One of our customers has a new problem: the application stops. A thread dump indicates that all threads are hanging on the IO network in JDBC calls.
We / I have never seen these "network IOs" hang. Usually problems with slow machines and databases have either a) one or two long queries, or b) some type of lock / deadlock. In any of these cases, threads are stuck by various methods. I have never seen all 30+ threads hanging on an IO network.
Below I have included an excerpt from a stream dump. All HTTP streams hang on one call java.net.SocketInputStream.read.
I talked with their double and the system administrator. According to them, recently nothing has changed in the environment that will cause this problem.
surroundings db
MSSQL 2005 64-bit Service Pack 2 Driver: sqljdbc.jar: 1.0 809 102
Note: the old jdbc driver works in them. AFAIK tried to update from 1.0 to 1.2 drivers, but also had other problems.
other environmental problems
They work both on the application server and on the db server in VMWare VM. I do not know how this setting affects network performance.
This is apparently the only application with this problem. I don't know anything about their network architecture.
Questions
* any ideas on this issue? * if it is a network, all the next steps for analysis?
Appendix A: Excerpt from a Flow Dump
All HTTP connections hang on the same method:
"TP-Processor31" daemon prio = 5 tid = 0x04085b78 nid = 0x970 runnable [0x0764d000..0x0764fd6c]
at java.net.SocketInputStream.socketRead0 (Native Method)
at java.net.SocketInputStream.read (SocketInputStream.java:129)
at com.microsoft.sqlserver.jdbc.DBComms.receive(Unknown Source)
at com.microsoft.sqlserver.jdbc.IOBuffer.sendCommand(Unknown Source)
- locked (a com.microsoft.sqlserver.jdbc.DBComms)
at com.microsoft.sqlserver.jdbc.SQLServerStatement.sendExecute(Unknown Source)
at com.microsoft.sqlserver.jdbc.SQLServerStatement.doExecuteQuery(Unknown Source)