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https://issues.apache.org/jira/browse/CALCITE-3460?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16988390#comment-16988390
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Chunwei Lei commented on CALCITE-3460:
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Could you please add a test? We might get it into 1.22:).
> Poor performance in RexReplacer for large queries
> -------------------------------------------------
>
> Key: CALCITE-3460
> URL: https://issues.apache.org/jira/browse/CALCITE-3460
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Reporter: Haisheng Yuan
> Priority: Major
> Labels: pull-request-available
> Time Spent: 2h 40m
> Remaining Estimate: 0h
>
> We have queries that have tens of thousands of RexCalls.
> reducibleExps.indexOf(call) is an O(n) operation, which takes 50% of the
> running time, causing the query runs for ever until timed out.
> In RexShuttle, ImmutableList iterator creation in {{visitList}} takes another
> 5~7% of running time, and it is creating millions of temporary iterator
> object, not only time consuming, but also memory consuming.
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