November 24, 2019 at 8:53 pm
I have a database called TestDB which is in simple recovery model. I performed index rebuild on my Test Server which has no other user transactions except me. Before an online index rebuild the sizes of mdf and ldf files were as below:
total size used free
mdf 13261 MB 13261 MB 0 MB
ldf 9697 MB 25 MB 9672 MB
After rebuilding of the largest index only with fragmentation percentage equivalent to 91% (size of index was approx 5858 MB) mdf and ldf files became as below:
total size used free
mdf 16854 MB 10061 MB 6792 MB
ldf 9697 MB 363 MB 9334 MB
The question is, if the size of the largest index was 5858 MB, and according to some books and resources on the internet which state that total size needed for rebuilding an index is equivalent to approx 120% of the largest index or maybe double size, then total size of mdf file after rebuilding should be just over 20000 MB, shouldn't it?
I calculated that like 5858*120%=7029 MB, and finally as we do not have space in mdf file then autogrowth will happen and final size of mdf will be 13261 MB + 7029 MB = 20.29 GB.
November 25, 2019 at 9:10 pm
Thanks for posting your issue and hopefully someone will answer soon.
This is an automated bump to increase visibility of your question.
December 3, 2019 at 7:04 am
What was the average percent of page fullness both before and after you started? I can show you how to make better estimates with that information and with knowing what the FILL FACTOR for the index is. The percent of fragmentation means nothing when it comes to page density.
--Jeff Moden
Change is inevitable... Change for the better is not.
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