ppkarwasz commented on issue #2856: URL: https://github.com/apache/logging-log4j2/issues/2856#issuecomment-2304705850
> ### 1. Do nothing > > * log4j2 > Firstly, without doing anything, the application's memory is about 160M: This graph isn't really reliable: you don't see any garbage-collection event, so it is entirely possible that most of the 160 MiB could be collected. > ### 2. Write log > > It was tested in the same way: http://127.0.0.1:8080/log4j2/pressure?minLengthInclusive=102400&; maxLengthExclusive=409600×=10000 What does `minLengthInclusive` and `maxLengthExclusive` parameters mean? If these are the sizes of log messages, their values greatly exceed the size of a typical log event. Log4j Core by default expects log messages up to 518 bytes and log events up to 8192 bytes in size. Besides these limits you start creating a **lot** of temporary objects and you are no longer garbage-free. See [Garbage Free logging](https://logging.staged.apache.org/log4j/2.x/manual/garbagefree.html) for more details. > the conclusion is that log4j2 is more powerful, but why isn't it the case when I test it myself? If by "powerful" you mean that Log4j Core always provides a better performance and lower memory usage than Logback, the conclusion is wrong. Everything depends on how your application is configured and how you use logging. Note that the astonishing 20M messages/s is a **peak** throughput that you can keep for **very small** periods of time (a couple of ms). You can compare this with the performance of SSDs: writing the first 8 MiB or so is lightning fast, but the sustainable rate is much lower. Regarding memory usage: - The **garbage-free** mode increases your memory usage, since many reusable buffers need to be allocated. You pay an initial memory price, but later on you will not experience GC pauses due to logging. Nowadays garbage collection is very fast, but a couple of years ago it was a "stop the world" event, which was very costly for financial applications. See [`log4j2.enableThreadlocals`](https://logging.staged.apache.org/log4j/2.x/manual/garbagefree.html#log4j2.enableThreadlocals) for details on how to disable garbage-free logging. - Using the Disruptor also costs memory, since it pre-allocates up to 256 × 1024 buffers. See [asynchronous loggers](https://logging.staged.apache.org/log4j/2.x/manual/async.html) on how to enable or disable the usage of the LMAX Disruptor. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
