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From brandonwilli...@apache.org
Subject [7/8] git commit: Document that list append/prepend are not idempotent and should be used with care
Date Fri, 23 Nov 2012 21:51:14 GMT
Document that list append/prepend are not idempotent and should be used with care


Project: http://git-wip-us.apache.org/repos/asf/cassandra/repo
Commit: http://git-wip-us.apache.org/repos/asf/cassandra/commit/64bc3354
Tree: http://git-wip-us.apache.org/repos/asf/cassandra/tree/64bc3354
Diff: http://git-wip-us.apache.org/repos/asf/cassandra/diff/64bc3354

Branch: refs/heads/trunk
Commit: 64bc3354d34bef9cff5a511f0045266f2c44f962
Parents: 6fb7512
Author: Sylvain Lebresne <sylvain@datastax.com>
Authored: Fri Nov 23 15:36:34 2012 +0100
Committer: Sylvain Lebresne <sylvain@datastax.com>
Committed: Fri Nov 23 15:36:34 2012 +0100

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 doc/cql3/CQL.textile |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
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http://git-wip-us.apache.org/repos/asf/cassandra/blob/64bc3354/doc/cql3/CQL.textile
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diff --git a/doc/cql3/CQL.textile b/doc/cql3/CQL.textile
index 931aa18..452407b 100644
--- a/doc/cql3/CQL.textile
+++ b/doc/cql3/CQL.textile
@@ -829,6 +829,8 @@ bc(sample).
 UPDATE plays SET players = 5, scores = scores + [ 14, 21 ] WHERE id = '123-afde';
 UPDATE plays SET players = 5, scores = [ 12 ] + scores WHERE id = '123-afde';
 
+It should be noted that append and prepend are not idempotent operations. This means that
if during an append or a prepend the operation timeout, it is not always safe to retry the
operation (as this could result in the record appended or prepended twice).
+
 Lists also provides the following operation: setting an element by its position in the list,
removing an element by its position in the list and remove all the occurrence of a given value
in the list. _However, and contrarily to all the other collection operations, these three
operations induce an internal read before the update, and will thus typically have slower
performance characteristics_. Those operations have the following syntax:
 
 bc(sample). 


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