通过触发器解决统计,count(*)问题

单表过千万，以按用户分表1024个，count(*)统计还是会慢

    所谓的慢，是指高并发了，MySQL就痿了。SAS硬盘，随机IO速率到达10～15M，IO就基本是100%了。
    这时就呵呵了。CPU有巨大的剩余也没用，内存也帮不上忙，只能SSD才能解决。
    所谓通过程序--异步事件之类的，去加1，减1地统计结果--好像是一种方案.
    最终上线后，数据量一大，并发量一大，数据最后出来负数---尼玛，这就是所谓的`数据一致性的bug`
    最终尝试使用MySQL的触发器解决，SQL代码如下：

CREATE TABLE if NOT EXISTS `yuec_users`(
 invite_id VARCHAR(255)
);

CREATE TABLE
IF NOT EXISTS `total_yuec_users_invite_id` (total BIGINT NOT NULL);

DROP TRIGGER IF EXISTS after_insert_yuec_users;
DROP TRIGGER IF EXISTS after_update_yuec_users;
DROP TRIGGER IF EXISTS before_delete_yuec_users;

CREATE TRIGGER after_insert_yuec_users
AFTER INSERT
ON yuec_users FOR EACH ROW
BEGIN 
IF NEW.invite_id != '1014766' AND NEW.invite_id != '' AND NEW.invite_id IS NOT NULL THEN
UPDATE `total_yuec_users_invite_id` SET total=`total`+1;
END IF;
END;


CREATE TRIGGER after_update_yuec_users
AFTER UPDATE
ON yuec_users FOR EACH ROW
BEGIN
IF NEW.invite_id != '1014766' AND NEW.invite_id != '' AND NEW.invite_id IS NOT NULL THEN
UPDATE `total_yuec_users_invite_id` SET total=`total`+1;
END IF;
        IF OLD.invite_id != '1014766' AND OLD.invite_id != '' AND OLD.invite_id IS NOT NULL THEN
UPDATE `total_yuec_users_invite_id` SET total=`total`-1;
END IF;
END;

CREATE TRIGGER before_delete_yuec_users
BEFORE DELETE
ON yuec_users FOR EACH ROW
BEGIN
IF OLD.invite_id != '1014766' AND OLD.invite_id != '' AND OLD.invite_id IS NOT NULL THEN
UPDATE `total_yuec_users_invite_id` SET total=`total`-1;
END IF;
END;