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https://issues.apache.org/jira/browse/FLINK-21738?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17299988#comment-17299988
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Jane Chan commented on FLINK-21738:
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Hi [~zoucao], thanks for bringing out this issue.
{quote}the same result will be returned for one module, so maybe a cache should
be used here to reduce time waste.
{quote}
IMO, a map (function definition -> which module it belongs to) in module
manager does accelerate the search speed. However, the resolution order makes a
difference. If there're two functions with the same name, Flink always resolves
the object reference to the one in the 1st loaded module. At the same time,
FLINK-21045 supports loading/unloading/changing resolution orders during a
running session. So if we decide to support the cache, we may also need to keep
the loading order as well. This causes the cache maintenance to become a little
bit complicated.
What do you think? [~jark]
> reduce unnecessary method calls in ModuleManager
> -------------------------------------------------
>
> Key: FLINK-21738
> URL: https://issues.apache.org/jira/browse/FLINK-21738
> Project: Flink
> Issue Type: Improvement
> Components: Table SQL / API
> Reporter: zoucao
> Priority: Major
>
> In flink sql, if we use many functions(hive func or flink built-in func),
> Flink will call method
> `getFunctionDefinition` in
> [ModuleManager|https://github.com/apache/flink/blob/97bfd049951f8d52a2e0aed14265074c4255ead0/flink-table/flink-table-api-java/src/main/java/org/apache/flink/table/module/ModuleManager.java#L44]
> many times to load func and each module's method `listFunctions` will be
> called at the same time. I think the same result will be returned for one
> module, so maybe a cache should be used here to reduce time waste.
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