mysql - 更新/插入不时需要几秒钟

Question

我在服务器上使用非常简单的 INSERT/UPDATES 时遇到问题。有时需要几秒钟才能完成这样的查询:

2.1062s - INSERT INTO `transaction` SET `idUser` = 72, `currency` = 50, `amount` = '10', `action` = 'buyCoins';
11.785s - UPDATE `user` SET `cash` = 10, `crystal` = 10, `expPoints` = 10, `energy` = 10 WHERE idUser = 72;
0.6296s - UPDATE `user` SET `lastEnergyUpdate` = CURRENT_TIMESTAMP WHERE idUser = 72;

看起来问题不取决于特定的表。我在那些 table 上没有触发器。

表定义:

CREATE TABLE `user` (
 `idUser` int(10) unsigned NOT NULL AUTO_INCREMENT,
 `expPoints` int(10) NOT NULL DEFAULT '0',
 `cash` int(10) NOT NULL DEFAULT '1000',
 `crystal` int(10) NOT NULL DEFAULT '10',
 `energy` int(4) NOT NULL DEFAULT '0',
 `name` varchar(50) DEFAULT NULL,
 `surname` varchar(50) DEFAULT NULL,
 `age` int(4) unsigned DEFAULT NULL,
 `sex` enum('men','women','unknown') DEFAULT NULL,
 `lastEnergyUpdate` timestamp NULL DEFAULT NULL,
 `lastLogin` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
 `insertDate` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
 PRIMARY KEY (`idUser`),
 UNIQUE KEY `serviceUnique` (`serviceName`,`serviceId`)
) ENGINE=InnoDB AUTO_INCREMENT=5333 DEFAULT CHARSET=utf8

CREATE TABLE `transaction` (
  `idTransaction` int(10) NOT NULL AUTO_INCREMENT,
  `idUser` int(10) unsigned NOT NULL,
  `currency` enum('crystal','partnerCurrency','cash') DEFAULT NULL,
  `amount` int(5) NOT NULL,
  `action` enum('unlockPlace','buyExtra','collectReleased') NOT NULL,
  `insertDate` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (`idTransaction`),
  KEY `fk_transaction_user1` (`idUser`),
  CONSTRAINT `fk_transaction_user1` FOREIGN KEY (`idUser`) REFERENCES `user` (`idUser`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=156329 DEFAULT CHARSET=utf8

在同一台服务器上，我有更多的数据库(~100)，但没什么大的。所有数据库的转储大约为 300MB。

Mysqltunner 输出:

 >>  MySQLTuner 1.0.1 - Major Hayden <major@mhtx.net>
 >>  Bug reports, feature requests, and downloads at http://mysqltuner.com/
 >>  Run with '--help' for additional options and output filtering

-------- General Statistics --------------------------------------------------
[--] Skipped version check for MySQLTuner script
[OK] Currently running supported MySQL version 5.1.66-0ubuntu0.11.10.2-log
[OK] Operating on 64-bit architecture

-------- Storage Engine Statistics -------------------------------------------
[--] Status: -Archive -BDB -Federated +InnoDB -ISAM -NDBCluster
[--] Data in MyISAM tables: 138M (Tables: 267)
[--] Data in InnoDB tables: 170M (Tables: 327)
[--] Data in MEMORY tables: 0B (Tables: 1)
[!!] Total fragmented tables: 329

-------- Performance Metrics -------------------------------------------------
[--] Up for: 20h 45m 57s (558K q [7.468 qps], 58K conn, TX: 685M, RX: 98M)
[--] Reads / Writes: 66% / 34%
[--] Total buffers: 1.1G global + 6.0M per thread (150 max threads)
[OK] Maximum possible memory usage: 2.0G (12% of installed RAM)
[OK] Slow queries: 0% (54/558K)
[OK] Highest usage of available connections: 6% (10/150)
[OK] Key buffer size / total MyISAM indexes: 16.0M/8.8M
[OK] Key buffer hit rate: 99.9% (245K cached / 258 reads)
[OK] Query cache efficiency: 51.5% (176K cached / 342K selects)
[OK] Query cache prunes per day: 0
[OK] Sorts requiring temporary tables: 6% (1K temp sorts / 19K sorts)
[!!] Temporary tables created on disk: 34% (2K on disk / 8K total)
[OK] Thread cache hit rate: 99% (10 created / 58K connections)
[!!] Table cache hit rate: 16% (786 open / 4K opened)
[OK] Open file limit used: 32% (714/2K)
[OK] Table locks acquired immediately: 99% (329K immediate / 329K locks)
[OK] InnoDB data size / buffer pool: 170.3M/512.0M

-------- Recommendations -----------------------------------------------------
General recommendations:
    Run OPTIMIZE TABLE to defragment tables for better performance
    MySQL started within last 24 hours - recommendations may be inaccurate
    Temporary table size is already large - reduce result set size
    Reduce your SELECT DISTINCT queries without LIMIT clauses
    Increase table_cache gradually to avoid file descriptor limits
Variables to adjust:
    table_cache (> 1024)

当然，它只发生在大约 1% 的查询中(99% 工作正常)，然后 HDD 真的很忙(13% - 20% wa 在 8 核服务器上)

我应该继续增加 table_cache 吗？还有其他想法吗？我该如何改进它？

我的 MySQL 服务器是 5.1.66。我尝试升级到 5.5.x，但这对我没有帮助，所以我将其降级。

Answer 1

当然它只发生在大约 1% 的查询中(99% 工作正常)，然后 HDD 真的很忙(13% - 20% 在 8 核服务器上)

1. 您的磁盘遇到了问题 - 我敢打赌这会在您的 innodb 日志刷新到磁盘时发生 - 我会尝试使用较小的(用于更频繁地刷新)和较大的日志大小(用于不太频繁的刷新) - 我希望您能从更频繁的冲洗中得到更多。

2. 另一件要看的事情是什么正在消耗您的 IO - 如果可以捕获罪魁祸首，请在这段时间内运行 iotop。

3. 否则，请确保您的 tmp、数据和日志分区在物理上是分开的(如果可以的话)。