[ [ AS ] <replaceable class="parameter">source_alias</replaceable> ]
and <replaceable class="parameter">when_clause</replaceable> is
{ WHEN MATCHED [ AND <replaceable class="parameter">condition</replaceable> ] THEN { <replaceable class="parameter">merge_update</replaceable> | <replaceable class="parameter">merge_delete</replaceable> } |
WHEN NOT MATCHED [ AND <replaceable class="parameter">condition</replaceable> ] THEN { <replaceable class="parameter">merge_insert</replaceable> | DO NOTHING }
}
and <replaceable class="parameter">merge_insert</replaceable> is
step merge_delete: MERGE INTO target t USING (SELECT 1 as key) s ON s.key = t.key WHEN MATCHED THEN DELETE;
step c1: COMMIT;
step update1: UPDATE target t SET val = t.val || ' updated by update1' WHERE t.key = 1;
step select2: SELECT * FROM target;
key val
step c2: COMMIT;
starting permutation: delete c1 merge2 select2 c2
step delete: DELETE FROM target t WHERE t.key = 1;
step c1: COMMIT;
step merge2: MERGE INTO target t USING (SELECT 1 as key, 'merge2a' as val) s ON s.key = t.key WHEN NOT MATCHED THEN INSERT VALUES (s.key, s.val) WHEN MATCHED THEN UPDATE set key = t.key + 1, val = t.val || ' updated by ' || s.val;
step merge_delete: MERGE INTO target t USING (SELECT 1 as key) s ON s.key = t.key WHEN MATCHED THEN DELETE;
step c1: COMMIT;
step merge2: MERGE INTO target t USING (SELECT 1 as key, 'merge2a' as val) s ON s.key = t.key WHEN NOT MATCHED THEN INSERT VALUES (s.key, s.val) WHEN MATCHED THEN UPDATE set key = t.key + 1, val = t.val || ' updated by ' || s.val;
step merge_delete: MERGE INTO target t USING (SELECT 1 as key) s ON s.key = t.key WHEN MATCHED THEN DELETE;
step update1: UPDATE target t SET val = t.val || ' updated by update1' WHERE t.key = 1; <waiting ...>
step c1: COMMIT;
step update1: <... completed>
step select2: SELECT * FROM target;
key val
step c2: COMMIT;
starting permutation: delete merge2 c1 select2 c2
step delete: DELETE FROM target t WHERE t.key = 1;
step merge2: MERGE INTO target t USING (SELECT 1 as key, 'merge2a' as val) s ON s.key = t.key WHEN NOT MATCHED THEN INSERT VALUES (s.key, s.val) WHEN MATCHED THEN UPDATE set key = t.key + 1, val = t.val || ' updated by ' || s.val; <waiting ...>
step merge_delete: MERGE INTO target t USING (SELECT 1 as key) s ON s.key = t.key WHEN MATCHED THEN DELETE;
step merge2: MERGE INTO target t USING (SELECT 1 as key, 'merge2a' as val) s ON s.key = t.key WHEN NOT MATCHED THEN INSERT VALUES (s.key, s.val) WHEN MATCHED THEN UPDATE set key = t.key + 1, val = t.val || ' updated by ' || s.val; <waiting ...>
step merge1: MERGE INTO target t USING (SELECT 1 as key, 'merge1' as val) s ON s.key = t.key WHEN NOT MATCHED THEN INSERT VALUES (s.key, s.val) WHEN MATCHED THEN UPDATE set val = t.val || ' updated by merge1';
step c1: COMMIT;
step select2: SELECT * FROM target;
key val
1 merge1
step c2: COMMIT;
starting permutation: merge1 c1 merge2 select2 c2
step merge1: MERGE INTO target t USING (SELECT 1 as key, 'merge1' as val) s ON s.key = t.key WHEN NOT MATCHED THEN INSERT VALUES (s.key, s.val) WHEN MATCHED THEN UPDATE set val = t.val || ' updated by merge1';
step c1: COMMIT;
step merge2: MERGE INTO target t USING (SELECT 1 as key, 'merge2' as val) s ON s.key = t.key WHEN NOT MATCHED THEN INSERT VALUES (s.key, s.val) WHEN MATCHED THEN UPDATE set val = t.val || ' updated by merge2';
step insert1: INSERT INTO target VALUES (1, 'insert1');
step merge2: MERGE INTO target t USING (SELECT 1 as key, 'merge2' as val) s ON s.key = t.key WHEN NOT MATCHED THEN INSERT VALUES (s.key, s.val) WHEN MATCHED THEN UPDATE set val = t.val || ' updated by merge2'; <waiting ...>
step c1: COMMIT;
step merge2: <... completed>
error in steps c1 merge2: ERROR: duplicate key value violates unique constraint "target_pkey"
step select2: SELECT * FROM target;
ERROR: current transaction is aborted, commands ignored until end of transaction block
step c2: COMMIT;
starting permutation: merge1 merge2 c1 select2 c2
step merge1: MERGE INTO target t USING (SELECT 1 as key, 'merge1' as val) s ON s.key = t.key WHEN NOT MATCHED THEN INSERT VALUES (s.key, s.val) WHEN MATCHED THEN UPDATE set val = t.val || ' updated by merge1';
