Paul Randal answers a question about caching of compressed values in SQL Server:
In the previous Curious Case post, I explained how to monitor how well page compression is working. That prompted a reader to ask me how to monitor the hit rate of lookups in the cache of decompressed column values. She was very surprised by my answer…
Read on for Paul’s answer. I’d say that even with the information Paul discloses, I don’t think I’ve ever seen page compression be a bad idea in any system I’ve worked with. There are specific tables in which it’s a bad idea but never have I seen a situation in which I could not use page compression at all due to a performance impact.