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From Tamar Fraenkel <ta...@tok-media.com>
Subject Counter column family
Date Tue, 17 Apr 2012 15:59:32 GMT
Hi!
I want to understand how incrementing of counter works.


   - I have a 3 node ring,
   - I use FailoverPolicy.FAIL_FAST,
   - RF is 2,

I have the following counter column family
ColumnFamily: tk_counters
      Key Validation Class: org.apache.cassandra.db.marshal.CompositeType(
org.apache.cassandra.db.marshal.UTF8Type,org.apache.cassandra.db.marshal.
UUIDType)
      Default column value validator: org.apache.cassandra.db.marshal.
CounterColumnType
      Columns sorted by: org.apache.cassandra.db.marshal.UTF8Type
      Row cache size / save period in seconds / keys to save : 0.0/0/all
      Row Cache Provider: org.apache.cassandra.cache.
SerializingCacheProvider
      Key cache size / save period in seconds: 0.0/14400
      GC grace seconds: 864000
      Compaction min/max thresholds: 4/32
      Read repair chance: 1.0
      Replicate on write: true
      Bloom Filter FP chance: default
      Built indexes: []
      Compaction Strategy:
org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy

My CL for this column family is Write=2, Read=1.

When I increment a counter (using hector mutator), and execute returns
without errors, what is the status of the nodes at that stage.
Can execute return before the nodes are really updated? So that if a read
is done immediately after the increment it will still read the previous
values?
Thanks,

*Tamar Fraenkel *
Senior Software Engineer, TOK Media

[image: Inline image 1]

tamar@tok-media.com
Tel:   +972 2 6409736
Mob:  +972 54 8356490
Fax:   +972 2 5612956

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