Return-Path: X-Original-To: apmail-parquet-commits-archive@minotaur.apache.org Delivered-To: apmail-parquet-commits-archive@minotaur.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id A999D17D8C for ; Fri, 29 Jan 2016 18:30:14 +0000 (UTC) Received: (qmail 91287 invoked by uid 500); 29 Jan 2016 18:30:14 -0000 Delivered-To: apmail-parquet-commits-archive@parquet.apache.org Received: (qmail 91257 invoked by uid 500); 29 Jan 2016 18:30:14 -0000 Mailing-List: contact commits-help@parquet.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: dev@parquet.apache.org Delivered-To: mailing list commits@parquet.apache.org Received: (qmail 91247 invoked by uid 99); 29 Jan 2016 18:30:14 -0000 Received: from git1-us-west.apache.org (HELO git1-us-west.apache.org) (140.211.11.23) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 29 Jan 2016 18:30:14 +0000 Received: by git1-us-west.apache.org (ASF Mail Server at git1-us-west.apache.org, from userid 33) id 717FBDFFF4; Fri, 29 Jan 2016 18:30:14 +0000 (UTC) Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: julien@apache.org To: commits@parquet.apache.org Message-Id: X-Mailer: ASF-Git Admin Mailer Subject: parquet-format git commit: PARQUET-450: Fix several typos in Parquet format documentation Date: Fri, 29 Jan 2016 18:30:14 +0000 (UTC) Repository: parquet-format Updated Branches: refs/heads/master c3682e3b3 -> 2a8f022a4 PARQUET-450: Fix several typos in Parquet format documentation It also changes parquet.thrift location to conform to maven layout and add a link to it from README.md Author: Laurent Goujon Closes #36 from laurentgo/update-format-specification and squashes the following commits: 244c119 [Laurent Goujon] Fix several typos/errors in Parquet documentation 90a2be4 [Laurent Goujon] Fix thrift source path to match maven layout Project: http://git-wip-us.apache.org/repos/asf/parquet-format/repo Commit: http://git-wip-us.apache.org/repos/asf/parquet-format/commit/2a8f022a Tree: http://git-wip-us.apache.org/repos/asf/parquet-format/tree/2a8f022a Diff: http://git-wip-us.apache.org/repos/asf/parquet-format/diff/2a8f022a Branch: refs/heads/master Commit: 2a8f022a49555fa7476dbb6804c9771397f8da12 Parents: c3682e3 Author: Laurent Goujon Authored: Fri Jan 29 10:30:06 2016 -0800 Committer: Julien Le Dem Committed: Fri Jan 29 10:30:06 2016 -0800 ---------------------------------------------------------------------- Encodings.md | 2 +- README.md | 27 +- pom.xml | 2 +- src/main/thrift/parquet.thrift | 573 ++++++++++++++++++++++++++++++++++++ src/thrift/parquet.thrift | 573 ------------------------------------ 5 files changed, 589 insertions(+), 588 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/parquet-format/blob/2a8f022a/Encodings.md ---------------------------------------------------------------------- diff --git a/Encodings.md b/Encodings.md index 42961ba..c4cdf70 100644 --- a/Encodings.md +++ b/Encodings.md @@ -53,7 +53,7 @@ using the [RLE/Bit-Packing Hybrid](#RLE) encoding. If the dictionary grows too b or number of distinct values, the encoding will fall back to the plain encoding. The dictionary page is written first, before the data pages of the column chunk. -Dictionary page format: the entries in the dictionary - in dictionary order - using the [plain](#PLAIN) enncoding. +Dictionary page format: the entries in the dictionary - in dictionary order - using the [plain](#PLAIN) encoding. Data page format: the bit width used to encode the entry ids stored as 1 byte (max bit width = 32), followed by the values encoded using RLE/Bit packed described above (with the given bit width). http://git-wip-us.apache.org/repos/asf/parquet-format/blob/2a8f022a/README.md ---------------------------------------------------------------------- diff --git a/README.md b/README.md index 904bb6a..b0423e6 100644 --- a/README.md +++ b/README.md @@ -46,30 +46,30 @@ The `parquet-compatibility` project contains compatibility tests that can be use ## Building -Java resources can be build using `mvn package.` The current stable version should always be available from Maven Central. +Java resources can be build using `mvn package`. The current stable version should always be available from Maven Central. C++ thrift resources can be generated via make. Thrift can be also code-genned into any other thrift-supported language. ## Glossary - - Block (hdfs block): This means a block in hdfs and the meaning is + - Block (HDFS block): This means a block in HDFS and the meaning is unchanged for describing this file format. The file format is - designed to work well on top of hdfs. + designed to work well on top of HDFS. - - File: A hdfs file that must include the metadata for the file. + - File: A HDFS file that must include the metadata for the file. It does not need to actually contain the data. - Row group: A logical horizontal partitioning of the data into rows. There is no physical structure that is guaranteed for a row group. A row group consists of a column chunk for each column in the dataset. - - Column chunk: A chunk of the data for a particular column. These live - in a particular row group and is guaranteed to be contiguous in the file. + - Column chunk: A chunk of the data for a particular column. They live + in a particular row group and are guaranteed to be contiguous in the file. - Page: Column chunks are divided up into pages. A page is conceptually an indivisible unit (in terms of compression and encoding). There can - be multiple page types which is interleaved in a column chunk. + be multiple page types which are interleaved in a column chunk. Hierarchically, a file consists of one or more row groups. A row group contains exactly one column chunk per column. Column chunks contain one or @@ -81,7 +81,7 @@ more pages. - Encoding/Compression - Page ## File format -This file and the thrift definition should be read together to understand the format. +This file and the [thrift definition](src/main/thrift/parquet.thrift) should be read together to understand the format. 