Csaba Ringhofer created IMPALA-11452:
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Summary: Improve handling in CollectionTableRef
Key: IMPALA-11452
URL: https://issues.apache.org/jira/browse/IMPALA-11452
Project: IMPALA
Issue Type: Improvement
Components: Frontend
Affects Versions: Impala 4.1.0
Reporter: Csaba Ringhofer
Currently a TableRef is expected to have 1 or 2 aliases:
1: it is an explicit alias, like "t" in "select * from db.tbl t"
2: the first is fully qualified name ("db.tbl"), the second is an implicit name
("tbl") in "select * from db.tbl"
https://github.com/apache/impala/blob/02043744beee8c57ee876cb8d94eba28660927cb/fe/src/main/java/org/apache/impala/analysis/TableRef.java#L83
The case with 2 aliases is not enough to properly express naming of collection
tables, e.g. "select item from db.tbl.arr_col".
The issue is that while the fully qualified alias is always enough to point to
the right collection, the second implicit alias is often not really usable, for
example for the inner collection of a 2d table it will be always "item" (while
the fully qualified alias will be "db.table.arr_col.item". If there are two
such collections in a query, only the fully qualified form becomes usable,
which is a bit too verbose. It could be useful to add an alias that starts at
the column name, e.g "arr_col.item" it the 2d example above.
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