Okay, I am on sql server 2012 sp2. I am doing a simple update on some large tables where there is an int column that allows nulls and I am changing the null values to be equal to the values in another integer column in the same table. (Please don't ask why I am doing dup data as that is a long story!)
So it's a very simple update and these tables are about 65 million rows I believe and so you can calculate how much space it should increase by. Basically, it should increase by 8 bytes * 65 million = ~500Mbytes, right?
However, when I run these updates the space increases by about 3 G per table. What would cause this behavior?
Also, the fill factor on the server is 90% and this column is not in the PK or any of the 7 nonclustered indexes. The table is used in horizonal partitioning but it is not part of the constraint.
Any help is much appreciated...