4-byte magic number "PAR1" @@ -98,13 +98,13 @@ This file and the thrift definition should be read together to understand the fo ... File Metadata - 4-byte length in bytes of file metadata + 4-byte length in bytes of file metadata (little endian) 4-byte magic number "PAR1" In the above example, there are N columns in this table, split into M row groups. The file metadata contains the locations of all the column metadata start locations. More details on what is contained in the metadata can be found -in the thrift files. +in the thrift definition. Metadata is written after the data to allow for single pass writing. @@ -139,7 +139,7 @@ by specifying how the primitive types should be interpreted. This keeps the set of primitive types to a minimum and reuses parquet's efficient encodings. For example, strings are stored as byte arrays (binary) with a UTF8 annotation. These annotations define how to further decode and interpret the data. -Annotations are stored as a `ConvertedType` in the file metadata and are +Annotations are stored as `ConvertedType` fields in the file metadata and are documented in [LogicalTypes.md][logical-types]. @@ -165,9 +165,10 @@ nothing else. ## Data Pages For data pages, the 3 pieces of information are encoded back to back, after the page header. We have the - - definition levels data, - repetition levels data, + - definition levels data, - encoded values. + The size of specified in the header is for all 3 pieces combined. The data for the data page is always required. The definition and repetition levels @@ -183,7 +184,7 @@ The supported encodings are described in [Encodings.md](https://github.com/Parqu ## Column chunks Column chunks are composed of pages written back to back. The pages share a common -header and readers can skip over page they are not interested in. The data for the +header and readers can skip over pages they are not interested in. The data for the page follows the header and can be compressed and/or encoded. The compression and encoding is specified in the page metadata. http://git-wip-us.apache.org/repos/asf/parquet-format/blob/2a8f022a/pom.xml ---------------------------------------------------------------------- diff --git a/pom.xml b/pom.xml index 78578b9..d5b3b60 100644 --- a/pom.xml +++ b/pom.xml @@ -96,7 +96,7 @@ maven-thrift-plugin 0.1.11 - src/thrift + src/main/thrift http://git-wip-us.apache.org/repos/asf/parquet-format/blob/2a8f022a/src/main/thrift/parquet.thrift ---------------------------------------------------------------------- diff --git a/src/main/thrift/parquet.thrift b/src/main/thrift/parquet.thrift new file mode 100644 index 0000000..d1b305e --- /dev/null +++ b/src/main/thrift/parquet.thrift @@ -0,0 +1,573 @@ +/** + * 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. + */ + +/** + * File format description for the parquet file format + */ +namespace cpp parquet +namespace java org.apache.parquet.format + +/** + * Types supported by Parquet. These types are intended to be used in combination + * with the encodings to control the on disk storage format. + * For example INT16 is not included as a type since a good encoding of INT32 + * would handle this. + */ +enum Type { + BOOLEAN = 0; + INT32 = 1; + INT64 = 2; + INT96 = 3; + FLOAT = 4; + DOUBLE = 5; + BYTE_ARRAY = 6; + FIXED_LEN_BYTE_ARRAY = 7; +} + +/** + * Common types used by frameworks(e.g. hive, pig) using parquet. This helps map + * between types in those frameworks to the base types in parquet. This is only + * metadata and not needed to read or write the data. + */ +enum ConvertedType { + /** a BYTE_ARRAY actually contains UTF8 encoded chars */ + UTF8 = 0; + + /** a map is converted as an optional field containing a repeated key/value pair */ + MAP = 1; + + /** a key/value pair is converted into a group of two fields */ + MAP_KEY_VALUE = 2; + + /** a list is converted into an optional field containing a repeated field for its + * values */ + LIST = 3; + + /** an enum is converted into a binary field */ + ENUM = 4; + + /** + * A decimal value. + * + * This may be used to annotate binary or fixed primitive types. The + * underlying byte array stores the unscaled value encoded as two's + * complement using big-endian byte order (the most significant byte is the + * zeroth element). The value of the decimal is the value * 10^{-scale}. + * + * This must be accompanied by a (maximum) precision and a scale in the + * SchemaElement. The precision specifies the number of digits in the