kszucs commented on code in PR #131: URL: https://github.com/apache/parquet-testing/pull/131#discussion_r4483650284
########## data/empty_data_pages.md: ########## @@ -0,0 +1,63 @@ +<!-- + ~ Licensed to the Apache Software Foundation (ASF) under one + ~ or more contributor license agreements. See the NOTICE file + ~ distributed with this work for additional information + ~ regarding copyright ownership. The ASF licenses this file + ~ to you under the Apache License, Version 2.0 (the + ~ "License"); you may not use this file except in compliance + ~ with the License. You may obtain a copy of the License at + ~ + ~ http://www.apache.org/licenses/LICENSE-2.0 + ~ + ~ Unless required by applicable law or agreed to in writing, + ~ software distributed under the License is distributed on an + ~ "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + ~ KIND, either express or implied. See the License for the + ~ specific language governing permissions and limitations + ~ under the License. + --> + +# `empty_data_pages_v1.parquet` and `empty_data_pages_v2.parquet` + +A single required INT64 column of three rows, whose column chunk contains data pages without +values (`num_values = 0`): the first page and one in the middle. Readers must skip these pages +instead of treating them as the end of the column chunk, and read `1, 2, 3`. + +Such pages are written by parquet-rs 58.1.0 to 60.1.0 with content-defined chunking enabled +([apache/arrow-rs#10929](https://github.com/apache/arrow-rs/issues/10929)). + +## Schema + +``` +message schema { + required int64 int64; +} +``` + +## Pages + +The column chunk has four uncompressed, PLAIN encoded data pages with empty statistics, DataPageV1 +in `empty_data_pages_v1.parquet` and DataPageV2 in `empty_data_pages_v2.parquet`: + +| Page | `num_values` | Values | +|------|--------------|--------| +| 0 | 0 | | +| 1 | 2 | 1, 2 | +| 2 | 0 | | +| 3 | 1 | 3 | + +In the DataPageV2 headers, `num_rows` equals `num_values` and `num_nulls` is 0. + +The files have no page index, since the OffsetIndex requires strictly increasing +`first_row_index` values, while a page without values has the same one as the next page. + +## How it was generated + +Arrow C++ writers only emit data pages holding values, so [empty_data_pages.cc](empty_data_pages.cc) Review Comment: Right, true. I can either document a pinned arrow-cpp version or simply remove it. -- 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] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
