What are dbca templates and how do they work?

What are dbca templates? 

Database Configuration Assistant (DBCA) templates are XML files that contain information required to create a database.

What are templates used for? 

Templates are used in DBCA to create new databases and duplicate existing databases. 

What information does a template contain?

The information in templates includes database options, initialization parameters, and storage attributes (for data files, tablespaces, control files, and online redo log files). 

Are there different types of templates?

Yes:

Type	File extension	Includes Data Files	Database Structure	Configurable?
Seed	.dbc	Yes	contains both the structure and the physical data files of an existing database, referred to as the seed database. The data files for the seed database are stored in compressed RMAN backup format in a file with a .dfb extension. The seed database control file is stored in a file with .ctl extension The .dbc file contains the location of the seed database data files and contains the source database name used to mount the control file.	No
nonseed	.dbt	No	This type of template is used to create a new database. It contains the characteristics of the database to be created. Nonseed templates are more flexible than their seed counterparts because all data files and online redo log files are created to your specification, and names, sizes, and other attributes can be changed as required.	Yes

Why use templates? 

Templates can be used just like scripts, but they are more powerful than scripts because you have the option of duplicating a database. Duplication saves time because you copy the files of an existing database, referred to as a seed database, to the correct locations.

When using templates, beware of the following:

1. Database options (for example, Data Vault or Spatial) can be configured or modified only for a custom database or nonseed template (.dbt file).
2. You cannot modify database options for a seed template (includes data file backups).
3. Using a seed template is a much quicker operation, than using a non-seed template, but less flexible.

What templates are delivered with a standard Oracle 19c software installation?

Upon completion of an Oracle 19c software installation, you will find the following files in the directory $ORACLE_HOME/assistants/dbca/templates:

New_Database.dbt

Seed_Database.dfb

Seed_Database.ctl

Data_Warehouse.dbc

General_Purpose.dbc

pdbseed.xml

They are used by the different templates:

Template	Workload	Files used
Data warehouse	Users perform numerous, complex queries that process large volumes of data.	Seed_Database.dbf
General Purpose or Transaction processing	Many concurrent users perform numerous transactions that require rapid access to data.	Seed_Database.dbf
Custom database	Allows for maximum flexibility in defining a database; you can change any of the settings for the database being created.	New_Database.dbt

Both the Data_Warehouse.dbc and the General_Purpose.dbc are pointing to the Seed_Database.dbf when they are used, which means they will be create a database for you quickly but you will have to accept the options and standard given by the template


Documentation:

2.3.5 Managing Templates with DBCA

How to remove the Oracle Workspace Manager component from an Oracle database

I have installed a database through dbca, unchecking all the options boxes when going through the setup wizard:

Upon completion, there is still a component left that I do not want to have installed: the Oracle Workspace Manager.

It is registred in the database's registry:

SYS@orcl>SQL>SELECT COMP_NAME,COMP_ID,VERSION,STATUS FROM DBA_REGISTRY;

COMP_NAME                                COMP_ID                        VERSION                        STATUS
---------------------------------------- ------------------------------ ------------------------------ ----------------
Oracle Database Catalog Views            CATALOG                        19.0.0.0.0                     VALID
Oracle Database Packages and Types       CATPROC                        19.0.0.0.0                     VALID
Oracle Real Application Clusters         RAC                            19.0.0.0.0                     OPTION OFF
Oracle XML Database                      XDB                            19.0.0.0.0                     VALID
Oracle Workspace Manager                 OWM                            19.0.0.0.0                     VALID

To remove the OWM component:

SYS@orcl>SQL> @?/rdbms/admin/owmuinst.plb

Session altered.

PL/SQL procedure executed.

PL/SQL procedure executed.

Session altered.

