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Nicolas Liochon commented on HBASE-10656: ----------------------------------------- Is there any reference to this bug in the high-scale-lib repo? > high-scale-lib's Counter depends on Oracle (Sun) JRE, and also has some bug > ---------------------------------------------------------------------------- > > Key: HBASE-10656 > URL: https://issues.apache.org/jira/browse/HBASE-10656 > Project: HBase > Issue Type: Bug > Reporter: Hiroshi Ikeda > Priority: Minor > Attachments: MyCounter.java, MyCounterTest.java > > > Cliff's high-scale-lib's Counter is used in important classes (for example, > HRegion) in HBase, but Counter uses sun.misc.Unsafe, that is implementation > detail of the Java standard library and belongs to Oracle (Sun). That > consequently makes HBase depend on the specific JRE Implementation. > To make matters worse, Counter has a bug and you may get wrong result if you > mix a reading method into your logic calling writing methods. > In more detail, I think the bug is caused by reading an internal array field > without resolving memory caching, which is intentional the comment says, but > storing the read result into a volatile field. That field may be not changed > after you can see the true values of the array field, and also may be not > changed after updating the "next" CAT instance's values in some race > condition when extending CAT instance chain. > Anyway, it is possible that you create a new alternative class which only > depends on the standard library. I know Java8 provides its alternative, but > HBase should support Java6 and Java7 for some time. -- This message was sent by Atlassian JIRA (v6.2#6252)