decimal + * and the scale stores the location of the decimal point. For example 1.23 + * would have precision 3 (3 total digits) and scale 2 (the decimal point is + * 2 digits over). + */ + DECIMAL = 5; + + /** + * A Date + * + * Stored as days since Unix epoch, encoded as the INT32 physical type. + * + */ + DATE = 6; + + /** + * A time + * + * The total number of milliseconds since midnight. The value is stored + * as an INT32 physical type. + */ + TIME_MILLIS = 7; + + /** + * A time. + * + * The total number of microseconds since midnight. The value is stored as + * an INT64 physical type. + */ + TIME_MICROS = 8; + + /** + * A date/time combination + * + * Date and time recorded as milliseconds since the Unix epoch. Recorded as + * a physical type of INT64. + */ + TIMESTAMP_MILLIS = 9; + + /** + * A date/time combination + * + * Date and time recorded as microseconds since the Unix epoch. The value is + * stored as an INT64 physical type. + */ + TIMESTAMP_MICROS = 10; + + + /** + * An unsigned integer value. + * + * The number describes the maximum number of meainful data bits in + * the stored value. 8, 16 and 32 bit values are stored using the + * INT32 physical type. 64 bit values are stored using the INT64 + * physical type. + * + */ + UINT_8 = 11; + UINT_16 = 12; + UINT_32 = 13; + UINT_64 = 14; + + /** + * A signed integer value. + * + * The number describes the maximum number of meainful data bits in + * the stored value. 8, 16 and 32 bit values are stored using the + * INT32 physical type. 64 bit values are stored using the INT64 + * physical type. + * + */ + INT_8 = 15; + INT_16 = 16; + INT_32 = 17; + INT_64 = 18; + + /** + * An embedded JSON document + * + * A JSON document embedded within a single UTF8 column. + */ + JSON = 19; + + /** + * An embedded BSON document + * + * A BSON document embedded within a single BINARY column. + */ + BSON = 20; + + /** + * An interval of time + * + * This type annotates data stored as a FIXED_LEN_BYTE_ARRAY of length 12 + * This data is composed of three separate little endian unsigned + * integers. Each stores a component of a duration of time. The first + * integer identifies the number of months associated with the duration, + * the second identifies the number of days associated with the duration + * and the third identifies the number of milliseconds associated with + * the provided duration. This duration of time is independent of any + * particular timezone or date. + */ + INTERVAL = 21; + +} + +/** + * Representation of Schemas + */ +enum FieldRepetitionType { + /** This field is required (can not be null) and each record has exactly 1 value. */ + REQUIRED = 0; + + /** The field is optional (can be null) and each record has 0 or 1 values. */ + OPTIONAL = 1; + + /** The field is repeated and can contain 0 or more values */ + REPEATED = 2; +} + +/** + * Statistics per row group and per page + * All fields are optional. + */ +struct Statistics { + /** min and max value of the column, encoded in PLAIN encoding */ + 1: optional binary max; + 2: optional binary min; + /** count of null value in the column */ + 3: optional i64 null_count; + /** count of distinct values occurring */ + 4: optional i64 distinct_count; +} + +/** + * Represents a element inside a schema definition. + * - if it is a group (inner node) then type is undefined and num_children is defined + * - if it is a primitive type (leaf) then type is defined and num_children is undefined + * the nodes are listed in depth first traversal order. + */ +struct SchemaElement { + /** Data type for this field. Not set if the current element is a non-leaf node */ + 1: optional Type type; + + /** If type is FIXED_LEN_BYTE_ARRAY, this is the byte length of the vales. + * Otherwise, if specified, this is the maximum bit length to store any of the values. + * (e.g. a low cardinality INT col could have this set to 3). Note that this is + * in the schema, and therefore fixed for the entire file. + */ + 2: optional i32 type_length; + + /** repetition of the field. The root of the schema does not have a repetition_type. + * All other nodes must have one */ + 3: optional FieldRepetitionType repetition_type; + + /** Name of the field in the schema */ + 4: required string name; + + /** Nested fields. Since thrift does not support nested fields, + * the nesting is flattened to a single list by a depth-first traversal. + * The children count is used to construct the nested relationship. + * This field is not set when the element is a primitive type + */ + 5: optional i32 num_children; + + /** When the schema is the result of a conversion from another model + * Used to record the original type to help with cross conversion. + */ + 6: optional ConvertedType converted_type; + + /** Used when this column contains decimal data. + * See the DECIMAL converted type for more details. + */ + 7: optional i32 scale + 8: optional i32 precision + + /** When the original schema supports field ids, this will save the + * original field id in the parquet schema + */ + 9: optional i32 field_id; + +} + +/** + * Encodings supported by Parquet. Not all encodings are valid for all types. These + * enums are also used to specify the encoding of definition and repetition levels. + * See the accompanying doc for the details of the more complicated encodings. + */ +enum Encoding { + /** Default encoding. + * BOOLEAN - 1 bit per value. 