[FLINK-17151][table] Align Calcite's and Flink's SYMBOL types #18107

twalthr · 2021-12-14T14:56:12Z

What is the purpose of the change

This reworks how we handle symbols throughout the stack. It removes the need for a conversion class and align the behavior with Calcite's representation of symbols. Even though we change a @PublicEvolving class this should have little impact for users as this type is not exposed through the API.

Brief change log

Simplify SymbolType
Remove usages of RAW type for symbols.

Verifying this change

This change is already covered by existing tests, such as (please describe tests).

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): yes
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
If yes, how is the feature documented? JavaDocs

flinkbot · 2021-12-14T15:00:42Z

CI report:

5cb0193 Azure: SUCCESS

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flinkbot · 2021-12-14T15:01:30Z

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matriv

Looks good, I left a few comments/questions.

matriv · 2021-12-14T15:19:12Z

...-table/flink-table-common/src/main/java/org/apache/flink/table/types/logical/SymbolType.java

 */
+@SuppressWarnings("unused")


this is used for the argument of the constructor

Then maybe only move it there on top of the ctor?

or like this: public SymbolType(@SuppressWarnings("unused") Class<T> clazz) { ?

matriv · 2021-12-14T15:21:30Z

.../main/java/org/apache/flink/table/types/inference/strategies/SymbolArgumentTypeStrategy.java

@@ -45,7 +44,8 @@ public SymbolArgumentTypeStrategy(Class<? extends Enum<? extends TableSymbol>> s
    public Optional<DataType> inferArgumentType(
            CallContext callContext, int argumentPos, boolean throwOnFailure) {
        final DataType argumentType = callContext.getArgumentDataTypes().get(argumentPos);
-        if (argumentType.getLogicalType().getTypeRoot() != LogicalTypeRoot.SYMBOL) {
+        if (argumentType.getLogicalType().getTypeRoot() != LogicalTypeRoot.SYMBOL
+                || !callContext.isArgumentLiteral(argumentPos)) {


Why is this needed now? is it tested somewhere?

This is always needed before calling getArgumentValue as written in the JavaDocs. A user would need to create a weird expression to have a symbol that is not a literal.

matriv · 2021-12-14T15:25:33Z

.../main/java/org/apache/flink/table/types/inference/strategies/SymbolArgumentTypeStrategy.java

                        symbolClass.getSimpleName(),
-                        symbolType.getDefaultConversion().getSimpleName());
+                        callContext
+                                .getArgumentValue(argumentPos, Enum.class)


I'm a bit confused, but if L58, we don't have a symbolClass, can we still have an Enum here?
is there a test covering this, and the "invalid" case?

SymbolArgumentTypeStrategyTest is testing this path. We are in control of creating symbols so we can safely assume an Enum here. Everything else is highly unlikely. For the invalid case I would need to create an invalid expression. The alternative would have been an InvalidArgumentException.

If it's easy to have a test like that, would be nice for completeness.

No, that is not easy. As I said, I would need to create a completely invalid expression. Maybe some constructor checks would already prevent that.

slinkydeveloper

Just a minor issue, otherwise LGTM

slinkydeveloper · 2021-12-14T15:30:55Z

...-table/flink-table-common/src/main/java/org/apache/flink/table/types/logical/SymbolType.java

+    public SymbolType(boolean isNullable) {
+        super(isNullable, LogicalTypeRoot.SYMBOL);
    }

-    public Class<T> getSymbolClass() {
-        return symbolClass;
+    public SymbolType() {
+        this(true);
    }


Perhaps create 2 singletons? As I see in different places you either instantiate new SymbolType() and new SymbolType(false)

Let's do this as a followup. We can do the same with IntType and many other predefined types. I was also thinking about reducing the creation of objects.

matriv

LGTM, responded to the original comments, thx for explaining!

This closes apache#18107.

[FLINK-17151][table] Align Calcite's and Flink's SYMBOL types

5cb0193

matriv reviewed Dec 14, 2021

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rmetzger added the component=TableSQL/API label Dec 14, 2021

slinkydeveloper reviewed Dec 14, 2021

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matriv approved these changes Dec 15, 2021

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slinkydeveloper approved these changes Dec 15, 2021

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twalthr closed this in a79e004 Dec 15, 2021

niklassemmler pushed a commit to niklassemmler/flink that referenced this pull request Feb 3, 2022

[FLINK-17151][table] Align Calcite's and Flink's SYMBOL types

2504094

This closes apache#18107.

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[FLINK-17151][table] Align Calcite's and Flink's SYMBOL types #18107

[FLINK-17151][table] Align Calcite's and Flink's SYMBOL types #18107

twalthr commented Dec 14, 2021

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		*/
		@SuppressWarnings("unused")

[FLINK-17151][table] Align Calcite's and Flink's SYMBOL types #18107

[FLINK-17151][table] Align Calcite's and Flink's SYMBOL types #18107

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twalthr commented Dec 14, 2021

What is the purpose of the change

Brief change log

Verifying this change

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

Documentation

flinkbot commented Dec 14, 2021 • edited

CI report:

flinkbot commented Dec 14, 2021

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flinkbot commented Dec 14, 2021 •

edited