MySQL按月自动设置表分区的实现

CREATE TABLE test_log (
  id INT AUTO_INCREMENT,
  log_date DATE,
  log_text VARCHAR(255)
) PARTITION BY RANGE ( MONTH(log_date) ) (
  PARTITION p202101 VALUES LESS THAN (2),
  PARTITION p202102 VALUES LESS THAN (3),
  PARTITION p202103 VALUES LESS THAN (4),
  ...
);

DELIMITER $$

DROP PROCEDURE IF EXISTS AddMonthlyPartition;
CREATE PROCEDURE AddMonthlyPartition()
BEGIN
  DECLARE done INT DEFAULT FALSE;
  DECLARE max_part INT;
  DECLARE new_part INT;
  DECLARE cur_date DATE;
  DECLARE cur_part_name VARCHAR(10);

  -- 获取当前日期和最大的分区
  SET cur_date = CURDATE();
  SET max_part = 12 * (YEAR(cur_date) - 2000) + MONTH(cur_date);

  -- 循环直到找到不存在的分区
  WHILE done = FALSE DO
    SET new_part = max_part + 1;
    SET cur_part_name = CONCAT('p', LPAD(YEAR(cur_date), 2, '0'), LPAD(new_part, 2, '0'));
    SELECT COUNT(*) INTO done FROM information_schema.partitions
      WHERE table_name = 'test_log' AND partition_name = cur_part_name LIMIT 1;
    IF done = 0 THEN
      SET @sql = CONCAT('ALTER TABLE test_log ADD PARTITION (PARTITION ', cur_part_name, ' VALUES LESS THAN (', new_part, '))');
      PREPARE stmt FROM @sql;
      EXECUTE stmt;
      DEALLOCATE PREPARE stmt;
      SET max_part = new_part;
    END IF;
    SET cur_date = DATE_ADD(cur_date, INTERVAL 1 MONTH);
  END WHILE;
END$$

DELIMITER ;

DELIMITER $$

DROP EVENT IF EXISTS CheckAndAddPartition;
CREATE EVENT CheckAndAddPartition
  ON SCHEDULE EVERY 1 DAY
  STARTS (TIMESTAMP(CURRENT_DATE) + INTERVAL 1 DAY)
  DO
  BEGIN
    CALL AddMonthlyPartition();
  END$$

DELIMITER ;

SET GLOBAL event_scheduler = ON;

SELECT partition_name, partition_description
FROM information_schema.partitions
WHERE table_name = 'test_log';