This particular use case is for user behavior data mining. The hardware is beefy, and has tablespaces split out onto SSD/spindle for new & old data. All of my queries are pretty much a nightly cron process, and I don't really care too much about the speed. Scanning the full 4 years of data takes about 30 seconds per query anyway... but I thought it'd be nice to speed it up when the difference is milliseconds vs 30 seconds.