/
merge.out
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merge.out
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--
-- MERGE
--
CREATE USER regress_merge_privs;
CREATE USER regress_merge_no_privs;
CREATE USER regress_merge_none;
DROP TABLE IF EXISTS target;
NOTICE: table "target" does not exist, skipping
DROP TABLE IF EXISTS source;
NOTICE: table "source" does not exist, skipping
CREATE TABLE target (tid integer, balance integer)
WITH (autovacuum_enabled=off);
CREATE TABLE source (sid integer, delta integer) -- no index
WITH (autovacuum_enabled=off);
INSERT INTO target VALUES (1, 10);
INSERT INTO target VALUES (2, 20);
INSERT INTO target VALUES (3, 30);
SELECT t.ctid is not null as matched, t.*, s.* FROM source s FULL OUTER JOIN target t ON s.sid = t.tid ORDER BY t.tid, s.sid;
matched | tid | balance | sid | delta
---------+-----+---------+-----+-------
t | 1 | 10 | |
t | 2 | 20 | |
t | 3 | 30 | |
(3 rows)
ALTER TABLE target OWNER TO regress_merge_privs;
ALTER TABLE source OWNER TO regress_merge_privs;
CREATE TABLE target2 (tid integer, balance integer)
WITH (autovacuum_enabled=off);
CREATE TABLE source2 (sid integer, delta integer)
WITH (autovacuum_enabled=off);
ALTER TABLE target2 OWNER TO regress_merge_no_privs;
ALTER TABLE source2 OWNER TO regress_merge_no_privs;
GRANT INSERT ON target TO regress_merge_no_privs;
SET SESSION AUTHORIZATION regress_merge_privs;
EXPLAIN (COSTS OFF)
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED THEN
DELETE;
QUERY PLAN
----------------------------------------
Merge on target t
-> Merge Join
Merge Cond: (t.tid = s.sid)
-> Sort
Sort Key: t.tid
-> Seq Scan on target t
-> Sort
Sort Key: s.sid
-> Seq Scan on source s
(9 rows)
--
-- Errors
--
MERGE INTO target t RANDOMWORD
USING source AS s
ON t.tid = s.sid
WHEN MATCHED THEN
UPDATE SET balance = 0;
ERROR: syntax error at or near "RANDOMWORD"
LINE 1: MERGE INTO target t RANDOMWORD
^
-- MATCHED/INSERT error
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED THEN
INSERT DEFAULT VALUES;
ERROR: syntax error at or near "INSERT"
LINE 5: INSERT DEFAULT VALUES;
^
-- incorrectly specifying INTO target
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN NOT MATCHED THEN
INSERT INTO target DEFAULT VALUES;
ERROR: syntax error at or near "INTO"
LINE 5: INSERT INTO target DEFAULT VALUES;
^
-- Multiple VALUES clause
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN NOT MATCHED THEN
INSERT VALUES (1,1), (2,2);
ERROR: syntax error at or near ","
LINE 5: INSERT VALUES (1,1), (2,2);
^
-- SELECT query for INSERT
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN NOT MATCHED THEN
INSERT SELECT (1, 1);
ERROR: syntax error at or near "SELECT"
LINE 5: INSERT SELECT (1, 1);
^
-- NOT MATCHED/UPDATE
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN NOT MATCHED THEN
UPDATE SET balance = 0;
ERROR: syntax error at or near "UPDATE"
LINE 5: UPDATE SET balance = 0;
^
-- UPDATE tablename
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED THEN
UPDATE target SET balance = 0;
ERROR: syntax error at or near "target"
LINE 5: UPDATE target SET balance = 0;
^
-- source and target names the same
MERGE INTO target
USING target
ON tid = tid
WHEN MATCHED THEN DO NOTHING;
ERROR: name "target" specified more than once
DETAIL: The name is used both as MERGE target table and data source.
-- used in a CTE
WITH foo AS (
MERGE INTO target USING source ON (true)
WHEN MATCHED THEN DELETE
) SELECT * FROM foo;
ERROR: MERGE not supported in WITH query
LINE 1: WITH foo AS (
^
-- used in COPY
COPY (
MERGE INTO target USING source ON (true)
WHEN MATCHED THEN DELETE
) TO stdout;
ERROR: MERGE not supported in COPY
-- unsupported relation types
-- view
CREATE VIEW tv AS SELECT * FROM target;
MERGE INTO tv t
USING source s
ON t.tid = s.sid
WHEN NOT MATCHED THEN
INSERT DEFAULT VALUES;
ERROR: cannot execute MERGE on relation "tv"
DETAIL: This operation is not supported for views.
