Author: jbellis
Date: Thu Aug 25 19:05:49 2011
New Revision: 1161701
URL: http://svn.apache.org/viewvc?rev=1161701&view=rev
Log:
clarify index_interval explanation
patch by mdennis for CASSANDRA-3074
Modified:
cassandra/branches/cassandra-0.8/conf/cassandra.yaml
Modified: cassandra/branches/cassandra-0.8/conf/cassandra.yaml
URL:
http://svn.apache.org/viewvc/cassandra/branches/cassandra-0.8/conf/cassandra.yaml?rev=1161701&r1=1161700&r2=1161701&view=diff
==============================================================================
--- cassandra/branches/cassandra-0.8/conf/cassandra.yaml (original)
+++ cassandra/branches/cassandra-0.8/conf/cassandra.yaml Thu Aug 25 19:05:49
2011
@@ -380,9 +380,16 @@ request_scheduler: org.apache.cassandra.
# the request scheduling. Currently the only valid option is keyspace.
# request_scheduler_id: keyspace
-# The Index Interval determines how large the sampling of row keys
-# is for a given SSTable. The larger the sampling, the more effective
-# the index is at the cost of space.
+# index_interval controls the sampling of entries from the primrary
+# row index in terms of space versus time. The larger the interval,
+# the smaller and less effective the sampling will be. In technicial
+# terms, the interval coresponds to the number of index entries that
+# are skipped between taking each sample. All the sampled entries
+# must fit in memory. Generally, a value between 128 and 512 here
+# coupled with a large key cache size on CFs results in the best trade
+# offs. This value is not often changed, however if you have many
+# very small rows (many to an OS page), then increasing this will
+# often lower memory usage without a impact on performance.
index_interval: 128
# Enable or disable inter-node encryption
