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71 lines
2.0 KiB
C++
71 lines
2.0 KiB
C++
#pragma once
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#include <ext/shared_ptr_helper.h>
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#include <Storages/StorageSet.h>
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#include <Parsers/ASTTablesInSelectQuery.h>
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namespace DB
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{
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class Join;
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using JoinPtr = std::shared_ptr<Join>;
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/** Allows you save the state for later use on the right side of the JOIN.
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* When inserted into a table, the data will be inserted into the state,
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* and also written to the backup file, to restore after the restart.
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* Reading from the table is not possible directly - only specifying on the right side of JOIN is possible.
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*
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* When using, JOIN must be of the appropriate type (ANY|ALL LEFT|INNER ...).
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*/
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class StorageJoin : public ext::shared_ptr_helper<StorageJoin>, public StorageSetOrJoinBase
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{
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public:
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String getName() const override { return "Join"; }
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void truncate(const ASTPtr &, const Context &) override;
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/// Access the innards.
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JoinPtr & getJoin() { return join; }
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/// Verify that the data structure is suitable for implementing this type of JOIN.
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void assertCompatible(ASTTableJoin::Kind kind_, ASTTableJoin::Strictness strictness_) const;
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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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QueryProcessingStage::Enum processed_stage,
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size_t max_block_size,
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unsigned num_streams) override;
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private:
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Block sample_block;
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const Names key_names;
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bool use_nulls;
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SizeLimits limits;
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ASTTableJoin::Kind kind; /// LEFT | INNER ...
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ASTTableJoin::Strictness strictness; /// ANY | ALL
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JoinPtr join;
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void insertBlock(const Block & block) override;
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size_t getSize() const override;
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protected:
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StorageJoin(
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const String & path_,
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const String & database_name_,
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const String & table_name_,
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const Names & key_names_,
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bool use_nulls_,
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SizeLimits limits_,
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ASTTableJoin::Kind kind_, ASTTableJoin::Strictness strictness_,
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const ColumnsDescription & columns_,
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bool overwrite);
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};
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}
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