There are various ways to obtain trace output. However, the easiest way to obtain trace output is to use the traceFile=path attribute on the URL in ij. The following example shows all tracing going to the file trace.out from an ij session.

ij>connect 'jdbc:derby://localhost:1527/mydb;
create=true;traceFile=trace.out;user=user1;password=secret4me';

You can use one of three methods to collect tracing data while obtaining connections from the ClientDataSource:

• Use the setLogWriter(java.io.PrintWriter) method of ClientDataSource and set the PrintWriter to a non-null value.
• Use the setTraceFile(String filename) method of ClientDataSource.
• Use the setTraceDirectory(String dirname) method of ClientDataSource to trace each connection flow in its own file for programs that have multiple connections.

Use one of the following two options to enable and collect tracing information while obtaining connections using the DriverManager:

• Use the setLogWriter(java.io.PrintWriter) method of DriverManager and set the PrintWriter to a non null-value.
• Use the traceFile=path or traceDirectory=path URL attributes to set these properties prior to creating the connection with the DriverManager.getConnection() method. For more information, see "traceFile=path attribute" and "traceDirectory=path attribute" in the Derby Reference Manual.

The default trace level is ClientDataSource.TRACE_ALL. You can choose the tracing level by calling the setTraceLevel(int level) method or by setting the traceLevel=value URL attribute:

String url = "jdbc:derby://samplehost.sampledomain.com:1528/mydb" +
 ";traceFile=/u/user1/trace.out" +
 ";traceLevel=" +
 org.apache.derby.jdbc.ClientDataSource.TRACE_PROTOCOL_FLOWS;
DriverManager.getConnection(url,"user1","secret4me");

To specify more than one trace level, use one of the following techniques:

• Use bitwise OR operators ( | ) with two or more trace values. For example, to trace PROTOCOL flows and connection calls, specify this value for traceLevel:

  TRACE_PROTOCOL_FLOWS | TRACE_CONNECTION_CALLS

• Use a bitwise complement operator ( ~ ) with a trace value to specify all except a certain trace. For example, to trace everything except PROTOCOL flows, specify this value for traceLevel:

  ~TRACE_PROTOCOL_FLOWS