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From Apache Wiki <wikidi...@apache.org>
Subject [Cassandra Wiki] Update of "FAQ" by JonathanEllis
Date Wed, 12 Nov 2014 03:48:23 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Cassandra Wiki" for change notification.

The "FAQ" page has been changed by JonathanEllis:
https://wiki.apache.org/cassandra/FAQ?action=diff&rev1=171&rev2=172

Comment:
Don't batch damn it

   * [[#iter_world|How can I iterate over all the rows in a ColumnFamily?]]
   * [[#gui|Is there a GUI admin tool for Cassandra?]]
   * [[#clustername_mismatch|Cassandra says "ClusterName mismatch: oldClusterName != newClusterName"
and refuses to start]]
-  * [[#batch_mutate_atomic|Are batch_mutate operations atomic?]]
+  * [[#batch_mutate_atomic|Are batch operations atomic?]]
+  * [[#batch_bulkload|Will batching my operations speed up my bulk load?]]
   * [[#hadoop_support|Is Hadoop (i.e. Map/Reduce, Pig, Hive) supported?]]
   * [[#multi_tenant|Can a Cassandra cluster be multi-tenant?]]
   * [[#using_cassandra|Who is using Cassandra and for what?]]
@@ -248, +249 @@

  
  <<Anchor(batch_mutate_atomic)>>
  
- == Are batch_mutate operations atomic? ==
+ == Are batchoperations atomic? ==
  
  Since Cassandra 1.2, CQL batches are atomic by default (http://www.datastax.com/dev/blog/atomic-batches-in-cassandra-1-2).
 Thrift API users must call atomic_batch_mutate instead of batch_mutate if they want this
behavior.
+ 
+ <<Anchor(batch_bulkload)>>
+ 
+ == Will batching my operations speed up my bulk load? ==
+ 
+ '''NO.'''  Using batches to load data will just add "spikes" of latency.  Don't do this.
 Use asynchronous INSERTs instead, or use true BulkLoading.
+ 
+ (Minor exception: batching updates to a single partition can be a Good Thing.  But never
ever blindly batch everything!)
  
  <<Anchor(hadoop_support)>>
  

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