Re: GSoC - code of implementation of materialized views

2010/6/25 Pavel Baros <baros(dot)p(at)seznam(dot)cz>:
>> On http://github.com/pbaros/postgres can be seen changes and my attempt to
>> implement materialized views. The first commit to the repository implements
>> following:
>>
>> Materialized view can be created, dropped and used in SELECT statement.
>>
>> CREATE MATERIALIZED VIEW mvname AS SELECT ...;
>> DROP MATERIALIZED VIEW mvname [CASCADE];
>> SELECT * FROM mvname;
>>
>> also works:
>> COMMENT ON MATERIALIZED VIEW mvname IS 'etc.';
>> SELECT pg_get_viewdef(mvname);
>
>
> ... also you can look at enclosed patch.

So, this patch doesn't actually seem to do very much. It doesn't
appear that creating the materialized view actually populates it with
any data; and the refresh command doesn't work either. So it appears
that you can create a "materialized view", but it won't actually
contain any data - which doesn't seem at all useful.

Some other problems:

- The command tag for CREATE MATERIALIZED VIEW should return CREATE
MATERIALIZED VIEW rather than CREATE VIEW, since we're treating it as
a separate object type. I note that dropping a materialized view
already uses DROP MATERIALIZED VIEW, so right now it isn't
symmetrical.
- Using "\d" with no argument doesn't list materialized views.
- Using "\d" with a materialized view as an argument doesn't work
properly - the first line says something like ?m? "public.m" instead
of materialized view "public.m".
- Using "\d+" with a materialized view as an argument should probably
should the view definition.
- Using "\dd" doesn't list comments on materialized views.
- Commenting on a column of a materialized view should probably be allowed.
- pg_dump fails with a message like this: failed sanity check, parent
table OID 24604 of pg_rewrite entry OID 24607 not found
- ALTER MATERIALIZED VIEW name OWNER TO role, RENAME TO role, and SET
SCHEMA schema either fall to work or fail to parse (plan ALTER VIEW
also doesn't work on a materialized view)
- ALTER MATERIALIZED VIEW name SET/DROP DEFAULT also doesn't work,
which is OK: it shouldn't work. But the error message needs work.
- The error message "CREATE OR REPLACE on materialized view is not
support!" shouldn't end with an exclamation point.
- The parser token OptMater should probably be called OptMaterialized
or opt_materialized, rather than abbreviating.
- There are no docs.
- There are no tests.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise Postgres Company