Valid formats for JDBC URLs

Format for JDBC URL with SID:

•jdbc:oracle:thin:@host:1521:sid
•jdbc:oracle:thin:user/password@host:1521:sid

Format for JDBC URL with Service Name:

•jdbc:oracle:thin:@//host:1521/servicename
•jdbc:oracle:thin:user/password@//host:1521/servicename

The difference is in the use of slashes (/) and colons (:)

Source: Oracle Documentation, note 832455.1

How to deinstall Oracle 10g database software

How to deinstall Oracle 10g database software

In oracle 10g, you need to use the oui (oracle universal installer) script supplied in the $ORACLE_HOME/oui/bin folder, as shown below.


# Log in as the oracle 10g user, and set the environment to the ORACLE_HOME you are about remove.
# Check the current ORACLE_HOME
echo $ORACLE_HOME
/u01/oracle/product/10.2.0.4/db

# run oui in silent mode, and point to the correct Oracle 10g home:

cd /u01/oracle/product/10.2.0.4/db/oui/bin
./runInstaller -deinstall -silent REMOVE_HOMES={"/u01/oracle/product/10.2.0.4/db"}

Expected output:

Starting Oracle Universal Installer...

No pre-requisite checks found in oraparam.ini, no system pre-requisite checks will be executed.

Preparing to launch Oracle Universal Installer from /tmp/OraInstall2015-05-20_08-51-59AM. Please wait ...
Oracle Universal Installer, Version 10.2.0.4.0 Production

Copyright (C) 1999, 2008, Oracle. All rights reserved.

Starting deinstall

Deinstall in progress (Wednesday, May 20, 2015 8:52:24 AM CEST)
Configuration assistant "iSQL*Plus Configuration Assistant" succeeded
Configuration assistant "Oracle Database Configuration Assistant" succeeded
Configuration assistant "Oracle Net Configuration Assistant - Deinstall Script" failed
............................................................................................................... 100% Done.

Deinstall successful

End of install phases.(Wednesday, May 20, 2015 8:56:17 AM CEST)
End of deinstallations

Please check '/u01/oracle/oraInventory/logs/silentInstall2015-05-20_08-51-59AM.log' for more details.

To verify the deinstallation, check the oracle inventory, in my case /u01/oracle/oraInventory/ContentsXML/inventory.xml

There should be a row similar to:

Remove the old ORACLE_HOME folder physically from disk:

cd /u01/oracle/product
rm -rf 10.2.0.4

How to deinstall Oracle 11g database software

In oracle 11g, you can use the deinstall script supplied in the $ORACLE_HOME/deinstall folder, as shown below.

In my example, I have two Oracle software installations on the host

/u01/oracle/product/11203 <-- not in use, can be removed

/u01/oracle/product/11204 <-- in use

cd /tmp

# first perform a trial run

/u01/oracle/product/11203/deinstall/deinstall -checkonly

# do the actual deinstall

/u01/oracle/product/11203/deinstall/deinstall

I have found that when you have a listener running on the host out of a different ORACLE_HOME, the deinstall script will often (but not always) want to deconfigure it, despite the fact that it runs out of a different ORACLE_HOME. So for a brief period, the host may be without a valid listener process. However, this was never a problem , simply change directory to the working /u01/oracle/product/11204/network/admin folder and restart the listener.

Sometimes (but not always) you may have to manually remove the deinstall folder under the ORACLE_HOME home you just deinstalled.

How to add a logfile group and a logfile member - syntax

alter database add logfile group 2
(
'/u01/app/oracle/flash_recovery_area/mydb/onlinelog/redo02a.log',
'/u01/app/oracle/oradata/mydb/onlinelog/redo02b.log'
) size 50M;

Remember, if you have just recently dropped the redo log members, they are still present physically on disk.
If you'd like to reuse the log file member names, and to avoid

ORA-00301: error in adding log file /u03/oradata/arutvt/redo03.log - file cannot be created,

add the REUSE keyword at the end of the statement:

alter database add logfile group 3 ('/u03/oradata/mydb/redo03.log') size 1024M REUSE;

To add another member to an already existing group:

ALTER DATABASE ADD LOGFILE MEMBER '/u03/oradata/mydb/redo03.log' TO GROUP 3;

If the redo log file member is already present on disk, use reuse:

ALTER DATABASE ADD LOGFILE MEMBER '/u03/oradata/mydb/redo3b.log' REUSE TO GROUP 3;

If you do not specifically say which log group number you want to create, Oracle will take add another group based on the largest log file group number in v$logfile. So if I have 3 groups already, and execute

alter database add logfile '/rdodata/mydb/redo04.log' size 2048M;

It will create group number 4 for you, even if you do not explicitly say so:

SYS@cdb>SQL>@redo

    GROUP# MEMBER                                                     MB ARC STATUS            SEQUENCE#
---------- -------------------------------------------------- ---------- --- ---------------- ----------
         1 /rdodata/mydbredo01.log                              2048 YES INACTIVE                220
         2 /rdodata/mydb/redo02.log                             2048 YES INACTIVE                221
         3 /rdodata/mydb/redo03.log                             2048 NO  CURRENT                 222
         4 /rdodata/mydb/redo04.log                             2048 YES UNUSED                    0

Documentation for Oracle 19c is found here

How to find information about CPUs on a Linux server

On RHEL-based Linux distributions, cat the file /proc/cpuinfo, and you will find detailed information about the server's CPUs, including model name, cache size and vendor.

cat /proc/cpuinfo | grep processor
processor       : 0
processor       : 1
processor       : 2
processor       : 3

Or

 lscpu
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                4
On-line CPU(s) list:   0-3
Thread(s) per core:    1
Core(s) per socket:    1
Socket(s):             4
NUMA node(s):          1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 58
Stepping:              0
CPU MHz:               2800.000
BogoMIPS:              5600.00
Hypervisor vendor:     VMware
Virtualization type:   full
L1d cache:             32K
L1i cache:             32K
L2 cache:              256K
L3 cache:              25600K
NUMA node0 CPU(s):     0-3

How to execute a stored dbms_scheduler job

In sqlplus, execute the following:

execute dbms_scheduler.run_job('CHANGE_PERMS',TRUE);

How to select rows from a specific partition

The syntax to use if you want to select directly from a specific partition:

SELECT row1, row2 ... 
FROM       my_partitioned_table
PARTITION (my_partition_name)
WHERE ....;

From a subpartition:

SELECT row1, row2 ... 
FROM       my_partitioned_table
SUBPARTITION (my_subpartition_name)
WHERE ....;

With Oracle 11g interval partitioning, the syntax has changed so that you can reference a date range, rather than a partition name, since the auto generated names won't say anything meaningful about their content:

select row1, row2 ..
from my_partitioned_table
PARTITION FOR (to_date('25-FEB-2015','dd-mon-yyyy')); 

Remember that aliases must be specified after the entire FROM-clause, including the PARTITION-part, like this:

select ee.col1
from my_partitioned_table
partition (SYS_P2447) ee
where ee.col2 = 'string1'
and ee.col3 like '%string2%'
order by ee.col1,col2;

If you place the alias immediately after the table name, you'll get the error:

partition (SYS_P2447)
          *
ERROR at line 3:
ORA-00924: missing BY keyword

upon execution.