DROP VIEW tv;
-- materialized view
CREATE MATERIALIZED VIEW mv AS SELECT * FROM target;
MERGE INTO mv t
USING source s
ON t.tid = s.sid
WHEN NOT MATCHED THEN
INSERT DEFAULT VALUES;
ERROR: cannot execute MERGE on relation "mv"
DETAIL: This operation is not supported for materialized views.
DROP MATERIALIZED VIEW mv;
-- permissions
SET SESSION AUTHORIZATION regress_merge_none;
MERGE INTO target
USING (SELECT 1) AS s
ON true
WHEN MATCHED THEN
DO NOTHING;
ERROR: permission denied for table target
SET SESSION AUTHORIZATION regress_merge_privs;
MERGE INTO target
USING source2
ON target.tid = source2.sid
WHEN MATCHED THEN
UPDATE SET balance = 0;
ERROR: permission denied for table source2
GRANT INSERT ON target TO regress_merge_no_privs;
SET SESSION AUTHORIZATION regress_merge_no_privs;
MERGE INTO target
USING source2
ON target.tid = source2.sid
WHEN MATCHED THEN
UPDATE SET balance = 0;
ERROR: permission denied for table target
GRANT UPDATE ON target2 TO regress_merge_privs;
SET SESSION AUTHORIZATION regress_merge_privs;
MERGE INTO target2
USING source
ON target2.tid = source.sid
WHEN MATCHED THEN
DELETE;
ERROR: permission denied for table target2
MERGE INTO target2
USING source
ON target2.tid = source.sid
WHEN NOT MATCHED THEN
INSERT DEFAULT VALUES;
ERROR: permission denied for table target2
-- check if the target can be accessed from source relation subquery; we should
-- not be able to do so
MERGE INTO target t
USING (SELECT * FROM source WHERE t.tid > sid) s
ON t.tid = s.sid
WHEN NOT MATCHED THEN
INSERT DEFAULT VALUES;
ERROR: invalid reference to FROM-clause entry for table "t"
LINE 2: USING (SELECT * FROM source WHERE t.tid > sid) s
^
HINT: There is an entry for table "t", but it cannot be referenced from this part of the query.
--
-- initial tests
--
-- zero rows in source has no effect
MERGE INTO target
USING source
ON target.tid = source.sid
WHEN MATCHED THEN
UPDATE SET balance = 0;
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED THEN
UPDATE SET balance = 0;
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED THEN
DELETE;
BEGIN;
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN NOT MATCHED THEN
INSERT DEFAULT VALUES;
ROLLBACK;
-- insert some non-matching source rows to work from
INSERT INTO source VALUES (4, 40);
SELECT * FROM source ORDER BY sid;
sid | delta
-----+-------
4 | 40
(1 row)
SELECT * FROM target ORDER BY tid;
tid | balance
-----+---------
1 | 10
2 | 20
3 | 30
(3 rows)
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN NOT MATCHED THEN
DO NOTHING;
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED THEN
UPDATE SET balance = 0;
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED THEN
DELETE;
BEGIN;
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN NOT MATCHED THEN
INSERT DEFAULT VALUES;
SELECT * FROM target ORDER BY tid;
tid | balance
-----+---------
1 | 10
2 | 20
3 | 30
|
(4 rows)
ROLLBACK;
-- index plans
INSERT INTO target SELECT generate_series(1000,2500), 0;
ALTER TABLE target ADD PRIMARY KEY (tid);
ANALYZE target;
EXPLAIN (COSTS OFF)
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED THEN
UPDATE SET balance = 0;
QUERY PLAN
----------------------------------------
Merge on target t
