Sybase 12.4.2 Manuale Utente

CHAPTER 12    Managing System Resources

Adaptive Server IQ tracks the number of open cursors and allocates memory 
accordingly. In certain circumstances, 

USER_RESOURCE_RESERVATION

 

option can be set to adjust the minimum number of current cursors that IQ 
thinks is currently using the product and hence allocate memory from the 
temporary cache more sparingly. 

This option should only be set after careful analysis shows it is actually 
required. Contact Sybase Technical Support with details if you need to set this 
option.

This section describes several ways to adjust your system for maximum 
performance or better use of disk space.

For better query performance, set the database to read-only, if possible, or 
schedule significant updates for low usage hours. Adaptive Server IQ allows 
multiple query users to read from a table while you are inserting or deleting 
from that table. However, performance can degrade during concurrent updates.

Disk cache is memory used by the operating system to store copies of disk 
blocks temporarily. All file-system based disk reads and writes usually pass 
through a disk cache. From an application’s standpoint, all reads and writes 
involving disk caches are equivalent to actual disk operations.