Doing about 5K writes / second. Avg Data Size = 1.6 TB / node. Total Data
Size = 21 TB.
And this is the nodetool cfstats output for one of our busiest column
families:
SSTable count: 10
Space used (live): 43239294899
Space used (total): 43239419603
SSTable Compression Ratio: 0.2954468408497778
Number of Keys (estimate): 63729152
Memtable Columns Count: 1921620
Memtable Data Size: 257680020
Memtable Switch Count: 9
Read Count: 6167
Read Latency: NaN ms.
Write Count: 770984
Write Latency: 0.098 ms.
Pending Tasks: 0
Bloom Filter False Positives: 370
Bloom Filter False Ratio: 0.00000
Bloom Filter Space Used: 80103200
Compacted row minimum size: 180
Compacted row maximum size: 3311
Compacted row mean size: 2631
Average live cells per slice (last five minutes): 73.0
Average tombstones per slice (last five minutes): 13.0
On Mon, Jul 28, 2014 at 10:14 AM, Mark Reddy <mark.re...@boxever.com> wrote:
> What is your data size and number of columns in Cassandra. Do you do many
> deletions?
>
>
> On Mon, Jul 28, 2014 at 2:53 PM, Ruchir Jha <ruchir....@gmail.com> wrote:
>
>> Really curious to know what's causing the spike in Columns and
>> DeletedColums below :
>>
>>
>> 2014-07-28T09:30:27.471-0400: 127335.928: [Full GC 127335.928: [Class
>> Histogram:
>> num #instances #bytes class name
>> ----------------------------------------------
>> 1: 132626060 6366050880 java.nio.HeapByteBuffer
>> 2: 28194918 3920045528 [B
>> 3: 78124737 3749987376
>> edu.stanford.ppl.concurrent.SnapTreeMap$Node
>> * 4: 67650128 2164804096
>> <2164804096> org.apache.cassandra.db.Column*
>> * 5: 16315310 522089920
>> org.apache.cassandra.db.DeletedColumn*
>> 6: 6818 392489608 [I
>> 7: 2844374 273059904
>> edu.stanford.ppl.concurrent.CopyOnWriteManager$COWEpoch
>> 8: 5727000 229080000 java.util.TreeMap$Entry
>> 9: 767742 182921376 [J
>> 10: 2932832 140775936
>> edu.stanford.ppl.concurrent.SnapTreeMap$RootHolder
>> 11: 2844375 91020000
>> edu.stanford.ppl.concurrent.CopyOnWriteManager$Latch
>> 12: 4145131 66322096
>> java.util.concurrent.atomic.AtomicReference
>> 13: 437874 64072392 [C
>> 14: 2660844 63860256
>> java.util.concurrent.ConcurrentSkipListMap$Node
>> 15: 4920 62849864 [[B
>> 16: 1632063 52226016
>> edu.stanford.ppl.concurrent.SnapTreeMap
>>
>
>
