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### What changes were proposed in this pull request? In Hive mode, permanent functions are shared with Hive metastore so that functions may be modified by other Hive client. With in long-lived spark scene, it's hard to update the change of function. Here are 2 reasons: * Spark cache the function in memory using `FunctionRegistry`. * User may not know the location or classname of udf when using `replace function`. Note that we use v2 command code path to add new command. ### Why are the changes needed? Give a easy way to make spark function registry sync with Hive metastore. Then we can call ``` refresh function functionName ``` ### Does this PR introduce _any_ user-facing change? Yes, new command. ### How was this patch tested? New UT. Closes #28840 from ulysses-you/SPARK-31999. Authored-by: ulysses <youxiduo@weidian.com> Signed-off-by: Wenchen Fan <wenchen@databricks.com>
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| layout | title | displayTitle | license |
|---|---|---|---|
| global | REFRESH FUNCTION | REFRESH FUNCTION | Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file to You under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. |
Description
REFRESH FUNCTION statement invalidates the cached function entry, which includes a class name
and resource location of the given function. The invalidated cache is populated right away.
Note that REFRESH FUNCTION only works for permanent functions. Refreshing native functions or temporary functions will cause an exception.
Syntax
REFRESH FUNCTION function_identifier
Parameters
-
function_identifier
Specifies a function name, which is either a qualified or unqualified name. If no database identifier is provided, uses the current database.
Syntax:
[ database_name. ] function_name
Examples
-- The cached entry of the function will be refreshed
-- The function is resolved from the current database as the function name is unqualified.
REFRESH FUNCTION func1;
-- The cached entry of the function will be refreshed
-- The function is resolved from tempDB database as the function name is qualified.
REFRESH FUNCTION db1.func1;