emkornfield commented on code in PR #185: URL: https://github.com/apache/parquet-format/pull/185#discussion_r1041775669
########## README.md: ########## @@ -144,6 +144,38 @@ documented in [LogicalTypes.md][logical-types]. [logical-types]: LogicalTypes.md +### Sort Order + +Parquet stores min/max statistics at several levels (e.g. RowGroup, Page Index, +etc). Comparison for values of a type follow the following logic: + +1. Each logical type has a specified comparison order. If a column is + annotated with an unknown logical type, statistics may not be used + for pruning data. The sort order for logical types is documented in + the [LogicalTypes.md][logical-types] page. +2. For primitives the following sort orders apply: + + * BOOLEAN - false, true + * INT32, INT64, FLOAT, DOUBLE - Signed comparison. Floating point values are + not totally ordered due to special case like NaN. They require special + handling when reading statistics. The details are documented in parquet.thrift in the + `ColumnOrder` union. They are summarized Review Comment: done. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
