[SPARK-6450] [SQL] Fixes metastore Parquet table conversion #5183
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The
ParquetConversionsanalysis rule generates a hash map, which maps from the originalMetastoreRelationinstances to the newly createdParquetRelation2instances. However,MetastoreRelation.equalsdoesn't compare output attributes. Thus, if a single metastore Parquet table appears multiple times in a query, only a single entry ends up in the hash map, and the conversion is not correctly performed.Proper fix for this issue should be overriding
equalsandhashCodefor MetastoreRelation. Unfortunately, this breaks more tests than expected. It's possible that these tests are ill-formed from the very beginning. As 1.3.1 release is approaching, we'd like to make the change more surgical to avoid potential regressions. The proposed fix here is to make both the metastore relations and their output attributes as keys in the hash map used in ParquetConversions.