locked (a oracle.jdbc.driver.T4CConnection

發現寫Oracle的線程掛住了，情境是從mysql讀資料，然後寫到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，就是串連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資料庫的情況，說寫庫有一張表被鎖住了，解鎖，重啟Data Replication System系統，恢複正常。

4 之前有人說過可能是oracle的bug，設定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。