step merge2: MERGE INTO target t USING (SELECT 1 as key, 'merge2' as val) s ON s.key = t.key WHEN NOT MATCHED THEN INSERT VALUES (s.key, s.val) WHEN MATCHED THEN UPDATE set val = t.val || ' updated by merge2'; <waiting ...>
step c1: COMMIT;
step merge2: <... completed>
error in steps c1 merge2: ERROR: duplicate key value violates unique constraint "target_pkey"
step select2: SELECT * FROM target;
ERROR: current transaction is aborted, commands ignored until end of transaction block
step c2: COMMIT;
starting permutation: merge1 merge2 a1 select2 c2
step merge1: MERGE INTO target t USING (SELECT 1 as key, 'merge1' as val) s ON s.key = t.key WHEN NOT MATCHED THEN INSERT VALUES (s.key, s.val) WHEN MATCHED THEN UPDATE set val = t.val || ' updated by merge1';
step merge2: MERGE INTO target t USING (SELECT 1 as key, 'merge2' as val) s ON s.key = t.key WHEN NOT MATCHED THEN INSERT VALUES (s.key, s.val) WHEN MATCHED THEN UPDATE set val = t.val || ' updated by merge2'; <waiting ...>
step insert1: INSERT INTO target VALUES (1, 'insert1');
step c1: COMMIT;
step merge2: MERGE INTO target t USING (SELECT 1 as key, 'merge2' as val) s ON s.key = t.key WHEN NOT MATCHED THEN INSERT VALUES (s.key, s.val) WHEN MATCHED THEN UPDATE set val = t.val || ' updated by merge2';
step insert1: INSERT INTO target VALUES (1, 'insert1');
step merge2: MERGE INTO target t USING (SELECT 1 as key, 'merge2' as val) s ON s.key = t.key WHEN NOT MATCHED THEN INSERT VALUES (s.key, s.val) WHEN MATCHED THEN UPDATE set val = t.val || ' updated by merge2'; <waiting ...>
step c1: COMMIT;
step merge2: <... completed>
error in steps c1 merge2: ERROR: duplicate key value violates unique constraint "target_pkey"
step select2: SELECT * FROM target;
ERROR: current transaction is aborted, commands ignored until end of transaction block
step insert1: INSERT INTO target VALUES (1, 'insert1');
step merge2i: MERGE INTO target t USING (SELECT 1 as key, 'merge2' as val) s ON s.key = t.key WHEN MATCHED THEN UPDATE set val = t.val || ' updated by merge2';
# This test looks at the interactions involving concurrent deletes
# comparing the behavior of MERGE, DELETE and UPDATE
setup
{
CREATE TABLE target (key int primary key, val text);
INSERT INTO target VALUES (1, 'setup1');
}
teardown
{
DROP TABLE target;
}
session "s1"
setup
{
BEGIN ISOLATION LEVEL READ COMMITTED;
}
step "delete" { DELETE FROM target t WHERE t.key = 1; }
step "merge_delete" { MERGE INTO target t USING (SELECT 1 as key) s ON s.key = t.key WHEN MATCHED THEN DELETE; }
step "c1" { COMMIT; }
step "a1" { ABORT; }
session "s2"
setup
{
BEGIN ISOLATION LEVEL READ COMMITTED;
}
step "update1" { UPDATE target t SET val = t.val || ' updated by update1' WHERE t.key = 1; }
step "merge2" { MERGE INTO target t USING (SELECT 1 as key, 'merge2a' as val) s ON s.key = t.key WHEN NOT MATCHED THEN INSERT VALUES (s.key, s.val) WHEN MATCHED THEN UPDATE set key = t.key + 1, val = t.val || ' updated by ' || s.val; }
# This looks at how we handle concurrent INSERTs, illustrating how the
# behavior differs from INSERT ... ON CONFLICT
setup
{
CREATE TABLE target (key int primary key, val text);
}
teardown
{
DROP TABLE target;
}
session "s1"
setup
{
BEGIN ISOLATION LEVEL READ COMMITTED;
}
step "merge1" { MERGE INTO target t USING (SELECT 1 as key, 'merge1' as val) s ON s.key = t.key WHEN NOT MATCHED THEN INSERT VALUES (s.key, s.val) WHEN MATCHED THEN UPDATE set val = t.val || ' updated by merge1'; }
step "delete1" { DELETE FROM target WHERE key = 1; }
step "insert1" { INSERT INTO target VALUES (1, 'insert1'); }
step "c1" { COMMIT; }
step "a1" { ABORT; }
session "s2"
setup
{
BEGIN ISOLATION LEVEL READ COMMITTED;
}
step "merge2" { MERGE INTO target t USING (SELECT 1 as key, 'merge2' as val) s ON s.key = t.key WHEN NOT MATCHED THEN INSERT VALUES (s.key, s.val) WHEN MATCHED THEN UPDATE set val = t.val || ' updated by merge2'; }
step "merge2i" { MERGE INTO target t USING (SELECT 1 as key, 'merge2' as val) s ON s.key = t.key WHEN MATCHED THEN UPDATE set val = t.val || ' updated by merge2'; }
