gszadovszky commented on a change in pull request #168:
URL: https://github.com/apache/parquet-format/pull/168#discussion_r591231620
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File path: src/main/thrift/parquet.thrift
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@@ -481,9 +481,10 @@ enum CompressionCodec {
SNAPPY = 1;
GZIP = 2;
LZO = 3;
- BROTLI = 4; // Added in 2.4
- LZ4 = 5; // Added in 2.4
- ZSTD = 6; // Added in 2.4
+ BROTLI = 4; // Added in 2.4
Review comment:
Since the thrift file (and the generated code) can be a starting point
to the parquet spec it would be a good idea to add a reference to the new
compressions spec in the comment.
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File path: Compression.md
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@@ -0,0 +1,86 @@
+<!--
+ - 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.
+ -->
+
+# Parquet compression definitions
+
+This document contains the specification of all supported compression codecs.
+
+## Overview
+
+Parquet allows the data block inside dictionary pages and data pages to
+be compressed for better space efficiency. The Parquet specification allows
+several compression codecs, most of which are optional to implement. Only the
Review comment:
I am not sure it is right place to say if a codec is optional to
implement or not. Are they all optional BTW? I think we should leave it to the
core features document to list if a codec is required or optional.
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