I'm looking through the plan cache, looking for low-hanging optimization fruit and came across this snippet:
Why are many of the costs listed above 100% ? Shouldn't that be impossible?
The visual cost estimator is crap. This sort of stuff happens all the time. Just go with the highest ones are the most expensive and attack those ones first.
I'd been also curious about why sometimes some cost is displayed as 100%, 200%, 300%...and even more. After analyse xml file of query plan, i got it.
The cost percentage = my
For example, your query plan shows