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https://issues.apache.org/jira/browse/CALCITE-987?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15033842#comment-15033842
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Pengcheng Xiong commented on CALCITE-987:
-----------------------------------------
Thanks [[email protected]] for the jumbo patch. Sorry that it is my bad to
make those mistakes. I reviewed the code and I have a question. So for the
intersect case, I think the logic should be
{code}
Double rowCount = Double.POSITIVE_INFINITY;
for (RelNode input : rel.getInputs()) {
Double partialRowCount = RelMetadataQuery.getMaxRowCount(input);
if (partialRowCount == null){
return null;
}
else{
if (partialRowCount < rowCount) {
rowCount = partialRowCount;
}
}
}
return rowCount;
{code}?
> Push limit 0 will result in an infinite loop
> --------------------------------------------
>
> Key: CALCITE-987
> URL: https://issues.apache.org/jira/browse/CALCITE-987
> Project: Calcite
> Issue Type: Bug
> Components: core
> Affects Versions: 1.5.0
> Reporter: Pengcheng Xiong
> Assignee: Pengcheng Xiong
> Fix For: 1.6.0
>
> Attachments: CALCITE-987.01.patch, CALCITE-987.02.patch,
> CALCITE-987.03.patch, CALCITE-987.04.patch
>
>
> We use "checkInputForCollationAndLimit" in RelMdUtil.java to check the input
> #rows. However, it calls RelMetadataQuery.getRowCount which will validate the
> #rows. The validation will change #row=0 to #row=1. This will result in an
> infinite loop to push limit. The affected rules include
> SortUnionTransposeRule and any Sort***TransposeRules that call
> checkInputForCollationAndLimit.
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