blake pointed out some psql documentation discouraging hash indexes:
15:36 < blake_r> jhobbs: Testing has shown PostgreSQL's hash indexes to perform no better than B-tree indexes, and the index size and build time for hash indexes is much worse. Furthermore, hash index operations are not presently WAL-logged, so hash indexes might need to be rebuilt with REINDEX after a database crash. For these reasons, hash index use is presently discouraged.
15:36 < blake_r> jhobbs: from psql documentation
blake pointed out some psql documentation discouraging hash indexes:
15:36 < blake_r> jhobbs: Testing has shown PostgreSQL's hash indexes to perform no better than B-tree indexes, and the index size and build time for hash indexes is
much worse. Furthermore, hash index operations are not presently WAL-logged, so hash indexes might need to be rebuilt with REINDEX after a database
crash. For these reasons, hash index use is presently discouraged.
15:36 < blake_r> jhobbs: from psql documentation