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https://issues.apache.org/jira/browse/IGNITE-6024?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Sergey Kalashnikov reassigned IGNITE-6024:
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Assignee: Sergey Kalashnikov
> SQL: execute DML statements on the server when possible
> -------------------------------------------------------
>
> Key: IGNITE-6024
> URL: https://issues.apache.org/jira/browse/IGNITE-6024
> Project: Ignite
> Issue Type: Improvement
> Components: sql
> Affects Versions: 2.1
> Reporter: Vladimir Ozerov
> Assignee: Sergey Kalashnikov
> Labels: performance
> Fix For: 2.2
>
>
> Currently we execute DML statements as follows:
> 1) Get query result set to the client
> 2) Construct entry processors and send them to servers in batches
> This approach is inefficient as it causes a lot of unnecessary network
> communication Instead, we should execute DML statements directly on server
> nodes when it is possible.
> Implementation considerations:
> 1) Determine set of queries which could be processed in this way. E.g.,
> {{LIMIT/OFFSET}}, {{GROUP BY}}, {{ORDER BY}}, {{DISTINCT}}, etc. are out of
> question - they must go through the client anyway. Probably
> {{skipMergeTable}} flag is a good starting point (good, not precise!)
> 2) Send request to every server and execute local DML right there
> 3) No failover support at the moment - throw "partial update" exception if
> topology is unstable
> 4) Handle partition reservation carefully
> 5) Transactions: we still have single coordinator - this is a client. When
> MVCC and TX SQL is ready, client will assign proper counters to server
> requests.
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