Rodri_gore Rodri_gore - 1 month ago 19
Java Question

JDBC ERROR:08S01 sometimes happens


SQLState relac: 08S01, thread:0

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
... more

Caused by: java.net.SocketException: No buffer space available (maximum connections reached?): connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:351)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:213)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:200)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
at java.net.Socket.connect(Socket.java:529)
at java.net.Socket.connect(Socket.java:478)
at java.net.Socket.(Socket.java:375)
at java.net.Socket.(Socket.java:218)
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:257)
at com.mysql.jdbc.MysqlIO.(MysqlIO.java:294)
... 20 more


I working with N threads and it happens just sometimes not in a specific time( X minutes)

I try with diferent driver but i can't solve the problem.

Answer

You're most likely either

  1. Opening sockets and not closing them. Over time the number of open sockets gets too large and the application crashes.
  2. You're opening way too many sockets at the same time. Maybe because you have a ton of threads.

I'm going to guess it's #1. Double check your code and make sure that you close all your Connection objects and ResultSet objects.

If you're running into #2 then you may want to consider using fewer threads (after a certain point having too many threads does more harm than good) or using a connection pool like c3p0 which will only create a set number of connections and allow your threads to share them. Using c3p0 is a good idea in general and should also allow you to detect #1 faster.

A third option is to use a higher level abstraction such as JPA or JDO which will take care of connection management for you.