tkprof arguments

From Oracle Support note 29012.1

 print=integer    List only the first 'integer' SQL statements.
   insert=filename  List SQL statements and data inside INSERT statements.
   sys=no           TKPROF does not list SQL statements run as user SYS.
   record=filename  Record statements found in the trace file.
   sort=option      Set of zero or more of the following sort options:

     prscnt  number of times parse was called
     prscpu  cpu time parsing
     prsela  elapsed time parsing
     prsdsk  number of disk reads during parse
     prsqry  number of buffers for consistent read during parse
     prscu   number of buffers for current read during parse
     prsmis  number of misses in library cache during parse

     execnt  number of execute was called
     execpu  cpu time spent executing
     exeela  elapsed time executing
     exedsk  number of disk reads during execute
     exeqry  number of buffers for consistent read during execute
     execu   number of buffers for current read during execute
     exerow  number of rows processed during execute
     exemis  number of library cache misses during execute

     fchcnt  number of times fetch was called
     fchcpu  cpu time spent fetching
     fchela  elapsed time fetching
     fchdsk  number of disk reads during fetch
     fchqry  number of buffers for consistent read during fetch
     fchcu   number of buffers for current read during fetch
     fchrow  number of rows fetched

     userid  userid of user that parsed the cursor

How to set up "RedoRoutes" in a Data Guard Broker configuration

In this example, the following members participate in my Data Guard Configuration: 

Database Name	Role	Open Mode	Function
pksprod	Primary	OPEN	Primary database
pks_stb	Cascading Physical Standby	MOUNTED	Used for failover
pks_ro	Active Data Guard	READ ONLY WITH APPLY	Used for reporting
pks_tstb	Terminal Physical Standby	MOUNTED	Used for migration to a new geographical location

I am using the concept of a "Terminal Standby Database" to move the database from one geographical location to another.
In order for the cascading database to send its redo log stream to the terminal standby database, I had to configure the Data Guard Broker attribute "redoroutes", like this:

edit database "pksprod" set property redoroutes='(LOCAL : pks_stb, pks_ro ASYNC) (pks_stb : pks_tstb ASYNC)';
edit database "pks_stb" set property redoroutes =' (LOCAL :pksprod ASYNC, pks_ro ASYNC)(pksprod : pks_tstb ASYNC)';

which means

* When pksprod is primary, it shall send redo to pks_stb and pks_ro, while pks_stb shall send its redo to pks_tstb
* When pks_stb is primary, it shall send redo to pksprod and pks_ro, while pksprod shall send its redo to pks_tstb

When done, check the outcome like this:

DGMGRL> show database "pksprod" redoroutes
  RedoRoutes = '(LOCAL : pks_stb,pks_ro ASYNC)(pks_stb : pks_tstb ASYNC)'
DGMGRL> show database "pks_stb" redoroutes
  RedoRoutes = '(LOCAL : pksprod ASYNC, pks_ro ASYNC)(pksprod : pks_tstb ASYNC)'

The 12.2 documentation for the RedoRoutes attribute can be found here. You should familarize yourself with the how you can set up the redoroutes to suit your needs. In my case it was the only way I was able to get the DG configuration to work the way I was intending. It was setup using the 12.2 version of the Oracle database software.

How to change ownership of a symlink in unix

As pointed out in a post on StackExchange.com:

On a Linux system, when changing the ownership of a symbolic link using chown, by default it changes the target of the symbolic link (ie, whatever the symbolic link is pointing to).

Make a mount point directory in the root of your server, and give it the ownership you require:

su - 
cd /
mkdir -p /u09/fra/PRODDB01
chown -R oracle:dba u09
cd /u09/fra/PRODDB01/

Create a symlink that points to your desired destination:

ln -s /data1/onlinelog/TESTDB01 onlinelog
 ls -altr
total 8
drwxr-xr-x 3 oracle dba  4096 Apr 14 10:05 ..
lrwxrwxrwx 1 root   root   19 Apr 14 10:13 onlinelog -> /data1/onlinelog/TESTDB01
drwxr-xr-x 2 oracle dba  4096 Apr 14 10:13 .

