51.5. Limitations

GIN doesn't support full index scans due to their extreme inefficiency: because there are often many keys per value, each heap pointer will returned several times.

When extractQuery returns zero keys, GIN will emit an error: for different opclasses and strategies the semantic meaning of a void query may be different (for example, any array contains the void array, but they don't overlap the void array), and GIN can't suggest a reasonable answer.

GIN searches keys only by equality matching. This may be improved in future.