Oracle database - File (Common Specification for data file, control file,...)

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2 - Size

The size of the file is in bytes but you can use:

  • K (kilobytes),
  • M (megabytes),
  • G (gigabytes),
  • or T (terabytes)
size unit
5m -- 5 megabytes
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3 - Autoextend

Syntax:

AUTOEXTEND OFF;
AUTOEXTEND ON [NEXT size clause] [MAXSIZE Size clause|MAXSIZE UNLIMITED ];

where:

  • OFF Specify OFF to turn off autoextend if is turned on. When you turn off autoextend, the values of NEXT and MAXSIZE are set to zero. If you turn autoextend back on in a subsequent statement, then you must reset these values.
  • ON Specify ON to enable autoextend.
  • NEXT Use the NEXT clause to specify the size in bytes of the next increment of disk space to be allocated automatically when more extents are required. The default is the size of one data block.
  • MAXSIZE. Use the UNLIMITED clause if you do not want to limit the disk space that Oracle can allocate to the datafile or tempfile.
File valid
datafiles Yes
tempfiles Yes
redo log files No
control file No
ALTER DATABASE CREATE DATAFILE No

If you omit this clause, then:

  • For Oracle-managed files:
    • If you specify SIZE, then Oracle Database creates a file of the specified size with AUTOEXTEND disabled.
    • If you do not specify SIZE, then the database creates a 100M file with AUTOEXTEND enabled. When autoextension is required, the database extends the file by its original size or 100MB, whichever is smaller. You can override this default behavior by specifying the NEXT clause.
  • For user-managed files, with or without SIZE specified, Oracle creates a file with AUTOEXTEND disabled.
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4 - Documentation / Reference