Caused by: java.sql.SQLException: Java heap space at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:129) at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError....
Caused by: java.sql.SQLException: Java heap space
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:129)
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97)
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeInternal(ClientPreparedStatement.java:970)
at com.mysql.cj.jdbc.ClientPreparedStatement.execute(ClientPreparedStatement.java:387)
at com.alibaba.druid.pool.DruidPooledPreparedStatement.execute(DruidPooledPreparedStatement.java:498)
at org.apache.shardingsphere.shardingjdbc.executor.SQLExecuteCallbackFactory$2.executeSQL(SQLExecuteCallbackFactory.java:62)
at org.apache.shardingsphere.shardingjdbc.executor.SQLExecuteCallbackFactory$2.executeSQL(SQLExecuteCallbackFactory.java:58)
at org.apache.shardingsphere.sharding.execute.sql.execute.SQLExecuteCallback.execute0(SQLExecuteCallback.java:82)
at org.apache.shardingsphere.sharding.execute.sql.execute.SQLExecuteCallback.execute(SQLExecuteCallback.java:58)
at org.apache.shardingsphere.underlying.executor.engine.ExecutorEngine.syncExecute(ExecutorEngine.java:97)
at org.apache.shardingsphere.underlying.executor.engine.ExecutorEngine.parallelExecute(ExecutorEngine.java:93)
at org.apache.shardingsphere.underlying.executor.engine.ExecutorEngine.execute(ExecutorEngine.java:76)
at org.apache.shardingsphere.sharding.execute.sql.execute.SQLExecuteTemplate.execute(SQLExecuteTemplate.java:68)
at org.apache.shardingsphere.sharding.execute.sql.execute.SQLExecuteTemplate.execute(SQLExecuteTemplate.java:51)
at org.apache.shardingsphere.shardingjdbc.executor.AbstractStatementExecutor.executeCallback(AbstractStatementExecutor.java:129)
at org.apache.shardingsphere.shardingjdbc.executor.PreparedStatementExecutor.execute(PreparedStatementExecutor.java:148)
at org.apache.shardingsphere.shardingjdbc.jdbc.core.statement.ShardingPreparedStatement.execute(ShardingPreparedStatement.java:145)
at sun.reflect.GeneratedMethodAccessor94.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.apache.ibatis.logging.jdbc.PreparedStatementLogger.invoke(PreparedStatementLogger.java:59)
at com.sun.proxy.$Proxy178.execute(Unknown Source)
at org.apache.ibatis.executor.statement.PreparedStatementHandler.query(PreparedStatementHandler.java:64)
at org.apache.ibatis.executor.statement.RoutingStatementHandler.query(RoutingStatementHandler.java:79)
at sun.reflect.GeneratedMethodAccessor109.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.apache.ibatis.plugin.Plugin.invoke(Plugin.java:63)
at com.sun.proxy.$Proxy176.query(Unknown Source)
at com.baomidou.mybatisplus.core.executor.MybatisSimpleExecutor.doQuery(MybatisSimpleExecutor.java:67)
at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:324)
at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:156)
at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:109)
at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:83)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:147)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:140)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:426)
由于表数量会很大,我就在在项目中使用了shadingphere进行分表,它的分页查询每次都取取出所有的数据,进行排序,分页。导致内存不足。
想到解决办法:
1)代码层面,优化sql查询。如优化分页查询的方式和设置数据库连接使用useCursorFetch=true&defaultFetchSize=100。---未尝试,planB
2)既然内存问题,物理办法增大,先试一下。
1)查看java的jvm启动参数。
2)解读参数并且分析报错原因。
查了一下,启动java项目时jvm的默认分配:JVM启动时,JVM堆会自动设置heap size值。通常情况下,初始空间(即-Xms)默认值是物理内存的1/64,最大空间是物理内存的1/4。可以利用JVM提供的-Xmn -Xms -Xmx等选项可进行设置。
查看本物理机的内存:
cat /proc/meminfo | grep MemTotal
本物理机的内存只有4G,最大时只有1G,估计进程超过了1G了。验证一下。
3)先进行1G的分配,验证一下1G够不够。
nohup /usr/local/jdk1.8.0_91/bin/java -jar -Xms2048m -Xmx2048m -Xss1024K -XX:PermSize=128m -XX:MaxPermSize=256m /data/apps/xxx/xxx.jar --spring.config.location=/data/apps/xxx/config/ > /data/logs/xxx/xxx.log 2>&1 &
4)重启运行项目,重现报错,并且查看进行使用内存大小。
## 查看当前java程序中内个对象的数量和占用空间
jmap -histo 9882 | head -n10
5)果然,分配的内存没有超过1G。
6)分配2G内存
7)运行没报错,具体内存消耗:1.2G左右。
这个问题算是解决了,2G分配内存能接受。
但项目中的count的消耗时间需要解决,多人使用也会叠加内存,所以,还是需要在代码中优化,准备尝试第一种解决方案。
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