Sybase 12.4.2 manual Choosing an IQ page size, 111

CHAPTER 3 Working with Database Objects

	• The Temporary Store is in c:\company\company.iqtmp
	• The IQ message log file is in c:\company\company.iqmsg
	CREATE DATABASE ’company.db’
	IQ SIZE 20
	IQ PATH ’c:\\company\\iqdata\\company.iq’
Example	The following statement creates an IQ database called company.db. This
	database consists of four UNIX files:
	• The Catalog Store is in company.db, in the directory where the server was
	started (in this case, /disk1/company)
	• The IQ Store is in /disk1/company/iqdata/company.iq
	• The Temporary Store is in /disk1/company/iqdata/company.iqtmp
	• The IQ message log file is in /disk1/company/iqdata/company.iqmsg
	CREATE DATABASE ’company.db’
	IQ SIZE 20
	IQ PATH ’/disk1/company/iqdata/company.iq’

Choosing an IQ page size

You set a page size for the IQ Store with the IQ PAGE SIZE option. This option determines memory and disk use. The IQ PAGE SIZE must be a power of 2, from 65536 to 524288 bytes. The IQ page size is the same for all dbspaces in the IQ Store.

To obtain the best performance, Sybase recommends the following minimum

IQ page sizes:

•64 KB ( IQ PAGE SIZE 65536) for databases whose largest table contains up to 1 billion rows. Note that this is the default IQ page size, and the absolute minimum for a new database.

•128 KB ( IQ PAGE SIZE 131072) for databases whose largest table contains more than 1 billion rows and fewer than 4billion rows.

•256 KB ( IQ PAGE SIZE 262144) for databases whose largest table contains more than 4 billion rows.

Multiuser environments, and systems with memory constraints, both benefit from an IQ page size of at least 64KB, as this size minimizes paging.

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