SQL/MP Reference Manual

HP NonStop SQL/MP Reference Manual—523352-013
B-5
BLOCKSIZE File Attribute

This example finds those items for which the part cost is less than $5 or more than
$800:
PARTCOST NOT BETWEEN 5.00 AND 800.00

This example finds those names between Jody Selby and Gene Wright. The name
Barbara Swift meets the criteria; the name Mike Wright does not.
LAST_NAME, FIRST_NAME BETWEEN
"SELBY", "JODY" AND
"WRIGHT", "GENE"
BLOCKSIZE File Attribute
BLOCKSIZE is a Guardian file attribute that specifies the number of bytes in a block.
BLOCKSIZE applies to key-sequenced, relative, and entry-sequenced tables, and to
indexes.
The default is BLOCKSIZE 4096.
num-bytes
is an integer that specifies the number of bytes in a block.
Block size can be 512, 1024, 2048, or 4096 bytes. If you specify a different block
size, SQL uses the next-higher block size and issues a warning. If you specify a
block size greater than 4096 for a CREATE TABLE or CREATE INDEX statement,
SQL issues an error.
Considerations—BLOCKSIZE
Recommendations for block size
For sequential processing, use the largest block size.
For key-sequenced tables, avoid small block sizes (less than 4096 bytes) if the
size of the table causes the number of index levels to increase over the number
required for 4096-byte blocks. Additional index levels can reduce online
performance.
If your application uses a table or an index to process data solely with random
access, choose one of the smaller block sizes for that table or index. Note,
however, that small block sizes require more disk space for the same number of
rows than large block sizes.
BLOCKSIZE num-bytes