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https://issues.apache.org/jira/browse/CASSANDRA-13289?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Ariel Weisberg updated CASSANDRA-13289:
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Description:
As an operator there are several issues related to multi-datacenter replication
and consistency you may want to have more information on from your production
database.
For instance. If your application writes at LOCAL_QUORUM how often are those
writes failing to achieve EACH_QUORUM at other data centers. If you failed your
application over to one of those data centers roughly how inconsistent might it
be given the number of writes that didn't propagate since the last incremental
repair?
You might also want to know roughly what the latency of writes would be if you
switched to a different consistency level. For instance you are writing at
LOCAL_QUORUM and want to know what would happen if you switched to EACH_QUORUM.
The proposed change is to allow an ideal_consistency_level to be specified in
cassandra.yaml as well as get/set via JMX. If no ideal consistency level is
specified no additional tracking is done.
if an ideal consistency level is specified then the
{{AbstractWriteResponesHandler}} will contain a delegate WriteResponseHandler
that tracks whether the ideal consistency level is met before a write times
out. It also tracks the latency for achieving the ideal CL of successful
writes.
These two metrics would be reported on a per keyspace basis.
was:
As an operator there are several issues related to multi-datacenter replication
and consistency you may want to have more information on from your production
database.
For instance. If your application writes at LOCAL_QUORUM how often are those
writes failing to achieve EACH_QUORUM at other data centers. If you failed your
application over to one of those data centers roughly how inconsistent might it
be given the number of writes that didn't propagate since the last incremental
repair?
You might also want to know roughly what the latency of writes would be if
switch to a different consistency level. For instance you are writing at
LOCAL_QUORUM and want to know what would happen if you switched to EACH_QUORUM.
The proposed change is to allow an ideal_consistency_level to be specified in
cassandra.yaml as well as get/set via JMX. If no ideal consistency level is
specified no additional tracking is done.
if an ideal consistency level is specified then the
{{AbstractWriteResponesHandler}} will contain a delegate WriteResponseHandler
that tracks whether the ideal consistency level is met before a write times
out. It also tracks the latency for achieving the ideal CL of successful
writes on.
These two metrics would be reported on a per Keyspace basis.
> Make it possible to monitor an ideal consistency level separate from actual
> consistency level
> ---------------------------------------------------------------------------------------------
>
> Key: CASSANDRA-13289
> URL: https://issues.apache.org/jira/browse/CASSANDRA-13289
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Reporter: Ariel Weisberg
> Assignee: Ariel Weisberg
>
> As an operator there are several issues related to multi-datacenter
> replication and consistency you may want to have more information on from
> your production database.
> For instance. If your application writes at LOCAL_QUORUM how often are those
> writes failing to achieve EACH_QUORUM at other data centers. If you failed
> your application over to one of those data centers roughly how inconsistent
> might it be given the number of writes that didn't propagate since the last
> incremental repair?
> You might also want to know roughly what the latency of writes would be if
> you switched to a different consistency level. For instance you are writing
> at LOCAL_QUORUM and want to know what would happen if you switched to
> EACH_QUORUM.
> The proposed change is to allow an ideal_consistency_level to be specified in
> cassandra.yaml as well as get/set via JMX. If no ideal consistency level is
> specified no additional tracking is done.
> if an ideal consistency level is specified then the
> {{AbstractWriteResponesHandler}} will contain a delegate WriteResponseHandler
> that tracks whether the ideal consistency level is met before a write times
> out. It also tracks the latency for achieving the ideal CL of successful
> writes.
> These two metrics would be reported on a per keyspace basis.
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