0 is false; 1 is true. + * INT32 - 4 bytes per value. Stored as little-endian. + * INT64 - 8 bytes per value. Stored as little-endian. + * FLOAT - 4 bytes per value. IEEE. Stored as little-endian. + * DOUBLE - 8 bytes per value. IEEE. Stored as little-endian. + * BYTE_ARRAY - 4 byte length stored as little endian, followed by bytes. + * FIXED_LEN_BYTE_ARRAY - Just the bytes. + */ + PLAIN = 0; + + /** Group VarInt encoding for INT32/INT64. + * This encoding is deprecated. It was never used + */ + // GROUP_VAR_INT = 1; + + /** + * Deprecated: Dictionary encoding. The values in the dictionary are encoded in the + * plain type. + * in a data page use RLE_DICTIONARY instead. + * in a Dictionary page use PLAIN instead + */ + PLAIN_DICTIONARY = 2; + + /** Group packed run length encoding. Usable for definition/reptition levels + * encoding and Booleans (on one bit: 0 is false; 1 is true.) + */ + RLE = 3; + + /** Bit packed encoding. This can only be used if the data has a known max + * width. Usable for definition/repetition levels encoding. + */ + BIT_PACKED = 4; + + /** Delta encoding for integers. This can be used for int columns and works best + * on sorted data + */ + DELTA_BINARY_PACKED = 5; + + /** Encoding for byte arrays to separate the length values and the data. The lengths + * are encoded using DELTA_BINARY_PACKED + */ + DELTA_LENGTH_BYTE_ARRAY = 6; + + /** Incremental-encoded byte array. Prefix lengths are encoded using DELTA_BINARY_PACKED. + * Suffixes are stored as delta length byte arrays. + */ + DELTA_BYTE_ARRAY = 7; + + /** Dictionary encoding: the ids are encoded using the RLE encoding + */ + RLE_DICTIONARY = 8; +} + +/** + * Supported compression algorithms. + */ +enum CompressionCodec { + UNCOMPRESSED = 0; + SNAPPY = 1; + GZIP = 2; + LZO = 3; +} + +enum PageType { + DATA_PAGE = 0; + INDEX_PAGE = 1; + DICTIONARY_PAGE = 2; + DATA_PAGE_V2 = 3; +} + +/** Data page header */ +struct DataPageHeader { + /** Number of values, including NULLs, in this data page. **/ + 1: required i32 num_values + + /** Encoding used for this data page **/ + 2: required Encoding encoding + + /** Encoding used for definition levels **/ + 3: required Encoding definition_level_encoding; + + /** Encoding used for repetition levels **/ + 4: required Encoding repetition_level_encoding; + + /** Optional statistics for the data in this page**/ + 5: optional Statistics statistics; +} + +struct IndexPageHeader { + /** TODO: **/ +} + +struct DictionaryPageHeader { + /** Number of values in the dictionary **/ + 1: required i32 num_values; + + /** Encoding using this dictionary page **/ + 2: required Encoding encoding + + /** If true, the entries in the dictionary are sorted in ascending order **/ + 3: optional bool is_sorted; +} + +/** + * New page format alowing reading levels without decompressing the data + * Repetition and definition levels are uncompressed + * The remaining section containing the data is compressed if is_compressed is true + **/ +struct DataPageHeaderV2 { + /** Number of values, including NULLs, in this data page. **/ + 1: required i32 num_values + /** Number of NULL values, in this data page. + Number of non-null = num_values - num_nulls which is also the number of values in the data section **/ + 2: required i32 num_nulls + /** Number of rows in this data page. which means pages change on record boundaries (r = 0) **/ + 3: required i32 num_rows + /** Encoding used for data in this page **/ + 4: required Encoding encoding + + // repetition levels and definition levels are always using RLE (without size in it) + + /** length of the repetition levels */ + 5: required i32 definition_levels_byte_length; + /** length of the definition levels */ + 6: required i32 repetition_levels_byte_length; + + /** whether the values are compressed. + Which means the section of the page between + definition_levels_byte_length + repetition_levels_byte_length + 1 and compressed_page_size (included) + is compressed with the compression_codec. + If missing it is considered compressed */ + 7: optional bool is_compressed = 1; + + /** optional statistics for this column chunk */ + 8: optional Statistics statistics; +} + +struct PageHeader { + /** the type of the page: indicates which of the *_header fields is set **/ + 1: required PageType type + + /** Uncompressed page size in bytes (not including this header) **/ + 2: required i32 uncompressed_page_size + + /** Compressed page size in bytes (not including this header) **/ + 3: required i32 compressed_page_size + + /** 32bit crc for the data below. This allows for disabling checksumming in HDFS + * if only a few pages needs to be read + **/ + 4: optional i32 crc + + // Headers for page specific data. One only will be set. + 5: optional DataPageHeader data_page_header; + 6: optional IndexPageHeader index_page_header; + 7: optional DictionaryPageHeader dictionary_page_header; + 8: optional DataPageHeaderV2 data_page_header_v2; +} + +/** + * Wrapper struct to store key values + */ + struct KeyValue { + 1: required string key + 2: optional string value +} + +/** + * Wrapper struct