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#pragma once
#include <Parsers/IAST_fwd.h>
#include <Core/Block.h>
#include <Core/NamesAndTypes.h>
#include <Interpreters/Aliases.h>
#include <Interpreters/SelectQueryOptions.h>
#include <Interpreters/DatabaseAndTableWithAlias.h>
#include <Storages/IStorage_fwd.h>
namespace DB
{
struct StorageInMemoryMetadata;
using StorageMetadataPtr = std::shared_ptr<const StorageInMemoryMetadata>;
/// Optimizer that tries to replace columns to equal columns (according to constraints)
/// with lower size (accorsing to compressed and uncomressed size).
class SubstituteColumnOptimizer
{
public:
SubstituteColumnOptimizer(
ASTSelectQuery * select_query,
const StorageMetadataPtr & metadata_snapshot,
const ConstStoragePtr & storage);
void perform();
private:
ASTSelectQuery * select_query;
const StorageMetadataPtr & metadata_snapshot;
ConstStoragePtr storage;
};
}
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