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I believe that if you have a Parquet file meeting certain criteria, it's directly parallelizable as multiple Spark partitions without any shuffling. The splits
by rsanders 8y ago
I believe that if you have a Parquet file meeting certain criteria, it's directly parallelizable as multiple Spark partitions without any shuffling. The splits would occur at Parquet row group boundaries, I believe.
See https://stackoverflow.com/questions/27194333/how-to-split-parquet-files-into-many-partitions-in-spark/29819133#29819133 https://stackoverflow.com/questions/27194333/how-to-split-pa..., https://parquet.apache.org/documentation/latest/ https://parquet.apache.org/documentation/latest/, etc.
Whether it's better to have multiple Parquet files or a single parallelizable Parquet file is dependent on your environment and application. At my company, we've tended to have a single row group per file (and one HDFS block per file), in part due to historical reasons.