Name

CREATE SNAPSHOT LOG

Synopsis

CREATE SNAPSHOT LOG ON
[schema.]table_name
   [PCTFREE integer]
   [PCTUSED integer]
   [INITRANS integer]
   [MAXTRANS integer]
   [TABLESPACE tablespace_name]
   [STORAGE (
      [INITIAL integer[K | M] ]
      [NEXT integer[K | M] ]
      [MINEXTENTS integer[K | M] ]
      [MAXEXTENTS {integer | UNLIMITED} ]
      [PCTINCREASE integer]
      [FREELISTS integer]
      [FREELIST GROUPS integer]
      ) ]

Creates a snapshot log (table_name), a table associated with the master table of a snapshot and used to control refreshes of snapshots.

Keywords

PCTFREE

Specifies the percentage of space to be reserved in each data block for future updates to rows contained in that block. Valid values are - 99, and the default value is 10.

PCTUSED

Specifies the minimum percentage of space that will be maintained as used in each data block. Valid values are 1- 99, and the default value is 40.

INITRANS

Specifies the initial number of transaction entries allocated to each block.

MAXTRANS

Specifies the maximum number of transaction entries allocated to each block.

TABLESPACE

Specifies the name of the tablespace in which this snapshot log will be created. The default is the default tablespace for the schema owner.

STORAGE

Specifies the physical characteristics of the snapshot log as follows:

INITIAL

Specifies the size of the first extent for this snapshot log in bytes, kilobytes, or megabytes. If this value is not a multiple of the database blocksize, it will be rounded up to a multiple of the database blocksize.

NEXT

Specifies the size of the next extent in bytes, kilobytes, or megabytes. If this value is not a multiple of the database blocksize, it will be rounded up to a multiple of the database blocksize.

MINEXTENTS

Specifies the number of extents to be allocated when this snapshot log is created. The minimum and default value is 1.

MAXEXTENTS

Specifies the maximum number of extents that may be allocated for this snapshot log. The default will vary according to the database blocksize. Specify UNLIMITED for unlimited expansion.

PCTINCREASE

Specifies the percentage by which each extent will grow over the previous extent. The default is 50, which means that each extent will be one-and-one-half times larger than the previous extent.

FREELISTS

Specifies the number of free lists contained in each freelist group in this snapshot log. The default is 1, and the maximum depends on the database blocksize.

FREELIST GROUPS

Specifies the number of groups of free lists for this snapshot. The default is 1. This parameter should be used only with the Parallel Server option running in parallel mode.

Note

You must have privileges sufficient to create a table in the master table’s schema to issue this command.

Example

The following example creates a snapshot log on scott’s emp table:

CREATE SNAPSHOT LOG ON scott.emp
   STORAGE (INITIAL 50K NEXT 50K PCTINCREASE 0)
   TABLESPACE USERS
..................Content has been hidden....................

You can't read the all page of ebook, please click here login for view all page.
Reset