-> Hash Join
Hash Cond: (s.sid = t.tid)
-> Seq Scan on source s
-> Hash
-> Seq Scan on target t
(6 rows)
EXPLAIN (COSTS OFF)
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED THEN
DELETE;
QUERY PLAN
----------------------------------------
Merge on target t
-> Hash Join
Hash Cond: (s.sid = t.tid)
-> Seq Scan on source s
-> Hash
-> Seq Scan on target t
(6 rows)
EXPLAIN (COSTS OFF)
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN NOT MATCHED THEN
INSERT VALUES (4, NULL);
QUERY PLAN
----------------------------------------
Merge on target t
-> Hash Left Join
Hash Cond: (s.sid = t.tid)
-> Seq Scan on source s
-> Hash
-> Seq Scan on target t
(6 rows)
DELETE FROM target WHERE tid > 100;
ANALYZE target;
-- insert some matching source rows to work from
INSERT INTO source VALUES (2, 5);
INSERT INTO source VALUES (3, 20);
SELECT * FROM source ORDER BY sid;
sid | delta
-----+-------
2 | 5
3 | 20
4 | 40
(3 rows)
SELECT * FROM target ORDER BY tid;
tid | balance
-----+---------
1 | 10
2 | 20
3 | 30
(3 rows)
-- equivalent of an UPDATE join
BEGIN;
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED THEN
UPDATE SET balance = 0;
SELECT * FROM target ORDER BY tid;
tid | balance
-----+---------
1 | 10
2 | 0
3 | 0
(3 rows)
ROLLBACK;
-- equivalent of a DELETE join
BEGIN;
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED THEN
DELETE;
SELECT * FROM target ORDER BY tid;
tid | balance
-----+---------
1 | 10
(1 row)
ROLLBACK;
BEGIN;
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED THEN
DO NOTHING;
SELECT * FROM target ORDER BY tid;
tid | balance
-----+---------
1 | 10
2 | 20
3 | 30
(3 rows)
ROLLBACK;
BEGIN;
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN NOT MATCHED THEN
INSERT VALUES (4, NULL);
SELECT * FROM target ORDER BY tid;
tid | balance
-----+---------
1 | 10
2 | 20
3 | 30
4 |
(4 rows)
ROLLBACK;
-- duplicate source row causes multiple target row update ERROR
INSERT INTO source VALUES (2, 5);
SELECT * FROM source ORDER BY sid;
sid | delta
-----+-------
2 | 5
2 | 5
3 | 20
4 | 40
(4 rows)
SELECT * FROM target ORDER BY tid;
tid | balance
-----+---------
1 | 10
2 | 20
3 | 30
(3 rows)
BEGIN;
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED THEN
UPDATE SET balance = 0;
ERROR: MERGE command cannot affect row a second time
HINT: Ensure that not more than one source row matches any one target row.
ROLLBACK;
BEGIN;
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED THEN
DELETE;
ERROR: MERGE command cannot affect row a second time
HINT: Ensure that not more than one source row matches any one target row.
ROLLBACK;
-- remove duplicate MATCHED data from source data
DELETE FROM source WHERE sid = 2;
INSERT INTO source VALUES (2, 5);
SELECT * FROM source ORDER BY sid;
sid | delta
-----+-------
2 | 5
3 | 20
4 | 40
(3 rows)
SELECT * FROM target ORDER BY tid;
tid | balance
-----+---------
1 | 10
2 | 20
3 | 30
(3 rows)
-- duplicate source row on INSERT should fail because of target_pkey
INSERT INTO source VALUES (4, 40);
BEGIN;
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN NOT MATCHED THEN
INSERT VALUES (4, NULL);
ERROR: duplicate key value violates unique constraint "target_pkey"
DETAIL: Key (tid)=(4) already exists.
