/*
* When table_tuple_update, table_tuple_delete, or table_tuple_lock fail
* because the target tuple is already outdated, they fill in this struct to
- * provide information to the caller about what happened.
+ * provide information to the caller about what happened. When those functions
+ * succeed, the contents of this struct should not be relied upon, except for
+ * `traversed`, which may be set in both success and failure cases.
*
* ctid is the target's ctid link: it is the same as the target's TID if the
* target was deleted, or the location of the replacement tuple if the target
* tuple); otherwise cmax is zero. (We make this restriction because
* HeapTupleHeaderGetCmax doesn't work for tuples outdated in other
* transactions.)
+ *
+ * traversed indicates if an update chain was followed in order to try to lock
+ * the target tuple. (This may be set in both success and failure cases.)
*/
typedef struct TM_FailureData
{
*
* Input parameters:
* relation: relation containing tuple (caller must hold suitable lock)
- * tid: TID of tuple to lock
+ * tid: TID of tuple to lock (updated if an update chain was followed)
* snapshot: snapshot to use for visibility determinations
* cid: current command ID (used for visibility test, and stored into
* tuple's cmax if lock is successful)
* TM_WouldBlock: lock couldn't be acquired and wait_policy is skip
*
* In the failure cases other than TM_Invisible and TM_Deleted, the routine
- * fills *tmfd with the tuple's t_ctid, t_xmax, and, if possible, t_cmax. See
- * comments for struct TM_FailureData for additional info.
+ * fills *tmfd with the tuple's t_ctid, t_xmax, and, if possible, t_cmax.
+ * Additionally, in both success and failure cases, tmfd->traversed is set if
+ * an update chain was followed. See comments for struct TM_FailureData for
+ * additional info.
*/
static inline TM_Result
table_tuple_lock(Relation rel, ItemPointer tid, Snapshot snapshot,
step c1: COMMIT;
+starting permutation: update1 update6 merge_bal c2 select1 c1
+step update1: UPDATE target t SET balance = balance + 10, val = t.val || ' updated by update1' WHERE t.key = 1;
+step update6: UPDATE target t SET balance = balance - 100, val = t.val || ' updated by update6' WHERE t.key = 1;
+step merge_bal:
+ MERGE INTO target t
+ USING (SELECT 1 as key) s
+ ON s.key = t.key
+ WHEN MATCHED AND balance < 100 THEN
+ UPDATE SET balance = balance * 2, val = t.val || ' when1'
+ WHEN MATCHED AND balance < 200 THEN
+ UPDATE SET balance = balance * 4, val = t.val || ' when2'
+ WHEN MATCHED AND balance < 300 THEN
+ UPDATE SET balance = balance * 8, val = t.val || ' when3';
+ <waiting ...>
+step c2: COMMIT;
+step merge_bal: <... completed>
+step select1: SELECT * FROM target;
+key|balance|status|val
+---+-------+------+-------------------------------------------------
+ 1| 140|s1 |setup updated by update1 updated by update6 when1
+(1 row)
+
+step c1: COMMIT;
+
+starting permutation: update1_pa update6_pa merge_bal_pa c2 select1_pa c1
+step update1_pa: UPDATE target_pa t SET balance = balance + 10, val = t.val || ' updated by update1_pa' WHERE t.key = 1;
+step update6_pa: UPDATE target_pa t SET balance = balance - 100, val = t.val || ' updated by update6_pa' WHERE t.key = 1;
+step merge_bal_pa:
+ MERGE INTO target_pa t
+ USING (SELECT 1 as key) s
+ ON s.key = t.key
+ WHEN MATCHED AND balance < 100 THEN
+ UPDATE SET balance = balance * 2, val = t.val || ' when1'
+ WHEN MATCHED AND balance < 200 THEN
+ UPDATE SET balance = balance * 4, val = t.val || ' when2'
+ WHEN MATCHED AND balance < 300 THEN
+ UPDATE SET balance = balance * 8, val = t.val || ' when3';
+ <waiting ...>
+step c2: COMMIT;
+step merge_bal_pa: <... completed>
+step select1_pa: SELECT * FROM target_pa;
+key|balance|status|val
