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https://issues.apache.org/jira/browse/CALCITE-4978?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17473160#comment-17473160
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Julian Hyde commented on CALCITE-4978:
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Thanks, that helps. I'm pushing back hard because everything can be 'product
dependent' but if we try hard we can find patterns.
Can you give a good definition of 'constant'? Clearly literals are constants.
Also pure functions whose arguments are all constant. But what else?
Your range function is a good example, but that simplification could
potentially be done using sarg range simplification. See
[Range.canonical(DiscreteDomain)|https://guava.dev/releases/23.0/api/docs/com/google/common/collect/Range.html#canonical-com.google.common.collect.DiscreteDomain-].
If there are ways that an operator could declare a call to be 'constant', that
would be useful. Maybe it should be a property of the operator; or maybe there
should be new kind of metadata that recognizes constants.
> Allow custom constant map in RelOptPredicateList
> ------------------------------------------------
>
> Key: CALCITE-4978
> URL: https://issues.apache.org/jira/browse/CALCITE-4978
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Affects Versions: 1.29.0
> Reporter: Vladimir Ozerov
> Assignee: Vladimir Ozerov
> Priority: Minor
>
> {{RelOptPredicateList}} tries to infer constants from the predicates passed
> to the {{of(...)}} factory methods. However, the underlying mechanic is
> limited and handles only a small subset of possible constant derivation
> strategies. We may want to implement such strategies gradually (inference
> from AND/OR, ranges, etc.), but it might be a big effort.
> This ticket proposes a new factory method that allows users to pass custom
> constant maps.
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