N-gram Bloom Filter Support

[aadant]

Describe the enhancement requested

Some database support bloom filters on n-grams from a String. This facilitates some operations like "like" operations.
Searching for a particular discriminant token with rare n-grams can be greatly sped up.

https://clickhouse.com/docs/optimize/skipping-indexes#bloom-filter-types

see ngrambf_v1

[aadant]

this one is language independent @wgtmac

[alamb]

• See also Token Bloom filter Support #489 (comment)

[alamb]

BTW it is possible today to add user defined indexes for this usecase

You can put such indices in Parquet files, as described here

• https://datafusion.apache.org/blog/2025/07/14/user-defined-parquet-indexes/

Or you can store such indices externally, as described here:

• https://datafusion.apache.org/blog/2025/08/15/external-parquet-indexes/