+---+-------+------+-------------------------------------------------------
+ 1| 140|s1 |setup updated by update1_pa updated by update6_pa when1
+(1 row)
+
+step c1: COMMIT;
+
+starting permutation: update1_tg update6_tg merge_bal_tg c2 select1_tg c1
+s2: NOTICE: Update: (1,160,s1,setup) -> (1,170,s1,"setup updated by update1_tg")
+step update1_tg: UPDATE target_tg t SET balance = balance + 10, val = t.val || ' updated by update1_tg' WHERE t.key = 1;
+s2: NOTICE: Update: (1,170,s1,"setup updated by update1_tg") -> (1,70,s1,"setup updated by update1_tg updated by update6_tg")
+step update6_tg: UPDATE target_tg t SET balance = balance - 100, val = t.val || ' updated by update6_tg' WHERE t.key = 1;
+step merge_bal_tg:
+ MERGE INTO target_tg t
+ USING (SELECT 1 as key) s
+ ON s.key = t.key
+ WHEN MATCHED AND balance < 100 THEN
+ UPDATE SET balance = balance * 2, val = t.val || ' when1'
+ WHEN MATCHED AND balance < 200 THEN
+ UPDATE SET balance = balance * 4, val = t.val || ' when2'
+ WHEN MATCHED AND balance < 300 THEN
+ UPDATE SET balance = balance * 8, val = t.val || ' when3';
+ <waiting ...>
+step c2: COMMIT;
+s1: NOTICE: Update: (1,70,s1,"setup updated by update1_tg updated by update6_tg") -> (1,140,s1,"setup updated by update1_tg updated by update6_tg when1")
+step merge_bal_tg: <... completed>
+step select1_tg: SELECT * FROM target_tg;
+key|balance|status|val
+---+-------+------+-------------------------------------------------------
+ 1| 140|s1 |setup updated by update1_tg updated by update6_tg when1
+(1 row)
+
+step c1: COMMIT;
+
+starting permutation: update7 update6 merge_bal c2 select1 c1
+step update7: UPDATE target t SET balance = 350, val = t.val || ' updated by update7' WHERE t.key = 1;
+step update6: UPDATE target t SET balance = balance - 100, val = t.val || ' updated by update6' WHERE t.key = 1;
+step merge_bal:
+ MERGE INTO target t
+ USING (SELECT 1 as key) s
+ ON s.key = t.key
+ WHEN MATCHED AND balance < 100 THEN
+ UPDATE SET balance = balance * 2, val = t.val || ' when1'
+ WHEN MATCHED AND balance < 200 THEN
+ UPDATE SET balance = balance * 4, val = t.val || ' when2'
+ WHEN MATCHED AND balance < 300 THEN
+ UPDATE SET balance = balance * 8, val = t.val || ' when3';
+ <waiting ...>
+step c2: COMMIT;
+step merge_bal: <... completed>
+step select1: SELECT * FROM target;
+key|balance|status|val
+---+-------+------+-------------------------------------------------
+ 1| 2000|s1 |setup updated by update7 updated by update6 when3
+(1 row)
+
+step c1: COMMIT;
+
+starting permutation: update1_pa_move merge_bal_pa c2 c1
+step update1_pa_move: UPDATE target_pa t SET balance = 210, val = t.val || ' updated by update1_pa_move' WHERE t.key = 1;
+step merge_bal_pa:
+ MERGE INTO target_pa t
+ USING (SELECT 1 as key) s
+ ON s.key = t.key
+ WHEN MATCHED AND balance < 100 THEN
+ UPDATE SET balance = balance * 2, val = t.val || ' when1'
+ WHEN MATCHED AND balance < 200 THEN
+ UPDATE SET balance = balance * 4, val = t.val || ' when2'
+ WHEN MATCHED AND balance < 300 THEN
+ UPDATE SET balance = balance * 8, val = t.val || ' when3';
+ <waiting ...>
+step c2: COMMIT;
+step merge_bal_pa: <... completed>
+ERROR: tuple to be locked was already moved to another partition due to concurrent update
+step c1: COMMIT;
+
+starting permutation: update1_pa update1_pa_move merge_bal_pa c2 c1
+step update1_pa: UPDATE target_pa t SET balance = balance + 10, val = t.val || ' updated by update1_pa' WHERE t.key = 1;
+step update1_pa_move: UPDATE target_pa t SET balance = 210, val = t.val || ' updated by update1_pa_move' WHERE t.key = 1;
+step merge_bal_pa:
+ MERGE INTO target_pa t
+ USING (SELECT 1 as key) s
+ ON s.key = t.key
+ WHEN MATCHED AND balance < 100 THEN
