@yurymalkov : trying to understand when this can happen
I have an index where i have few hundred thousand elements , no deletions.
my topK is around range 100-500,, search_ef is ~400

Could you please elaborate in what scenarios can the algorithm run into such case ? what is the correct way to handle this
increasing M eads to increase in index sizes and slow search times , so i am not too inclined to go this route .