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https://issues.apache.org/jira/browse/CALCITE-3409?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17200286#comment-17200286
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Julian Hyde commented on CALCITE-3409:
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[~xzh_dz] We should keep the materialization rules separate from the 
materializations. The materialization rules are likely to be the same each time 
your project prepares a query, but the materializations will likely be 
different.

Let's start by adding a parameter, that is in an immutable list of 
materialization rules, to every method that needs materialization rules. (I 
don't know this code very well any more... someone needs to get in there, 
understand it, and refactor.)

> Add an interface in MaterializedViewSubstitutionVisitor to allow registering 
> UnifyRule
> --------------------------------------------------------------------------------------
>
>                 Key: CALCITE-3409
>                 URL: https://issues.apache.org/jira/browse/CALCITE-3409
>             Project: Calcite
>          Issue Type: Improvement
>            Reporter: Jin Xing
>            Assignee: Jin Xing
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 4h 10m
>  Remaining Estimate: 0h
>
> In current code of MaterializedViewSubstitutionVisitor, all matching rules 
> are internal defined. The existing rules support the most popular scenarios. 
> But my customers sometimes ask for the ability to self define some matching 
> rules, thus to support some special scenarios.
> I take below example as an illustration:
> {code:java}
> Query:
> select * from table
> where from_unixtime(_EVENT_TIME_, "yyyymmdd hh") >= "20190909 00"
> and from_unixtime(_EVENT_TIME_, "yyyymmdd hh") <= "20190909 23" ;
> Materialized View:
> select * from table 
> where from_unixtime(_EVENT_TIME_, "yyyymmdd") = "20190909";{code}
> It's hard to enumerate the matching pattern for different functions in 
> internal matching rules. We can expose a method to register new UnifyRules 
> and allow user to extend the ability of MV matching



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