NonStop SQL/MP Reference Manual

NonStop SQL/MP Reference Manual—142115
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Considerations—EXTENT
partition, or you can specify one size for the primary (first) extent and another size for
the secondary extents.
The default is 16 pages for the primary extent and 64 pages for each secondary extent.
The default unit type is PAGE.
integer
is an integer that specifies the number of pages, bytes, recs, or megabytes in the
extent. The ranges allowed are:
A PAGE consists of 2048 bytes. (Note that these are not the same as memory
pages.)
Considerations—EXTENT
•
Requirements for extent size
A file's extent size must be at least as large as its block size and must be a multiple
of the block size and a multiple of page size (2048 bytes). If you specify extent sizes
that do not meet these conditions, SQL uses the next block size or the next full page
size. For example, 0 PAGE rounds up to 1 PAGE.
A file (or a partition of a partitioned file) must fit on a disk, so the size of the
primary extent plus the total size of all secondary extents must not exceed the disk
size.
•
Choosing extent sizes
A primary extent should be large enough to hold the file at the initial load, and
secondary extents should be large enough to accommodate growth. The faster the
growth, the larger the secondary extents should be.
EXTENT { ext-size }
{ ( pri-ext-size [, sec-ext-size ] ) }
ext-size, pri-ext-size, or sec-ext-size is:
integer [ PAGE[S] ]
[ BYTE[S] ]
[ REC[S] ]
[ MEGABYTE[S] ]
PAGES 0 to 65,535
BYTES 0 to 134,215,680
RECS 0 to 134,215,680
MEGABYTES 0 to 134