發現寫Oracle的線程掛住了，場景是從mysql讀數據，然后寫到Oracle。
1 定位線程
因為在同一台機器上運行了多個java進程，要找到對應的pid，就是連接mysql的的那個進程。
[admin@arch036075.sqa.cm4 logs]$ ss -p | grep "10.232.31.67"
ESTAB 0 0 10.232.36.75:41790 10.232.31.67:mysql users:(("java",1978,184))
ESTAB 0 0 10.232.36.75:41789 10.232.31.67:mysql users:(("java",1978,179))
紅色部分就是掛住線程的pid
2 jstack
"Stage Task: mysql-to-dbsync" daemon prio=10 tid=0x00002aaac8699000 nid=0x7e33 runnable [0x0000000043cfb000]
java.lang.Thread.State: RUNNABLE
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.read(SocketInputStream.java:129)
at oracle.net.ns.Packet.receive(Unknown Source)
at oracle.net.ns.NSProtocol.sendReset(Unknown Source)
at oracle.jdbc.driver.T4CMAREngine.unmarshalUB1(T4CMAREngine.java:1112)
at oracle.jdbc.driver.T4CMAREngine.unmarshalSB1(T4CMAREngine.java:1075)
at oracle.jdbc.driver.T4C8Oall.receive(T4C8Oall.java:480)
at oracle.jdbc.driver.T4CPreparedStatement.doOall8(T4CPreparedStatement.java:216)
at oracle.jdbc.driver.T4CPreparedStatement.executeForRows(T4CPreparedStatement.java:966)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1170)
at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3339)
at oracle.jdbc.driver.OraclePreparedStatement.executeUpdate(OraclePreparedStatement.java:3423)
- locked <0x00002aaab4575880> (a oracle.jdbc.driver.T4CPreparedStatement)
- locked <0x00002aaab4cda408> (a oracle.jdbc.driver.T4CConnection)
發現寫oracle的異常
- locked <0x00002aaab4575880> (a oracle.jdbc.driver.T4CPreparedStatement)
- locked <0x00002aaab4cda408> (a oracle.jdbc.driver.T4CConnection)
3 詢問dba對應oracle數據庫的情況，說寫庫有一張表被鎖住了，解鎖，重啟精衛系統，恢復正常。
4 之前有人說過可能是oracle的bug，設置connection的timeout可解決，也用這種方法解決了第一次遇這個的問題的應用（這是第二次遇到），重啟應用，發現是鎖表導致的。
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作者：arkblue
來源：CSDN
原文：https://blog.csdn.net/arkblue/article/details/7870518
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