Managing the size of first and next extents for the tblspace tblspace

The tblspace tblspace is a collection of pages that describe the location and structure of all tblspaces in a dbspace. Each dbspace has one tblspace tblspace. When you create a dbspace, you can use the TBLTBLFIRST and TBLTBLNEXT configuration parameters to specify the first and next extent sizes for the tblspace tblspace in a root dbspace.

You can use the onspaces utility to specify the initial and next extent sizes for the tblspace tblspace in non-root dbspaces.

Specify the initial and next extent sizes if you want to reduce the number of tblspace tblspace extents and reduce the frequency of situations when you need to place the tblspace tblspace extents in non-primary chunks.

The ability to specify a first extent size that is larger than the default provides flexibility for managing space. When you create an extent, you can reserve space during creation of the dbspace, thereby decreasing the risk of needing additional extents created in chunks that are not initial chunks.

You can only specify the first and next extent sizes when you create a dbspace. You cannot alter the specification of the first and next extents sizes after the creation of the dbspace. In addition, you cannot specify extent sizes for temporary dbspaces, sbspaces, blobspaces, or external spaces.

If you do not specify first and next extent sizes for the tblspace tblspace, Informix® uses the existing default extent sizes.


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