What are nodeapps in an Oracle RAC environment?

Nodeapps are a standard set of Oracle application services that are automatically launched for RAC (Real Application Cluster). The following service are lunched by nodeapps:

•Virtual IP (VIP)
•Oracle Net Listener
•Global Services Daemon (GSD)
•Oracle Notification Service (ONS)

Nodeapp services that run on each node can be relocated to other nodes through the virtual IP.

How to use the dbms_metadata package to generate DDL for a user

-- Arg #1 schema name
-- Arg #2 DB Directory
whenever sqlerror exit 1
whenever oserror  exit 2
set long 100000 verify off feedback off
accept user_name prompt 'User name: '
accept directory_name prompt 'Directory name to write to: '
declare
begin
DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM,'SQLTERMINATOR',TRUE);
declare
no_grant      EXCEPTION;
PRAGMA EXCEPTION_INIT (no_grant, -31608);
CURSOR get_username
IS
SELECT username
FROM all_users
WHERE username = UPPER('&user_name');

file_handle   UTL_FILE.file_type;
stmt          CLOB;
BEGIN
file_handle := UTL_FILE.fopen(UPPER('&directory_name'), 'cr_user_&user_name..sql', 'w', 32767);

FOR l_user IN get_username
LOOP

-- USERS
stmt:=DBMS_METADATA.get_ddl('USER', l_user.username)||chr(10);
begin
stmt:=stmt||'---------------------------------------'||chr(10);
stmt:=stmt||'-- SYSTEM_GRANT'||chr(10);
stmt:=stmt||'---------------------------------------'||chr(10);
stmt:=stmt||DBMS_METADATA.get_granted_ddl('SYSTEM_GRANT', l_user.username)||chr(10);
exception
when no_grant then stmt := stmt||'-- no system grants'||chr(10);
end;
begin
stmt:=stmt||'---------------------------------------'||chr(10);
stmt:=stmt||'-- OBJECT_GRANT'||chr(10);
stmt:=stmt||'---------------------------------------'||chr(10);
stmt:=stmt||DBMS_METADATA.get_granted_ddl('OBJECT_GRANT', l_user.username)||chr(10);
exception
when no_grant then stmt := stmt||'-- no object grants'||chr(10);
end;
begin
stmt:=stmt||'---------------------------------------'||chr(10);
stmt:=stmt||'-- ROLE_GRANT'||chr(10);
stmt:=stmt||'---------------------------------------'||chr(10);
stmt := stmt||DBMS_METADATA.GET_GRANTED_DDL('ROLE_GRANT', l_user.username)||chr(10);
exception
when no_grant then stmt := stmt||'-- no role grants'||chr(10);
end;
begin
stmt:=stmt||'---------------------------------------'||chr(10);
stmt:=stmt||'-- TABLESPACE_QUOTA'||chr(10);
stmt:=stmt||'---------------------------------------'||chr(10);
stmt:=stmt||DBMS_METADATA.GET_GRANTED_DDL('TABLESPACE_QUOTA',l_user.username)||chr(10);
exception
when no_grant then stmt := stmt||'-- no tablespace quota'||chr(10);
end;
begin
stmt:=stmt||'---------------------------------------'||chr(10);
stmt:=stmt||'-- DEFAULT_ROLE'||chr(10);
stmt:=stmt||'---------------------------------------'||chr(10);
stmt := stmt||DBMS_METADATA.GET_GRANTED_DDL('DEFAULT_ROLE', l_user.username)||chr(10);
exception
when no_grant then stmt := stmt||'-- no default role'||chr(10);
end;

UTL_FILE.put (file_handle, stmt);

end loop;
UTL_FILE.fclose (file_handle);
END;
DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM,'SQLTERMINATOR',FALSE);
end;

