[ https://issues.apache.org/jira/browse/ARROW-1983?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16849106#comment-16849106 ]
Wes McKinney commented on ARROW-1983: ------------------------------------- Probably the most flexible thing for writing would be a function that appends a metadata to an OutputStream {code:java} Status AppendFileMetaData(const FileMetaData& metadata, arrow::io::OutputStream* out); {code} Correspondingly, please also write a function that parses a multiple-metadata file like {code} Status ParseMetaDataFile(arrow::io::InputStream* input, std::vector<std::shared_ptr<FileMetaData>>* out); {code} Lastly, AFAIK we are not able to instantiate {{ParquetFileReader}} given previously-read {{FileMetaData}} -- probably can do that in a separate JIRA > [Python] Add ability to write parquet `_metadata` file > ------------------------------------------------------ > > Key: ARROW-1983 > URL: https://issues.apache.org/jira/browse/ARROW-1983 > Project: Apache Arrow > Issue Type: Improvement > Components: C++, Python > Reporter: Jim Crist > Priority: Major > Labels: beginner, parquet, pull-request-available > Fix For: 0.14.0 > > Time Spent: 6h 20m > Remaining Estimate: 0h > > Currently {{pyarrow.parquet}} can only write the {{_common_metadata}} file > (mostly just schema information). It would be useful to add the ability to > write a {{_metadata}} file as well. This should include information about > each row group in the dataset, including summary statistics. Having this > summary file would allow filtering of row groups without needing to access > each file beforehand. > This would require that the user is able to get the written RowGroups out of > a {{pyarrow.parquet.write_table}} call and then give these objects as a list > to new function that then passes them on as C++ objects to {{parquet-cpp}} > that generates the respective {{_metadata}} file. -- This message was sent by Atlassian JIRA (v7.6.3#76005)