War Against Pakistan

War Against Pakistan

  • Submitted By: stiver
  • Date Submitted: 03/31/2011 11:23 PM
  • Category: Biographies
  • Words: 9522
  • Page: 39
  • Views: 636

• Redo log buffer contains committed and uncommitted data
• Server process goto data buffer then datafile.
• Server process only read data.
• When state of data in Buffer cache change, because of update etc, then it is called dirty buffer.
• Pinned: Multiple session write same block and other session wait.
• Clean: unpinned and ready to aged out when not referenced again
• Free or Unused: empty buffer when instance started
• Dirty: No longer pinned and change and flush to disk by DBWn

Control File:
Having info of DB structure.
Have atleast 1 control file
If more than one, all should have mirrored

Data file:
Data of user and application.

Redo Log files:
Have change data
By default 3 files
Min-2 and max 255
Log writer writes in 5 conditions.
When 1 MB full
Every 3 sec
When 1/3 full
At commit
At checkpoint
Work on circular fashion.
•        The Redo Log file to which LGWR is actively writing is called the current log file.
•        Log files required for instance recovery are categorized as active log files.
•        Log files no longer needed for instance recovery are categorized as inactive log files.
•        Default is two ARCn processes – you can specify up to 10 processes.

Parameter File:
Contains info of parameters require when instance start. (Shared pool size, buffer cache size etc)
Init.ora, spfile, pfile

Shutdown Immediate:

SYSTEM: core functionality, data dictionary table (Meta data info).

SYSAUX: working and tables of enterprise manager.
Can be make offline. But database not stop.

Storage Hierarchy:
Table Space ( Segment ( multiple extents ( data blocks

One data file belong to one table space

A BLOCK is the smallest allocation unit. 2K to 32K.

Segment: is a set of extents. It is logical storage unit
1- Data Segment 2-Index Segment 3- Undo Segment 4- Temporary Segment

• Table space is a logical storage...

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