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87 lines
3.4 KiB
C++
87 lines
3.4 KiB
C++
#include <Storages/MergeTree/MergeTreeSelectProcessor.h>
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#include <Storages/MergeTree/MergeTreeBaseSelectProcessor.h>
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#include <Storages/MergeTree/IMergeTreeReader.h>
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#include <Interpreters/Context.h>
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namespace DB
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{
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MergeTreeSelectProcessor::MergeTreeSelectProcessor(
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const MergeTreeData & storage_,
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const StorageMetadataPtr & metadata_snapshot_,
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const MergeTreeData::DataPartPtr & owned_data_part_,
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UInt64 max_block_size_rows_,
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size_t preferred_block_size_bytes_,
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size_t preferred_max_column_in_block_size_bytes_,
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Names required_columns_,
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MarkRanges mark_ranges_,
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bool use_uncompressed_cache_,
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const PrewhereInfoPtr & prewhere_info_,
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ExpressionActionsSettings actions_settings,
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const MergeTreeReaderSettings & reader_settings_,
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const Names & virt_column_names_,
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size_t part_index_in_query_,
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bool has_limit_below_one_block_,
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std::optional<ParallelReadingExtension> extension_)
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: MergeTreeBaseSelectProcessor{
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metadata_snapshot_->getSampleBlockForColumns(required_columns_, storage_.getVirtuals(), storage_.getStorageID()),
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storage_, metadata_snapshot_, prewhere_info_, std::move(actions_settings), max_block_size_rows_,
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preferred_block_size_bytes_, preferred_max_column_in_block_size_bytes_,
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reader_settings_, use_uncompressed_cache_, virt_column_names_, extension_},
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required_columns{std::move(required_columns_)},
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data_part{owned_data_part_},
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sample_block(metadata_snapshot_->getSampleBlock()),
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all_mark_ranges(std::move(mark_ranges_)),
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part_index_in_query(part_index_in_query_),
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has_limit_below_one_block(has_limit_below_one_block_),
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total_rows(data_part->index_granularity.getRowsCountInRanges(all_mark_ranges))
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{
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/// Actually it means that parallel reading from replicas enabled
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/// and we have to collaborate with initiator.
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/// In this case we won't set approximate rows, because it will be accounted multiple times
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if (!extension_.has_value())
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addTotalRowsApprox(total_rows);
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ordered_names = header_without_virtual_columns.getNames();
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}
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void MergeTreeSelectProcessor::initializeReaders()
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{
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task_columns = getReadTaskColumns(
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storage, metadata_snapshot, data_part,
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required_columns, prewhere_info);
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/// Will be used to distinguish between PREWHERE and WHERE columns when applying filter
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const auto & column_names = task_columns.columns.getNames();
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column_name_set = NameSet{column_names.begin(), column_names.end()};
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if (use_uncompressed_cache)
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owned_uncompressed_cache = storage.getContext()->getUncompressedCache();
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owned_mark_cache = storage.getContext()->getMarkCache();
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reader = data_part->getReader(task_columns.columns, metadata_snapshot, all_mark_ranges,
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owned_uncompressed_cache.get(), owned_mark_cache.get(), reader_settings);
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if (prewhere_info)
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pre_reader = data_part->getReader(task_columns.pre_columns, metadata_snapshot, all_mark_ranges,
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owned_uncompressed_cache.get(), owned_mark_cache.get(), reader_settings);
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}
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void MergeTreeSelectProcessor::finish()
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{
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/** Close the files (before destroying the object).
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* When many sources are created, but simultaneously reading only a few of them,
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* buffers don't waste memory.
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*/
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reader.reset();
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pre_reader.reset();
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data_part.reset();
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}
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MergeTreeSelectProcessor::~MergeTreeSelectProcessor() = default;
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}
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