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https://issues.apache.org/jira/browse/CASSANDRA-13983?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16273156#comment-16273156
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Blake Eggleston commented on CASSANDRA-13983:
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+1 with the recent changes. Thanks for dividing the fixes between a few commits
> Support a means of logging all queries as they were invoked
> -----------------------------------------------------------
>
> Key: CASSANDRA-13983
> URL: https://issues.apache.org/jira/browse/CASSANDRA-13983
> Project: Cassandra
> Issue Type: New Feature
> Components: CQL, Observability, Testing, Tools
> Reporter: Ariel Weisberg
> Assignee: Ariel Weisberg
> Fix For: 4.0
>
>
> For correctness testing it's useful to be able to capture production traffic
> so that it can be replayed against both the old and new versions of Cassandra
> while comparing the results.
> Implementing this functionality once inside the database is high performance
> and presents less operational complexity.
> In [this patch|https://github.com/apache/cassandra/pull/169] there is an
> implementation of a full query log that logs uses chronicle-queue (apache
> licensed, the maven artifacts are labeled incorrectly in some cases,
> dependencies are also apache licensed) to implement a rotating log of queries.
> * Single thread asynchronously writes log entries to disk to reduce impact on
> query latency
> * Heap memory usage bounded by a weighted queue with configurable maximum
> weight sitting in front of logging thread
> * If the weighted queue is full producers can be blocked or samples can be
> dropped
> * Disk utilization is bounded by deleting old log segments once a
> configurable size is reached
> * The on disk serialization uses a flexible schema binary format
> (chronicle-wire) making it easy to skip unrecognized fields, add new ones,
> and omit old ones.
> * Can be enabled and configured via JMX, disabled, and reset (delete on disk
> data), logging path is configurable via both JMX and YAML
> * Introduce new {{fqltool}} in /bin that currently implements {{Dump}} which
> can dump in a human readable format full query logs as well as follow active
> full query logs
> Follow up work:
> * Introduce new {{fqltool}} command Replay which can replay N full query logs
> to two different clusters and compare the result and check for
> inconsistencies. <- Actively working on getting this done
> * Log not just queries but their results to facilitate a comparison between
> the original query result and the replayed result. <- Really just don't have
> specific use case at the moment
> * "Consistent" query logging allowing replay to fully replicate the original
> order of execution and completion even in the face of races (including CAS).
> <- This is more speculative
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