What’s so cool about the Exadata Smart Flash Cache?
This flash cache is quite smart: it can differentiate between full table scans and single I/O reads. There’s been speculation that the cache can even prioritize things like file headers, controlfile headers and index root blocks, but I have no official information on the subject. The granularity is all the way to the object level, where you can define higher priority for caching (KEEP) or not to cache at all (NONE). NOTE: When you use the KEEP option on objects, even full table scans will become cacheable, with reads happening concurrently on flash cache and disk for maximum throughput. To achieve the 51 GB/sec marked scan speed, the objects need to have that option. Unfortunately, there is no easy way to monitor what’s in that cache. All Oracle has provided is a “list flashcachecontent” command in the cellcli tool, which has no summarization options, and only displays object numbers.