/
exit

How to use the dbms_metadata package to generate DDL for table

accept table_name prompt 'Table name: '
accept owner prompt 'Table owner: '

set long 90000
set longchunksize 300
set pagesize 0
set linesize 300
set trimspool on
set heading off
set verify off
set echo off
set feedback off
spool table_ddl.lst

exec DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM,'SEGMENT_ATTRIBUTES',FALSE);
exec DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM,'STORAGE',TRUE);
exec DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM,'SQLTERMINATOR',TRUE);
select dbms_metadata.get_ddl('TABLE',UPPER('&&table_name'),UPPER('&&owner'))
from dba_tables where table_name = UPPER('&&table_name');
exit

How to perform a clone from active database

With Oracle 11g, a new method to clone databases was introduced: "Clone from Active Database".
This method allows for cloning of a database using RMAN's DUPLICATE command, but without being dependent on any previous backups being available.

The following are my notes on how to use this feature to produce a clone from production database PRODDB01 to test database TESTDB01.

In file run_duplication.cmd:

connect catalog cataloguser/password@RMANCAT
connect target sys/clonedb@PRODDB01
connect auxiliary sys/clonedb@TESTDB01;
allocate channel c1 type disk;
allocate channel c2 type disk;
allocate auxiliary channel aux1 type disk;
allocate auxiliary channel aux2 type disk;
configure device type disk parallelism 2;
run {
debug io;
DUPLICATE TARGET DATABASE TO TESTDB01
FROM ACTIVE DATABASE
SKIP TABLESPACE TOOLS;
debug off;
}
exit

to execute:

rman cmdfile='run_duplication.cmd' debug trace='run_duplication.trc' log='run_duplication.log'


For this to work smoothly I followed the principles below:

• Script executed from the target server
• Auxiliary database must be in NOMOUNT mode
• Sys passwords must be identical on both source and target.
• Use the notation uid/pwd@<ORACLE_SID> when you Connect to both target and auxiliary. Do not use operating system authenticaion ( connect / ) - it will throw an error
• The db_block_size parameter must be identical on both source and target
• TNS connection must exist on both sides e.g. communication must be able to go from and from the source and the target. If not you will see the error

RMAN-03002: failure of Duplicate Db command at 07/21/2015 10:06:15
RMAN-05501: aborting duplication of target database
RMAN-03015: error occurred in stored script Memory Script
RMAN-03009: failure of backup command on c1 channel at 07/21/2015 10:06:15
ORA-17629: Cannot connect to the remote database server
ORA-17627: ORA-12154: TNS:could not resolve the connect identifier specified
ORA-17629: Cannot connect to the remote database server

• I set the db_file_name_convert and the log_file_name_convert parameter in the auxiliary database. Make sure you check the location of the tempfiles, too, and include this in the db_file_name_convert value.
• I had no success using the TABLESPACE clause (which means an implicit EXCLUDE of all other tablespaces except those named explicitly)
• Using SKIP TABLESPACE ,, etc works, if the tablespaces are self-contained, meaning there are no referential constraints from object in one tablespace to another (even if both are skipped!)

Remember to reregister the duplicated database if it's backed up using a catalog database:

RMAN> connect target /
RMAN> list incarnation of database;
RMAN> register database;
RMAN> list incarnation of database;


The prerequisites for ACTIVE DATABASE cloning as laid out in the Oracle documentation are:

• At least one normal target channel and at least one AUXILIARY channel are required.
• When you connect RMAN to the source database as TARGET, you must specify a password, even if RMAN uses operating system authentication.
• The source database must be mounted or open. If the source database is open, then archiving must be enabled.
• If the source database is not open, then it must have been shut down consistently.
• When you connect RMAN to the auxiliary instance, you must provide a net service name. This requirement applies even if the auxiliary instance is on the local host.
• The source database and auxiliary instances must use the same SYSDBA password, which means that both instances must have password files.
• You cannot use the UNTIL clause when performing active database duplication. RMAN chooses a time based on when the online data files have been completely copied, so that the data files can be recovered to a consistent point in time.

