G
George Potemkin
Guest
> imo, it is a largely useless metric. It can't explain/predict, for example, how long dbanalys will scan RM chains. Of course, an application does not scan these chains. But scatter factor can't also explain the time to scan the free cluster chain - the clusters that were owned by the real but now deleted objects. Dbanalys scans them a few times slower than the sequencial scan dirung "Area Block Analysis" phase. > more useful to know would be "if i use index x, how well does its ordering match the physical storage ordering and how many i/o's will that require?" It's exactly what my SeekRatio.p program does: ftp://ftp.progress-tech.ru/pub/Users/george/Programs/SeekRatio.p You can see the huge difference between the indexes even in the sports database. Best regards, George
Continue reading...
Continue reading...