10G: getGeneratedKeys() and multithreaded code

Question

Hi there,
I'm trying to use JDBC to retrieve auto-generated keys in my code. This seems to work fine when used by a single thread, but when I have multiple threads trying to insert records into the same table, I get "Protocol Violation" errors. Here's a snippet of my code -
          int[] returnArray = new int [] { 1 };
          ps = db.prepareStatement(DB_LOAD_STMT, returnArray);
//I set the various fields here
          if (ps.executeUpdate() > 0) {          
                    rs = ps.getGeneratedKeys();
                    if (rs.next()) {
                         int key = rs.getInt(1);
                         eventMap.put("evt_seqno", Integer.toString(key));
Is this a known issue?
Thanks in Advance,
Rajesh

Answer 1

Hi!
If you are using the 10g JDBC:
Try to use the connection cache feature. This workes like a connection pool.
I am using it in a tomcat application but without JNDI.
_ods = new OracleDataSource();
ods.setURL( connURL );
ods.setUser( odsUser ); // user name
ods.setPassword( odsPass ); // password
ods.setConnectionCachingEnabled( CONNECTION_CACHE_ENABLED );
Properties cacheProperties = new Properties();
cacheProperties.setProperty( "InitialLimit", "10" );
cacheProperties.setProperty( "MinLimit", "200" );
cacheProperties.setProperty( "MaxLimit", "300" );
_ods.setConnectionCacheProperties( cacheProperties );
_occm = OracleConnectionCacheManager.getConnectionCacheManagerInstance();
occm.createCache( CONNECTION_CACHE_NAME, _ods, cacheProperties );
_l.finest( "Cache created: " + "active connections: " +
occm.getNumberOfActiveConnections( CONNECTION_CACHE_NAME ) +
", available connections: " +
occm.getNumberOfAvailableConnections( CONNECTION_CACHE_NAME ) );
It creates "InitialLimit" connections in the statement:
occm.createCache( CONNECTION_CACHE_NAME, _ods, cacheProperties );
Then you can get a connection with:
conn = ( OracleConnection ) _ods.getConnection( );
from the chached connections.
I read "Expert Oracle JDBC Programming" R.M.Menon --> its excelent.
Maybe this workes with the multithreading.
Klaus