log_archive_format default value

Having trouble finding out why the value of the parameter LOG_ARCHIVE_FORMAT does not seem to apply to your database?

From Oracle 10g and onwards, the default value for LOG_ARCHIVE_FORMAT is %t_%S_%r.dbf

However, this parameter will only make a difference if you are NOT using a "Fast Recovery Area" (in Version 10 Oracle called the same thing a "Flash Recovery Area")

If you have defined a FRA by using the parameters db_recovery_file_dest and db_recovery_file_dest_size, the archivelogs will be automatically named according to OMF (Oracle Managed Files) standard and the value of LOG_ARCHIVE_FORMAT will be ignored.

An example of an OMF managed file in the FRA:

/fra/PRODDB01/archivelog/2014_06_30/o1mv_1_1_9vxzch5_.arc

From the documentation:

"The fast recovery area is an Oracle Database managed space that can be used to hold RMAN disk backups, control file autobackups and archived redo log files. The files placed in this location are maintained by Oracle Database and the generated file names are maintained in Oracle Managed Files (OMF) format."

At first glance, letting the LOG_ARCHIVE_FORMAT default to such a poor naming standard may seem like a bad idea, but I guess it illustrates the point of defining an FRA vs. using conventional archive log destinations.

How to gather dictionary statistics and fixed-objects statistics

Use the procedures

dbms_stats.gather_dictionary_stats
and
dbms_stats.gather_fixed_objects_stats

Examples:

BEGIN
   DBMS_STATS.GATHER_DICTIONARY_STATS (
     estimate_percent  => DBMS_STATS.AUTO_SAMPLE_SIZE
     ,method_opt        => 'FOR ALL COLUMNS SIZE AUTO'
     ,degree            => NULL
     ,cascade           => DBMS_STATS.AUTO_CASCADE
     ,granularity       => 'AUTO'
     ,no_Invalidate     => DBMS_STATS.AUTO_INVALIDATE);
 END;
 /

 BEGIN
   DBMS_STATS.GATHER_FIXED_OBJECTS_STATS;
 END;
 /

Used in a simple shell script:

#!/usr/bin/ksh
# Gather dictionary and fixed objects stats as recommended by oracle

cat << EoF > ${SCRIPT_BASE}/sql/gather_dict_stats.sql
alter session set nls_date_format='DD-MM-YYYY HH24:MI:SS';
spool ${SCRIPT_BASE}/log/gather_dict_stats.log append
set timing on
select 'Start time: ' || sysdate as "startime" from dual;
execute dbms_stats.gather_dictionary_stats(estimate_percent=>DBMS_STATS.AUTO_SAMPLE_SIZE,method_opt=>'FOR ALL COLUMNS SIZE AUTO',degree=>DBMS_STATS.DEFAULT_DEGREE,granularity=>'ALL',cascade=>DBMS_STATS.AUTO_CASCADE,options=>'GATHER AUTO',no_invalidate=>DBMS_STATS.AUTO_INVALIDATE);
execute dbms_stats.gather_fixed_objects_stats(NULL);
select 'End time: ' || sysdate as "endtime" from dual;
exit
EoF
sqlplus / as sysdba @${SCRIPT_BASE}/sql/gather_dict_stats.sql
rm -r ${SCRIPT_BASE}/sql/gather_dict_stats.sql
exit

Good sources for further reading: Maria Colgan's blog

Where to find the database characterset in the dictionary

SQL> select value$ from sys.props$ where name = 'NLS_CHARACTERSET';

 VALUE$
 --------------------------------------------------------------------------------
 WE8MSWIN1252

 SQL> select * from nls_database_parameters WHERE PARAMETER='NLS_CHARACTERSET';

 PARAMETER                      VALUE
 ------------------------------ ----------------------------------------
 NLS_CHARACTERSET               WE8MSWIN1252

How to work around dbca error "The Oracle system identifier ... already exists, specify another SID"

If you have previously created a database through dbca and saved it as a template for future use, you may see the following error when trying to specify the same SID again:

The Oracle system identifier ... alerady exists, specify another SID

Solution to the problem is to remove the entry for the SID in /etc/oratab

Then click next in dbca, and the configuration wizard will proceed.

Thanks to Elena for pointing this out in her blog.

