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Posted to commits@cassandra.apache.org by Apache Wiki <wi...@apache.org> on 2014/11/12 04:48:23 UTC
[Cassandra Wiki] Update of "FAQ" by JonathanEllis
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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)>>