This commit adds a cascade_to_materializations flag to the scheduled
version of drop_chunks that behaves much like the one from manual
drop_chunks: if a hypertable that has a continuous aggregate tries to
drop chunks, and this flag is not set, the chunks will not be dropped.
This commit switches the remaining JOIN in the continuous_aggs_stats
view to LEFT JOIN. This way we'll still see info from the other columns
even when the background worker has not run yet.
This commit also switches the time fields to output text in the correct
format for the underlying time type.
Add the query definition to
timescaledb_information.continuous_aggregates.
The user query (specified in the CREATE VIEW stmt of a continuous
aggregate) is transformed in the process of creating a continuous
aggregate and this modified query is saved in the pg_rewrite catalog
tables. In order to display the original query, we create an internal
view which is a replica of the user query. This is used to display the
definition in timescaledb_information.continuous_aggregates.
As an alternative we could save the original user query in our internal
catalogs. But this approach involves replicating a lot of postgres code
and causes portability problems.
Add views so that users can see what the parameters are for policies they have created
and a separate view so that they can see policies that have been created and scheduled on hypertables.
Currently the view displays the current edition, expiry date, and
whether the license is expired. We're not displaying the license key
itself in the view as it can get rather long, and get be read via SHOW.
We also do not display the license's ID since that is for internal use.
