"Mark Liberman" <mliberman@xxxxxxxxxxxxxxxx> wrote > > Now, my follow-up question / assumption. I am assuming that the IO time > is > so long on that index because it has to read the entire index (for that > file_id) into memory > > any confirmation / corrections to my assumptions are greatly appreciated. > E.g. is > the compound index the way to go, or the solo index on file_id? > Only part of the index file is read. It is a btree index. Keep the index smaller but sufficient to guide your search is always good because even by the guidiance of the index, a heap visit to get the real data is not avoidable. Regards, Qingqing
