Zoltán Borók-Nagy created IMPALA-9228: -----------------------------------------
Summary: ORC scanner could be vectorized Key: IMPALA-9228 URL: https://issues.apache.org/jira/browse/IMPALA-9228 Project: IMPALA Issue Type: Improvement Reporter: Zoltán Borók-Nagy The ORC scanners uses an external library to read ORC files. The library reads the file contents into its own memory representation. It is a vectorized representation similar to the Arrow format. Impala needs to convert the ORC row batch to an Impala row batch. Currently the conversion happens row-wise and column-by-column via a virtual function call: [https://github.com/apache/impala/blob/85425b81f04c856d7d5ec375242303f78ec7964e/be/src/exec/hdfs-orc-scanner.cc#L671] [https://github.com/apache/impala/blob/85425b81f04c856d7d5ec375242303f78ec7964e/be/src/exec/orc-column-readers.cc#L352] Instead of this approach it could work similarly to the Parquet scanner that fills the columns one-by-one into a scratch batch, then evaluate the conjuncts on the scratch batch. For more details see HdfsParquetScanner::AssembleRows(): [https://github.com/apache/impala/blob/85425b81f04c856d7d5ec375242303f78ec7964e/be/src/exec/parquet/hdfs-parquet-scanner.cc#L1077-L1088] This way we'll need a lot less virtual function calls, also the memory reads/writes will be much more localized and predictable. -- This message was sent by Atlassian Jira (v8.3.4#803005)