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From Ran Tavory <ran...@gmail.com>
Subject Re: Key cache capacity: 1 when using KeysCached="50%"
Date Tue, 25 May 2010 17:24:35 GMT
 https://issues.apache.org/jira/browse/CASSANDRA-1129

On Tue, May 25, 2010 at 3:42 PM, Jonathan Ellis <jbellis@gmail.com> wrote:

> That does look like a bug.  Can you create a ticket and upload a
> (preferably small-ish) sstable that illustrates the problem?
>
> On Mon, May 24, 2010 at 12:07 PM, Ran Tavory <rantav@gmail.com> wrote:
> > I'd like to have 100% keys cached. Sorry if my example of Super2 wasn't
> > correct, but I do think there's a problem. Here's with my own data:
> > When using actual numbers (in this case for RowsCached) it works as
> > expected, however when specifying KeysCached="100%" I get only 1.
> >       <ColumnFamily CompareWith="BytesType" Name="KvAds"
> >         KeysCached="100%"
> >         RowsCached="10000"
> >         />
> >
> >                 Column Family: KvAds
> >                 SSTable count: 7
> >                 Space used (live): 797535964
> >                 Space used (total): 797535964
> >                 Memtable Columns Count: 42292
> >                 Memtable Data Size: 10514176
> >                 Memtable Switch Count: 24
> >                 Read Count: 2563704
> >                 Read Latency: 4.590 ms.
> >                 Write Count: 1963804
> >                 Write Latency: 0.025 ms.
> >                 Pending Tasks: 0
> >                 Key cache capacity: 1
> >                 Key cache size: 1
> >                 Key cache hit rate: 0.0
> >                 Row cache capacity: 10000
> >                 Row cache size: 10000
> >                 Row cache hit rate: 0.2206178354382234
> >                 Compacted row minimum size: 386
> >                 Compacted row maximum size: 9808
> >                 Compacted row mean size: 616
> >
> > On Mon, May 24, 2010 at 6:30 PM, Jonathan Ellis <jbellis@gmail.com>
> wrote:
> >>
> >> If you really want a cache capacity of 0 then you need to use 0
> >> explicitly, otherwise the % versions will give you at least 1.
> >>
> >> On Mon, May 24, 2010 at 12:34 AM, Ran Tavory <rantav@gmail.com> wrote:
> >> > I've noticed that when defining KeysCached="50%" (or KeysCached="100%"
> >> > and I
> >> > didn't test other values with %) then cfstats reports Key cache
> >> > capacity: 1
> >> > This looks weird... is this expected? (version 0.6.1)
> >> > For example, in the default configuration:
> >> >       <ColumnFamily Name="Super2"
> >> >                     ColumnType="Super"
> >> >                     CompareWith="UTF8Type"
> >> >                     CompareSubcolumnsWith="UTF8Type"
> >> >                     RowsCached="10000"
> >> >                     KeysCached="50%"/>
> >> >
> >> > ----------------
> >> > Keyspace: Keyspace1
> >> >         Read Count: 0
> >> >         Read Latency: NaN ms.
> >> >         Write Count: 0
> >> >         Write Latency: NaN ms.
> >> >         Pending Tasks: 0
> >> >                 Column Family: Super1
> >> >                 SSTable count: 0
> >> >                 Space used (live): 0
> >> >                 Space used (total): 0
> >> >                 Memtable Columns Count: 0
> >> >                 Memtable Data Size: 0
> >> >                 Memtable Switch Count: 0
> >> >                 Read Count: 0
> >> >                 Read Latency: NaN ms.
> >> >                 Write Count: 0
> >> >                 Write Latency: NaN ms.
> >> >                 Pending Tasks: 0
> >> >                 Key cache capacity: 200000
> >> >                 Key cache size: 0
> >> >                 Key cache hit rate: NaN
> >> >                 Row cache: disabled
> >> >                 Compacted row minimum size: 0
> >> >                 Compacted row maximum size: 0
> >> >                 Compacted row mean size: 0
> >> >                 Column Family: Super2
> >> >                 SSTable count: 0
> >> >                 Space used (live): 0
> >> >                 Space used (total): 0
> >> >                 Memtable Columns Count: 0
> >> >                 Memtable Data Size: 0
> >> >                 Memtable Switch Count: 0
> >> >                 Read Count: 0
> >> >                 Read Latency: NaN ms.
> >> >                 Write Count: 0
> >> >                 Write Latency: NaN ms.
> >> >                 Pending Tasks: 0
> >> >                 Key cache capacity: 1
> >> >                 Key cache size: 0
> >> >                 Key cache hit rate: NaN
> >> >                 Row cache capacity: 10000
> >> >                 Row cache size: 0
> >> >                 Row cache hit rate: NaN
> >> >                 Compacted row minimum size: 0
> >> >                 Compacted row maximum size: 0
> >> >                 Compacted row mean size: 0
> >> >
> >>
> >>
> >>
> >> --
> >> Jonathan Ellis
> >> Project Chair, Apache Cassandra
> >> co-founder of Riptano, the source for professional Cassandra support
> >> http://riptano.com
> >
> >
>
>
>
> --
> Jonathan Ellis
> Project Chair, Apache Cassandra
> co-founder of Riptano, the source for professional Cassandra support
> http://riptano.com
>

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