The Postgres Pro Enterprise source distribution includes
several examples of index methods implemented using
GiST. The core system currently provides text search
support (indexing for tsvector and tsquery) as well as
R-Tree equivalent functionality for some of the built-in geometric data types
(see src/backend/access/gist/gistproc.c). The following
contrib modules also contain GiST
operator classes:
btree_gistB-tree equivalent functionality for several data types
cubeIndexing for multidimensional cubes
hstoreModule for storing (key, value) pairs
intarrayRD-Tree for one-dimensional array of int4 values
ltreeIndexing for tree-like structures
pg_trgmText similarity using trigram matching
segIndexing for “float ranges”