How to set up ssh connection between two servers for user oracle

How to set up ssh connection between two servers for user oracle

1. connect to the remote system as user oracle
2. rm -rf $HOME/.ssh
3. /usr/local/bin/ssh-keygen -t dsa -f "$HOME/.ssh/id_dsa" -N ""
or: /usr/bin/ssh-keygen -t dsa -f "$HOME/.ssh/id_dsa" -N ""
4. cd $HOME/.ssh
5. cat id_dsa.pub >> authorized_keys2
6. check local connection, i.e. the following command should now work without having to enter a password (you might have to confirm with "yes" the first time, though):

ssh localhost date

If it doesn't work, i.e. if you're prompted to enter oracle's password, please check ownership and permissions on $HOME, it should owned by oracle:dba with permissions 755, i.e.:

ls -ld $HOME
drwxr-xr-x 10 oracle dba 5120 Jun 26 17:07 /app/oracle

7. Logon to the remote machine as user oracle.
8. Repeat the procedure above
9. When done, put the contents of id_dsa.pub in the other server's autorized_keys2 file.
10. Exchange is now done. You should be able to use ssh in both directions between the servers.

What is the difference between "in line" and "out of line" constraints?

The following examples create an "in line" constraint, since they both declare a constraint in the columns' definitions:

CREATE TABLE STAFF (
  PERSONELL_ID NUMBER PRIMARY KEY, 
  LNAME VARCHAR2(30),
  FNAME VARCHAR2(20)
);

An anonymous primary key constraint with a system generated name is created on the column PERSONELL_ID.
Optinally, give the constraint a specific name:

CREATE TABLE STAFF (
  PERSONELL_ID NUMBER CONSTRAINT STAFF_PK PRIMARY KEY, 
  LNAME VARCHAR2(30),
  FNAME VARCHAR2(20)
);

The following examples create an "out of line" constraint, since they are both declared separately from the columns' definitions:

CREATE TABLE STAFF (
  PERSONELL_ID NUMBER, 
  LNAME VARCHAR2(30),
  FNAME VARCHAR2(20),
  PRIMARY KEY (PERSONELL_ID)
);

An anonymous primary key constraint with a system generated name is created on the column PERSONELL_ID.
Optinally, give the constraint a specific name:

CREATE TABLE STAFF (
  PERSONELL_ID NUMBER, 
  LNAME VARCHAR2(30),
  FNAME VARCHAR2(20),
  CONSTRAINT STAFF_PK PRIMARY KEY (PERSONELL_ID)
);

The "ALTER TABLE" equivalent of the "in line" syntax is:

ALTER TABLE STAFF 
MODIFY PERSONELL_ID PRIMARY KEY;

Or with explicitly named constraint:

ALTER TABLE STAFF 
MODIFY PERSONELL_ID CONSTRAINT STAFF_ID PRIMARY KEY;

The "ALTER TABLE" equivalent of the "out of line" syntax is:

ALTER TABLE STAFF
ADD PRIMARY KEY (PERSONELL_ID);

Or with explicitly named constraint:

ALTER TABLE STAFF
ADD CONSTRAINT STAFF_PK PRIMARY KEY(PERSONELL_ID);

Note that NOT NULL constraints cannot be created "out of line".

How to use the different options for DATE datatype in Oracle

Datatypes that support dates and times come in two flavours:

Datetime data types, which are DATE, TIMESTAMP, TIMESTAMP WITH TIME ZONE, and TIMESTAMP WITH LOCAL TIME ZONE.

Interval data types, which are INTERVAL YEAR TO MONTH and INTERVAL DAY TO SECOND. Interval data types store time durations.

First, create a test table where the different types of DATE datatypes are bing used:

CREATE TABLE DATETYPETEST
    (TESTDATE1 DATE,
     TESTDATE2 TIMESTAMP,
     TESTDATE3 TIMESTAMP WITH TIME ZONE,
     TESTDATE4 TIMESTAMP WITH LOCAL TIME ZONE,
     TESTDATE5 INTERVAL YEAR TO MONTH,
     TESTDATE6 INTERVAL YEAR(4) TO MONTH,
     TESTDATE7 INTERVAL DAY TO SECOND,
     TESTDATE8 INTERVAL DAY TO SECOND(2)
     );

