I am also suffering a very high performance hit if I rely on H5Oget_info. I downloaded the source code of version 1.10 and found the internal function
H5O_get_info(const H5O_loc_t *loc, hid_t dxpl_id, hbool_t want_ih_info, H5O_info_t *oinfo). That function has the parameter want_ih_info to skip walking the B-tree and getting heap metadata storage size. Unfortunately, the public function H5Oget_info sets this parameter to 'TRUE'. So for me it seems that the solution to the performance hit is almost available. Is there any chance that in the next release(s) this boolean parameter will somehow be directly settable using the public interface?
Best regards,
Vincent