[
https://issues.apache.org/jira/browse/FLINK-13741?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16909015#comment-16909015
]
Bowen Li commented on FLINK-13741:
----------------------------------
Thanks [~Terry1897] for the summary of existing systems!
Hi [~twalthr], w.r.t. "Once FunctionCatalog has been integrated into the
catalog API and built-in functions are stored there as well, this should be
easily doable.", currently {{FunctionCatalog}} wraps {{CatalogManager}} and
builtin functions can be easily obtained thru
{{BuiltInFunctionDefinitions.getDefinitions()}}, thus my understanding is it's
already doable, no?
seems to me what need to be done is 1) add {{listFuntions()}} API to
TableEnvironment and FunctionCatalog 2) add new {{Executor.listFunctions()}}
API (I'll just keep {{Executor.listUserDefinedFunctions()}} API for now in case
we want to support showing UDFs only in the future) 3) make {{SHOW FUNCTIONS;}}
call {{executor.listFunctions()}}
W.r.t. "We should also introduce a syntax SHOW EXTENDED FUNCTION", shall they
be {{DESCRIBE FUNCTION <function_name>;}} and {{DESCRIBE FUNCTION EXTENDED
<function_name>;}}?
> "SHOW FUNCTIONS" should include Flink built-in functions' names
> ---------------------------------------------------------------
>
> Key: FLINK-13741
> URL: https://issues.apache.org/jira/browse/FLINK-13741
> Project: Flink
> Issue Type: Bug
> Components: Table SQL / API
> Affects Versions: 1.9.0
> Reporter: Bowen Li
> Assignee: Bowen Li
> Priority: Critical
> Labels: pull-request-available
> Fix For: 1.10.0
>
> Time Spent: 10m
> Remaining Estimate: 0h
>
> Currently "SHOW FUNCTIONS;" only returns catalog functions and
> FunctionDefinitions registered in memory, but does not include Flink built-in
> functions' names.
> AFAIK, it's standard for "SHOW FUNCTIONS;" to show all available functions
> for use in queries in SQL systems like Hive, Presto, Teradata, etc, thus it
> includes built-in functions naturally. Besides,
> {{FunctionCatalog.lookupFunction(name)}} resolves calls to built-in
> functions, it's not feeling right to not displaying functions but can
> successfully resolve to them.
> It seems to me that the root cause is the call stack for "SHOW FUNCTIONS;"
> has been a bit messy - it calls {{tEnv.listUserDefinedFunctions()}} which
> further calls {{FunctionCatalog.getUserDefinedFunctions()}}, and I'm not sure
> what's the intention of those two APIs. Are they dedicated to getting all
> functions, or just user defined functions excluding built-in ones?
> In the end, I believe "SHOW FUNCTIONS;" should display built-in functions. To
> achieve that, we either need to modify and/or rename existing APIs mentioned
> above, or add new APIs to return all functions from FunctionCatalog.
> cc [~xuefuz] [~lirui] [~twalthr]
--
This message was sent by Atlassian JIRA
(v7.6.14#76016)
