[FLINK-31398][sql-gateway] OperationExecutor is no longer set context classloader when executing statement.

[reswqa]

What is the purpose of the change

Currently, method OperationExecutor#executeStatement in sql client will wrap currently with sessionContext.getSessionState().resourceManager.getUserClassLoader(). Actually, it's not necessary.

It'll will cause the exception Trying to access closed classloader. Please check if you store xxx after quiting sql client.
The reason is in ShutdownHookManager, it will register a hook after jvm shutdown. In ShutdownHookManager, it will
create Configuration. It will then access Thread.currentThread().getContextClassLoader() which is FlinkUserClassLoader, the FlinkUserClassLoader has been closed before. So, it'll then cause Trying to access closed classloader exception.

Brief change log

• OperationExecutor is no longer set context classloader when executing statement.

Verifying this change

This change is a trivial rework / code cleanup without any test coverage.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): no
• The public API, i.e., is any changed class annotated with @Public(Evolving): no
• The serializers: no
• The runtime per-record code paths (performance sensitive): no
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: no
• The S3 file system connector: no

Documentation

• Does this pull request introduce a new feature? no

[flinkbot]

CI report:

• 01c9b98 Azure: SUCCESS

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[luoyuxia]

@reswqa Thanks for contribution. LGTM. Could you please rebase master to see if the ci still pass?

[luoyuxia]

Althogh the comment said we need make HiveParserUtils#getFunctionInfo use ResourceManager explicitly.
But after do some investigation, I found it's not necessary.
Currently, there's two callers to call method HiveParserUtils#getFunctionInfo
1:

FunctionInfo fi = HiveParserUtils.getFunctionInfo(funcText);
 if (fi == null) {
 desc = convertSqlOperator(funcText, children, ctx);
}
....

The fi will be null after we remove the classloader wrapper as it can't load the function using Thread.currentThread().getContextClassLoader(). But it's fine since it will then try to find the function from the function catalog. Such case have been convered in flink-sql-client by set.q.

2: getFuncExprNodeDescWithUdfData
There're two places call method getFuncExprNodeDescWithUdfData.
a: convertGenericFunc(ExprNodeGenericFuncDesc func), but it will only be called when it's hive build-in function, so it can be found in Thread.currentThread().getContextClassLoader() as use must put flink-connector-hive jar which include hive built-in functions to FLINK_HOME/lib to use Hive Dialect.
b:

// type conversion for LHS
            if (TypeInfoUtils.isConversionRequiredForComparison(lhsType, commonType)) {
                lhsDesc =
                        HiveASTParseUtils.createConversionCast(
                                lhsDesc, (PrimitiveTypeInfo) commonType);
            }

Also, HiveParserUtils.getFunctionInfo(funcText) will only be called to when it's build-in function which can then be loaded.

AFAIC, it's not easy to make HiveParserUtils#getFunctionInfo use ResourceManager explicitly which will involves much modification. I think it's fine to remove the usage of the context classloader in here.
cc @fsk119

[reswqa]

Thanks @luoyuxia for the review, I have rebased this pr.