The overhead is absolutely minimal - it's generally around 2-5 milliseconds. And worst I've ever seen is around 50 milliseconds (remember that's still only 5/100s of a second). This includes doing a join of data.Are Symlabs, Radiant Logic and other vendors seeing the same results? Perhaps, a skilled SI may want to chime in? If so, then why does anyone use a persistent cache? Anyone?
Also, Blink Technologies put the following comment on my previous post:
I thought the whole point of the cache is to lighten the load against the system as a whole. It's a compromise of data freshness for performance. Plus the entire point of a cache is to "cache" frequently used data, of course depending on the algorithm used (LRU, MRU, etc.). I also assume that the cache is adjustable and can have specific timeouts for freshness. I think for a highly trafficked directory this is a great trade-off.