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24 lines
637 B
C++
24 lines
637 B
C++
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#pragma once
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#include <Parsers/ASTFunction.h>
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#include <Interpreters/InDepthNodeVisitor.h>
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namespace DB
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{
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/// Rewrites functions to subcolumns, if possible, to reduce amount of read data.
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/// E.g. 'length(arr)' -> 'arr.size0', 'col IS NULL' -> 'col.null'
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class RewriteFunctionToSubcolumnData
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{
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public:
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using TypeToVisit = ASTFunction;
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void visit(ASTFunction & function, ASTPtr & ast);
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const NameSet & columns_to_rewrite;
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};
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using RewriteFunctionToSubcolumnMatcher = OneTypeMatcher<RewriteFunctionToSubcolumnData>;
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using RewriteFunctionToSubcolumnVisitor = InDepthNodeVisitor<RewriteFunctionToSubcolumnMatcher, true>;
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}
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