Socket unexpectedly closed by a frontend while communicating with the backend
Hello guys! I'm a little bit confused with the following case.
I've got a Postgressql server running on host A, and a java based client
running on host B. The client uses org.postgresql.Driver JDBC driver
(version 9.1-901.jdbc3).
sometimes while executing long running stored procedure I get exception
"java.net.SocketException: Socket closed". I'm using
org.apache.commons.dbcp.BasicDataSource for retrieving
connections. DBCP pool is configured with default options.
I got tcp dump in order to figure out on which side (client or server)
socket is being closed;
Here is what I've got:
1. Client B sends a test query message when tries to borrow connection
from dbcp pool ("Select 1")
2. Server A sends successful response back (Type: Command completion,
Ready for query)
3. Client B sends ACK message in response on server A response (see the
item 2).
4. Client B sends query message to the server A.
5. Server A sends ACK message in response on client Query message (see
the item 4).
6. Client B sends terminating message (Type : Termination) after some
time passed (from 3 to 10 or sometimes even more minutes).
7 Client B sends FIN ACK message to the server.
8. Server A sends back ACK on termination message.
9. Server A sends ACK on (FIN, ACK) message (item 7).
10. Server A sends back a response on the client query (from item 4) Type:
Row description Columns: 40.
11. Client B sends RST message (reset).
12. Server A continues sending response on the query Type: Data row
Length: 438 Columns 40 and so on.
13 Client B sends RST message (reset) again.
14. Server A continues sending response on the query Type: Data row
Length: 438 Columns 40 and so on.
15. Client B sends RST message (reset).
After that communication seems to be finished.
After the item 6, in my client logs I got Exception like the following:
Caused by: java.net.SocketException: Socket closed
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.read(SocketInputStream.java:152)
at java.net.SocketInputStream.read(SocketInputStream.java:122)
at
org.postgresql.core.VisibleBufferedInputStream.readMore(VisibleBufferedInputStream.java:145)
at
org.postgresql.core.VisibleBufferedInputStream.ensureBytes(VisibleBufferedInputStream.java:114)
at
org.postgresql.core.VisibleBufferedInputStream.read(VisibleBufferedInputStream.java:73)
at org.postgresql.core.PGStream.ReceiveChar(PGStream.java:274)
at
org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1661)
at
org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:257)
Could you please help me to figure out the reason of such a failure. (This
bug happens once per 10 successful cases.)
Thanks in advance!
Best regards, Mike Pryakhin.