Previously, IMMV including IMMV in its definition can be created by
create_immv(), but it should not be supported by IMMV because we
cannot maintain it recursively for now. This patch prevents it by raising
an error for such view definition on create_immv().
Previously, we used an event trigger and executed DELETE command,
but it caused a privilege error when non-superuser dropped a table
even if it is irrelevant to IMMV.
To fix it, we now use object_access_hook and an entry is deleted
via CatalogTupleDelete which doesn't need the superuser privilege.
Issue #25
In order to re-calculate min/max values for groups where the min
or max value is deleted, we need the view query definition in string
form. However, pg_get_viewdef cannot be used for this purpose because
IMMV's defenition is in pg_ivm_immv but not pg_rewrite. Therefore,
we have to convert query definition in pg_ivm_immv to query
definition string. We can use pg_get_querydef in PG15, but we cannot
in PG14 or earlier, so we use codes in ruleutil.c copied from PG13
or PG14 depending versions.
- Allow to use qualified name
- Confirm if executed by the owner of the IMMV
- Improve the message when specified relation is not an IMMV
- Create a unique index at refresh with no dat if possible
This is actually required, but we want it behave as same
as the pgsql-ivm version for now.
refresh_immv(immv_name, with_data) is a function to refresh IMMV like
REFRESH MATERIALIZED VIEW command. It has two argument.
immv_name is incrementally maintainable materialized view's name, and
with_data is an option that is corresponding to the WITH [NO] DATA option.
When with_data is set false, the IMMV gets unpopulated.
One of differences between IMMVs unpopulated by this function and
normal materialized views unpopulated by REFRESH ... WITH NO DATA
is that such IMMVs can be referenced by SELECT but return no rows,
while unpopulated materialized views are not scanable.
The behaviour may be changed in future to raise an error when unpopulated
an IMMV is scanned.
