Name

ALTER SNAPSHOT LOG

Synopsis

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

Changes the storage characteristics of a snapshot log (table_name).

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.

STORAGE

Specifies the physical characteristics of the snapshot log as follows:

NEXT

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

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 log. The default is 1. This parameter should be used only with the Parallel Server option running in parallel mode.

Note

You must own the snapshot log or have the ALTER ANY TABLE privilege to issue this command.

Example

The following example changes the next extent size for scott’s employee table to 50K:

ALTER SNAPSHOT LOG scott.employee
   STORAGE (NEXT 50K)
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