tedster - 8:32 pm on Sep 5, 2009 (gmt 0)

It's the complexity effect - the GFS isn't like a mysql database. Data is sharded into various kinds of pieces and then stored across a huge server farm. When a query comes in, that data (now in smithereens) gets accessed and re-assembled into SERPs -- with all kinds of odd anomalies along the way.

Remember the last major infrastructure change - Big Daddy? That didn't even go down as deep as changing the file structure itself.