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Working with databases
Specifying the size of your database
Choosing a Catalog page size
112
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"
When you create a database, you set the size in MB of the initial IQ database
file (the
IQ_SYSTEM_MAIN
parameter.
•
For raw partitions, you do not specify
determines the size of the raw device and sets
•
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
IQ page
Default size
size
of IQ Store
65536
4096000
131072
8192000
262144
16384000
524288
32768000
You can select a page size for the Catalog Store, with the
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.
dbspace). This value is defined in the
; Adaptive Server IQ
IQ SIZE
IQ SIZE
Minimum
Default size
IQ Store
of
size when
Temporary
specified
Store
explicitly
2048000
4MB
4096000
8MB
8192000
16MB
16384000
32MB
IQ SIZE
to that value.
Minimum
Temporary
Store size
when
specified
explicitly
2MB
4MB
8MB
16MB
option.
PAGE SIZE
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