How to know your Session Trace file Name

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How to know your Session’s Trace file Name

Oracle server has been provided with the power of Instrumented Code. With this power you can get diagnostic as well as performance related information out of the server as required. One of the ways to get that information is by the use of trace files.

Naming Convention

The trace file naming convention changes from time to time in Oracle, but if you have an example trace file name from your system, it is easy to see the template in use. For example, a trace file name looks like:

Sample Trace File Names

Trace File Name               Database Version

ora_10583.trc                 9i Release 1
ora9ir2_ora_1905.trc          9i Release 2
ora10gr2_ora_6793.trc         10g Release 2
ora11gr2_ora_1990.trc         11g Release 2

The trace file name can be broken down as follows:
• The first part of the file name is the ORACLE_SID (with the exception of Oracle9i Release 1, where Oracle decided to leave that off).
• The next bit of the file name is just ora.
• The number in the trace file name is the process ID of your dedicated server (SPID), available to you from the V$PROCESS view.

Assuming you are using dedicated server mode) you need access to four views to determine your trace file name:
• V$PARAMETER, which is used to locate the trace file for user_dump_dest and to find the optional tracefile_identifier that might be used in your trace file name.
• V$PROCESS, which is used to find the process ID.
• V$SESSION, which is used to correctly identify your session’s information in the other views.
• V$INSTANCE, which is used to get the ORACLE_SID.

Often you simply “know” the ORACLE_SID and USER_DUMP_DEST, so technically you might only need access to V$SESSION and V$PROCESS, but for ease of use you’d want access to all four.

A query, then, to generate your trace file name could be:

select c.value || '/' || d.instance_name || '_ora_' ||
a.spid ||
case when e.value is not null then '_'||e.value end || '.trc' trace
from v$process a, v$session b, v$parameter c, v$instance d, v$parameter e
where a.addr = b.paddr
and b.audsid = userenv('sessionid')
and c.name = 'user_dump_dest'
and e.name = 'tracefile_identifier'
/

TRACE
-------------------------------------------------------
…..\trace\mynewdb_ora_192.trc

And this just shows that if the file exists, you’ll be able to access it via that name (assuming you have the permissions to read the trace directory!).

Note:

You will not see the trace file with that name in the trace directory until you enable tracing in that session with one of the tracing method enabled. Till then no file will exist.
As soon as tracing is enabled, however, you will be able to see it.

You can check the contents of the trace file to make sure that you are looking at correct trace file. Like the file will contain the statements/queries for which you had enabled the tracing or Oracle instance name.

It should be obvious that on Windows you’d replace the / with \. If you are using 9i Release 1, instead of adding the instance name into the trace file name, you’d simply issue the following:
select c.value || 'ora_' || a.spid || '.trc'

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