Potential cause of ORA-12547: TNS:lost contact

I was running a script against the database directly on the host, when the script timed out with:

ERROR:
 ORA-12547: TNS:lost contact

After a search on Oracle's support site I found doc 555565.1: Troubleshooting ORA-12547 TNS: Lost Contact

One potential cause was incorrect permissions on the oracle binary in the $ORACLE_HOME/bin directory. I checked my old OH and compared it with the new OH:

server1>cd $ORACLE_HOME
server1>pwd
 /u01/oracle/product/11204
server1>ls -latr bin/oracle
 -rwxr-x--x    1 ora11g   dba       309704130 Jun 11 11:00 bin/oracle
server1>ls -latr /u01/oracle/product/11.2.0.2/bin/oracle
 -rwsr-s--x    1 ora11g   dba       279291858 Mar 12 13:42 /u01/oracle/product/11.2.0.2/bin/oracle

As can be seen from the above statement, the oracle server executable was lacking the setuid bit

This bit is needed, since we need to make sure that any user who runs the executable file will inherit the user ID of the owner (or group) of the executable file. Note that LOCAL connections would work just fine, even if the permissions on the oracle executable is set incorrectly; only connections that are passed from the listener to the Oracle server are affected. These sessions must be able to spawn a new server process.

Oracle points out that this error is commonly seen "in environments where the listener is running in the GRID home and servicing connections to an instance in a different $ORACLE_HOME."

Connections via the listener are failing with ORA-12547. It is likely in this scenario that LOCAL or BEQ connections to the instance are successful.

Solution to my particular problem this time was to give $ORACLE_HOME/bin/oracle the proper permissions:

server1> sqlplus / as sysdba
SQL> shutdown immediate

server1>chmod 6751 oracle
server1>ls -latr oracle
 -rwsr-s--x    1 ora11g   dba       309704130 Jun 11 11:00 oracle

server1> sqlplus / as sysdba
SQL> startup

After this change the script ran through with no ORA-12547 errors.

Sources: Oracle System Administration Guide

How to disable or drop an SQL Profile

Find the profiles currently saved in the database:

SELECT NAME, CREATED,LAST_MODIFIED,TYPE,STATUS,FORCE_MATCHING
FROM DBA_SQL_PROFILES
ORDER BY CREATED DESC;

NAME	CREATED	LAST_MODIFIED	TYPE	STATUS	FORCE_MATCHING
SYS_SQLPROF_0146b2c081f9011a	19.06.2014 08:11:39,000000	19.06.2014 08:11:39,000000	MANUAL	ENABLED	NO
SYS_SQLPROF_0146b2bf0d430118	19.06.2014 08:10:03,000000	19.06.2014 08:10:03,000000	MANUAL	ENABLED	NO
SYS_SQLPROF_0146af25274a0117	18.06.2014 15:23:06,000000	18.06.2014 15:23:06,000000	MANUAL	ENABLED	NO
SYS_SQLPROF_0146af1a61f40116	18.06.2014 15:11:20,000000	18.06.2014 15:11:20,000000	MANUAL	ENABLED	NO
SYS_SQLPROF_0146af18d0960115	18.06.2014 15:09:37,000000	18.06.2014 15:09:37,000000	MANUAL	ENABLED	NO
SYS_SQLPROF_0146af150fc30114	18.06.2014 15:05:31,000000	18.06.2014 15:05:31,000000	MANUAL	ENABLED	NO
SYS_SQLPROF_01462313623f0113	22.05.2014 10:36:51,000000	22.05.2014 10:36:51,000000	MANUAL	ENABLED	NO
SYS_SQLPROF_01461857e9680112	20.05.2014 08:35:53,000000	20.05.2014 08:35:53,000000	MANUAL	ENABLED	NO
SYS_SQLPROF_014614c584ab0111	19.05.2014 15:57:07,000000	19.05.2014 15:57:07,000000	MANUAL	ENABLED	NO

To disable the profile, which means they will not any longer be considered by the CBO until you once again accept them:

set serveroutput on
 begin
   dbms_sqltune.alter_sql_profile(name=>'SYS_SQLPROF_0146af25274a0117', attribute_name=>'STATUS',value=>'DISABLED');
 end;
/

To completely drop the profile:

set serveroutput on
 begin
   dbms_sqltune.drop_sql_profile(name=>'SYS_SQLPROF_0146af25274a0117');
end;
/

What does the TERRITORY component of the NLS_LANG parameter control?

From OTN:

"The territory component of the NLS_LANG parameter controls the operation of a subset of globalization support features.
It specifies conventions such as the default date, monetary, and numeric formats. Each supported territory has a unique name, for example, AMERICA, FRANCE, or CANADA.
If the territory is not specified, then the value is derived from the language value."

For examples please see the Globalization Support Guide