kangpinghuang commented on a change in pull request #2050: segment_v2: Support bitmap index build URL: https://github.com/apache/incubator-doris/pull/2050#discussion_r348018276
########## File path: be/src/olap/rowset/segment_v2/index_page.h ########## @@ -0,0 +1,142 @@ +// 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. + +#pragma once + +#include <cstddef> +#include <memory> +#include <vector> + +#include "common/status.h" +#include "gen_cpp/segment_v2.pb.h" +#include "gutil/macros.h" +#include "olap/rowset/segment_v2/page_pointer.h" +#include "util/faststring.h" +#include "util/slice.h" + +namespace doris { +namespace segment_v2 { + +class IndexPageIterator; // forward decl. + +// IndexPage is the building block for IndexedColumn's ordinal index and value index. +// It is used to guide searching for a particular key to the data page containing it. +// We use the same general format for all index pages, regardless of the data type and node type (leaf or internal) +// IndexPage := IndexEntry^NumEntry, StartOffset(4)^NumEntry, IndexPageFooterPB, IndexPageFooterPBSize(4) +// IndexEntry := IndexKey, PagePointer +// IndexKey := KeyLength(vint32), KeyData(KeyLength bytes) +// PagePointer := PageOffset(vint64), PageSize(vint32) +// +// IndexPageFooterPB records NumEntry and type (leaf/internal) of the index page. +// For leaf, IndexKey records the first/smallest key of the data page PagePointer points to. +// For internal, IndexKey records the first/smallest key of the next-level index page PagePointer points to. +// +// All keys are treated as binary string and compared with memcpy. Keys of other data type are encoded first by +// KeyCoder, e.g., ordinal index's original key type is uint32_t but is encoded to binary string. +class IndexPageBuilder { +public: + explicit IndexPageBuilder(size_t index_page_size, bool is_leaf) + : _index_page_size(index_page_size), _is_leaf(is_leaf) { + } + + void add(const Slice& key, const PagePointer& ptr); + + bool is_full() const; + + size_t count() const { return _entry_offsets.size(); } + + Slice finish(); + + // Return the key of the first entry in this index block. + // The pointed-to data is only valid until the next call to this builder. + Status get_first_key(Slice* key) const; + + void reset() { + _finished = false; + _buffer.clear(); + _entry_offsets.clear(); + } + +private: + DISALLOW_COPY_AND_ASSIGN(IndexPageBuilder); + const size_t _index_page_size; + const bool _is_leaf; + // is the builder currently between finish() and reset()? + bool _finished = false; + faststring _buffer; + std::vector<uint32_t> _entry_offsets; +}; + +class IndexPageReader { Review comment: Maybe IndexPage is a better name. ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@doris.apache.org For additional commands, e-mail: commits-h...@doris.apache.org
