bitmap-index

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

问题 I have been "googling" at least for an hour but I was unable to find how to create a bitmap index in postgresql, so my question is very simple how to write this command (from oracle) in postgresql CREATE BITMAP INDEX name ON table (column); 回答1: The bitmap of pages is created dynamically for each query. It is not cached or re-used, and is discarded at the end of the bitmap index scan. It doesn't make sense to create the page bitmap in advance because its contents depend on the query