Mandatory processes in Oracle DBA

Mandatory processes

Screenshot_24

The SMON performs recovery when a failed instance starts up again.

 

Emoked ………… whenever any commit transaction found in redo log files

………… whenever any Tx updated db files before the server down then SMON rolls back the contents from undo log file. [craoh recovery]

 

Screenshot_25

The PMON performs process when a user process fails.

It will rollback uncommitted transactions

it will unlocks the resources [tables] if any locked for longer time.

 

Screenshot_26

 

The DBWR writes the directly buffers present in the database buffer cache to respective files.

When a check point & issuedindex filesdb files

undo files

  1. Every 3 seconds time-out
  2. When a log switch occurs
  3. When dirty-blocks are becoming LRU blocks
  4. When dirty-blocks reaches to threshold value.
  5. When database shuts down.

Screenshot_27

 

The writer is activated under the following conditionsThe log writer process writes data from the redo log buffers to the redo log files.

  1. Every 3 seconds
  2. When a tx is committed or rolled back.

  • When the redo log buffer is 1/3 full

 

 

Screenshot_28

Check point process signals the synchronization of all database files with the check point      information

The CKPT process is invoked under the followings it ensures data consistency and farter database recovery in case of crash.

  1. When a log switch is done
  2. For all occasions [before in fact] the DBWR invokes.
  3. Whenever an event like “offline” occurs.

whenever the state of redo log files is ACTIVE

Then the DBWR & ARCH files invokes.

Then the state is called ‘PAUSE’ state The solution is

The archive files are not cyclic and helps in crash recovery

whenever the existing 2 redo log files are in the state of ‘Active’

  1. Adding 1 more redo log file the size of existing redo log files

 

Ermine  log 

Installation          : operating system can be installed

Restoring             : database can be restored

Recovery             :  archive files, we can be recovered the data

ORACLE stores the data

 

Screenshot_29

Logically in table space

&

Physically in data files.

 

Screenshot_31

 

[done transitions]

already involved but not get writtened  to their respected files

 

Screenshot_32

 

WEBr applications dba12

Login: raj6x 71A

[dba12 raj6x71A] $ ls  -a

.bash-profile

[dba12  raj6x71A]$ vi .bash-profile

~

~

~

~

Export ORACLE –SID = rajpar

Export ORACLE _HOME=/oraeng/app/oracle/product/10.2.0

Export PATH=$ORACLE_HOME/bin:$PATH:

~

~

~

~

: wq

[dba12 raj6x71A]$ . .bash – profile

[dba12 raj6x 71A] $ echo $ORACLE_SID rajpan

[dba12 raj6x71A] $ echo $ ORACLE_HOME/oraeng/app/oracle/product/10.2.0

[dba12 raj6x71A]$ echo $PATH

……………..

…………….

dba12 raj671a/oraeng/app/oracle/product/ 10.2.0/bim::..

…………….

[dba12 raj6x71A]$C

[dba12 raj6x 71A] $cd     $ORACLE _ HOME

[dba12 10.2.0] $ ls

……………               …………..                                ……………….           ……………….

dbs      …………..                                …………..                                ……………….           ……………….

……………               …………..                                ……………….           ………………..

……………               …………..                                ……………….           ………………..

[dba12 10.2.0] $ cd dbs

[dba12 dbs] $ ls

……………..             ………………            ………………            ……………….           ……………….

……………..             ………………            ………………            ……………….           ……………….

……………..             ………………            ………………            ……………….           ……………….

……………..             ………………            ………………            ………………            ………………..

……………..             ………………            ………………            ……………….           …………………

init.ora                  ……………..             ………………            ……………….           …………………

……………..             ……………..             ………………            ……………….           …………………

[dba12 dbs] $ cp init.ora                init$ORACLE_SID.ora

[dba12 dbs] $ ls

…………..                                ……………..             ……………..             …………….              ………………

…………..                .               ……………..             ……………..             …………….              ………………

…………..                                ……………...           ………………            ……………..             ………………

……………               ………………            ……………..             ………………            ……………….

…………..                                ……………..             ……………..             initrajpar.ora      ……………….

…………..                                ……………….           ……………….           ………………..         …………………

……………               ………………            ………………..         ………………            …………………

……………               ……………..             ………………            ……………….           ………………..

……………               ………………            ………………..         ……………….           …………………

……………               ………………            ……………….           ……………….           …………………

…………..                                ……………….           ……………….           ………………..         …………………

……………               ………………            ………………..         ………………            …………………

……………               ……………..             ………………            ……………….           ………………..

……………               ………………            ………………..         ……………….           …………………

……………               ………………            ……………….           ……………….           …………………                         ……………               ……………….                ………………..         ………………            ………………….

[dba12 dbs] $ c

[dba12 dbs]$ vi initrajpar.ora

#

#

#

#

#

#

#

db_name=rajpal

instance_name=rajpar

..

..

~

~

~

~

#

Control_files=/disk3/oradata/pal/cont.ctl

user-dump-dest=/disk3/oradata/pal/cdump

core_dump_dest=/disk3/oradata/pal/cdump

background_dump_dest=disk3/oradata/pal/bdump

 

~

~

~

~

#

#

:wq

[dba12 dbs] $C

[dba12 dbs] $ cd

[dba12 ~] $ cd / disk3

[dba12 disk3 ] $ cd / oradata

[dba12 oradata] $ mkdir pal

[dba12 oradata] $ ls

............                                …………                   ……………               ……………               …………….              …………..                                ………….

............                                …………                   ……………               ……………               …………….              …………..                                …………..

............                                …………                   ……………               pal                          …………….              …………..                                ………….

[dba12 oradata] $ cd pal

[dba12 pal] $ ls

[dba12 pal] $ mkdir udump cdump bdump

[dba12 pal] $ ls

bdump cdump udump

[dba12 pal] $ cd

[dba12 ~] $ sqlplus “/as sysdba”

Screenshot_33

SQL > startup nomount

Total system global area

Fixed size

variable size

database buffers

redo buffers

SQL > ed cr8db

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