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https://issues.apache.org/jira/browse/CASSANDRA-7622?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14539841#comment-14539841
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Tupshin Harper commented on CASSANDRA-7622:
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I think the assumption should be that each virtual table supports a subset of
the queries performed on regular tables. If the virtual table can support all
operations great, but otherwise noops or unsupported exceptions should be fine
if a given operation doesn't make sense for the table.
The locality of the data (and whether distributed or not), should be internal
to the implementation of each virtual table.
Using JMX, I suggest this as a simplified starting point:
CREATE TABLE jmx (
node_id uuid,
metric_type text,
attributes map<text, text>,
host_ip text static,
PRIMARY KEY ((node_id), metric_type)
)
CREATE INDEX host_by_ip ON jmx (host_ip) #this will work after CASSANDRA-8103
SELECT attributes FROM jmx where node_id =
'eedea3e3-e36d-4371-8937-57f5a8303165' #returns all metrics for a given node
SELECT attributes FROM jmx where host_ip = '10.10.10.10' and
metric_type='CompactionManager' #returns all compaction metrics for a given
node, looking up the node by a pseudo secondary index
> Implement virtual tables
> ------------------------
>
> Key: CASSANDRA-7622
> URL: https://issues.apache.org/jira/browse/CASSANDRA-7622
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Tupshin Harper
> Assignee: Benjamin Lerer
> Fix For: 3.x
>
>
> There are a variety of reasons to want virtual tables, which would be any
> table that would be backed by an API, rather than data explicitly managed and
> stored as sstables.
> One possible use case would be to expose JMX data through CQL as a
> resurrection of CASSANDRA-3527.
> Another is a more general framework to implement the ability to expose yaml
> configuration information. So it would be an alternate approach to
> CASSANDRA-7370.
> A possible implementation would be in terms of CASSANDRA-7443, but I am not
> presupposing.
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