單表過千萬,以按用戶分表1024個,count(*)統計還是會慢
所謂的慢,是指高併發了,MySQL就痿了。SAS硬盤,隨機IO速率到達10~15M,IO就基本是100%了。
這時就呵呵了。CPU有巨大的剩餘也沒用,內存也幫不上忙,只能SSD才能解決。
所謂通過程序--異步事件之類的,去加1,減1地統計結果--好像是一種方案.
最終上線後,數據量一大,併發量一大,數據最後出來負數---尼瑪,這就是所謂的`數據一致性的bug`
最終嘗試使用MySQL的觸發器解決,SQL代碼如下:
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;