text: #pragma once
  
  #if !defined(ARCADIA_BUILD)
  #include "config_core.h"
  #endif
  #include "DictionaryStructure.h"
  #include "IDictionarySource.h"
  
  #if USE_LIBPQXX
  #include "ExternalQueryBuilder.h"
  #include <Core/Block.h>
  #include <common/LocalDateTime.h>
  #include <common/logger_useful.h>
  #include <Storages/StoragePostgreSQL.h>
  #include <pqxx/pqxx>
  
  
  namespace DB
  {
  
  /// Allows loading dictionaries from a PostgreSQL database
  class PostgreSQLDictionarySource final : public IDictionarySource
  {
  public:
      PostgreSQLDictionarySource(
          const DictionaryStructure & dict_struct_,
          const Poco::Util::AbstractConfiguration & config_,
          const std::string & config_prefix,
          PostgreSQLConnectionPtr connection_,
          const Block & sample_block_);
  
      /// copy-constructor is provided in order to support cloneability
      PostgreSQLDictionarySource(const PostgreSQLDictionarySource & other);
      PostgreSQLDictionarySource & operator=(const PostgreSQLDictionarySource &) = delete;
  
      BlockInputStreamPtr loadAll() override;
      BlockInputStreamPtr loadUpdatedAll() override;
      BlockInputStreamPtr loadIds(const std::vector<UInt64> & ids) override;
      BlockInputStreamPtr loadKeys(const Columns & key_columns, const std::vector<size_t> & requested_rows) override;
  
      bool isModified() const override;
      bool supportsSelectiveLoad() const override;
      bool hasUpdateField() const override;
  
      DictionarySourcePtr clone() const override;
      std::string toString() const override;
  
  private:
      std::string getUpdateFieldAndDate();
      std::string doInvalidateQuery(const std::string & request) const;
  
      const DictionaryStructure dict_struct;
      Block sample_block;
      PostgreSQLConnectionPtr connection;
      Poco::Logger * log;
  
      const std::string db;
      const std::string table;
      const std::string where;
      ExternalQueryBuilder query_builder;
      const std::string load_all_query;
      std::string invalidate_query;
      std::chrono::time_point<std::chrono::system_clock> update_time;
      const std::string update_field;
      mutable std::string invalidate_query_response;
  
  };
  
  }
  #endif
  