com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Row size too large (> 8126)

同样是工作中遇到的问题，写下来留个纪念。

一个老系统已经跑了一年多了，最近报出这个问题的，具体问题贴出来给大家看

org.springframework.jdbc.BadSqlGrammarException: 

### Error updating database.  Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Row size too large (> 8126). 

Changing some columns to TEXT or BLOB or using ROW_FORMAT=DYNAMIC or ROW_FORMAT=COMPRESSED may help. In current row format, 

BLOB prefix of 768 bytes is stored inline.

### The error occurred while setting parameters

### SQL: update test    SET product_id=?,    sp_id=?,    key1=?,    key2=?,    key3=?,    key4=?,    key5=?,    key6=?,    key7=?,    key8=?,    key9=?,    key10=?,    key11=?,    key12=?,    key13=?,    key14=?,    key15=?,    key16=?,    key17=?,    key18=?,    key19=?,    key20=?,    key21=?,    key22=?,    key23=?,    key24=?,    key25=?,    key26=?,    key27=?,    key28=?,    key29=?,    key30=?,    gmt_modify=?,    json_data=?,    record_no=?,    hash_no=?,    gmt_create=?,    is_repack=?    where ID=?

### Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Row size too large (> 8126). Changing some columns to TEXT or BLOB or using ROW_FORMAT=DYNAMIC or ROW_FORMAT=COMPRESSED may help. In current row format, BLOB prefix of 768 bytes is stored inline.

; bad SQL grammar []; nested exception is com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Row size too large (> 8126). Changing some columns to TEXT or BLOB or using ROW_FORMAT=DYNAMIC or ROW_FORMAT=COMPRESSED may help. In current row format, BLOB prefix of 768 bytes is stored inline.

at org.springframework.jdbc.support.SQLExceptionSubclassTranslator.doTranslate(SQLExceptionSubclassTranslator.java:95)

at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:73)

at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:81)

at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:73)

at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:371)

at com.sun.proxy.$Proxy18.update(Unknown Source)

at org.mybatis.spring.SqlSessionTemplate.update(SqlSessionTemplate.java:254)

at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:49)

at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:43)

at com.sun.proxy.$Proxy27.update(Unknown Source)

at com.ancun.webank.biz.service.TestRowSize.testCompBqData(TestRowSize.java:109)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

at java.lang.reflect.Method.invoke(Unknown Source)

at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)

at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)

at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)

at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)

at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)

at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83)

at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)

at org.springframework.test.context.junit4.SpringJUnit4Cla***unner.runChild(SpringJUnit4Cla***unner.java:232)

at org.springframework.test.context.junit4.SpringJUnit4Cla***unner.runChild(SpringJUnit4Cla***unner.java:89)

at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)

at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)

at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)

at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)

at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)

at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)

at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)

at org.junit.runners.ParentRunner.run(ParentRunner.java:309)

at org.springframework.test.context.junit4.SpringJUnit4Cla***unner.run(SpringJUnit4Cla***unner.java:175)

at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)

at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)

at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)

at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)

at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)

at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)

由于test表中存储了一个text字段用于接收非结构化数据，并且预留了30个字段用于解析这个非结构化数据。在解析这个text字段时报上述错误，行大小超过限制8192。

通过SHOW VARIABLES LIKE '%engine%'，确认目前数据库用的是innodb的引擎。

通过innodb_page_size可以确认每页大小为16k；

INNODB存储引擎是索引组织的，即每页中至少有两行记录，因此如果页中只能存放一行记录，INNODB会自动将行数据放到溢出页中。当发生溢出行的时候，实际数据保存在BLOB页中，数据页只保存数据的前768字节（老的文件格式），新的文件格式（Barracuda）采用完全行溢出的方式，数据页只保存20个字节的指针，BLOB也保存所有数据。

所以每个row的zise不能大于8k，即8192个字节。