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From jbel...@apache.org
Subject [4/9] git commit: update comments for partitioner and snitch
Date Tue, 25 Mar 2014 18:29:07 GMT
update comments for partitioner and snitch


Project: http://git-wip-us.apache.org/repos/asf/cassandra/repo
Commit: http://git-wip-us.apache.org/repos/asf/cassandra/commit/f8229c3f
Tree: http://git-wip-us.apache.org/repos/asf/cassandra/tree/f8229c3f
Diff: http://git-wip-us.apache.org/repos/asf/cassandra/diff/f8229c3f

Branch: refs/heads/cassandra-2.0
Commit: f8229c3fb25c9f823939ac39558e5f29dd46ee3a
Parents: 4f9d050
Author: Jonathan Ellis <jbellis@apache.org>
Authored: Tue Mar 25 13:28:45 2014 -0500
Committer: Jonathan Ellis <jbellis@apache.org>
Committed: Tue Mar 25 13:28:45 2014 -0500

----------------------------------------------------------------------
 conf/cassandra.yaml | 60 ++++++++++++++++++++----------------------------
 1 file changed, 25 insertions(+), 35 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/cassandra/blob/f8229c3f/conf/cassandra.yaml
----------------------------------------------------------------------
diff --git a/conf/cassandra.yaml b/conf/cassandra.yaml
index d3c91ef..2edd498 100644
--- a/conf/cassandra.yaml
+++ b/conf/cassandra.yaml
@@ -78,27 +78,16 @@ authorizer: AllowAllAuthorizer
 # Will be disabled automatically for AllowAllAuthorizer.
 permissions_validity_in_ms: 2000
 
-# The partitioner is responsible for distributing rows (by key) across
-# nodes in the cluster.  Any IPartitioner may be used, including your
-# own as long as it is on the classpath.  Out of the box, Cassandra
-# provides org.apache.cassandra.dht.{Murmur3Partitioner, RandomPartitioner
-# ByteOrderedPartitioner, OrderPreservingPartitioner (deprecated)}.
-# 
-# - RandomPartitioner distributes rows across the cluster evenly by md5.
-#   This is the default prior to 1.2 and is retained for compatibility.
-# - Murmur3Partitioner is similar to RandomPartioner but uses Murmur3_128
-#   Hash Function instead of md5.  When in doubt, this is the best option.
-# - ByteOrderedPartitioner orders rows lexically by key bytes.  BOP allows
-#   scanning rows in key order, but the ordering can generate hot spots
-#   for sequential insertion workloads.
-# - OrderPreservingPartitioner is an obsolete form of BOP, that stores
-# - keys in a less-efficient format and only works with keys that are
-#   UTF8-encoded Strings.
-# - CollatingOPP collates according to EN,US rules rather than lexical byte
-#   ordering.  Use this as an example if you need custom collation.
-#
-# See http://wiki.apache.org/cassandra/Operations for more on
-# partitioners and token selection.
+# The partitioner is responsible for distributing groups of rows (by
+# partition key) across nodes in the cluster.  You should leave this
+# alone for new clusters.  The partitioner can NOT be changed without
+# reloading all data, so when upgrading you should set this to the
+# same partitioner you were already using.
+#
+# Besides Murmur3Partitioner, partitioners included for backwards
+# compatibility include RandomPartitioner, ByteOrderedPartitioner, and
+# OrderPreservingPartitioner.
+#
 partitioner: org.apache.cassandra.dht.Murmur3Partitioner
 
 # Directories where Cassandra should store data on disk.  Cassandra
@@ -538,23 +527,18 @@ cross_node_timeout: false
 #
 # Out of the box, Cassandra provides
 #  - SimpleSnitch:
-#    Treats Strategy order as proximity. This improves cache locality
-#    when disabling read repair, which can further improve throughput.
-#    Only appropriate for single-datacenter deployments.
+#    Treats Strategy order as proximity. This can improve cache
+#    locality when disabling read repair.  Only appropriate for
+#    single-datacenter deployments.
+#  - GossipingPropertyFileSnitch
+#    This should be your go-to snitch for production use.  The rack
+#    and datacenter for the local node are defined in
+#    cassandra-rackdc.properties and propagated to other nodes via
+#    gossip.  If cassandra-topology.properties exists, it is used as a
+#    fallback, allowing migration from the PropertyFileSnitch.
 #  - PropertyFileSnitch:
 #    Proximity is determined by rack and data center, which are
 #    explicitly configured in cassandra-topology.properties.
-#  - GossipingPropertyFileSnitch
-#    The rack and datacenter for the local node are defined in
-#    cassandra-rackdc.properties and propagated to other nodes via gossip.  If
-#    cassandra-topology.properties exists, it is used as a fallback, allowing
-#    migration from the PropertyFileSnitch.
-#  - RackInferringSnitch:
-#    Proximity is determined by rack and data center, which are
-#    assumed to correspond to the 3rd and 2nd octet of each node's
-#    IP address, respectively.  Unless this happens to match your
-#    deployment conventions (as it did Facebook's), this is best used
-#    as an example of writing a custom Snitch class.
 #  - Ec2Snitch:
 #    Appropriate for EC2 deployments in a single Region. Loads Region
 #    and Availability Zone information from the EC2 API. The Region is
@@ -568,6 +552,12 @@ cross_node_timeout: false
 #    ssl_storage_port on the public IP firewall.  (For intra-Region
 #    traffic, Cassandra will switch to the private IP after
 #    establishing a connection.)
+#  - RackInferringSnitch:
+#    Proximity is determined by rack and data center, which are
+#    assumed to correspond to the 3rd and 2nd octet of each node's IP
+#    address, respectively.  Unless this happens to match your
+#    deployment conventions, this is best used as an example of
+#    writing a custom Snitch class and is provided in that spirit.
 #
 # You can use a custom Snitch by setting this to the full class name
 # of the snitch, which will be assumed to be on your classpath.


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