11g SQLNet Client trace files

I spent half an hour wondering why I was not able to generate a SQL* Net client trace file from a 11g client to a 10.2 database.
Here are the contents of my client sqlnet.ora

bart:ELEV:/opt/oracle/product/11.1.0/db_1/network/admin> cat sqlnet.ora
#SQLNET.OUTBOUND_CONNECT_TIMEOUT = 3
TRACE_LEVEL_CLIENT= 16
TRACE_DIRECTORY_CLIENT = /tmp
TRACE_FILE_CLIENT= cli.trc
TRACE_TIMESTAMP_CLIENT = ON
TRACE_UNIQUE_CLIENT = ON

It took me a while to realize that thanks to ADR the client trace files were actually going to $ORACLE_BASE/diag/clients/user_oracle/host_xxx/trace

The only way to disable this is to add the following in the sqlnet.ora
DIAG_ADR_ENABLED=off

After setting the above line in the sqlnet.ora the client trace files were generated in /tmp

One off patches, conflicts and merges

So you are applying one of the zillion patches on top of 10.2.0.3 and you hit the following error

************************************************************************

ApplySession applying interim patch '6338357' to OH
'/opt/oracle/product/10.2.0/db_1'
Interim patch 6338357 has File Conflict with patch(es) [ 5399670 ]
in OH /opt/oracle/product/10.2.0/db_1

************************************************************************

Wouldn't it be nice if you could check for conflicts before you apply a patch
Here is one way to do the same

1. You can check which source code file is being modified by doing the following

cd 6338357/etc/config
cat actions | grep .o
oneoff_actions
oracle.rdbms version="10.2.0.3.0" opt_req="R"
archive name="libserver10.a" path="%ORACLE_HOME%/lib" object_name="lib/libserver10.a/kelt.o"
make change_dir="%ORACLE_HOME%/rdbms/lib" make_file="ins_rdbms.mk" make_target="ioracle"
oracle.rdbms
oneoff_actions

2. Then go to the $ORACLE_HOME/.patch_storage and see if any of the previous patches have modified the same file

bart:TEST:/opt/oracle/product/10.2.0/db_1/.patch_storage> find . -name 'kelt.o' -print
./verify/archive/lib/libserver10.a/kelt.o
./5399670_Mar_20_2008_20_30_34/backup/.patch_storage/5399670_Mar_20_2008_20_30_34/files/lib/libserver10.a/kelt.o
./5399670_Mar_20_2008_20_30_34/original_patch/files/lib/libserver10.a/kelt.o
./5399670_Mar_20_2008_20_30_34/scratch/kelt.o./5399670_Mar_20_2008_20_30_34/files/lib/libserver10.a/kelt.o

So this clearly shows that Patch 5399670 was previously applied which modified the same source code file and you need a merge patch for both bugs (5399670 and 6338357)