2020-06-17T12:54:16.995+0800: 681976.777: [GC (Allocation Failure) 2020-06-17T12:54:16.995+0800: 681976.777: [ParNew (0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3) (0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3) (0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3) (0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3) (0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3) (0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3) (0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3) (0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3) (0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3) (0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3) (0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3) (0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3) (0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3) (0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3) (0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3) (0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3) (0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3) (0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3) (0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3) (0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3) (0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3) (0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3) (0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3) (promotion failed): 1823484K->1883608K(1887488K), 0.4255307 secs]
2020-06-17T12:54:17.421+0800: 681977.202: [CMS: 952879K->532413K(2097152K), 2.9620031 secs] 2776364K->532413K(3984640K), [Metaspace: 211696K->211696K(1241088K)], 3.3881912 secs] [Times: user=3.23 sys=0.65, real=3.39 secs]
我的问题是，这个日志是什么意思？
(0: promotion failure size = 2) (1: promotion failure size = 3) (2: promotion failure size = 17912169) (3: promotion failure size = 3)
你没有说你使用哪个JDK/JVM和什么垃圾收集，但根据我发现的，它是CMS，它很久以前就被弃用并在JDK 14中删除：https://openjdk.java.net/jeps/363您应该认真考虑切换到更现代的JDK/GC。
也就是说，由于旧世代的空间(内存(不足或其碎片化，GC 似乎未能将对象从 Youn 一代"提升"到老一代。 以下是他们讨论此问题的一些链接：
- Java GC 升级失败
- 避免在 Java CMS GC 中升级失败
- https://serverfault.com/questions/698858/gc-taking-big-pause-and-parnew-promotion-failed
- https://blogs.oracle.com/poonam/troubleshooting-long-gc-pauses