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https://issues.apache.org/jira/browse/CASSANDRA-9966?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14747267#comment-14747267
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Benedict commented on CASSANDRA-9966:
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I mean when applying a batch we use special resolution rules of always taking
the new value.
If we want to avoid surprising users we probably would need to implement a
special resolution of only incrementing the timestamp on a conflicting
resolution, as otherwise users with more than 1000 batch statements would see a
behavioural change that may (possibly) break things? And when applying
individual statements we do effectively resolve this way (just with timestamp
increments). So in order to minimise surprise, it seems simulating timestamp
increments, without actually incrementing them (since we have the necessary
information to do so) seems perhaps the least surprising option.
> Option to apply statements within a batch sequentially
> ------------------------------------------------------
>
> Key: CASSANDRA-9966
> URL: https://issues.apache.org/jira/browse/CASSANDRA-9966
> Project: Cassandra
> Issue Type: New Feature
> Components: Core
> Reporter: Sam Overton
> Fix For: 3.x, 2.2.x
>
>
> It is possible to batch CAS statements such that their outcome is different
> to the outcome were they executed sequentially outside of a batch.
> eg.
> a | b | c
> a | 1 | 1
> BEGIN BATCH
> UPDATE foo SET b=2 WHERE a='a' iF c=1
> UPDATE foo SET c=2 WHERE a='a' IF b=1
> APPLY BATCH
> results in
> a | b | c
> a | 2 | 2
> If these statements were not batched, the outcome would be
> UPDATE foo SET b=2 WHERE a='a' iF c=1
> a | b | c
> a | 2 | 1
> UPDATE foo SET c=2 WHERE a='a' IF b=1
> applied=false (pre-condition b=1 not met)
> Cassandra already checks for incompatible preconditions within a batch (eg
> one statement with IF c=1 and another statement with IF c=2). It should also
> check for mutations to columns in one statement that affect the
> pre-conditions of another statement, or it should evaluate the statement
> pre-conditions sequentially after applying the mutations of the previous
> statement to an in-memory model of the partition.
> For backwards compatibility this would have to be a new "strict" batch mode,
> eg.
> BEGIN STRICT BATCH
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