RE: Implementing Incremental View Maintenance

From: Yugo Nagata <nagata(at)sraoss(dot)co(dot)jp>
> On Mon, 23 Dec 2019 08:08:53 +0000
> "tsunakawa(dot)takay(at)fujitsu(dot)com" <tsunakawa(dot)takay(at)fujitsu(dot)com> wrote:
> > How about unlogged tables ? I thought the point of using a temp table is to
> avoid WAL overhead.
>
> Hmm... this might be another option. However, if we use unlogged tables,
> we will need to create them in a special schema similar to pg_toast
> to split this from user tables. Otherwise, we need to create and drop
> unlogged tables repeatedly for each session.

Maybe we can create the work tables in the same schema as the materialized view, following:

* Prefix the table name to indicate that the table is system-managed, thus alluding to the user that manually deleting the table would break something. This is like the system attribute __imv_count you are proposing.

* Describe the above in the manual. Columns of serial and bigserial data type similarly create sequences behind the scenes.

* Make the work tables depend on the materialized view by recording the dependency in pg_depend, so that Dropping the materialized view will also drop its work tables.

Regards
Takayuki Tsunakawa