Neoview SQL Reference Manual (R2.5)

Partitions
Typically, there is a one-to-one correspondence between a table definition and a physical file.
However, large tables or tables with special performance requirements might require partitioning
into multiple physical files.
A partition is the part of a table or index that resides on a single disk volume. Each table or index
consists of at least one partition. A nonpartitioned table or index consists of exactly one partition.
A partitioned table or index consists of more than one partition.
You create partitions by using the PARTITION clause in a CREATE TABLE or CREATE INDEX
statement.
For more information, see “CREATE TABLE Statement” (page 72) and “CREATE INDEX
Statement” (page 60).
Hash Partition Keys
SQL supports hash partitioning. Hash partitioning provides an even distribution of data across
CPUs and disks. To take the best advantage of this distribution, objects can be created by
specifying the columns to be considered for hashing. For details on hash partition keys, see
“Keys” (page 272).
Automatically Creating Partitions
When creating a table, users can specify that the table is not partitioned using the NO PARTITION
clause. The default is for the table to be partitioned.
Users may also specify the MAX TABLE SIZE clause that will be used to decide on the table
extent sizes. If this option is not specified Neoview SQL will decide. If the table is partitioned
then the table is partitioned across all the disk volumes on the system.
Partitions 285