我在服务器上使用非常简单的INSERT/UPDATES时遇到问题。有时需要花费几秒钟以上的时间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;
看来问题并不取决于特定的表。我在那些桌子上没有触发器。
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个)，但是没什么大的。所有数据库的转储约为300MB。
Mysqltunner输出:
>> MySQLTuner 1.0.1 - Major Hayden <[email protected]>
>> 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，这种情况仅发生在大约1％的查询中(99％可以正常工作)，然后HDD确实很忙(在8核服务器上浪费13％-20％)
我应该继续增加table_cache吗？还有其他想法吗？我该如何改善？
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，因此我将其降级了。
最佳答案
当然，这种情况仅发生在大约1％的查询中(99％正常工作)，然后HDD确实很忙(13％-20％在8核服务器上)