WASH_AREA_BUFFERS_PERCENT Option

Specifies the percentage of the buffer caches above the wash marker.

Allowed Values

1 – 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. You must shut down the database and restart it for the change to take effect.

Description

SAP Sybase IQ buffer caches are organized as a long MRU/LRU chain. The area above the wash marker is used to sweep out (that is, write) dirty pages to disk.

In the IQ Monitor -cache report, the Gdirty column shows the number of times the LRU buffer was grabbed in a “dirty” (modified) state. If GDirty is greater than 0 for more than a brief time, you might need to increase SWEEPER_THREADS_PERCENT or WASH_AREA_BUFFERS_PERCENT.

Note: Before changing this option, check the value of the CACHE_AFFINITY_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.

The default setting of this option is almost always appropriate. Occasionally, SAP Sybase Technical Support might ask you to increase this value.