Sybase 12.4.2 User Manual

CHAPTER 12    Managing System Resources

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To set the maximum number of threads a single user will use, issue the 
command 

SET OPTION MAX_IQ_THREADS_PER_CONNECTION

. This 

can be used to control the amount of memory a particular operation 
consumes. For example, the DBA can set this option before issuing an 

INSERT 

or 

LOAD 

command.

This section explains the importance of balancing I/O on your system. It 
explains how to use disk striping and how to locate files on separate disks to 
gain better performance.

 Most UNIX files systems divide disks into fixed size partitions. Partitions are 
physical subsets of the disk that are accessed separately by the operating 
system. Disk partitions are typically accessed in two modes: cooked mode 
(through the UFS file system) or raw mode. Raw mode (sometimes called 
character mode) does unbuffered I/O, generally making a data transfer to or 
from the device with every read or write system call. The UFS (cooked) mode 
is a UNIX file system and a buffered I/O system which collects data in a buffer 
until it can transfer an entire buffer at a time.

When you create a database or a dbspace, you can place it on either a raw 
device or a file system file. Adaptive Server IQ determines automatically from 
the pathname you specify whether it is a raw partition or a file system file. Raw 
partitions can be up to 128GB.

For more information, see “Working with databases”.