Note that the symbolic link is owned by root, not user oracle, as I intended. The normal way of chaning ownership did not work:

chown oracle:dba onlinelog

However, add the -h option:

 chown -h oracle:dba onlinelog

And you will have your ownership of the symlink changed:

 ls -la
total 8
drwxr-xr-x 2 oracle dba 4096 Apr 14 10:14 .
drwxr-xr-x 3 oracle dba 4096 Apr 14 10:05 ..
lrwxrwxrwx 1 oracle dba   19 Apr 14 10:14 onlinelog -> /data1/onlinelog/TESTDB01

How to solve "RMAN-04014: startup failed: ORA-01261: Parameter db_recovery_file_dest destination string cannot be translated" during cloning

During an attempt to clone for active database I had created pfile with my desired value for the parameter db_recovery_file_dest, which was /fradata. Excerpt from init.ora used to start the instance (nomount):

cat initproddb01.ora |grep db_recovery_file_dest

*.db_recovery_file_dest='/fradata'

This directory exists on my auxilliary server and is indeed writable by the oracle software installation owner (for most installation, this user is called "oracle") After having started the instance, and executed the clone script:

DUPLICATE TARGET DATABASE
FOR STANDBY
FROM ACTIVE DATABASE
DORECOVER
SPFILE
SET DB_UNIQUE_NAME='STBY01' COMMENT 'Stanby db 1'
USING COMPRESSED BACKUPSET
NOFILENAMECHECK;

This message appears:

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of Duplicate Db command at 04/13/2021 08:07:31
RMAN-05501: aborting duplication of target database
RMAN-03015: error occurred in stored script Memory Script
RMAN-04014: startup failed: ORA-01261: Parameter db_recovery_file_dest destination string cannot be translated
ORA-01262: Stat failed on a file destination directory
Linux-x86_64 Error: 2: No such file or directory

Cause: The spfile that is created contains the target's db_recovery_file_dest setting, not the auxiliary's:

strings spfileproddb01.ora | grep db_recovery_file_dest
*.db_recovery_file_dest='/FRA' <--- this is inherited from the target database, and doesn't exist on the auxiliary server

Solution: Add a new spfile directive to your clone script:

SET DB_RECOVERY_FILE_DEST='/fradata'

and rerun.

What is the difference between dynamic and static partition pruning

From the documentation:

Depending upon the actual SQL statement, Oracle Database may use static or dynamic pruning.

* Static pruning occurs at compile-time, with the information about the partitions accessed being known beforehand.
* Dynamic pruning occurs at run-time, meaning that the exact partitions to be accessed by a statement are not known beforehand.

A sample scenario for static pruning is a SQL statement containing a WHERE condition with a constant literal on the partition key column:

SELECT s.salesID AS ID,
       s.SalesDate AS SoldDate,
       s.pointofsalesID AS PoSID
FROM sales s
WHERE s.pointofsalesID = 1001;

There are some exceptions to this rule, listed here, for example if the partition pruning occurs using the results of a sub-query.

An exampel of Oracle using dynamic pruning is when operators or functions are used in the predicat (WHERE-condition). Also, statements that use bind variables against partition columns result in dynamic pruning:

var b1 number;
exec :B1 := 1001;

SELECT s.salesID AS ID,
       s.SalesDate AS SoldDate,
       s.pointofsalesID AS PoSID
FROM sales s
WHERE s.pointofsalesID = :B1;

How to view a specific property for a databasen using dgmgrl

DGMGRL> show database 'PROD_STB' 'DbFileNameConvert';

How to set timing in a posgreSQL session

Open session in psql:

psql mydb
psql (11.11)
Type "help" for help.

Toggle timing on/off like this:

mydb=# \timing
Timing is on.
mydb=#  \timing
Timing is off.