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https://issues.apache.org/jira/browse/IGNITE-4106?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15650767#comment-15650767
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Andrew Mashenkov commented on IGNITE-4106:
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It seems that
Every query thread read full node index and then filter data within its own
partition subset. Thus, query splitted to several threads will induce full node
index to be read once per partition subset.
In current (1 thread per node) approach, all query threads work with its own
smaller index.
> SQL: parallelize sql queries over cache local partitions
> --------------------------------------------------------
>
> Key: IGNITE-4106
> URL: https://issues.apache.org/jira/browse/IGNITE-4106
> Project: Ignite
> Issue Type: Improvement
> Components: SQL
> Affects Versions: 1.6, 1.7
> Reporter: Andrew Mashenkov
> Assignee: Andrew Mashenkov
> Labels: performance
> Attachments: 1node-4thread.jfr, 4node-1thread.jfr
>
>
> If we run SQL query on cache partitioned over several cluster nodes, it will
> be split into several queries running in parallel. But really we will have
> one thread per query on each node.
> So, for now, to improve SQL query performance we need to run more Ignite
> instances or split caches manually.
> It seems to be better to split local SQL queries over cache partitions, so we
> would be able to parallelize SQL query on every single node and utilize CPU
> more efficiently.
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