At least in the articles on Plenty of Fish and Slashdot it was mentioned that one can achieve higher performance by creating read-only and write-only databases where possible. I have read the comments and tried unsuccessfully to find more information on the net about this. I still do not understand the concept. Can someone explain it in more detail, as well as recommend resources for further investigation? (Are there books written specifically about this technique?) I think it is a very important issue, because databases are oftentimes the bottleneck.