to specify sort order + */ +struct SortingColumn { + /** The column index (in this row group) **/ + 1: required i32 column_idx + + /** If true, indicates this column is sorted in descending order. **/ + 2: required bool descending + + /** If true, nulls will come before non-null values, otherwise, + * nulls go at the end. */ + 3: required bool nulls_first +} + +/** + * statistics of a given page type and encoding + */ +struct PageEncodingStats { + + /** the page type (data/dic/...) **/ + 1: required PageType page_type; + + /** encoding of the page **/ + 2: required Encoding encoding; + + /** number of pages of this type with this encoding **/ + 3: required i32 count; + +} + +/** + * Description for column metadata + */ +struct ColumnMetaData { + /** Type of this column **/ + 1: required Type type + + /** Set of all encodings used for this column. The purpose is to validate + * whether we can decode those pages. **/ + 2: required list encodings + + /** Path in schema **/ + 3: required list path_in_schema + + /** Compression codec **/ + 4: required CompressionCodec codec + + /** Number of values in this column **/ + 5: required i64 num_values + + /** total byte size of all uncompressed pages in this column chunk (including the headers) **/ + 6: required i64 total_uncompressed_size + + /** total byte size of all compressed pages in this column chunk (including the headers) **/ + 7: required i64 total_compressed_size + + /** Optional key/value metadata **/ + 8: optional list key_value_metadata + + /** Byte offset from beginning of file to first data page **/ + 9: required i64 data_page_offset + + /** Byte offset from beginning of file to root index page **/ + 10: optional i64 index_page_offset + + /** Byte offset from the beginning of file to first (only) dictionary page **/ + 11: optional i64 dictionary_page_offset + + /** optional statistics for this column chunk */ + 12: optional Statistics statistics; + + /** Set of all encodings used for pages in this column chunk. + * This information can be used to determine if all data pages are + * dictionary encoded for example **/ + 13: optional list encoding_stats; +} + +struct ColumnChunk { + /** File where column data is stored. If not set, assumed to be same file as + * metadata. This path is relative to the current file. + **/ + 1: optional string file_path + + /** Byte offset in file_path to the ColumnMetaData **/ + 2: required i64 file_offset + + /** Column metadata for this chunk. This is the same content as what is at + * file_path/file_offset. Having it here has it replicated in the file + * metadata. + **/ + 3: optional ColumnMetaData meta_data +} + +struct RowGroup { + /** Metadata for each column chunk in this row group. + * This list must have the same order as the SchemaElement list in FileMetaData. + **/ + 1: required list columns + + /** Total byte size of all the uncompressed column data in this row group **/ + 2: required i64 total_byte_size + + /** Number of rows in this row group **/ + 3: required i64 num_rows + + /** If set, specifies a sort ordering of the rows in this RowGroup. + * The sorting columns can be a subset of all the columns. + */ + 4: optional list sorting_columns +} + +/** + * Description for file metadata + */ +struct FileMetaData { + /** Version of this file **/ + 1: required i32 version + + /** Parquet schema for this file. This schema contains metadata for all the columns. + * The schema is represented as a tree with a single root. The nodes of the tree + * are flattened to a list by doing a depth-first traversal. + * The column metadata contains the path in the schema for that column which can be + * used to map columns to nodes in the schema. + * The first element is the root **/ + 2: required list schema; + + /** Number of rows in this file **/ + 3: required i64 num_rows + + /** Row groups in this file **/ + 4: required list row_groups + + /** Optional key/value metadata **/ + 5: optional list key_value_metadata + + /** String for application that wrote this file. This should be in the format + * version (build ). + * e.g. impala version 1.0 (build 6cf94d29b2b7115df4de2c06e2ab4326d721eb55) + **/ + 6: optional string created_by +} + http://git-wip-us.apache.org/repos/asf/parquet-format/blob/2a8f022a/src/thrift/parquet.thrift ---------------------------------------------------------------------- diff --git a/src/thrift/parquet.thrift b/src/thrift/parquet.thrift deleted file mode 100644 index d1b305e..0000000 --- a/src/thrift/parquet.thrift +++ /dev/null @@ -1,573 +0,0 @@ -/** - * 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. - */ - -/** - * File format description for the parquet file format - */ -namespace cpp parquet -namespace java org.apache.parquet.format - -/** - * Types supported by Parquet. These types are intended to be used in combination - * with the encodings to control the on disk storage format. - * For example INT16 is not included as a type since a good encoding of INT32 - * would handle this. - */ -enum Type { - BOOLEAN = 0; - INT32 = 1; - INT64 = 2; - INT96 = 3; - FLOAT = 4; - DOUBLE = 5; - BYTE_ARRAY = 6; - FIXED_LEN_BYTE_ARRAY = 7; -} - -/** - * Common types used by frameworks(e.g. hive, pig) using parquet. This helps map - * between types