HSDB

• Intro(HSDB) #

  -XX:-UseCompressedOopsoops: ordinary object pointer，普通对象指针压缩，例如Object o = new Object();其中o就是个指向new Object()对象的指针，o在指针压缩前占用8个字节，在指针压缩后占用4个字节。
  -XX:-UseCompressedClassPointers压缩Klass Pointer，压缩前8个字节，压缩后4个字节。

  sudo java -cp $JAVA_HOME/lib/sa-jdi.jar sun.jvm.hotspot.HSDB

• Reference #

  • https://github.com/openjdk/jdk/blob/jdk8-b120/hotspot/agent/src/share/classes/sun/jvm/hotspot/HSDB.java
  • https://openjdk.org/groups/hotspot/docs/Serviceability.html#bsa
  • https://docs.oracle.com/en/java/javase/11/tools/jhsdb.html#GUID-0345CAEB-71CE-4D71-97FE-AA53A4AB028E
  • https://github.com/openjdk/jdk/tree/jdk8-b120/hotspot/agent/doc #下面站点可以渲染里面的html.
    1. https://htmlpreview.github.io/?https://github.com/openjdk/jdk/blob/jdk8-b120/hotspot/agent/doc/index.html
    2. https://svn.netlabs.org/repos/java/trunk/openjdk/hotspot/agent/doc/index.html