Sybase 12.4.2 - Manual (Page 132)

Working with databases
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Adaptive Server IQ stores data on disk in compressed form. It uncompresses
the data and moves data pages into memory for processing. The IQ page size
determines the amount of disk compression and the default I/O transfer block
size for the IQ Store. For most applications, this default value is best. For a
complete explanation of how the page size and related options affect resource
use and performance, see Chapter 12, “Managing System Resources”
Specifying the size of your database
When you create a database, you set the size in MB of the initial IQ database
file (the
IQ_SYSTEM_MAIN dbspace). This value is defined in the IQ SIZE
parameter.
• For raw partitions, you do not specify IQ SIZE ; Adaptive Server IQ
determines the size of the raw device and sets IQ SIZE to that value.
• For operating system files you can rely on the defaults listed below; or
specify a value based on the size of your data, from the required minimum
listed below up to a maximum of 128GB, in 1MB increments.
Table 3-1: Default and minimum sizes of IQ and Temporary Stores
Choosing a Catalog page size
You can select a page size for the Catalog Store, with the PAGE SIZE option.
You should always use 4096 for this option. Each database server can support
only one Catalog page size. If you start additional databases on a server, each
one acquires the Catalog page size of the first database opened on that server.
By always setting this value at 4096 (4KB), you ensure that you will always
have an adequate page size for the Catalog.
IQ page
size Default size
of IQ Store
Default size
of
Temporary
Store
Minimum
IQ Store
size when
specified
explicitly
Minimum
Temporary
Store size
when
specified
explicitly
65536 4096000 2048000 4MB 2MB
131072 8192000 4096000 8MB 4MB
262144 16384000 8192000 16MB 8MB
524288 32768000 16384000 32MB 16MB