What ndb failover means

[Pietro Romanazzi]

Dear all

We are testing a simple cluster configuration with three server: one manager and two ndb+Mysql.
Established a jdbc connection we start a transaction.
During the transaction we kill one ndb process. We get the following error:

java.sql.SQLException: Got temporary error 4025 'Node failure caused abort of transaction' from ndbcluster
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2928)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1571)
at com.mysql.jdbc.ServerPreparedStatement.serverExecute(ServerPreparedStatement
.java:1124)
At com.mysql.jdbc.ServerPreparedStatement.executeInternal(ServerPreparedStateme
nt.java:676)
at com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:773)
at tno.LoopMySQL.main(LoopMySQL.java:49)

If we try to establish a new connection immediately after the error and re-execute the transaction (with one ndb node off) the transaction completes correctly.

Now the question is: what does failover mean in MySQL? Does it mean that in case of crash the application is aware of the (temporary) problem? Note that this behaviour does non cause any loss of data. The application should just repeat the last transaction.
Should anyone confirm that the behaviour is as expected and indicate if there is any hint to cope with this.

Thanks and regards,

Pietro