2019-01-17 14:23:12 +00:00
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#include <Storages/MarkCache.h>
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#include <Storages/MergeTree/MarkRange.h>
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#include <Storages/MergeTree/MergeTreeData.h>
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#include <Storages/MergeTree/MergeTreeRangeReader.h>
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#include <Compression/CachedCompressedReadBuffer.h>
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#include <Compression/CompressedReadBufferFromFile.h>
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namespace DB
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{
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2019-02-06 08:24:16 +00:00
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/// Class for reading a single column (or index).
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2019-01-17 14:23:12 +00:00
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class MergeTreeReaderStream
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{
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public:
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MergeTreeReaderStream(
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2019-02-06 08:17:57 +00:00
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const String & path_prefix_, const String & extension_, size_t marks_count_,
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const MarkRanges & all_mark_ranges,
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MarkCache * mark_cache, bool save_marks_in_cache,
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UncompressedCache * uncompressed_cache,
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2019-02-27 20:02:48 +00:00
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size_t file_size, size_t aio_threshold, size_t max_read_buffer_size,
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2019-02-06 08:17:57 +00:00
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const ReadBufferFromFileBase::ProfileCallback & profile_callback, clockid_t clock_type);
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2019-01-17 14:23:12 +00:00
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void seekToMark(size_t index);
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void seekToStart();
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2019-02-06 08:17:57 +00:00
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ReadBuffer * data_buffer;
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2019-01-17 14:23:12 +00:00
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private:
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/// NOTE: lazily loads marks from the marks cache.
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2019-02-06 08:17:57 +00:00
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const MarkInCompressedFile & getMark(size_t index);
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2019-01-17 14:23:12 +00:00
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void loadMarks();
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std::string path_prefix;
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std::string extension;
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size_t marks_count;
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2019-02-06 08:17:57 +00:00
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MarkCache * mark_cache;
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2019-01-17 14:23:12 +00:00
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bool save_marks_in_cache;
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MarkCache::MappedPtr marks;
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std::unique_ptr<CachedCompressedReadBuffer> cached_buffer;
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std::unique_ptr<CompressedReadBufferFromFile> non_cached_buffer;
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};
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2019-01-29 20:00:12 +00:00
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}
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