I've created a materialized view between a primary system (Oracle 18c) and an external system (Oracle 19c):
create materialized view primary_system.workorder_mv
build immediate
refresh force
on demand
start with sysdate next sysdate + (30/(60*60*24))
as
select
cast(workorderid as number(38,0)) as objectid,
wonum,
status,
--other fields
longitudex,
latitudey
from
external_system.workorder_vw@gistomax --view in external system that is served up by dblink (gistomax)
--the view looks like this: select * from workorder where isgis=1
create materialized view log on external_system.workorder with rowid;
The docs say materialized views are supposed to purge automatically:
Oracle automatically tracks which rows in a materialized view log have been used during the refreshes of materialized views, and purges these rows from the log so that the log does not grow endlessly. Because multiple simple materialized views can use the same materialized view log, rows already used to refresh one materialized view might still be needed to refresh another materialized view. Oracle does not delete rows from the log until all materialized views have used them.
- I don't have any other materialized views that reference the MV logs.
- Here are the MV log properties (Toad).
- Here is what
all_registered_mviews
looks like. - The MV has been syncing successfully. If I create or update records in the WORKORDER table in the external system, the records get synced to the primary system on the 30-second schedule.
Question:
So far, the MV log data doesn't seem to be purging automatically:
Why aren't' the MV logs automatically purging once the records are synced?
dba_registered_mviews
?can_use_log
is NO which means that the materialized view can't use the materialized view log. Since nothing is using the materialized view log, the log won't be purged-- it's assuming that you're going to be creating a materialized view that does use the log.