graham sanderson created CASSANDRA-6483: -------------------------------------------
Summary: Possible Collections.sort assertion failure in STCS.filterColdSSTables Key: CASSANDRA-6483 URL: https://issues.apache.org/jira/browse/CASSANDRA-6483 Project: Cassandra Issue Type: Bug Components: Core Reporter: graham sanderson We have observed the following stack trace periodically: {code} java.lang.IllegalArgumentException: Comparison method violates its general contract! at java.util.TimSort.mergeLo(TimSort.java:747) at java.util.TimSort.mergeAt(TimSort.java:483) at java.util.TimSort.mergeCollapse(TimSort.java:410) at java.util.TimSort.sort(TimSort.java:214) at java.util.TimSort.sort(TimSort.java:173) at java.util.Arrays.sort(Arrays.java:659) at java.util.Collections.sort(Collections.java:217) at org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy.filterColdSSTables(SizeTieredCompactionStrategy.java:94) at org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy.getNextBackgroundSSTables(SizeTieredCompactionStrategy.java:59) at org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy.getNextBackgroundTask(SizeTieredCompactionStrategy.java:229) at org.apache.cassandra.db.compaction.CompactionManager$BackgroundCompactionTask.run(CompactionManager.java:191) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) at java.util.concurrent.FutureTask.run(FutureTask.java:262) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at java.lang.Thread.run(Thread.java:744) {code} The comparator ant SizeTieredCompactionStrategy line 94 breaks the assertions in the new JDK7 default sort algorithm, because (I think just) the hotness value (based on meter) may be modified concurrently by another thread This bug appears to have been introduced in CASSANDRA-6109 -- This message was sent by Atlassian JIRA (v6.1.4#6159)