... GiST . ... GiST is now concurrent and have recovery support ! The gist of our work is that all GiST based extensions, such as tsearch2, ltree, intarray, PosGIS automatically inherit concurrency and recovery support after upgrading of PostgreSQL software and thereby provides applications an industrial strength. ... However, current GiST implementation (as of 8.0.3) still doesn't support concurrent access, transactional isolation or recovery, which PostgreSQL provides for B-tree access method. ...