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.
On SPD Engine, a large block size would be 131,072 bytes. In contrast,
random access favors a smaller block size. The default value of 32,768
bytes is the smallest allowed value.