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https://issues.apache.org/jira/browse/CALCITE-2635?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16738592#comment-16738592
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Julian Hyde commented on CALCITE-2635:
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Sure, we can merge this with no extra tests.
But I would be grateful for help getting to a performance testing framework.
> getMonotonocity is slow on wide tables
> --------------------------------------
>
> Key: CALCITE-2635
> URL: https://issues.apache.org/jira/browse/CALCITE-2635
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Reporter: Gian Merlino
> Assignee: Gian Merlino
> Priority: Major
> Labels: performance
>
> RelOptTableImpl's getMonotonocity does an indexOf on
> {{rowType.getFieldNames()}}, which is O(N) in the number of fields.
> IdentifierNamespace calls getMonotonicity once for every field in the table
> namespace, so it becomes O(N^2) in the number of fields. We observed 2-4
> second query planning times with a table that had 18,000 columns, reduced to
> about 150ms after patching getMonotonicity to be O(1) in the number of fields.
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