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94 lines
2.9 KiB
C++
94 lines
2.9 KiB
C++
#pragma once
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#include <Core/QueryProcessingStage.h>
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#include <Storages/SelectQueryInfo.h>
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#include <Storages/MergeTree/MergeTreeData.h>
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#include <Storages/MergeTree/RangesInDataPart.h>
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namespace DB
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{
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class KeyCondition;
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/** Executes SELECT queries on data from the merge tree.
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*/
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class MergeTreeDataSelectExecutor
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{
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public:
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MergeTreeDataSelectExecutor(const MergeTreeData & data_);
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/** When reading, selects a set of parts that covers the desired range of the index.
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* max_blocks_number_to_read - if not nullptr, do not read all the parts whose right border is greater than max_block in partition.
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*/
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using PartitionIdToMaxBlock = std::unordered_map<String, Int64>;
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BlockInputStreams read(
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const Names & column_names,
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const SelectQueryInfo & query_info,
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const Context & context,
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size_t max_block_size,
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unsigned num_streams,
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const PartitionIdToMaxBlock * max_block_numbers_to_read = nullptr) const;
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BlockInputStreams readFromParts(
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MergeTreeData::DataPartsVector parts,
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const Names & column_names,
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const SelectQueryInfo & query_info,
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const Context & context,
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size_t max_block_size,
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unsigned num_streams,
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const PartitionIdToMaxBlock * max_block_numbers_to_read = nullptr) const;
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private:
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const MergeTreeData & data;
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Logger * log;
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BlockInputStreams spreadMarkRangesAmongStreams(
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RangesInDataParts && parts,
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size_t num_streams,
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const Names & column_names,
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size_t max_block_size,
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bool use_uncompressed_cache,
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const PrewhereInfoPtr & prewhere_info,
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const Names & virt_columns,
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const Settings & settings) const;
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BlockInputStreams spreadMarkRangesAmongStreamsFinal(
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RangesInDataParts && parts,
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const Names & column_names,
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size_t max_block_size,
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bool use_uncompressed_cache,
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const PrewhereInfoPtr & prewhere_info,
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const Names & virt_columns,
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const Settings & settings) const;
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/// Get the approximate value (bottom estimate - only by full marks) of the number of rows falling under the index.
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size_t getApproximateTotalRowsToRead(
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const MergeTreeData::DataPartsVector & parts,
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const KeyCondition & key_condition,
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const Settings & settings) const;
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/// Create the expression "Sign == 1".
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void createPositiveSignCondition(
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ExpressionActionsPtr & out_expression,
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String & out_column,
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const Context & context) const;
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MarkRanges markRangesFromPKRange(
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const MergeTreeData::DataPart::Index & index,
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const KeyCondition & key_condition,
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const Settings & settings) const;
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MarkRanges filterMarksUsingIndex(
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MergeTreeIndexPtr index,
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IndexConditionPtr condition,
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MergeTreeData::DataPartPtr part,
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const MarkRanges & ranges,
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const Settings & settings) const;
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};
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}
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