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https://issues.apache.org/jira/browse/CASSANDRA-1311?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12976313#action_12976313
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Jonathan Ellis commented on CASSANDRA-1311:
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bq. if the write has been acknowledged, the client can be sure the trigger will
be executed (at least once)
the problem is with the inverse scenario:
if a write *has not* been acknowledged, it may still have succeeded in the base
columnfamily (Table.apply) but not the trigger
(TriggerSlave.storeDanglingTrigger). So, because [from my look at the code at
least] trigger execution is not part of log replay, you can end up with data
that never had the trigger fire.
In this situation, the client will see a TimedOutException, which it is
important to remember is NOT the same as failure; it means instead "we don't
know what happened."
> Support (asynchronous) triggers
> -------------------------------
>
> Key: CASSANDRA-1311
> URL: https://issues.apache.org/jira/browse/CASSANDRA-1311
> Project: Cassandra
> Issue Type: New Feature
> Components: Contrib
> Reporter: Maxim Grinev
> Fix For: 0.8
>
> Attachments: HOWTO-PatchAndRunTriggerExample-update1.txt,
> HOWTO-PatchAndRunTriggerExample.txt, ImplementationDetails-update1.pdf,
> ImplementationDetails.pdf, trunk-967053.txt, trunk-984391-update1.txt,
> trunk-984391-update2.txt
>
>
> Asynchronous triggers is a basic mechanism to implement various use cases of
> asynchronous execution of application code at database side. For example to
> support indexes and materialized views, online analytics, push-based data
> propagation.
> Please find the motivation, triggers description and list of applications:
> http://maxgrinev.com/2010/07/23/extending-cassandra-with-asynchronous-triggers/
> An example of using triggers for indexing:
> http://maxgrinev.com/2010/07/23/managing-indexes-in-cassandra-using-async-triggers/
> Implementation details are attached.
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