Hi , I have a field in collection and it contains values like "-" but when i try to pull that record with the filter fieldname:["-"] in filter_by i get zero records ,

Hyphens are not indexed by default. You have to add them to

symbols_to_index

in collection configuration if you wish to search or filter on it.

After adding

symbols_to_index

Should i update typesense using patch method?

We don't support adding

symbols_to_index

via PATCH alter. You have to recreate the collection.

That means whole collection on typesense needs to be dropped and restored again ?

Yes