SELECT * FROM target ORDER BY tid;
ERROR: current transaction is aborted, commands ignored until end of transaction block
ROLLBACK;
-- remove duplicate NOT MATCHED data from source data
DELETE FROM source WHERE sid = 4;
INSERT INTO source VALUES (4, 40);
SELECT * FROM source ORDER BY sid;
sid | delta
-----+-------
2 | 5
3 | 20
4 | 40
(3 rows)
SELECT * FROM target ORDER BY tid;
tid | balance
-----+---------
1 | 10
2 | 20
3 | 30
(3 rows)
-- remove constraints
alter table target drop CONSTRAINT target_pkey;
alter table target alter column tid drop not null;
-- multiple actions
BEGIN;
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN NOT MATCHED THEN
INSERT VALUES (4, 4)
WHEN MATCHED THEN
UPDATE SET balance = 0;
SELECT * FROM target ORDER BY tid;
tid | balance
-----+---------
1 | 10
2 | 0
3 | 0
4 | 4
(4 rows)
ROLLBACK;
-- should be equivalent
BEGIN;
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED THEN
UPDATE SET balance = 0
WHEN NOT MATCHED THEN
INSERT VALUES (4, 4);
SELECT * FROM target ORDER BY tid;
tid | balance
-----+---------
1 | 10
2 | 0
3 | 0
4 | 4
(4 rows)
ROLLBACK;
-- column references
-- do a simple equivalent of an UPDATE join
BEGIN;
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED THEN
UPDATE SET balance = t.balance + s.delta;
SELECT * FROM target ORDER BY tid;
tid | balance
-----+---------
1 | 10
2 | 25
3 | 50
(3 rows)
ROLLBACK;
-- do a simple equivalent of an INSERT SELECT
BEGIN;
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN NOT MATCHED THEN
INSERT VALUES (s.sid, s.delta);
SELECT * FROM target ORDER BY tid;
tid | balance
-----+---------
1 | 10
2 | 20
3 | 30
4 | 40
(4 rows)
ROLLBACK;
-- and again with duplicate source rows
INSERT INTO source VALUES (5, 50);
INSERT INTO source VALUES (5, 50);
-- do a simple equivalent of an INSERT SELECT
BEGIN;
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN NOT MATCHED THEN
INSERT VALUES (s.sid, s.delta);
SELECT * FROM target ORDER BY tid;
tid | balance
-----+---------
1 | 10
2 | 20
3 | 30
4 | 40
5 | 50
5 | 50
(6 rows)
ROLLBACK;
-- removing duplicate source rows
DELETE FROM source WHERE sid = 5;
-- and again with explicitly identified column list
BEGIN;
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN NOT MATCHED THEN
INSERT (tid, balance) VALUES (s.sid, s.delta);
SELECT * FROM target ORDER BY tid;
tid | balance
-----+---------
1 | 10
2 | 20
3 | 30
4 | 40
(4 rows)
ROLLBACK;
-- and again with a subtle error: referring to non-existent target row for NOT MATCHED
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN NOT MATCHED THEN
INSERT (tid, balance) VALUES (t.tid, s.delta);
ERROR: invalid reference to FROM-clause entry for table "t"
LINE 5: INSERT (tid, balance) VALUES (t.tid, s.delta);
^
HINT: There is an entry for table "t", but it cannot be referenced from this part of the query.
-- and again with a constant ON clause
BEGIN;
MERGE INTO target t
USING source AS s
ON (SELECT true)
WHEN NOT MATCHED THEN
INSERT (tid, balance) VALUES (t.tid, s.delta);
ERROR: invalid reference to FROM-clause entry for table "t"
LINE 5: INSERT (tid, balance) VALUES (t.tid, s.delta);
^
HINT: There is an entry for table "t", but it cannot be referenced from this part of the query.
