set the Logging Threshold parameter to DEBUG.

To increase productivity:

1. modify ConversionPattern to use less expensive date and time formatting, and (more importantly) avoid the characters "C", "F", "L" and "M", as they are especially expensive.
2. change the Registration Threshold to INFO or WARNING or ERROR to reduce the number of registrations,
3. put a call to Logger.debug(...) in an if that checks if debug logging is enabled. This saves the cost of compiling the log message in cases where it is not needed; see. In log4j isDebugEnabled performance check before logging improves performance? .
4. log4j version 2 (log4j2) has overloads associated with logging methods that take format and parameters. This reduces logging overhead at a level that is disabled.
5. look also at logback.

You can also adjust logging at the Logger level ... as described in the log4j documentation. In fact, the documentation answers most of the questions you asked, and contains a lot of details on topics related to performance logging and logging configuration.

Answer 2

Short answer: yes, it reduces application performance because it uses some processor cycles and other resources (memory, etc.).

See also this question: log4j performance

Answer 3

Logging can be 30% of the processor time or more. As for jitter, it is bigger (and more often) than your GC delays.

An easy way to reduce overhead is to use a shutdown template from which you log each message. In your case, these are% C% M and% L, since the stack trace (entier stack) is required to get this information.

Answer 4

Yes Yes. That is why you should only register a mistake or something that must be registered. You can also record information useful for debugging in the debug channel, so that this will not affect performance.

Answer 5

You can limit spam logs as follows. Set the root log as INFO so that unnecessary debug logs do not come and populate your log file.

 log4j.rootCategory=INFO, A1 

If you want a specific class or package to produce DEBUG logs, you can do this as follows.

 log4j.logger.org.hibernate.event.def.DefaultLoadEventListener=DEBUG,A1 

The above will print DEBUG level logs from the DefaultLoadEventListener class in your log file along with other INFO level logs.

Answer 6

What about?

 log4j.category.org.displaytag.tags.TableTag=ERROR, A1