Once we have the diff table, we perform set-based DELETE and INSERT
operations against the materialized view, and discard both temporary tables.Here the temporary tables are "discard" meaning the temporary tables are deleted and the temporary tables' spaces are reclaimed immediately?Or the temporary tables are deleted and the spaces will be reclaimed by another mechanism?simplify:does refreshing materialized view make the database bloat.
The materialized view itself bloats. The temp tables are removed immediately (the “drop table” docs don’t say this explicitly though it the most logical behavior and implied by the fact it takes an access exclusive lock).
David J.