SELECT * FROM target ORDER BY tid;
ERROR: current transaction is aborted, commands ignored until end of transaction block
ROLLBACK;
-- now the classic UPSERT
BEGIN;
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED THEN
UPDATE SET balance = t.balance + s.delta
WHEN NOT MATCHED THEN
INSERT VALUES (s.sid, s.delta);
SELECT * FROM target ORDER BY tid;
tid | balance
-----+---------
1 | 10
2 | 25
3 | 50
4 | 40
(4 rows)
ROLLBACK;
-- unreachable WHEN clause should ERROR
BEGIN;
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED THEN /* Terminal WHEN clause for MATCHED */
DELETE
WHEN MATCHED THEN
UPDATE SET balance = t.balance - s.delta;
ERROR: unreachable WHEN clause specified after unconditional WHEN clause
ROLLBACK;
-- conditional WHEN clause
CREATE TABLE wq_target (tid integer not null, balance integer DEFAULT -1)
WITH (autovacuum_enabled=off);
CREATE TABLE wq_source (balance integer, sid integer)
WITH (autovacuum_enabled=off);
INSERT INTO wq_source (sid, balance) VALUES (1, 100);
BEGIN;
-- try a simple INSERT with default values first
MERGE INTO wq_target t
USING wq_source s ON t.tid = s.sid
WHEN NOT MATCHED THEN
INSERT (tid) VALUES (s.sid);
SELECT * FROM wq_target;
tid | balance
-----+---------
1 | -1
(1 row)
ROLLBACK;
-- this time with a FALSE condition
MERGE INTO wq_target t
USING wq_source s ON t.tid = s.sid
WHEN NOT MATCHED AND FALSE THEN
INSERT (tid) VALUES (s.sid);
SELECT * FROM wq_target;
tid | balance
-----+---------
(0 rows)
-- this time with an actual condition which returns false
MERGE INTO wq_target t
USING wq_source s ON t.tid = s.sid
WHEN NOT MATCHED AND s.balance <> 100 THEN
INSERT (tid) VALUES (s.sid);
SELECT * FROM wq_target;
tid | balance
-----+---------
(0 rows)
BEGIN;
-- and now with a condition which returns true
MERGE INTO wq_target t
USING wq_source s ON t.tid = s.sid
WHEN NOT MATCHED AND s.balance = 100 THEN
INSERT (tid) VALUES (s.sid);
SELECT * FROM wq_target;
tid | balance
-----+---------
1 | -1
(1 row)
ROLLBACK;
-- conditions in the NOT MATCHED clause can only refer to source columns
BEGIN;
MERGE INTO wq_target t
USING wq_source s ON t.tid = s.sid
WHEN NOT MATCHED AND t.balance = 100 THEN
INSERT (tid) VALUES (s.sid);
ERROR: invalid reference to FROM-clause entry for table "t"
LINE 3: WHEN NOT MATCHED AND t.balance = 100 THEN
^
HINT: There is an entry for table "t", but it cannot be referenced from this part of the query.
SELECT * FROM wq_target;
ERROR: current transaction is aborted, commands ignored until end of transaction block
ROLLBACK;
MERGE INTO wq_target t
USING wq_source s ON t.tid = s.sid
WHEN NOT MATCHED AND s.balance = 100 THEN
INSERT (tid) VALUES (s.sid);
SELECT * FROM wq_target;
tid | balance
-----+---------
1 | -1
(1 row)
-- conditions in MATCHED clause can refer to both source and target
SELECT * FROM wq_source;
balance | sid
---------+-----
100 | 1
(1 row)
MERGE INTO wq_target t
USING wq_source s ON t.tid = s.sid
WHEN MATCHED AND s.balance = 100 THEN
UPDATE SET balance = t.balance + s.balance;
SELECT * FROM wq_target;
tid | balance
-----+---------
1 | 99
(1 row)
MERGE INTO wq_target t
USING wq_source s ON t.tid = s.sid
WHEN MATCHED AND t.balance = 100 THEN
UPDATE SET balance = t.balance + s.balance;
SELECT * FROM wq_target;
tid | balance
-----+---------
1 | 99
(1 row)
-- check if AND works
MERGE INTO wq_target t
USING wq_source s ON t.tid = s.sid
WHEN MATCHED AND t.balance = 99 AND s.balance > 100 THEN
UPDATE SET balance = t.balance + s.balance;
SELECT * FROM wq_target;
tid | balance
-----+---------
1 | 99
(1 row)
MERGE INTO wq_target t
USING wq_source s ON t.tid = s.sid
WHEN MATCHED AND t.balance = 99 AND s.balance = 100 THEN
UPDATE SET balance = t.balance + s.balance;
SELECT * FROM wq_target;
tid | balance
-----+---------
1 | 199
(1 row)
-- check if OR works
MERGE INTO wq_target t
USING wq_source s ON t.tid = s.sid
WHEN MATCHED AND t.balance = 99 OR s.balance > 100 THEN
UPDATE SET balance = t.balance + s.balance;
SELECT * FROM wq_target;
tid | balance
-----+---------
1 | 199
(1 row)
MERGE INTO wq_target t
USING wq_source s ON t.tid = s.sid
WHEN MATCHED AND t.balance = 199 OR s.balance > 100 THEN
UPDATE SET balance = t.balance + s.balance;
SELECT * FROM wq_target;
tid | balance
-----+---------
1 | 299
(1 row)
-- check source-side whole-row references
BEGIN;
MERGE INTO wq_target t
USING wq_source s ON (t.tid = s.sid)
WHEN matched and t = s or t.tid = s.sid THEN
UPDATE SET balance = t.balance + s.balance;
SELECT * FROM wq_target;
tid | balance
-----+---------
1 | 399
(1 row)
ROLLBACK;
-- check if subqueries work in the conditions?
