DROP TABLE IF EXISTS MYCAT_SEQUENCE;  
CREATE TABLE MYCAT_SEQUENCE (  name VARCHAR(50) NOT NULL,  current_value INT NOT NULL,  increment INT NOT NULL DEFAULT 100, PRIMARY KEY (name) ) ENGINE=InnoDB;

-- ----------------------------
-- Function structure for `mycat_seq_currval`
-- ----------------------------
DROP FUNCTION IF EXISTS `mycat_seq_currval`;
DELIMITER ;;
CREATE DEFINER=`root`@`%` FUNCTION `mycat_seq_currval`(seq_name VARCHAR(50)) RETURNS varchar(64) CHARSET latin1
    DETERMINISTIC
BEGIN
    DECLARE retval VARCHAR(64);
    SET retval="-1,0";
    SELECT concat(CAST(current_value AS CHAR),",",CAST(increment AS CHAR) ) INTO retval FROM MYCAT_SEQUENCE  WHERE name = seq_name;
    RETURN retval ;
END
;;
DELIMITER ;

-- ----------------------------
-- Function structure for `mycat_seq_nextval`
-- ----------------------------
DROP FUNCTION IF EXISTS `mycat_seq_nextval`;
DELIMITER ;;
CREATE DEFINER=`root`@`%` FUNCTION `mycat_seq_nextval`(seq_name VARCHAR(50)) RETURNS varchar(64) CHARSET latin1
    DETERMINISTIC
BEGIN
    DECLARE retval VARCHAR(64);
    DECLARE val BIGINT;
    DECLARE inc INT;
    DECLARE seq_lock INT;
    set val = -1;
    set inc = 0;
    SET seq_lock = -1;
    SELECT GET_LOCK(seq_name, 15) into seq_lock;
    if seq_lock = 1 then
      SELECT current_value + increment, increment INTO val, inc FROM MYCAT_SEQUENCE WHERE name = seq_name for update;
      if val != -1 then
          UPDATE MYCAT_SEQUENCE SET current_value = val WHERE name = seq_name;
      end if;
      SELECT RELEASE_LOCK(seq_name) into seq_lock;
    end if;
    SELECT concat(CAST((val - inc + 1) as CHAR),",",CAST(inc as CHAR)) INTO retval;
    RETURN retval;
END
;;
DELIMITER ;

-- ----------------------------
-- Function structure for `mycat_seq_setval`
-- ----------------------------
DROP FUNCTION IF EXISTS `mycat_seq_setval`;
DELIMITER ;;
CREATE DEFINER=`root`@`%` FUNCTION `mycat_seq_setval`(seq_name VARCHAR(50), value INTEGER) RETURNS varchar(64) CHARSET latin1
    DETERMINISTIC
BEGIN
    DECLARE retval VARCHAR(64);
    DECLARE inc INT;
    SET inc = 0;
    SELECT increment INTO inc FROM MYCAT_SEQUENCE WHERE name = seq_name;
    UPDATE MYCAT_SEQUENCE SET current_value = value WHERE name = seq_name;
    SELECT concat(CAST(value as CHAR),",",CAST(inc as CHAR)) INTO retval;
    RETURN retval;
END
;;
DELIMITER ;

INSERT INTO MYCAT_SEQUENCE VALUES ('GLOBAL', 0, 100);
SELECT MYCAT_SEQ_SETVAL('GLOBAL', 1);
SELECT MYCAT_SEQ_CURRVAL('GLOBAL');
SELECT MYCAT_SEQ_NEXTVAL('GLOBAL');