Setting cache strategy

You can select a cache strategy for a table. This selection overrides the default strategy, determined by the Adaptive Server optimizer, for reading data pages from a table into the buffers in data cache. You set cache strategy in the index property sheet.

In the Indexes folder for a table, select the index, then select File | Properties.
Select the Miscellaneous tab.
Select one or both of the following options:
- Most recently used replacement – specifies that Adaptive Server uses the most recently used (MRU) strategy for determining where in cache to place data pages when reading in new data.
  
  If you clear the check box, Adaptive Server reads new pages into the MRU end of the chain of buffers in cache. Subsequent reads move the pages along the chain towards the least recently used (LRU) end until they are flushed out by new reads at the MRU end. If you select Most Recently Used Replacement, Adaptive Server reads new pages into the LRU end. They are used and immediately flushed when a new page enters the MRU end.
  
  This strategy is advantageous when a page is needed only once for a query. It tends to keep such pages from flushing out other pages that can potentially be reused while still in cache.
- Large buffer prefetch – If memory pools for large I/O are configured for the cache used by a table or an index, the optimizer can choose to prefetch data or index pages by performing large I/Os of up to eight data pages at a time. This prefetch strategy can be used on the data pages of a table or on the leaf-level pages of a nonclustered index. By default, prefetching is enabled for all tables, indexes, and text or image objects. Setting the prefetch option to "off" disables prefetch for the specified object.