MERGE INTO wq_target t
USING wq_source s ON t.tid = s.sid
WHEN MATCHED AND t.balance > (SELECT max(balance) FROM target) THEN
UPDATE SET balance = t.balance + s.balance;
-- check if we can access system columns in the conditions
MERGE INTO wq_target t
USING wq_source s ON t.tid = s.sid
WHEN MATCHED AND t.xmin = t.xmax THEN
UPDATE SET balance = t.balance + s.balance;
ERROR: cannot use system column "xmin" in MERGE WHEN condition
LINE 3: WHEN MATCHED AND t.xmin = t.xmax THEN
^
MERGE INTO wq_target t
USING wq_source s ON t.tid = s.sid
WHEN MATCHED AND t.tableoid >= 0 THEN
UPDATE SET balance = t.balance + s.balance;
SELECT * FROM wq_target;
tid | balance
-----+---------
1 | 499
(1 row)
DROP TABLE wq_target, wq_source;
-- test triggers
create or replace function merge_trigfunc () returns trigger
language plpgsql as
$$
DECLARE
line text;
BEGIN
SELECT INTO line format('%s %s %s trigger%s',
TG_WHEN, TG_OP, TG_LEVEL, CASE
WHEN TG_OP = 'INSERT' AND TG_LEVEL = 'ROW'
THEN format(' row: %s', NEW)
WHEN TG_OP = 'UPDATE' AND TG_LEVEL = 'ROW'
THEN format(' row: %s -> %s', OLD, NEW)
WHEN TG_OP = 'DELETE' AND TG_LEVEL = 'ROW'
THEN format(' row: %s', OLD)
END);
RAISE NOTICE '%', line;
IF (TG_WHEN = 'BEFORE' AND TG_LEVEL = 'ROW') THEN
IF (TG_OP = 'DELETE') THEN
RETURN OLD;
ELSE
RETURN NEW;
END IF;
ELSE
RETURN NULL;
END IF;
END;
$$;
CREATE TRIGGER merge_bsi BEFORE INSERT ON target FOR EACH STATEMENT EXECUTE PROCEDURE merge_trigfunc ();
CREATE TRIGGER merge_bsu BEFORE UPDATE ON target FOR EACH STATEMENT EXECUTE PROCEDURE merge_trigfunc ();
CREATE TRIGGER merge_bsd BEFORE DELETE ON target FOR EACH STATEMENT EXECUTE PROCEDURE merge_trigfunc ();
CREATE TRIGGER merge_asi AFTER INSERT ON target FOR EACH STATEMENT EXECUTE PROCEDURE merge_trigfunc ();
CREATE TRIGGER merge_asu AFTER UPDATE ON target FOR EACH STATEMENT EXECUTE PROCEDURE merge_trigfunc ();
CREATE TRIGGER merge_asd AFTER DELETE ON target FOR EACH STATEMENT EXECUTE PROCEDURE merge_trigfunc ();
CREATE TRIGGER merge_bri BEFORE INSERT ON target FOR EACH ROW EXECUTE PROCEDURE merge_trigfunc ();
CREATE TRIGGER merge_bru BEFORE UPDATE ON target FOR EACH ROW EXECUTE PROCEDURE merge_trigfunc ();
CREATE TRIGGER merge_brd BEFORE DELETE ON target FOR EACH ROW EXECUTE PROCEDURE merge_trigfunc ();
CREATE TRIGGER merge_ari AFTER INSERT ON target FOR EACH ROW EXECUTE PROCEDURE merge_trigfunc ();
CREATE TRIGGER merge_aru AFTER UPDATE ON target FOR EACH ROW EXECUTE PROCEDURE merge_trigfunc ();
CREATE TRIGGER merge_ard AFTER DELETE ON target FOR EACH ROW EXECUTE PROCEDURE merge_trigfunc ();
-- now the classic UPSERT, with a DELETE
BEGIN;
UPDATE target SET balance = 0 WHERE tid = 3;
NOTICE: BEFORE UPDATE STATEMENT trigger
NOTICE: BEFORE UPDATE ROW trigger row: (3,30) -> (3,0)
