MAX AI DATA CACHING field (MXAIDTCACH subsystem parameter)
The MXAIDTCACH subsystem parameter specifies the maximum amount of memory, in MB, that is to be allocated for AI data caching for each thread.
| Acceptable values: | 0–512 |
|---|---|
| Default: | 0 |
| Update: | option 30 on panel DSNTIPB |
| DSNZPxxx: | DSN6SPRM MXAIDTCACH |
| Data sharing scope | Member |
| Online changeable | Yes |
MXAIDTCACH controls memory allocation for AI queries that use sparse index access.
- 0
- Specifies the default value. Db2 does not allocate any additional memory for AI data caching and disables batching for vector fetching.
- 1–512
-
Specifies a value in the range 1–512 (in MB). Db2 allocates the specified memory from above the 2 GB bar pool for AI data caching and enables batching for vector fetching.
If vector prefetching is enabled and if a query consists of multiple threads, Db2 allocates the specified amount of memory to each thread for AI data caching.
Db2 dynamically chooses between vector prefetching and row-by-row processing based on the AI object (table vs. view) and the AI cache size. If the MXAIDTCACH parameter is set to a value greater than 0 and a query invokes a SQL DI function on a table, Db2 automatically disables vector prefetching to optimize the CPU usage of the function.
