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https://issues.apache.org/jira/browse/CALCITE-2970?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17077429#comment-17077429
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Julian Hyde commented on CALCITE-2970:
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bq. RelBuilder should be used for logical operators only
I disagree. Building any RelNode can be quite complex. For example, if the
input has a distribution trait, you need to make sure that that trait is
propagated to the outputs. And you need to derive the names, types and
nullability of the output fields. And it's useful to carry out simplifications.
That logic needs to live somewhere. It can't live in the constructor of the
RelNode base class (e.g. Filter) because complex constructors are an
anti-pattern. We used to have it live in {{create}} methods (e.g.
{{LogicalFilter.create}}) and in {{RelOptUtil}}, but re-use wasn't great.
{{RelBuilder}} is the right place for it.
Of course if you're simply converting logical to physical - e.g. LogicalFilter
to MongoFilter - then you're probably copying most fields, and you can do
without a RelBuilder. But physical rules do more than convert logical to
physical.
Note that you can create a physical {{RelBulder}} by swapping out its
[RelBuilder.struct
field|https://github.com/apache/calcite/blob/38e2566178dedf2aafe5700dd8fc45b9b30153da/core/src/main/java/org/apache/calcite/tools/RelBuilder.java#L153]
for one that contains factories for the particular convention you are
targeting.
> Performance issue when enabling abstract converter for EnumerableConvention
> ---------------------------------------------------------------------------
>
> Key: CALCITE-2970
> URL: https://issues.apache.org/jira/browse/CALCITE-2970
> Project: Calcite
> Issue Type: Bug
> Components: core
> Reporter: Haisheng Yuan
> Priority: Major
> Labels: pull-request-available
> Time Spent: 12h
> Remaining Estimate: 0h
>
> If we enable the use of abstract converter for {{EnumerableConvention}}, by
> making {{useAbstractConvertersForConversion}} return true,
> {{JDBCTest.testJoinManyWay}} will not complete.
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