PG_MATVIEW

'd': indicates "deferred", which means that data is contained in the materialized view only when the view is refreshed for the first time.
'i': indicates "immediate", which means that the latest data is included when the materialized view is created.

PG_MATVIEW records materialized view information about the current node.

**Table 1** PG_MATVIEW columns
Column	Type	Description
mvid	oid	OID of the materialized view.
build_mode	char	Build mode of the materialized view. 'd': indicates "deferred", which means that data is contained in the materialized view only when the view is refreshed for the first time. 'i': indicates "immediate", which means that the latest data is included when the materialized view is created.
refresh_method	char	'c' indicates that the data is completely refreshed.
refresh_mode	char	Refresh mode of the materialized view. 'd': indicates manual refresh. 'a': indicates that the materialized view is always active and is automatically refreshed in the background.
rewrite_enable	boolean	Indicates whether query rewriting of the materialized view is supported.
active	boolean	Indicates whether the materialized view needs to be refreshed.
relnum	Int	Number of materialized view base tables.
start_time	timestamptz	Time when the materialized view is refreshed for the first time. If this parameter is left blank, the first refresh time is the current time plus the interval.
interval	interval	Interval for refreshing the materialized view.
refresh_time	timestamptz	Last refresh time of the materialized view.
refresh_finish_time	timestamptz	End time of the last refresh of a materialized view.