The problem of memory overflow when creating many small HNSWs

Hello, I found that using hnswlib to create many relatively small (the total number of points is guaranteed) HNSWs will explode very large. For example, if I create 1e6 hnsws of size 1, the expected memory should not exceed 100M. I directly output the storage space size, but when I actually run the program, it is killed. I don't know why?