This creates a bug, not fixes one. It's intentional that "insert into a"
is shown as returning zero rows, because that's what it did. If you'd
written "insert ... returning", you'd have gotten a different result:
Maybe I didn't understand you correctly, but I didn't touch the number of affected rows in EXPLAIN output.
It's just a simple patch that adds 1 row after using commands: EXPLAIN INSERT, EXPLAIN UPDATE, EXPLAIN DELETE.
It was done because the commands INSERT/UPDATE/DELETE return one row after execution: "UPDATE 7" or "INSERT 0 4".
EXPLAIN (ANALYZE) INSERT/UPDATE/DELETE does the same thing as these commands, but doesn't output this row. So I added it.
Patch is fixed. There is no row "EXPLAIN" in queries like:
postgres=# explain (analyze) select * from t;
QUERY PLAN
-----------------------------------------------------------------------------------------------
Seq Scan on t (cost=0.00..35.50 rows=2550 width=4) (actual time=0.064..0.075 rows=5 loops=1)
Planning Time: 1.639 ms
Execution Time: 0.215 ms
(3 rows)
EXPLAIN
What is about queries EXPLAIN INSERT/UPDATE/DELETE without ANALYZE?
Now it is outputting a row with 0 affected (inserted) rows at the end: "INSERT 0 0", "UPDATE 0". Example:
explain update a set n = 2;
QUERY PLAN
------------------------------------------------------------
Update on a (cost=0.00..35.50 rows=0 width=0)
-> Seq Scan on a (cost=0.00..35.50 rows=2550 width=10)
(2 rows)
UPDATE 0
Regards,
Damir Belyalov
Postgres Professional
