Recommended ef_construct and m Values for Large Collections

[yanpeng7]

I currently have a collection of around 8*10^8 dim 256 image vectors and I was wondering in your experience what the optimal values for m and ef_construct are. Currently we are just using the default value of 16 and 100. If the time to compute the index is not an issue, should we just increase those 2 values and are we going to hit diminishing returns at certain values?
Furthermore, what is the difference between setting hnsw_config in the top level of create_collection vs in the params/vectors struct of create_collection?
Thanks in advance!

[generall]

. If the time to compute the index is not an issue

Usually, values beyond m=64, ef_construct=512 won't won't give much more improvement.

Furthermore, what is the difference between setting hnsw_config in the top level of create_collection vs in the params/vectors struct of create_collection?

No difference, qdrant simply allows to specify configuration for each individual vector field, in case you are using multi-vector setup.