Oracle Statistics

Implementation of automated statistics collection for application schemas in Oracle 9iR2.

dbms_stats is a supplied package, and is the recommended method of gathering statistics. dbms_utility and analyze are no longer recommended for production systems.

Table monitoring is a feature that counts the approximate number of changes to a table. dbms_stats with "gather stale" will analyze tables that have had more than 10% of their rows changed.

Overview
Determine application schemas to analyze.
Begin table monitoring for the schemas.
Schedule job to analyze stale for the schemas.

Details
Determine application schemas to analyze.

SQL> select username from dba_users order by 1;

Begin table monitoring for the schemas.

SQL> exec dbms_stats.alter_schema_tab_monitoring('SCHEMA_NAME', TRUE)
PL/SQL procedure successfully completed.

Schedule dbms_stats without or with histograms.

exec dbms_stats.gather_schema_stats( -
ownname => 'SCHEMA_NAME', -
options => 'GATHER AUTO' -
);

exec dbms_stats.gather_schema_stats( -
ownname => 'SCHEMA_NAME', -
options => 'GATHER AUTO', -
method_opt => 'FOR ALL INDEXED COLUMNS SIZE 254' -
);

Oracle sqlplus Hide Password

There are several ways to keep the Oracle account password off of the unix command line and away from prying eyes. Connecting as sysdba or using an operating system authenticated account avoids a password altogether.
If you would prefer to hard code a password, this method may be used. It can easily be placed in a script.

$ORACLE_HOME/bin/sqlplus /nolog << EOF
conn username/password@SID

select sysdate
from dual
/
EOF

Some operating systems have the "w" command.

$ w
8:55pm up 9 days, 15:59, 5 users, load average: 0.02, 0.04, 0.89
User tty login@ idle JCPU PCPU what
user1 pts/0 6:58pm 1:57 -ksh
oracle pts/2 1:37pm 25 -ksh
user2 pts/5 7:06pm 54 19 19 sqlplus -s username/pass@THESID

Using "ps" to view the process list, notice how user1 does not expose the password.

$ ps -ef|grep sqlplus
user2 24595 24458 4 19:15:32 pts/5 0:20 sqlplus -s username/pass@THESID
oracle 2758 25017 0 20:55:17 pts/3 0:00 grep sqlplus
user1 28815 28641 0 20:00:02 ? 0:00 sqlplus -s /nolog

Oracle Tablespace Transport

Oracle's transportable tablespace feature is can save a lot of time when copying a user's data. All objects will need to be in one tablespace, so it may not work for all environments. When a schema's objects are in one tablespace, this is a quick way to copy a schema and data.


Verify all objects are in one tablespace. Then SELECT to see any problems.
SQL> exec sys.dbms_tts.transport_set_check('TABLE_SPACE_NAME', true)

PL/SQL procedure successfully completed.

SQL> select * from sys.transport_set_violations;

no rows selected


Determine names of data files.
SQL> select file_name, file_id, tablespace_name from dba_data_files where tablespace_name='TABLE_SPACE_NAME'

FILE_NAME
--------------------------------------------------------------------------------
FILE_ID TABLESPACE_NAME
---------- ------------------------------
/u01/oradata/SID/ts01.dbf
6 TABLE_SPACE_NAME

/u01/oradata/SID/ts02.dbf
43 TABLE_SPACE_NAME


Set the tablespace to read only.
SQL> alter tablespace TABLE_SPACE_NAME read only;

Tablespace altered.


To export transportable, user must log on as sysdba: as sysdba
File expdat.dmp will be created. The file will be small because it will contain just metadata.
$ exp transport_tablespace=y tablespaces=TABLE_SPACE_NAME


Copy data files to new location, then and set ORACLE_SID.
$ cp ...
$ export ORACLE_SID=NEWSID


To import transportable, the user must log on as sysdba: as sysdba
$ imp file=expdat.dmp transport_tablespace=y "datafiles=(/u02/oradata/NEWSID/ts01.dbf,/u02/oradata/NEWSID/ts02.dbf)" tts_owner=SCHEMA_OWNER_NAME

Import: Release 9.2.0.5.0 - Production on Mon Jun 12 13:31:48 2006

Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.

Username: username as sysdba
Password:

Connected to: Oracle9i Enterprise Edition Release 9.2.0.5.0 - 64bit Production
JServer Release 9.2.0.5.0 - Production

Export file created by EXPORT:V09.02.00 via conventional path
About to import transportable tablespace(s) metadata...
import done in UTF8 character set and AL16UTF16 NCHAR character set
. importing SYS's objects into SYS
. importing SCHEMA_OWNER_NAME's objects into SCHEMA_OWNER_NAME
. . importing table "TABLE1"
. . importing table "TABLE2"
Import terminated successfully without warnings.


The imported tablespace is read only and the objects have been imported.
SQL> select tablespace_name, status from dba_tablespaces where tablespace_name = 'TABLE_SPACE_NAME';

TABLESPACE_NAME STATUS
------------------------------ ---------
TABLE_SPACE_NAME READ ONLY


If desired, set the tablespace to read write.
SQL> alter tablespace TABLE_SPACE_NAME read write;

Tablespace altered.