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https://issues.apache.org/jira/browse/CALCITE-4203?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17188937#comment-17188937
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Chunwei Lei commented on CALCITE-4203:
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I have no problem with that. I would update the PR.
> RelMdUniqueKeys should not return empty when meeting Intersect and Minus if
> its input has unique keys
> -----------------------------------------------------------------------------------------------------
>
> Key: CALCITE-4203
> URL: https://issues.apache.org/jira/browse/CALCITE-4203
> Project: Calcite
> Issue Type: Improvement
> Reporter: Chunwei Lei
> Assignee: Chunwei Lei
> Priority: Major
> Labels: pull-request-available
> Time Spent: 20m
> Remaining Estimate: 0h
>
> Currently, we get an empty unique key for Intersect and Minus if its all is
> true.
>
> {code:java}
> // code placeholder
> public Set<ImmutableBitSet> getUniqueKeys(SetOp rel, RelMetadataQuery mq,
> boolean ignoreNulls) {
> if (!rel.all) {
> return ImmutableSet.of(
> ImmutableBitSet.range(rel.getRowType().getFieldCount()));
> }
> return ImmutableSet.of();
> }
> {code}
> However, from the semantic of Intersect and Minus, we can get their unique
> keys from its input even if its all is true.
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