Option is now deinstalled:

SYS@orcl>SQL>SELECT COMP_NAME,COMP_ID,VERSION,STATUS FROM DBA_REGISTRY;

COMP_NAME                                COMP_ID                        VERSION                        STATUS
---------------------------------------- ------------------------------ ------------------------------ ------------------
Oracle Database Catalog Views            CATALOG                        19.0.0.0.0                     VALID
Oracle Database Packages and Types       CATPROC                        19.0.0.0.0                     VALID
Oracle Real Application Clusters         RAC                            19.0.0.0.0                     OPTION OFF
Oracle XML Database                      XDB                            19.0.0.0.0                     VALID

What exactly is the OWM ?

In a nutshell, it's a version tool for data within a schema. It has been around since Oracle 9i

See documentation here

Particulary the whitepaper

Check out Tim Hall's article on oracle-base.com about the subject.

How to install an extension in a postgreSQL database

Are the desired extensions available in our installation?

[postgres@myserver.no ~]$ echo "SELECT * FROM pg_available_extensions;" | psql | egrep 'cube|earthdistance';
 cube               | 1.5             |                   | data type for multidimensional cubes
 earthdistance      | 1.1             |                   | calculate great-circle distances on the surface of the Earth

Yes they are.

Source : https://www.postgresql.org/docs/current/view-pg-available-extensions.html

Connect to the relevant database and create the extensions in the schema you want them:

postgres=# \connect mydb1
You are now connected to database "mydb1" as user "postgres".
mydb1=# create extension if not exists cube with schema myschema1 cascade;
CREATE EXTENSION
mydb1=# create extension if not exists earthdistance  with schema myschema1 cascade;
CREATE EXTENSION
mydb1=# exit

Check if they have indeed been installed:

[postgres@myserver.no ~]$ psql mydb01
psql (15.4)
Type "help" for help.

sit1=# \dx
                                                List of installed extensions
        Name        | Version |       Schema        |                              Description
--------------------+---------+---------------------+------------------------------------------------------------------------
 cube               | 1.5     | myschema1           | data type for multidimensional cubes
 earthdistance      | 1.1     | myschema1           | calculate great-circle distances on the surface of the Earth
 pg_qualstats       | 2.0.4   | public              | An extension collecting statistics about quals
 pg_stat_statements | 1.10    | public              | track planning and execution statistics of all SQL statements executed
 plpgsql            | 1.0     | pg_catalog          | PL/pgSQL procedural language
(5 rows)

Create extension is documented here

Solution for [WARNING] ORA-01081: cannot start already-running ORACLE - shut it down first when running dbca

I received the following error multiple times, when executing dbca like below:

dbca -createDatabase -responsefile ./cdb.rsp -silent
 2023-09-14 15:05:45.435 CEST ] Prepare for db operation
DBCA_PROGRESS : 10%
[ 2023-09-14 15:05:45.505 CEST ] Copying database files
DBCA_PROGRESS : 12%
[ 2023-09-14 15:05:47.250 CEST ] [WARNING] ORA-01081: cannot start already-running ORACLE - shut it down first

DBCA_PROGRESS : 40%
DBCA_PROGRESS : 100%
[ 2023-09-14 15:05:47.616 CEST ] [FATAL] Recovery Manager failed to restore datafiles. Refer logs for details.
DBCA_PROGRESS : 10%
DBCA_PROGRESS : 0%

At first I thought it was because I had forgotten to terminate some processes owned by oracle. And I also made sure that /etc/oratab was empty before I started.

Reason:

Turns out, there were old memory segments left behind that dbca considers a part of a running instance. Even if

ps -fu oracle

gave no processes in the list.

Solution:

su - oracle
sqlplus / as sysdba
shutdown abort

Given that you've set ORACLE_SID to the same value you used in your response file, this will properly shut down your instance, and clean up the memory segments left behind from the previous run.

