String.toUpperCase（）上的Java阻塞线程>> [

Question

查询Oracle数据库时，其中一个线程的锁超过3秒钟。在访问Oracle数据库时，这会导致许多阻塞的线程，因此，线程数量突然增加，导致应用程序失效。我正在使用Tomcat 8.5，Tomcat连接池，Java8。跟踪阻塞线程：

***"http-nio-80-exec-433" #4207 daemon prio=5 os_prio=0 tid=0x00007fd9d8042000 nid=0x503b runnable [0x00007fd839f04000]
   java.lang.Thread.State: RUNNABLE
    at java.util.Hashtable.get(Hashtable.java:363)
    - locked <0x000000070193caa0> (a java.util.Hashtable)
    at java.lang.ConditionalSpecialCasing.lookUpTable(ConditionalSpecialCasing.java:151)
    at java.lang.ConditionalSpecialCasing.toUpperCaseEx(ConditionalSpecialCasing.java:123)
    at java.lang.String.toUpperCase(String.java:2775)
    at java.lang.String.toUpperCase(String.java:2833)
    at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1638)
    at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:4401)
    at oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePreparedStatement.java:4482)
    - locked <0x000000074cd7d868> (a oracle.jdbc.driver.T4CConnection)
    at oracle.jdbc.driver.OraclePreparedStatementWrapper.executeQuery(OraclePreparedStatementWrapper.java:6272)
    at sun.reflect.GeneratedMethodAccessor400.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.tomcat.jdbc.pool.interceptor.AbstractQueryReport$StatementProxy.invoke(AbstractQueryReport.java:210)
    at com.sun.proxy.$Proxy637.executeQuery(Unknown Source)
    at sun.reflect.GeneratedMethodAccessor400.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.tomcat.jdbc.pool.StatementFacade$StatementProxy.invoke(StatementFacade.java:114)
    at com.sun.proxy.$Proxy637.executeQuery(Unknown Source)
    at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:208)
    at org.hibernate.loader.Loader.getResultSet(Loader.java:1953)
    at org.hibernate.loader.Loader.doQuery(Loader.java:802)
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:274)
    at org.hibernate.loader.Loader.doList(Loader.java:2533)
    at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2276)
    at org.hibernate.loader.Loader.list(Loader.java:2271)***

这里是10个以上已阻塞线程之一的踪迹

***"http-nio-80-exec-271" #2777 daemon prio=5 os_prio=0 tid=0x00007fd9c8941800 nid=0x19c3 waiting for monitor entry [0x00007fd8356ca000]
   java.lang.Thread.State: BLOCKED (on object monitor)
    at java.util.Hashtable.get(Hashtable.java:363)
    - waiting to lock <0x000000070193caa0> (a java.util.Hashtable)
    at java.lang.ConditionalSpecialCasing.lookUpTable(ConditionalSpecialCasing.java:151)
    at java.lang.ConditionalSpecialCasing.toUpperCaseEx(ConditionalSpecialCasing.java:123)
    at java.lang.String.toUpperCase(String.java:2775)
    at java.lang.String.toUpperCase(String.java:2833)
    at oracle.jdbc.driver.CharCommonAccessor.init(CharCommonAccessor.java:164)
    at oracle.jdbc.driver.VarcharAccessor.<init>(VarcharAccessor.java:88)
    at oracle.jdbc.driver.T4CVarcharAccessor.<init>(T4CVarcharAccessor.java:108)
    at oracle.jdbc.driver.T4CTTIdcb.fillupAccessors(T4CTTIdcb.java:431)
    at oracle.jdbc.driver.T4CTTIdcb.receiveCommon(T4CTTIdcb.java:209)
    at oracle.jdbc.driver.T4CTTIdcb.receive(T4CTTIdcb.java:145)
    at oracle.jdbc.driver.T4C8Oall.readDCB(T4C8Oall.java:963)
    at oracle.jdbc.driver.T4CTTIfun.receive(T4CTTIfun.java:447)
    at oracle.jdbc.driver.T4CTTIfun.doRPC(T4CTTIfun.java:235)
    at oracle.jdbc.driver.T4C8Oall.doOALL(T4C8Oall.java:543)
    at oracle.jdbc.driver.T4CPreparedStatement.doOall8(T4CPreparedStatement.java:239)
    at oracle.jdbc.driver.T4CPreparedStatement.executeForDescribe(T4CPreparedStatement.java:1246)
    at oracle.jdbc.driver.OracleStatement.executeMaybeDescribe(OracleStatement.java:1500)
    at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1717)
    at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:4401)
    at oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePreparedStatement.java:4482)
    - locked <0x000000074d203f60> (a oracle.jdbc.driver.T4CConnection)
    at oracle.jdbc.driver.OraclePreparedStatementWrapper.executeQuery(OraclePreparedStatementWrapper.java:6272)
    at sun.reflect.GeneratedMethodAccessor400.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.tomcat.jdbc.pool.interceptor.AbstractQueryReport$StatementProxy.invoke(AbstractQueryReport.java:210)
    at com.sun.proxy.$Proxy637.executeQuery(Unknown Source)
    at sun.reflect.GeneratedMethodAccessor400.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.tomcat.jdbc.pool.StatementFacade$StatementProxy.invoke(StatementFacade.java:114)
    at com.sun.proxy.$Proxy637.executeQuery(Unknown Source)
    at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:208)***

我不知道为什么toUpperCase（）会锁定某些东西（据我发现，这是某个Integer对象被锁定了）超过30秒钟，但这每天仍会发生多次。线程转储分析器在转储中未发现任何死锁。 Tomcat池日志查询阻塞线程http-nio-80-exec-433耗时5分钟。

这可能是jvm，内存或其他问题吗？像jdbc驱动程序或连接池配置问题？

查询Oracle数据库时，其中一个线程的锁超过3秒钟。访问Oracle数据库时，这会导致许多阻塞的线程，因此线程数量突然增加，并且...

Answer 1

看来问题与代码无关。我们有10GB大小的catalina.out日志文件，以及4个bash脚本，它们每五分钟分析一次该文件的特定错误，并且由于文件很大，每个这样的分析（主要是tail / wc命令）花费了3-4分钟。我不知道catalina.out是否被锁定，但是“ tail”和“ wc”命令的CPU使用率非常高。内存使用没有明显增加。