Generally all trace files have read and write permission for Oracle software owner and group of Oracle installation has permission of read only. Other users don’t have privilege of read.
$cd /oradump/diag/rdbms/ABCPROD1/trace
$ls -lrt
-rw-r----- 1 ora11g dba 156 Feb 18 13:35 ABCPROD1_lmhb_37332.trm
-rw-r----- 1 ora11g dba 1892 Feb 18 13:35 ABCPROD1_lmhb_37332.trc
-rw-r----- 1 ora11g dba 72499 Feb 18 13:39 ABCPROD1_lms0_37322.trm
-rw-r----- 1 ora11g dba 448097 Feb 18 13:39 ABCPROD1_lms0_37322.trc
-rw-r----- 1 ora11g dba 71272 Feb 18 13:40 ABCPROD1_mmon_37350.trm
Because trace files may have some important information about database security or may have some sensitive details of data.
Oracle applies this permission using hidden parameter called _TRACE_FILES_PUBLIC.
Default value of _TRACE_FILES_PUBLIC is FALSE. Due to this parameter trace files don’t have read permission to other users or public. It is not recommended to change value of this parameter because it is security risk. But in some scenario it has needed to change permission to make it readable trace files to other users or PUBLIC.
We can change this parameter using parameter file or spfile and make it TRUE.
select value from v$parameter where name = '_trace_files_public';
VALUE
----------
FALSE
For modifing this parameter login as SYSDBA and execute ALTER SYSTEM command as follows.
SQL> ALTER SYSTEM SET “_trace_files_public” = TRUE SCOPE=SPFILE;
After changing _TRACE_FILES_PUBLIC parameter to TRUE. Newly generated trace has readable permission to other users and public too.
select value from v$parameter where name = '_trace_files_public';
VALUE
----------
TRUE
$cd /oradump/diag/rdbms/ABCPROD1/trace
$ls -lrt
-rw-r--r-- 1 ora11g dba 2247 Feb 18 13:48 ABCPROD1_lmhb_1907.trc
-rw-r--r-- 1 ora11g dba 156 Feb 18 13:48 ABCPROD1_dbrm_1885.trm
-rw-r--r-- 1 ora11g dba 1496 Feb 18 13:48 ABCPROD1_dbrm_1885.trc