Yes, that is currently used for REFRESH, and will be used to drive the incremental maintenance when that is added. Without it, CREATE MATERIALIZED VIEW wouldn't be different from CREATE TABLE AS.
A materialized view is pretty much like a view, but with the results materialized. -Kevin On Mon, Jun 3, 2013 at 6:58 AM, Dave Page <dp...@pgadmin.org> wrote: > Hi > > In playing with materialized views, I noticed that they still seem to > have an _RETURN rule implicitly created like a regular view. This > doesn't seem right to me - is there a reason? > > viper:~ dpage$ /usr/local/pgsql-9.3/bin/psql -p 5433 -U postgres > psql (9.3beta1) > Type "help" for help. > > postgres=# CREATE MATERIALIZED VIEW ruletest AS SELECT * FROM pg_class; > SELECT 298 > postgres=# SELECT pg_get_ruledef(oid) FROM pg_rewrite WHERE ev_class = > 'ruletest'::regclass; > pg_get_ruledef > ----------------------------------------------------------------- > CREATE RULE "_RETURN" AS + > ON SELECT TO ruletest DO INSTEAD SELECT pg_class.relname, + > pg_class.relnamespace, + > pg_class.reltype, + > pg_class.reloftype, + > pg_class.relowner, + > pg_class.relam, + > pg_class.relfilenode, + > pg_class.reltablespace, + > pg_class.relpages, + > pg_class.reltuples, + > pg_class.relallvisible, + > pg_class.reltoastrelid, + > pg_class.reltoastidxid, + > pg_class.relhasindex, + > pg_class.relisshared, + > pg_class.relpersistence, + > pg_class.relkind, + > pg_class.relnatts, + > pg_class.relchecks, + > pg_class.relhasoids, + > pg_class.relhaspkey, + > pg_class.relhasrules, + > pg_class.relhastriggers, + > pg_class.relhassubclass, + > pg_class.relispopulated, + > pg_class.relfrozenxid, + > pg_class.relminmxid, + > pg_class.relacl, + > pg_class.reloptions + > FROM pg_class; > (1 row) > > > -- > Dave Page > Blog: http://pgsnake.blogspot.com > Twitter: @pgsnake > > EnterpriseDB UK: http://www.enterprisedb.com > The Enterprise PostgreSQL Company >
