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https://issues.apache.org/jira/browse/CALCITE-952?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14990218#comment-14990218
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Julian Hyde commented on CALCITE-952:
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Could MaterializationTest.ListComparator be replaced with Guava's
Orderings.lexicographical()?
> Organize applicable materializations in reversed topological order
> ------------------------------------------------------------------
>
> Key: CALCITE-952
> URL: https://issues.apache.org/jira/browse/CALCITE-952
> Project: Calcite
> Issue Type: Improvement
> Reporter: Maryann Xue
> Assignee: Maryann Xue
> Attachments: CALCITE-952.patch
>
>
> With CALCITE-890, we now try applying each materialization with all possible
> substitution combinations. And this works fine if all applicable
> materializations are independent of each other. But with dependent
> materializations, the order of materializations in which we perform
> substitution matters.
> For example, if we have tables {{A}} and {{B}}, a materialization table {{C}}
> that uses {{A}}, and another materialization table {{D}} that uses tables
> {{C}} and {{B}}. Thus, we should apply materialization {{C}} before applying
> materialization {{D}}.
> Right now we output the applicable materialization list as we iterate through
> the input materialization list which could be of random order (and it
> actually is). A directed graph is used to find all the applicable
> materializations, but we can also take advantage of this graph to organize
> them in the desired order.
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