This section discusses updates and clarifications for the prefetch parameter, used in the select, update, and delete commands.
When using prefetch and designating the prefetch size (prefetch_size) the minimum is 2K and any power of two on the logical page size up to 16K. Usually, the prefetch_size is used in select, update and delete statements.
prefetch size options in kilobytes:
Logical page size |
Prefetch size options |
|---|---|
2 |
2, 4, 8 16 |
4 |
4, 8, 16, 32 |
8 |
8, 16, 32, 64 |
16 |
16, 32, 64, 128 |
The prefetch size specified in the query is only a suggestion. To allow the size specification configure the data cache at that size. If you do not configure the data cache to a specific size, the default prefetch size is used.
To configure the data cache size, use sp_cacheconfigure.