How to delete a pluggable database with dbca using the command line

dbca -silent -deletePluggableDatabase \
-sourceDB cdb \
-pdbName pdb3 \

How to create a pluggable database with dbca using the command line

In the following code snippet, I am creating the pluggable database "pdb3" as a copy of the already existing pluggable database "pdb1":

dbca -silent -createPluggableDatabase \
-sourceDB cdb.skead.no \
-pdbName pdb3 \
-sourcePDB pdb1 \
-createPDBFrom PDB \
-pdbDatafileDestination "/dbfiles/oradata/cdb/pdb3/" \
-pdbAdminPassword mysecretpassword1 \
-sysPassword mysecretpassword2 \
-systemPassword mysecretpassword3 \

If you want to use the SEED database as source instead of an already existing database, remove the directive

-sourcePDB pdb1 \

and use this directive instead:

-createPDBFrom DEFAULT \

Source: Oracle 19c documentation

Script for creating a multitenant database with dbca

Prerequisites:

You have a valid Oracle 19c installation in a server

You have set your Oracle environment already, so that your PATH, ORACLE_SID etc already exists when you execute your script

The script called run_dbca.sh:

#!/bin/bash
start=$(date +%s.%N)
export GLOGFILE=run_dbca.log
touch ${GLOGFILE}
chmod 666 ${GLOGFILE}
exec 1> ${GLOGFILE} 2>&1
echo "Now running run_dbca.sh"
echo "Resetting oratab..."
echo '' > /etc/oratab
if [ $? -ne 0 ]; then
 echo "Could not erase oratab. Exit."
 exit 1
else
 echo "oratab erased. Continuing..."
fi
export instanceAlive=`ps -ef| grep pmon | grep -v grep |awk '{ print $8}' | cut -f 3 -d"_"`

if [ ! -z ${instanceAlive} ]; then
 echo "Instance for database $ORACLE_SID is already running. Shut it down first"
 exit 1
fi
dbca -createDatabase -responsefile ./${ORACLE_SID}.rsp -silent
echo "Finished running run_dbca.sh"
dur=$(echo "$(date +%s.%N) - $start" | bc)
printf "Total execution time for run_dbca.sh: %.6f seconds\n" $dur
exit 0

The response file can be seen below. I saved it in a file called cdb.rsp and put it in the same directory.

I commented out most instructions, as they are not needed.

The original template db_install.rsp is delivered by default with your oracle installation and resides in your $ORACLE_HOME/install/response.

#-------------------------------------------------------------------------------
# Do not change the responseFileVersion diretive!
#-------------------------------------------------------------------------------
responseFileVersion=/oracle/assistants/rspfmt_dbca_response_schema_v19.0.0
gdbName=cdb.oric.no
sid=cdb
createAsContainerDatabase=true
numberOfPDBs=1
pdbName=pdb1
useLocalUndoForPDBs=true
pdbAdminPassword=mysecretpassword
templateName=New_Database.dbt
sysPassword=mysyspassword
systemPassword=mysystempassword
datafileDestination=/data01/oradata/cdb
recoveryAreaDestination=/data02/fra
characterSet=AL32UTF8
initParams=max_pdbs=3,db_create_file_dest_size=1024GB
memoryPercentage=75
automaticMemoryManagement=false
enableArchive=true
redoLogFileSize=2048
dbOptions=JSERVER:false,DV:false,ORACLE_TEXT:false,IMEDIA:false,CWMLITE:false,SPATIAL:false,OMS:false,APEX:false

Execute the script like this:

./run_dbca.sh

Follow the progression of the creation in the log run_dbca.log:

tail -f run_dbca.log

Sources:

Oracle 19c documentation: About creating a database with dbca

Oracle 19c documentation: Managing templates with dbca

Oracle-Base.com: Multitenant : Create and Configure a Pluggable Database (PDB) in Oracle Database 12c Release 1 (12.1) - still a relevant and good source.

Oracle-base.com: a dbca template

Oracle-base.com: Database Configuration Assistant (DBCA) : Creating Databases in Silent Mode