#pragma once #include #include #include namespace DB { /** Helper class, that can analyze MergeTree order key * and required sort description to get their * common prefix, which is needed for * performing reading in order of PK. */ class Context; class ReadInOrderOptimizer { public: ReadInOrderOptimizer( const ManyExpressionActions & elements_actions, const SortDescription & required_sort_description, const TreeRewriterResultPtr & syntax_result); InputOrderInfoPtr getInputOrder(const StorageMetadataPtr & metadata_snapshot, ContextPtr context) const; private: /// Actions for every element of order expression to analyze functions for monotonicity ManyExpressionActions elements_actions; NameSet forbidden_columns; SortDescription required_sort_description; }; }