Oracle - SQL_TRACE

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Steps

• Set a trace identifier:

alter session set tracefile_identifier = 'myIdentifier';

The trace file identifier is added to the name of the trace files.

• Set Trace on:

alter session set sql_trace = true;

• Perform SQL Actions

select * from ...
select * from

• Set off

alter session set sql_trace = false;

• Where are the trace files?

show parameter user_dump_dest

• To find the trace file on Linux with grep

grep "A little bit of my statement" *.trc

• Formatting of the trace file with tkprof.

tkprof oracl_ora.....trc

Connection Pool

With a typical connection pool, a database session (the level at which we generally trace) is shared across multiple unrelated end-user sessions. Without a connection pool, the application would own a database connection, the level at which Oracle is built to “trace” at from start to finish.

With a connection pool, that one connection is shared by perhaps every end-user session in the system. We end up with a trace file that hase not only the trace information we are interested in, but the trace information from any-end user session that used the connection. The resulting trace file would be intermingled with my SQL, and with their SQL, and with everyone's SQL.

With a connection pool :

• we must have the ability to turn on tracing for a specific user of for a specific module
• when the connection pool grab a connection, it should issue alter session set sql_trace = true;
• prior to returning the connection to the pool, it should issue set sql_trace = false;

Reference

• Oracle® Database Reference SQL_TRACE
• Using the SQL Trace Facility and TKPROF