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I have been monitoring gcstats from last couple of days and can't believe the value it return is correct.

nodetool gcstats [GC Reclaimed (MB)] shows below values in last 5 runs when nothing is running against the database

30356680056

663531768

4222674760

567091224

2147418944

The total keyspace size is less than 1 GB.

user2704472
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1 Answers1

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Thats the result of the java's jvm garbage collection not anything specific to C*. The difference of the garbage collector mbean values: http://docs.oracle.com/javase/7/docs/api/java/lang/management/GarbageCollectorMXBean.html since the last time gcstats was called.

Chris Lohfink
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  • I fail to understand how come java's jvm garbage collection shows a value which is not possible , when i don't even have that sort of space on the system .gcstats [GC Reclaimed (MB)] : 30356680056 will be 1264861669 GB – user2704472 Aug 22 '15 at 00:54
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    it should be bytes, not mb. the mbean returns bytes but C* never changes it. Can open a bug to change the wording in GcStats.java to label units correctly. Keep in mind you can have many GCs in between each time you call gcstats, and that is the sum of all of them. – Chris Lohfink Aug 22 '15 at 16:36
  • If i understand correctly , between each call of gcstats there could be multiple GC's executed and it will return the sum of those GC's – user2704472 Aug 24 '15 at 11:43