Specifies the percentage of SAP Sybase IQ threads used to sweep out buffer caches.
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.
SAP Sybase IQ uses a small percentage of its processing threads as sweeper threads. These sweeper threads clean out dirty pages in the main and temp buffer caches.
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.
The default setting of this option is almost always appropriate. Occasionally, SAP Sybase Technical Support might ask you to increase this value.