Hi Xintong, Thanks for your answer！
I also think that is not a big problem because it’ takes less than 0.5 second。I only want to find what was caused. "JVM also does that automatically, as long as there are continuous activities of creating / destroying objects in heap” I also find some answers like yours： “You may be interested to know that IBM provide a command-line option to disable System.gc() entirely. To get the behaviour, add -Xdisableexplicitgc to your command-line (the equivalent Sun option is -XX:+DisableExplicitGC). However, completely disabling System.gc() may have unintended consequences, because some System.gc() calls are useful and necessary (those which are used to generate seeds for crypto operations, or to free up resources associated with NIO buffers, for example) [1].” [1] https://www.ibm.com/developerworks/community/blogs/troubleshootingjava/entry/whats_calling_system_gc?lang=en <https://www.ibm.com/developerworks/community/blogs/troubleshootingjava/entry/whats_calling_system_gc?lang=en> Darling Andrew D.Lin > 下面是被转发的邮件： > > 发件人: Xintong Song <tonysong...@gmail.com> > 主题: 回复： Flink program，Full GC (System.gc()） > 日期: 2019年8月13日 GMT+8 下午10:24:13 > 收件人: Andrew Lin <chendonglin...@gmail.com> > 抄送: user <user@flink.apache.org> > >