in those frameworks to the base types in parquet. This is only - * metadata and not needed to read or write the data. - */ -enum ConvertedType { - /** a BYTE_ARRAY actually contains UTF8 encoded chars */ - UTF8 = 0; - - /** a map is converted as an optional field containing a repeated key/value pair */ - MAP = 1; - - /** a key/value pair is converted into a group of two fields */ - MAP_KEY_VALUE = 2; - - /** a list is converted into an optional field containing a repeated field for its - * values */ - LIST = 3; - - /** an enum is converted into a binary field */ - ENUM = 4; - - /** - * A decimal value. - * - * This may be used to annotate binary or fixed primitive types. The - * underlying byte array stores the unscaled value encoded as two's - * complement using big-endian byte order (the most significant byte is the - * zeroth element). The value of the decimal is the value * 10^{-scale}. - * - * This must be accompanied by a (maximum) precision and a scale in the - * SchemaElement. The precision specifies the number of digits in the decimal - * and the scale stores the location of the decimal point. For example 1.23 - * would have precision 3 (3 total digits) and scale 2 (the decimal point is - * 2 digits over). - */ - DECIMAL = 5; - - /** - * A Date - * - * Stored as days since Unix epoch, encoded as the INT32 physical type. - * - */ - DATE = 6; - - /** - * A time - * - * The total number of milliseconds since midnight. The value is stored - * as an INT32 physical type. - */ - TIME_MILLIS = 7; - - /** - * A time. - * - * The total number of microseconds since midnight. The value is stored as - * an INT64 physical type. - */ - TIME_MICROS = 8; - - /** - * A date/time combination - * - * Date and time recorded as milliseconds since the Unix epoch. Recorded as - * a physical type of INT64. - */ - TIMESTAMP_MILLIS = 9; - - /** - * A date/time combination - * - * Date and time recorded as microseconds since the Unix epoch. The value is - * stored as an INT64 physical type. - */ - TIMESTAMP_MICROS = 10; - - - /** - * An unsigned integer value. - * - * The number describes the maximum number of meainful data bits in - * the stored value. 8, 16 and 32 bit values are stored using the - * INT32 physical type. 64 bit values are stored using the INT64 - * physical type. - * - */ - UINT_8 = 11; - UINT_16 = 12; - UINT_32 = 13; - UINT_64 = 14; - - /** - * A signed integer value. - * - * The number describes the maximum number of meainful data bits in - * the stored value. 8, 16 and 32 bit values are stored using the - * INT32 physical type. 64 bit values are stored using the INT64 - * physical type. - * - */ - INT_8 = 15; - INT_16 = 16; - INT_32 = 17; - INT_64 = 18; - - /** - * An embedded JSON document - * - * A JSON document embedded within a single UTF8 column. - */ - JSON = 19; - - /** - * An embedded BSON document - * - * A BSON document embedded within a single BINARY column. - */ - BSON = 20; - - /** - * An interval of time - * - * This type annotates data stored as a FIXED_LEN_BYTE_ARRAY of length 12 - * This data is composed of three separate little endian unsigned - * integers. Each stores a component of a duration of time. The first - * integer identifies the number of months associated with the duration, - * the second identifies the number of days associated with the duration - * and the third identifies the number of milliseconds associated with - * the provided duration. This duration of time is independent of any - * particular timezone or date. - */ - INTERVAL = 21; - -} - -/** - * Representation of Schemas - */ -enum FieldRepetitionType { - /** This field is required (can not be null) and each record has exactly 1 value. */ - REQUIRED = 0; - - /** The field is optional (can be null) and each record has 0 or 1 values. */ - OPTIONAL = 1; - - /** The field is repeated and can contain 0 or more values */ - REPEATED = 2; -} - -/** - * Statistics per row group and per page - * All fields are optional. - */ -struct Statistics { - /** min and max value of the column, encoded in PLAIN encoding */ - 1: optional binary max; - 2: optional binary min; - /** count of null value in the column */ - 3: optional i64 null_count; - /** count of distinct values occurring */ - 4: optional i64 distinct_count; -} - -/** - * Represents a element inside a schema definition. - * - if it is a group (inner node) then type is undefined and num_children is defined - * - if it is a primitive type (leaf) then type is defined and num_children is undefined - * the nodes are listed in depth first traversal order. - */ -struct SchemaElement { - /** Data type for this field. Not set if the current element is a non-leaf node */ - 1: optional Type type; - - /** If type is FIXED_LEN_BYTE_ARRAY, this is the byte length of the vales. - * Otherwise, if specified, this is the maximum bit length to store any of the values. - * (e.g. a low cardinality INT col could have this set to 3). Note that this is - * in the schema, and therefore fixed for the entire file. - */ - 2: optional i32 type_length; - - /** repetition of the field. The root of the schema does not have a repetition_type. - * All other nodes must have one */ - 3: optional FieldRepetitionType repetition_type; - - /** Name