CACHE_AFFINITY_PERCENT Option

The maximum percentage of main cache to use for affinity. Non-affinity data can use this area if insufficient affinity data exists.

Allowed Values

0 - 100 %

Default

Scope

Option can be set at the database (PUBLIC) level only.

Requires the SET ANY SYSTEM OPTION system privilege to set this option. The database server must be shut down and restarted for the change to take effect

Description

This option defines the percentage of the buffer cache used for affinitized data buffers. SAP Sybase IQ buffer caches are organized as a long MRU/LRU chain. Non-affinitized data buffers are put into the chain after affinitized buffers when this percentage is non-zero, so that affinitized data stay in the cache longer than non-affinitized data. If there are insufficient affinitized data buffers to fill this entire percentage, non-affinitized data may consume the remainder.

Note: Before changing this option, check the value of the WASH_AREA_BUFFERS_PERCENT option. WASH_AREA_BUFFERS_PERCENT affects the LRU side of the buffer cache and CACHE_AFFINITY_PERCENT affects the MRU side. The total of these two values cannot exceed 100 percent.