Re: Implicit rule created for materialized views

On Mon, Jun 3, 2013 at 1:06 PM, Kevin Grittner
<kevin(dot)grittner(at)enterprisedb(dot)com> wrote:
> 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.

OK.

> A materialized view is pretty much like a view, but with the results
> materialized.

Yeah, I get that, but what is confusing is that this now seems to be a
special kind of relation where there is an ON SELECT DO INSTEAD rule
which isn't actually executed on SELECTs from the view but at some
arbitrary time in the future.

> On Mon, Jun 3, 2013 at 6:58 AM, Dave Page <dpage(at)pgadmin(dot)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
>
>

--
Dave Page
Blog: http://pgsnake.blogspot.com
Twitter: @pgsnake

EnterpriseDB UK: http://www.enterprisedb.com
The Enterprise PostgreSQL Company