of the field in the schema */ - 4: required string name; - - /** Nested fields. Since thrift does not support nested fields, - * the nesting is flattened to a single list by a depth-first traversal. - * The children count is used to construct the nested relationship. - * This field is not set when the element is a primitive type - */ - 5: optional i32 num_children; - - /** When the schema is the result of a conversion from another model - * Used to record the original type to help with cross conversion. - */ - 6: optional ConvertedType converted_type; - - /** Used when this column contains decimal data. - * See the DECIMAL converted type for more details. - */ - 7: optional i32 scale - 8: optional i32 precision - - /** When the original schema supports field ids, this will save the - * original field id in the parquet schema - */ - 9: optional i32 field_id; - -} - -/** - * Encodings supported by Parquet. Not all encodings are valid for all types. These - * enums are also used to specify the encoding of definition and repetition levels. - * See the accompanying doc for the details of the more complicated encodings. - */ -enum Encoding { - /** Default encoding. - * BOOLEAN - 1 bit per value. 0 is false; 1 is true. - * INT32 - 4 bytes per value. Stored as little-endian. - * INT64 - 8 bytes per value. Stored as little-endian. - * FLOAT - 4 bytes per value. IEEE. Stored as little-endian. - * DOUBLE - 8 bytes per value. IEEE. Stored as little-endian. - * BYTE_ARRAY - 4 byte length stored as little endian, followed by bytes. - * FIXED_LEN_BYTE_ARRAY - Just the bytes. - */ - PLAIN = 0; - - /** Group VarInt encoding for INT32/INT64. - * This encoding is deprecated. It was never used - */ - // GROUP_VAR_INT = 1; - - /** - * Deprecated: Dictionary encoding. The values in the dictionary are encoded in the - * plain type. - * in a data page use RLE_DICTIONARY instead. - * in a Dictionary page use PLAIN instead - */ - PLAIN_DICTIONARY = 2; - - /** Group packed run length encoding. Usable for definition/reptition levels - * encoding and Booleans (on one bit: 0 is false; 1 is true.) - */ - RLE = 3; - - /** Bit packed encoding. This can only be used if the data has a known max - * width. Usable for definition/repetition levels encoding. - */ - BIT_PACKED = 4; - - /** Delta encoding for integers. This can be used for int columns and works best - * on sorted data - */ - DELTA_BINARY_PACKED = 5; - - /** Encoding for byte arrays to separate the length values and the data. The lengths - * are encoded using DELTA_BINARY_PACKED - */ - DELTA_LENGTH_BYTE_ARRAY = 6; - - /** Incremental-encoded byte array. Prefix lengths are encoded using DELTA_BINARY_PACKED. - * Suffixes are stored as delta length byte arrays. - */ - DELTA_BYTE_ARRAY = 7; - - /** Dictionary encoding: the ids are encoded using the RLE encoding - */ - RLE_DICTIONARY = 8; -} - -/** - * Supported compression algorithms. - */ -enum CompressionCodec { - UNCOMPRESSED = 0; - SNAPPY = 1; - GZIP = 2; - LZO = 3; -} - -enum PageType { - DATA_PAGE = 0; - INDEX_PAGE = 1; - DICTIONARY_PAGE = 2; - DATA_PAGE_V2 = 3; -} - -/** Data page header */ -struct DataPageHeader { - /** Number of values, including NULLs, in this data page. **/ - 1: required i32 num_values - - /** Encoding used for this data page **/ - 2: required Encoding encoding - - /** Encoding used for definition levels **/ - 3: required Encoding definition_level_encoding; - - /** Encoding used for repetition levels **/ - 4: required Encoding repetition_level_encoding; - - /** Optional statistics for the data in this page**/ - 5: optional Statistics statistics; -} - -struct IndexPageHeader { - /** TODO: **/ -} - -struct DictionaryPageHeader { - /** Number of values in the dictionary **/ - 1: required i32 num_values; - - /** Encoding using this dictionary page **/ - 2: required Encoding encoding - - /** If true, the entries in the dictionary are sorted in ascending order **/ - 3: optional bool is_sorted; -} - -/** - * New page format alowing reading levels without decompressing the data - * Repetition and definition levels are uncompressed - * The remaining section containing the data is compressed if is_compressed is true - **/ -struct DataPageHeaderV2 { - /** Number of values, including NULLs, in this data page. **/ - 1: required i32 num_values - /** Number of NULL values, in this data page. - Number of non-null = num_values - num_nulls which is also the number of values in the data section **/ - 2: required i32 num_nulls - /** Number of rows in this data page. which means pages change on record boundaries (r = 0) **/ - 3: required i32 num_rows - /** Encoding used for data in this page **/ - 4: required Encoding encoding - - // repetition levels and definition levels are always using RLE (without size in it) - - /** length of the repetition levels */ - 5: required i32 definition_levels_byte_length; - /** length of the definition levels */ - 6: required i32 repetition_levels_byte_length; - - /** whether the values are compressed. - Which means the section of the page between - definition_levels_byte_length + repetition_levels_byte_length + 1 and compressed_page_size (included) - is compressed with the compression_codec. - If missing it is considered compressed */ - 7: