While the index merge access types certainly are useful
for a number of queries, there has been some frustration
expressed both from customers and the community about how
it...
- is not used when it should have been
- is used when ref access is obviously better
- merges suboptimal indexes
- is too restricted in which conditions can be used
I could come up with numerous examples of related bugs and feature requests dating back more than six years. To list a few: 17673, 30151, 23322, 65274, …
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