+ UPDATE SET balance = balance * 2, val = t.val || ' when1'
+ WHEN MATCHED AND balance < 200 THEN
+ UPDATE SET balance = balance * 4, val = t.val || ' when2'
+ WHEN MATCHED AND balance < 300 THEN
+ UPDATE SET balance = balance * 8, val = t.val || ' when3';
+ <waiting ...>
+step c2: COMMIT;
+step merge_bal_pa: <... completed>
+ERROR: tuple to be locked was already moved to another partition due to concurrent update
+step c1: COMMIT;
+
starting permutation: update1 merge_delete c2 select1 c1
step update1: UPDATE target t SET balance = balance + 10, val = t.val || ' updated by update1' WHERE t.key = 1;
step merge_delete:
BEGIN ISOLATION LEVEL READ COMMITTED;
}
step "update1" { UPDATE target t SET balance = balance + 10, val = t.val || ' updated by update1' WHERE t.key = 1; }
+step "update1_pa" { UPDATE target_pa t SET balance = balance + 10, val = t.val || ' updated by update1_pa' WHERE t.key = 1; }
+step "update1_pa_move" { UPDATE target_pa t SET balance = 210, val = t.val || ' updated by update1_pa_move' WHERE t.key = 1; }
step "update1_tg" { UPDATE target_tg t SET balance = balance + 10, val = t.val || ' updated by update1_tg' WHERE t.key = 1; }
step "update2" { UPDATE target t SET status = 's2', val = t.val || ' updated by update2' WHERE t.key = 1; }
step "update2_tg" { UPDATE target_tg t SET status = 's2', val = t.val || ' updated by update2_tg' WHERE t.key = 1; }
step "update3_tg" { UPDATE target_tg t SET status = 's3', val = t.val || ' updated by update3_tg' WHERE t.key = 1; }
step "update5" { UPDATE target t SET status = 's5', val = t.val || ' updated by update5' WHERE t.key = 1; }
step "update5_tg" { UPDATE target_tg t SET status = 's5', val = t.val || ' updated by update5_tg' WHERE t.key = 1; }
+step "update6" { UPDATE target t SET balance = balance - 100, val = t.val || ' updated by update6' WHERE t.key = 1; }
+step "update6_pa" { UPDATE target_pa t SET balance = balance - 100, val = t.val || ' updated by update6_pa' WHERE t.key = 1; }
+step "update6_tg" { UPDATE target_tg t SET balance = balance - 100, val = t.val || ' updated by update6_tg' WHERE t.key = 1; }
+step "update7" { UPDATE target t SET balance = 350, val = t.val || ' updated by update7' WHERE t.key = 1; }
step "update_bal1" { UPDATE target t SET balance = 50, val = t.val || ' updated by update_bal1' WHERE t.key = 1; }
step "update_bal1_pa" { UPDATE target_pa t SET balance = 50, val = t.val || ' updated by update_bal1_pa' WHERE t.key = 1; }
step "update_bal1_tg" { UPDATE target_tg t SET balance = 50, val = t.val || ' updated by update_bal1_tg' WHERE t.key = 1; }
permutation "update_bal1_pa" "merge_bal_pa" "c2" "select1_pa" "c1"
permutation "update_bal1_tg" "merge_bal_tg" "c2" "select1_tg" "c1"
+# merge_bal sees row concurrently updated twice and rechecks WHEN conditions, different check passes, so final balance = 140
+permutation "update1" "update6" "merge_bal" "c2" "select1" "c1"
+permutation "update1_pa" "update6_pa" "merge_bal_pa" "c2" "select1_pa" "c1"
+permutation "update1_tg" "update6_tg" "merge_bal_tg" "c2" "select1_tg" "c1"
+
+# merge_bal sees row concurrently updated twice, first update would cause all checks to fail, second update causes different check to pass, so final balance = 2000
+permutation "update7" "update6" "merge_bal" "c2" "select1" "c1"
+
+# merge_bal sees concurrently updated row moved to new partition, so fails
+permutation "update1_pa_move" "merge_bal_pa" "c2" "c1"
+permutation "update1_pa" "update1_pa_move" "merge_bal_pa" "c2" "c1"
+
# merge_delete sees concurrently updated row and rechecks WHEN conditions, but recheck passes and row is deleted
permutation "update1" "merge_delete" "c2" "select1" "c1"
permutation "update1_tg" "merge_delete_tg" "c2" "select1_tg" "c1"
projects / postgresql.git / commitdiff