The PostgreSQL source distribution includes several examples of index methods implemented using GiST. The core system currently provides text search support (indexing for tsvectorand 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_gist
B-tree equivalent functionality for several data typescube
Indexing for multidimensional cubeshstore
Module for storing (key, value) pairsintarray
RD-Tree for one-dimensional array of int4 valuesltree
Indexing for tree-like structurespg_trgm
Text similarity using trigram matchingseg
Indexing for “float ranges”