GIN Index

A Gin Index is an index structure which stores a set of (key, posting list) pairs.

This is useful for full-text search (e.g. for a search engine).

GIN allows the following operations:

contains: value_array @> query_array
overlap: value_array && query_array
contained: value_array <@ query_array

and can be created this way:

create index gin_idx on aa using gin(a);

You can set fuzzy search with a GIN index using gin_fuzzy_search_limit.

Limitations:

No support for multicolumn indices
Gin doesn't uses scan->kill_prior_tuple & scan->ignore_killed_tuples
Gin searches entries only by equality matching. This may be improved in future.
Gin doesn't support full scans of indices.
Gin doesn't index NULL values.