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Don Burleson Blog 







SQL*Net Tracing Tips

Expert Oracle Database Tips by Donald BurlesonDecember 3, 2015

Question: I am getting the ORA-12560 error and I need to take a full SQL*Net trace to find the root cause of my problem.  What is the procedure for doing a SQL*Net trace?

Answer:  You should check the details on ORA-12560 error troubleshooting.

Also note that when you see bad SQL*Net performance, you can trace the SQL*net round trips.

There are several ways to trace SQL*net connections, and here is how to do a SQL*net trace for both a SQL*Net client trace and server SQL*Net tracing:

Server side SQL*Net trace:

By default, trace on UNIX systems is written to $ORACLE_HOME/network/trace/sqlnet.trc, and log is written to sqlnet.log file under the same directory. On the server side, log and trace destinations can be defined with the following parameters: log_directory_, log_file_, trace_directory_ and trace_file_.

All these parameters should be configured in the listener.ora file. By default, server logs and traces are stored in listener.log and listener.trc files under the $ORACLE_HOME/network/trace directory.

Note that, by default, logging is turned on and this behavior can be changed with the logging_ parameter of the listener.ora file. One can switch between different trace standards on the client side using the trace_level_client parameter of sqlnet.ora. At the server side, the trace level parameter is called trace_level_ and it should be included in the listener.ora.

Client side SQL*Net tracing:

On the client side, it is possible to define the directory where to put log and trace files in the sqlnet.ora file using the log_directory_client and trace_directory_client parameters, respectively.  The SQL*Net tracing log and trace file names are defined with the log_directory_client and trace_directory_client parameters of the sqlnet.ora file.

STEP 1:  Make a SQL*net trace file directory on the client machine called c:\trace

STEP 2:  Add the following lines to your sqlnet.ora file on your client PC:

trace_level_client = 16
trace_file_client = cli
trace_directory_client = c:\trace
trace_unique_client = on
trace_timestamp_client = on
trace_filelen_client = 100
trace_fileno_client = 2
log_file_client = cli
log_directory_client = c:\trace\log
tnsping.trace_directory = c:\trace\trace
tnsping.trace_level = admin

STEP 3:  When you are finished with the SQL*trace, be sure to remove the lines from the sqlnet.ora file.

Also, check this page for additional SQL*Net troubleshooting and diagnostics tips.

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