IOBLOCKSIZE= Table Option

Specifies the number of rows in a block to be used in an I/O operation.

Category: Table Control
Data source: SPD Engine data set, SPD Server table

Syntax

IOBLOCKSIZE= n

Arguments

n

specifies the size of the block in bytes. The default value is smallest block size supported by the data source.

Details

The software reads and stores rows in the table in blocks. IOBLOCKSIZE= is useful on compressed or encrypted tables. The software does not use IOBLOCKSIZE= on noncompressed or nonencrypted tables.
For tables that you compress or encrypt, the IOBLOCKSIZE= specification determines the number of rows to include in the block. The specification applies to block compression as well as data I/O to and from disk. The IOBLOCKSIZE= value affects the table's organization on disk.
When using compression or encryption, specify an IOBLOCKSIZE= value that complements how the data is to be accessed, sequentially or randomly. Sequential access or operations requiring full table scans favor a large block size. In contrast, random access favors a smaller block size. On SPD Engine, a large block size would be 131,072 bytes. The smallest allowed value is 32,768 bytes. For SPD Server, a large block size is 64,000 bytes. The smallest allowed value is 8,000 bytes.
Last updated: February 23, 2017