Joris Van den Bossche created ARROW-10131: ---------------------------------------------
Summary: [C++][Dataset] Lazily parse parquet metadata / statistics in ParquetDatasetFactory and ParquetFileFragment Key: ARROW-10131 URL: https://issues.apache.org/jira/browse/ARROW-10131 Project: Apache Arrow Issue Type: Improvement Components: C++ Reporter: Joris Van den Bossche Related to ARROW-9730, parsing of the statistics in parquet metadata is expensive, and therefore should be avoided when possible. For example, the {{ParquetDatasetFactory}} ({{ds.parquet_dataset()}} in python) parses all statistics of all files and all columns. While when doing a filtered read, you might only need the statistics of certain files (eg if a filter on a partition field already excluded many files) and certain columns (eg only the columns on which you are actually filtering). The current API is a bit all-or-nothing (both ParquetDatasetFactory, or a later EnsureCompleteMetadata parse all statistics, and don't allow parsing a subset, or only parsing the other (non-statistics) metadata, ...), so I think we should try to think of better abstractions. cc [~rjzamora] [~bkietz] -- This message was sent by Atlassian Jira (v8.3.4#803005)