![TDS_EMPTY_STRING_IS_NULL option [database]](arrow-right.gif){kind=icon}
Specifies the percentage of IQ threads used to sweep out buffer caches
1 to 40
Can be set only for the PUBLIC group. DBA authority is required to set the option. You must shut down and restart the database server for the change to take effect.
10 (percent)
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 may need to increase SWEEPER_THREADS_PERCENT or WASH_AREA_BUFFERS_PERCENT.
The default setting of this option is almost always appropriate. Occasionally, Sybase Technical Support may ask you to increase this value.
“WASH_AREA_BUFFERS_PERCENT option”
Chapter 5, “Monitoring and Tuning Performance” in the Sybase IQ Performance and Tuning Guide
