Purpose
Specifies the number of segments maintained for the Optimizer statistics cache on each PE vproc.
Field Group
Performance
Valid Range
2 through 200
Default
4
Changes Take Effect
After the next Teradata Database restart.
Usage Notes
The default size of each segment is 1024 KB.
The following situations may require a change from the default setting:
- If parsing time increases for tables that have many statistics, increasing the number of cache segments may improve performance.
- Systems with large amounts of memory can dedicate more memory to parsing when the number of cache segments is increased. This is useful for large memory systems.
- If event logging on the statistics cache shows a low hit ratio, increasing the size of the cache can help.