instance method exec_cache

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 801
        def exec_cache(sql, binds)
          stmt_key = prepare_statement sql

          # Clear the queue
          @connection.get_last_result
          @connection.send_query_prepared(stmt_key, binds.map { |col, val|
            type_cast(val, col)
          })
          @connection.block
          @connection.get_last_result
        rescue PGError => e
          # Get the PG code for the failure.  Annoyingly, the code for
          # prepared statements whose return value may have changed is
          # FEATURE_NOT_SUPPORTED.  Check here for more details:
          # http://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/backend/utils/cache/plancache.c#l573
          begin
            code = e.result.result_error_field(PGresult::PG_DIAG_SQLSTATE)
          rescue
            raise e
          end
          if FEATURE_NOT_SUPPORTED == code
            @statements.delete sql_key(sql)
            retry
          else
            raise e
          end
        end