optional bool is_compressed = 1; - - /** optional statistics for this column chunk */ - 8: optional Statistics statistics; -} - -struct PageHeader { - /** the type of the page: indicates which of the *_header fields is set **/ - 1: required PageType type - - /** Uncompressed page size in bytes (not including this header) **/ - 2: required i32 uncompressed_page_size - - /** Compressed page size in bytes (not including this header) **/ - 3: required i32 compressed_page_size - - /** 32bit crc for the data below. This allows for disabling checksumming in HDFS - * if only a few pages needs to be read - **/ - 4: optional i32 crc - - // Headers for page specific data. One only will be set. - 5: optional DataPageHeader data_page_header; - 6: optional IndexPageHeader index_page_header; - 7: optional DictionaryPageHeader dictionary_page_header; - 8: optional DataPageHeaderV2 data_page_header_v2; -} - -/** - * Wrapper struct to store key values - */ - struct KeyValue { - 1: required string key - 2: optional string value -} - -/** - * Wrapper struct to specify sort order - */ -struct SortingColumn { - /** The column index (in this row group) **/ - 1: required i32 column_idx - - /** If true, indicates this column is sorted in descending order. **/ - 2: required bool descending - - /** If true, nulls will come before non-null values, otherwise, - * nulls go at the end. */ - 3: required bool nulls_first -} - -/** - * statistics of a given page type and encoding - */ -struct PageEncodingStats { - - /** the page type (data/dic/...) **/ - 1: required PageType page_type; - - /** encoding of the page **/ - 2: required Encoding encoding; - - /** number of pages of this type with this encoding **/ - 3: required i32 count; - -} - -/** - * Description for column metadata - */ -struct ColumnMetaData { - /** Type of this column **/ - 1: required Type type - - /** Set of all encodings used for this column. The purpose is to validate - * whether we can decode those pages. **/ - 2: required list encodings - - /** Path in schema **/ - 3: required list path_in_schema - - /** Compression codec **/ - 4: required CompressionCodec codec - - /** Number of values in this column **/ - 5: required i64 num_values - - /** total byte size of all uncompressed pages in this column chunk (including the headers) **/ - 6: required i64 total_uncompressed_size - - /** total byte size of all compressed pages in this column chunk (including the headers) **/ - 7: required i64 total_compressed_size - - /** Optional key/value metadata **/ - 8: optional list key_value_metadata - - /** Byte offset from beginning of file to first data page **/ - 9: required i64 data_page_offset - - /** Byte offset from beginning of file to root index page **/ - 10: optional i64 index_page_offset - - /** Byte offset from the beginning of file to first (only) dictionary page **/ - 11: optional i64 dictionary_page_offset - - /** optional statistics for this column chunk */ - 12: optional Statistics statistics; - - /** Set of all encodings used for pages in this column chunk. - * This information can be used to determine if all data pages are - * dictionary encoded for example **/ - 13: optional list encoding_stats; -} - -struct ColumnChunk { - /** File where column data is stored. If not set, assumed to be same file as - * metadata. This path is relative to the current file. - **/ - 1: optional string file_path - - /** Byte offset in file_path to the ColumnMetaData **/ - 2: required i64 file_offset - - /** Column metadata for this chunk. This is the same content as what is at - * file_path/file_offset. Having it here has it replicated in the file - * metadata. - **/ - 3: optional ColumnMetaData meta_data -} - -struct RowGroup { - /** Metadata for each column chunk in this row group. - * This list must have the same order as the SchemaElement list in FileMetaData. - **/ - 1: required list columns - - /** Total byte size of all the uncompressed column data in this row group **/ - 2: required i64 total_byte_size - - /** Number of rows in this row group **/ - 3: required i64 num_rows - - /** If set, specifies a sort ordering of the rows in this RowGroup. - * The sorting columns can be a subset of all the columns. - */ - 4: optional list sorting_columns -} - -/** - * Description for file metadata - */ -struct FileMetaData { - /** Version of this file **/ - 1: required i32 version - - /** Parquet schema for this file. This schema contains metadata for all the columns. - * The schema is represented as a tree with a single root. The nodes of the tree - * are flattened to a list by doing a depth-first traversal. - * The column metadata contains the path in the schema for that column which can be - * used to map columns to nodes in the schema. - * The first element is the root **/ - 2: required list schema; - - /** Number of rows in this file **/ - 3: required i64 num_rows - - /** Row groups in this file **/ - 4: required list row_groups - - /** Optional key/value metadata **/ - 5: optional list key_value_metadata - - /** String for application that wrote this file. This should be in the format - * version (build ). - * e.g. impala version 1.0 (build 6cf94d29b2b7115df4de2c06e2ab4326d721eb55) - **/ - 6: optional string created_by -} -