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We have a java application that talks to oracle 11.2 using jdbc. We are using oracle-jdbc-7.jar
Created-By: 20.12-b01 (Sun Microsystems Inc.)
Implementation-Vendor: Oracle Corporation
Implementation-Title: JDBC
Implementation-Version: 12.1.0.1.0
We are also using Statement.setQueryTimeout()
However, every few days, the thread talking to oracle hangs while doing a ResultSet.next().
Code looks like this:
PreparedStatement ps = createPreparedStatement();
ps.setQueryTimeout(60);
while (true) {
ps.executeQuery();
//iterate over the ResultSet doing ResultSet.next() continuously
//do something with the ResultSet
//sleep for 1 second.
}
Threaddump:
java.lang.Thread.State: RUNNABLE
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.read(SocketInputStream.java:152)
at java.net.SocketInputStream.read(SocketInputStream.java:122)
at oracle.net.ns.Packet.receive(Packet.java:311)
at oracle.net.ns.DataPacket.receive(DataPacket.java:105)
at oracle.net.ns.NetInputStream.getNextPacket(NetInputStream.java:305)
at oracle.net.ns.NetInputStream.read(NetInputStream.java:249)
at oracle.net.ns.NetInputStream.read(NetInputStream.java:171)
at oracle.net.ns.NetInputStream.read(NetInputStream.java:89)
at oracle.jdbc.driver.T4CSocketInputStreamWrapper.readNextPacket(T4CSocketInputStreamWrapper.java:123)
at oracle.jdbc.driver.T4CSocketInputStreamWrapper.read(T4CSocketInputStreamWrapper.java:79)
at oracle.jdbc.driver.T4CMAREngineStream.unmarshalUB1(T4CMAREngineStream.java:426)
at oracle.jdbc.driver.T4CTTIfun.receive(T4CTTIfun.java:390)
at oracle.jdbc.driver.T4CTTIfun.doRPC(T4CTTIfun.java:249)
at oracle.jdbc.driver.T4C8Oall.doOALL(T4C8Oall.java:566)
at oracle.jdbc.driver.T4CPreparedStatement.doOall8(T4CPreparedStatement.java:215)
at oracle.jdbc.driver.T4CPreparedStatement.fetch(T4CPreparedStatement.java:1022)
at oracle.jdbc.driver.OracleStatement.fetchMoreRows(OracleStatement.java:3590)
at oracle.jdbc.driver.InsensitiveScrollableResultSet.fetchMoreRows(InsensitiveScrollableResultSet.java:1008)
at oracle.jdbc.driver.InsensitiveScrollableResultSet.absoluteInternal(InsensitiveScrollableResultSet.java:972)
at oracle.jdbc.driver.InsensitiveScrollableResultSet.next(InsensitiveScrollableResultSet.java:572)
- locked <0x00000000d0873738> (a oracle.jdbc.driver.T4CConnection)
Any ideas on resolving this would be appreciated?
We have tried using openjdk7 and oracle's JDK 7 but it did not help.
Thanks.
234
The next() method of the ResultSet interface moves the pointer of the current (ResultSet) object to the next row, from the current position. Statement stmt = con. createStatement(); ResultSet rs = stmt.
As to the concrete question about rs. next() , it shifts the cursor to the next row of the result set from the database and returns true if there is any row, otherwise false .
The default ResultSet type is TYPE_FORWARD_ONLY .
To set the fetch size for a query, call setFetchSize on the statement object prior to running the query. If you set the fetch size to N, then N rows are fetched with each trip to the database.
Try to find the blocking session.
SELECT
s.blocking_session,
s.sid,
s.serial#,
s.seconds_in_wait
FROM
v$session s
WHERE
blocking_session IS NOT NULL
If it is your session, then your query might need optimization. Otherwise something else is causing the issue.
P.S. : I am no SQL expert
79
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