First I will test the Datetime data types:

INSERT INTO DATETYPETEST(TESTDATE1) VALUES(SYSDATE);
INSERT INTO DATETYPETEST(TESTDATE1) VALUES(TRUNC(SYSDATE));

TRUNC(SYSDATE)
17.01.2014 10:15:45
17.01.2014

INSERT INTO DATETYPETEST (TESTDATE2) VALUES (SYSTIMESTAMP);
INSERT INTO DATETYPETEST (TESTDATE2) VALUES (TRUNC(SYSTIMESTAMP));

TRUNC(SYSTIMESTAMP)
17.01.2014 10:15:45.978004
17.01.2014 00:00:00.000000

Interestingly enough, TRUNC on datatype TIMESTAMP does not strip of the time precision per se, Oracle simply sets it to zero altogether.

INSERT INTO DATETYPETEST (TESTDATE3) VALUES (SYSDATE);

TIMESTAMP WITH TIMEZONE
17.01.2014 10:15:46.000000 +01:00

INSERT INTO DATETYPETEST (TESTDATE4) VALUES (SYSDATE);

TIMESTAMP WITH LOCAL TIMEZONE
17.01.2014 10:15:46.000000

Remember that TIMESTAMP WITH LOCAL TIME ZONE does not store the time zone offset with the column value; however, when the column value is retrieved in a query, the value is sent in the user's local session time zone.

Let's move on to the interval data types.

First, I will insert the interval as a literal:

INSERT INTO DATETYPETEST (TESTDATE5) VALUES (INTERVAL '2-11' YEAR TO MONTH);

INTERVAL YEAR TO MONTH
+2-11

Below, I am using the TO_YMINTERVAL function to convert a string representing a number of years and a number of months into a INTERVAL YEAR TO MONTH datatype:

INSERT INTO DATETYPETEST (TESTDATE5) VALUES(TO_YMINTERVAL('14-01'));

INTERVAL YEAR TO MONTH
+14-01

The statement below, however, fails with ORA-01873: the leading precision of the interval is too small because used the default precision for year(2):

SQL> INSERT INTO DATETYPETEST (TESTDATE5) VALUES(TO_YMINTERVAL('2014-01'));

INSERT INTO DATETYPETEST (TESTDATE5) VALUES(TO_YMINTERVAL('2014-01'))
*
ERROR at line 1:
ORA-01873: the leading precision of the interval is too small

So instead, let's insert the values into a column which allows for larger precision for the INTERVAL YEAR(n) TO MONTH datatype:

SQL> INSERT INTO DATETYPETEST (TESTDATE6) VALUES(TO_YMINTERVAL('2014-01'));

1 row created.

Of course, even values of less precision would be accepted here:

SQL> INSERT INTO DATETYPETEST (TESTDATE6) VALUES(TO_YMINTERVAL('14-01'));

1 row created.

INTERVAL YEAR(4) TO MONTH
+2014-01
+14-01

Again, I will first insert the interval as a literal:

INSERT INTO DATETYPETEST (TESTDATE7) VALUES(INTERVAL '2 6:30:01.222' DAY TO SECOND(3) ));

INTERVAL DAY TO SECOND
+02 6:30:01.222

Use the TO_DSINTERVAL function to convert the string representing a number of days, hours, minutes and seconds into an INTERVAL DAY TO SECOND datatype:

INSERT INTO DATETYPETEST (TESTDATE7) VALUES(TO_DSINTERVAL('7 12:30:000001'));

INTERVAL DAY TO SECOND
+07 12:30:01.000000

In the next example, I am limiting the number of fractional seconds according to the specifications of the column INTERVAL DAY TO SECOND(2):

INSERT INTO DATETYPETEST (TESTDATE8) VALUES(TO_DSINTERVAL('21 12:30:000001'));

INTERVAL DAY TO SECOND(2)
+21 12:30:01.00

The TO_DSINTERVAL is very flexible. Here is another post on the same topic.

An overview of conversion functions used with the INTERVAL data types can be found here

Sources: Oracle Documentation on intervals