I guess I'm still feeling fuzzy on this because my actual use-case isn't so black-and-white. I don't have any CFs that are accessed purely, or even mostly, in once-through batch mode. What I have is CFs with more and less data, and CFs that are accessed more and less frequently.
On Mon, May 2, 2011 at 7:52 PM, Tyler Hobbs <ty...@datastax.com> wrote: > On Mon, May 2, 2011 at 5:05 AM, David Boxenhorn <da...@taotown.com> wrote: > >> Wouldn't it be the case that the once-used rows in your batch process >> would quickly be traded out of the cache, and replaced by frequently-used >> rows? >> > > Yes, and you'll pay a cache miss penalty for each of the replacements. > > >> This would be the case even if your batch process goes on for a long time, >> since caching is done on a row-by-row basis. In effect, it would mean that >> part of your cache is taken up by the batch process, much as if you >> dedicated a permanent cache to the batch - except that it isn't permanent, >> so it's better! >> > > Right, but we didn't want to cache any of the batch CF in the first place, > because caching that CF is worth very little. With separate CFs, we could > explicitly give it no cache. Now we have no control over how much of the > cache it evicts. > >
