问题
If we put the select performance aside, which one is faster when it comes to insert. I couldn't find any thorough explanation for this. Can someone please explain? This question just labels bitmaps as inefficient but I want to know why.
Thanks,
回答1:
Bitmap indexes can be problematic for inserts if there is contention. If you have a single thread doing the inserts they are fine, but if there are multiple threads doing inserts and perhaps updates and deletes they tend to limit performance due to locking.
A single key in the index may point to a large number of records, so when the index is changed many rows are locked.
As a general rule, go for normal indexes. In special cases bitmap indexes can shine - normally for read-mostly applications rather than OLTP systems.
来源：https://stackoverflow.com/questions/41852423/insert-performance-bitmap-vs-b-tree