MySQL支援的兩種主要表格儲存體格式MyISAM，InnoDB，上個月做個項目時，先使用了InnoDB，結果速度特別慢，1秒鐘只能插入10幾條。後來換成MyISAM格式，一秒鐘插入上萬條。當時決定這兩個表的效能也差別太大了吧。後來自己推測，不應該差別這麼慢，估計是寫的插入語句有問題，決定做個測試：
測試環境：Redhat Linux9，4CPU，記憶體2G，MySQL版本為4.1.6-gamma-standard
測試程式：Python＋Python-MySQL模組。
測試方案：
1、MyISAM格式分別測試，事務和不用事務兩種情況：
2、InnoDB格式分別測試AutoCommit＝1（不用begin transaction和用begin transaction模式），
AutoCommit=0 （不用begin transaction和用begin transaction模式）四種情況。
測試方法為插入10000條記錄。為了測試不互相影響，單獨建立了專用的測試表，建表語句如下：
1、MyISAM不用事務表：
CREATE TABLE `MyISAM_NT` (
`TableId` int(11) NOT NULL default '0',
`TableString` varchar(21) NOT NULL default ''
) ENGINE=MyISAM;
2、MyISAM用事務表:
CREATE TABLE `MyISAM_TS` (
`TableId` int(11) NOT NULL default '0',
`TableString` varchar(21) NOT NULL default ''
) ENGINE=MyISAM;
3、InnoDB關閉AutoCommit，不用事務:
CREATE TABLE `INNODB_NA_NB` (
`TableId` int(11) NOT NULL default '0',
`TableString` varchar(21) NOT NULL default ''
) ENGINE=InnoDB;
4、InnoDB關閉AutoCommit，用事務:
CREATE TABLE `INNODB_NA_BE` (
`TableId` int(11) NOT NULL default '0',
`TableString` varchar(21) NOT NULL default ''
) ENGINE=InnoDB;
5、InnoDB開啟AutoCommit，不用事務:
CREATE TABLE `INNODB_AU_NB` (
`TableId` int(11) NOT NULL default '0',
`TableString` varchar(21) NOT NULL default ''
) ENGINE=InnoDB;
6、InnoDB開啟AutoCommit，用事務:
CREATE TABLE `INNODB_AU_BE` (
`TableId` int(11) NOT NULL default '0',
`TableString` varchar(21) NOT NULL default ''
) ENGINE=InnoDB;
測試的Python指令碼如下：
#!/usr/bin/env Python
'''
MyISAM,InnoDB效能比較
作者：空心菜（Invalid）
時間：2004-10-22
'''
import MySQLdb
import sys
import os
import string
import time
c = None
testtables = [("MyISAM_NT",None,0),
("MyISAM_TS",None,1),
("INNODB_NA_NB",0,0),
("INNODB_NA_BE",0,1),
("INNODB_AU_NB",1,0),
("INNODB_AU_BE",1,1)
]
def BeginTrans():
print "ExecSQL:BEGIN;"
c.execute("BEGIN;")
return
def Commit():
print "ExecSQL:COMMIT;"
c.execute("COMMIT;")
return
def AutoCommit(flag):
print "ExecSQL:Set AUTOCOMMIT = "+str(flag)
c.execute("Set AUTOCOMMIT = "+str(flag))
return
def getcount(table):
#print "ExecSQL:select count(*) from "+table
c.execute("select count(*) from "+table)
return c.fetchall()[0][0]
def AddTable (Table,TableId,TableString):
sql = "INSERT INTO "+Table+"(TableId, TableString) VALUES( "+ TableId+ ",'" + TableString +"')"
try:
c.execute(sql)
except MySQLdb.OperationalError,error:
print "AddTable Error:",error
return -1;
return c.rowcount
def main():
argv = sys.argv
if len(argv) < 2:
print 'Usage:',argv[0],' TableId TestCount \n'
sys.exit(1)
global c #mysql訪問cursor
db_host = "localhost"
db_name = "demo"
db_user = "root"
db_user_passwd = ""
print "Config:[%s %s/%s %s] DB\n"%(db_host,db_user,db_user_passwd,db_name)
if len(argv) > 2:
tableid = argv[1]
testcount = int(argv[2]) #
for test in testtables:
#每次操作前都重寫建立資料庫連接
try:
mdb = MySQLdb.connect(db_host, db_user, db_user_passwd, db_name)
except MySQLDb.OperationalError,error:
print "Connect Mysql[%s %s/%s %s] DB Error:"%(db_host,db_user,db_user_passwd,db_name),error,"\n"
sys.exit(1)
else:
c = mdb.cursor()
table,autocommit,trans = test
starttime = time.time()
print table," ",time.strftime("%y-%m-%d %H:%M:%S",time.localtime())
if autocommit != None:
AutoCommit(autocommit)
if trans == 1:
BeginTrans()
for i in xrange(testcount):
tablestring = "%020d"%i
if (AddTable(table,tableid,tablestring)<1):
print "AddTable Error",tablestring
if trans == 1:
Commit()
print time.strftime("%y-%m-%d %H:%M:%S",time.localtime())
endtime = time.time()
usedtime = endtime-starttime
print table,"count:",getcount(table)," used time:",usedtime
c.close()
mdb.close()
if __name__ == '__main__':
main()
測試結果如下：
Config:[localhost root/ demo] DB
MyISAM_NT 04-10-22 16:33:24
04-10-22 16:33:26
MyISAM_NT count: 10000 used time: 2.1132440567
MyISAM_TS 04-10-22 16:33:26
ExecSQL:BEGIN;
ExecSQL:COMMIT;
04-10-22 16:33:29
MyISAM_TS count: 10000 used time: 2.65475201607
INNODB_NA_NB 04-10-22 16:33:29
ExecSQL:Set AUTOCOMMIT = 0
04-10-22 16:33:31
INNODB_NA_NB count: 10000 used time: 2.51947999001
INNODB_NA_BE 04-10-22 16:33:31
ExecSQL:Set AUTOCOMMIT = 0
ExecSQL:BEGIN;
ExecSQL:COMMIT;
04-10-22 16:33:35
INNODB_NA_BE count: 10000 used time: 3.85625100136
INNODB_AU_NB 04-10-22 16:33:35
ExecSQL:Set AUTOCOMMIT = 1
04-10-22 16:34:19
INNODB_AU_NB count: 10000 used time: 43.7153041363
INNODB_AU_BE 04-10-22 16:34:19
ExecSQL:Set AUTOCOMMIT = 1
ExecSQL:BEGIN;
ExecSQL:COMMIT;
04-10-22 16:34:22
INNODB_AU_BE count: 10000 used time: 3.14328193665
結論：
由此得知影響速度的主要原因是AUTOCOMMIT預設設定是開啟的，
我當時的程式沒有顯式調用BEGIN;開始事務，導致每插入一條都自動Commit，嚴重影響了速度。
算來也是個低級錯誤！
相關參考：
http://dev.mysql.com/doc/mysql/en/COMMIT.html
http://dev.mysql.com/doc/mysql/en/InnoDB_and_AUTOCOMMIT.html
