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Posted to commits@cassandra.apache.org by "Jonathan Ellis (Assigned) (JIRA)" <ji...@apache.org> on 2011/10/13 23:45:12 UTC
[jira] [Assigned] (CASSANDRA-3073) liveSize() calculation is wrong
in case of overwrite
[ https://issues.apache.org/jira/browse/CASSANDRA-3073?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Jonathan Ellis reassigned CASSANDRA-3073:
-----------------------------------------
Assignee: Yang Yang
> liveSize() calculation is wrong in case of overwrite
> ----------------------------------------------------
>
> Key: CASSANDRA-3073
> URL: https://issues.apache.org/jira/browse/CASSANDRA-3073
> Project: Cassandra
> Issue Type: Bug
> Reporter: Yang Yang
> Assignee: Yang Yang
> Priority: Minor
> Attachments: 0001-liveSize-is-different-from-throughput-particularly-w.patch
>
>
> currently liveSize() is the sum of currentThroughput.
> this definition is wrong if most of the operations are overwrite, or counter (which is essentially overwrite).
> for example, the following code should always keep a single entry in db, with one row, one cf, one column, and supposedly should have a size of only about 100 bytes.
> connect localhost/9160;
> create keyspace blah;
> use blah;
> create column family cf2 with memtable_throughput=1024 and memtable_operations=10000 ;
> set the cassandra.yaml
> memtable_total_space_in_mb: 20
> to make the error appear faster (but if u set to default, still same issue will appear)
> then we use a simple pycassa script:
> >>> pool = pycassa.connect('blah')
> >>> mycf = pycassa.ColumnFamily(pool,"cf2");
> >>> for x in range(1,10000000) :
> ... xx = mycf.insert('key1',{'col1':"{}".format(x)})
> ...
> you will see sstables being generated with only sizes of a few k, though we set the CF options to get high SSTable sizes
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