wuchong commented on a change in pull request #12335:
URL: https://github.com/apache/flink/pull/12335#discussion_r435963387
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File path:
flink-table/flink-table-api-java/src/main/java/org/apache/flink/table/api/internal/TableEnvironmentImpl.java
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@@ -490,8 +490,11 @@ private void insertIntoInternal(UnresolvedIdentifier
unresolvedIdentifier, Table
private Optional<CatalogQueryOperation>
scanInternal(UnresolvedIdentifier identifier) {
ObjectIdentifier tableIdentifier =
catalogManager.qualifyIdentifier(identifier);
- return catalogManager.getTable(tableIdentifier)
- .map(t -> new CatalogQueryOperation(tableIdentifier,
t.getTable().getSchema()));
+ return catalogManager.getTable(tableIdentifier).map(t -> {
+ CatalogTableSchemaResolver resolver = new
CatalogTableSchemaResolver(parser);
Review comment:
We had a long discussion in FLINK-17189 and had a conclusion that the
TimestampType#kind shoudn't be stored in catalog. IMO, there are several
reasons:
1) the metadata stored in catalog should simply store the information of
DDL. In other words, we should only store the pure DDL into catalog.
2) the result datatype of computed column is not trusted, they may changed
across versions, including `PROCTIME()` and user-defined functions. There are
some users reported that the result type of `PROCTIME()` should be `TIMESTAMP
WITH LOCAL TIME ZONE`, not `TIMESTAMP WITHOUT TIME ZONE`. Users may also
change their UDF implementation. If we just use the result type stored in
catalog, there of course will be an exception during code generation or
runtime, because of type mismatch.
3) I don't want to treat proctime attribute and rowtime attribute specially
when storing them in catalog. They are not different than other computed
columns and regular columns.
Thus, we **have to** resolve the result type of computed columns again, when
we get the `CatalogTable` from catalog. Actually, the initial `CatalogTable`
get from catalog is a unresovled table (like UnresolvedExpression). That's why
we need a `CatalogTableShemaResolver` to resolve `CatalogTableSchema`.
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