Sergey Kalashnikov reassigned IGNITE-6024:

    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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