As I understand it, the current patch performs immediate IVM using AFTER STATEMENT trigger transition tables.
However, multiple tables can be modified *before* AFTER STATEMENT triggers are fired. CREATE TABLE example1 (a int); CREATE TABLE example2 (a int); CREATE INCREMENTAL MATERIALIZED VIEW mv AS SELECT example1.a, example2.a FROM example1 JOIN example2 ON a; WITH insert1 AS (INSERT INTO example1 VALUES (1)), insert2 AS (INSERT INTO example2 VALUES (1)) SELECT NULL; Changes to example1 are visible in an AFTER STATEMENT trigger on example2, and vice versa. Would this not result in the (1, 1) tuple being "double-counted"? IVM needs to either: (1) Evaluate deltas "serially' (e.g. EACH ROW triggers) (2) Have simultaneous access to multiple deltas: delta_mv = example1 x delta_example2 + example2 x delta_example1 - delta_example1 x delta_example2 This latter method is the "logged" approach that has been discussed for deferred evaluation. tl;dr It seems that AFTER STATEMENT triggers required a deferred-like implementation anyway.
