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https://issues.apache.org/jira/browse/CALCITE-2636?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17946190#comment-17946190
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Gian Merlino commented on CALCITE-2636:
---------------------------------------
Sorry, I missed the original ping from 2018. I see the change has already been
merged, but fwiw, looks good to me (we're initializing a char buffer upfront to
the size of the string that will be read into it). Thanks!
> SQL parser has quadratic running time when SQL string is very large
> -------------------------------------------------------------------
>
> Key: CALCITE-2636
> URL: https://issues.apache.org/jira/browse/CALCITE-2636
> Project: Calcite
> Issue Type: Bug
> Reporter: Julian Hyde
> Assignee: Julian Hyde
> Priority: Major
> Labels: pull-request-available
> Fix For: 1.40.0
>
>
> SQL parser has quadratic running time when SQL string is very large.
> This is due to {{SimpleCharStream.ExpandBuff(boolean)}} increasing the buffer
> in increments of 2,048 (2k) chars. If the SQL string is, say, 1,024k
> characters, then it will re-alloc at size 2k, 4k, 6k, ..., 1023k, and each
> time copy the whole string.
> This issue was discovered by [~gian].
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