NOTICE: AFTER UPDATE ROW trigger row: (3,30) -> (3,0)
NOTICE: AFTER UPDATE STATEMENT trigger
--EXPLAIN (ANALYZE ON, COSTS OFF, SUMMARY OFF, TIMING OFF)
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED AND t.balance > s.delta THEN
UPDATE SET balance = t.balance - s.delta
WHEN MATCHED THEN
DELETE
WHEN NOT MATCHED THEN
INSERT VALUES (s.sid, s.delta);
NOTICE: BEFORE INSERT STATEMENT trigger
NOTICE: BEFORE UPDATE STATEMENT trigger
NOTICE: BEFORE DELETE STATEMENT trigger
NOTICE: BEFORE DELETE ROW trigger row: (3,0)
NOTICE: BEFORE UPDATE ROW trigger row: (2,20) -> (2,15)
NOTICE: BEFORE INSERT ROW trigger row: (4,40)
NOTICE: AFTER DELETE ROW trigger row: (3,0)
NOTICE: AFTER UPDATE ROW trigger row: (2,20) -> (2,15)
NOTICE: AFTER INSERT ROW trigger row: (4,40)
NOTICE: AFTER DELETE STATEMENT trigger
NOTICE: AFTER UPDATE STATEMENT trigger
NOTICE: AFTER INSERT STATEMENT trigger
SELECT * FROM target ORDER BY tid;
tid | balance
-----+---------
1 | 10
2 | 15
4 | 40
(3 rows)
ROLLBACK;
-- Test behavior of triggers that turn UPDATE/DELETE into no-ops
create or replace function skip_merge_op() returns trigger
language plpgsql as
$$
BEGIN
RETURN NULL;
END;
$$;
SELECT * FROM target full outer join source on (sid = tid);
tid | balance | sid | delta
-----+---------+-----+-------
3 | 30 | 3 | 20
2 | 20 | 2 | 5
| | 4 | 40
1 | 10 | |
(4 rows)
create trigger merge_skip BEFORE INSERT OR UPDATE or DELETE
ON target FOR EACH ROW EXECUTE FUNCTION skip_merge_op();
DO $$
DECLARE
result integer;
BEGIN
MERGE INTO target t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED AND s.sid = 3 THEN UPDATE SET balance = t.balance + s.delta
WHEN MATCHED THEN DELETE
WHEN NOT MATCHED THEN INSERT VALUES (sid, delta);
IF FOUND THEN
RAISE NOTICE 'Found';
ELSE
RAISE NOTICE 'Not found';
END IF;
GET DIAGNOSTICS result := ROW_COUNT;
RAISE NOTICE 'ROW_COUNT = %', result;
END;
$$;
NOTICE: BEFORE INSERT STATEMENT trigger
NOTICE: BEFORE UPDATE STATEMENT trigger
NOTICE: BEFORE DELETE STATEMENT trigger
NOTICE: BEFORE UPDATE ROW trigger row: (3,30) -> (3,50)
NOTICE: BEFORE DELETE ROW trigger row: (2,20)
NOTICE: BEFORE INSERT ROW trigger row: (4,40)
NOTICE: AFTER DELETE STATEMENT trigger
NOTICE: AFTER UPDATE STATEMENT trigger
NOTICE: AFTER INSERT STATEMENT trigger
NOTICE: Not found
NOTICE: ROW_COUNT = 0
SELECT * FROM target FULL OUTER JOIN source ON (sid = tid);
tid | balance | sid | delta
-----+---------+-----+-------
3 | 30 | 3 | 20
2 | 20 | 2 | 5
| | 4 | 40
1 | 10 | |
(4 rows)
DROP TRIGGER merge_skip ON target;
DROP FUNCTION skip_merge_op();
-- test from PL/pgSQL
-- make sure MERGE INTO isn't interpreted to mean returning variables like SELECT INTO
BEGIN;
DO LANGUAGE plpgsql $$
BEGIN
MERGE INTO target t