From what I read on the web fragmentation can have a great impact on performance. So I've done a test... "luckily" some of my tables where highly fragmented. So I made my test with a table that was 98% fragmented and rebuilt its clustered index with
the alter index command. fragmentation dropped to 0%. BUT, my test results did not show any improvement in performance (I calculated the elapsed time that took for a simple query on that table with a where clause on the first column of the clustered index.
I used "dbcc dropcleanbuffers" before each run). "Problem" is that it took the same time before defragmentation (through rebuild) as after defragmentation. Is my test correct? If not, how do I check the performance fragmenation correctly?
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