issue: #29419
* If a sparse vector with 0 non-zero value is inserted, no ANN search on
this sparse vector field will return it as a result. User may retrieve
this row via scalar query or ANN search on another vector field though.
* If the user uses an empty sparse vector as the query vector for a ANN
search, no neighbor will be returned.
Signed-off-by: Buqian Zheng <zhengbuqian@gmail.com>
issue: #29419
added helper functions to parse JSON representation of sparse float
vectors, will be used by both the restful server and the import utils.
Signed-off-by: Buqian Zheng <zhengbuqian@gmail.com>