set default_storage_engine=innodb; CREATE TABLE `t` ( `a` VARCHAR(100), `b` VARCHAR(100), `c` VARCHAR(200) GENERATED ALWAYS AS (CONCAT(a,b)) VIRTUAL, `h` VARCHAR(10) DEFAULT NULL, `i` int ) ENGINE=InnoDB; INSERT INTO t VALUES (REPEAT('g', 100), REPEAT('x', 10), DEFAULT, "kk", 1); INSERT INTO t VALUES (REPEAT('a', 100), REPEAT('b', 100), DEFAULT, "mm", 2); CREATE INDEX idx ON t(c(100)); SET session debug_dbug="+d,ib_alter_add_virtual_fail"; ALTER TABLE t ADD COLUMN x VARCHAR(200) GENERATED ALWAYS AS (a) VIRTUAL, ALGORITHM = INPLACE; ERROR 42000: The storage engine InnoDB can't index column `x` ALTER TABLE t DROP COLUMN c, ALGORITHM = INPLACE; ERROR 42000: The storage engine InnoDB can't index column `c` SET session debug_dbug=""; DROP TABLE t; CREATE TABLE t (a INT, b INT, c INT GENERATED ALWAYS AS(a+b), h VARCHAR(10)); INSERT INTO t VALUES (11, 3, DEFAULT, 'mm'); INSERT INTO t VALUES (18, 1, DEFAULT, 'mm'); INSERT INTO t VALUES (28, 1, DEFAULT, 'mm'); INSERT INTO t VALUES (null, null, DEFAULT, "mx"); SET DEBUG_SYNC = 'innodb_inplace_alter_table_enter SIGNAL start_create WAIT_FOR go_ahead'; CREATE INDEX idx ON t(c); connect con1,localhost,root,,; SET DEBUG_SYNC = 'now WAIT_FOR start_create'; update t set a=0 where a = 11; start transaction; update t set a=1 where a = 0; ROLLBACK; SET DEBUG_SYNC = 'now SIGNAL go_ahead'; connection default; SELECT c FROM t; c NULL 3 19 29 SHOW CREATE TABLE t; Table Create Table t CREATE TABLE `t` ( `a` int(11) DEFAULT NULL, `b` int(11) DEFAULT NULL, `c` int(11) GENERATED ALWAYS AS (`a` + `b`) VIRTUAL, `h` varchar(10) DEFAULT NULL, KEY `idx` (`c`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci SELECT * FROM t; a b c h 0 3 3 mm 18 1 19 mm 28 1 29 mm NULL NULL NULL mx ALTER TABLE t FORCE, LOCK=NONE; ERROR 0A000: LOCK=NONE is not supported. Reason: online rebuild with indexed virtual columns. Try LOCK=SHARED disconnect con1; DROP TABLE t; SET DEBUG_SYNC = 'RESET'; CREATE TABLE t (a INT, b INT, c INT GENERATED ALWAYS AS(a+b), h VARCHAR(10)); INSERT INTO t VALUES (11, 3, DEFAULT, 'mm'); INSERT INTO t VALUES (18, 1, DEFAULT, 'mm'); INSERT INTO t VALUES (28, 1, DEFAULT, 'mm'); INSERT INTO t VALUES (null, null, DEFAULT, 'mm'); CREATE INDEX idx_1 on t(c); SET @saved_dbug = @@SESSION.debug_dbug; SET debug_dbug = '+d,create_index_fail'; ALTER TABLE t ADD COLUMN x INT GENERATED ALWAYS AS(a+b), ADD INDEX idx (x), ADD INDEX idcx (c,x); ERROR 23000: Duplicate entry '' for key '*UNKNOWN*' UPDATE t SET a=a+1; affected rows: 3 info: Rows matched: 4 Changed: 3 Warnings: 0 ALTER TABLE t ADD INDEX idc(c); ERROR 23000: Duplicate entry '' for key '*UNKNOWN*' SET debug_dbug = @saved_dbug; affected rows: 0 UPDATE t SET b=b-1; SHOW CREATE TABLE t; Table Create Table t CREATE TABLE `t` ( `a` int(11) DEFAULT NULL, `b` int(11) DEFAULT NULL, `c` int(11) GENERATED ALWAYS AS (`a` + `b`) VIRTUAL, `h` varchar(10) DEFAULT NULL, KEY `idx_1` (`c`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci SELECT c FROM t; c NULL 14 19 29 DROP TABLE t; SET DEBUG_SYNC = 'RESET'; # # Bug#28825718 - ASSERTION FAILURE: TRX0REC.CC:NNN:N_IDX > 0 WHILE DOING REPLACE/INSERT # CREATE TABLE t1(a INT PRIMARY KEY, b INT, c INT GENERATED ALWAYS AS(b+1) VIRTUAL) ENGINE=InnoDB; INSERT INTO t1(a, b) VALUES(1, 1); connect con1,localhost,root,,; SET DEBUG_SYNC = 'row_log_apply_after SIGNAL s1 WAIT_FOR s2'; SET lock_wait_timeout = 1; ALTER TABLE t1 ADD UNIQUE INDEX(c, b); connection default; SET DEBUG_SYNC = 'now WAIT_FOR s1'; SET DEBUG_SYNC = 'row_ins_sec_index_enter SIGNAL s2 WAIT_FOR s3'; INSERT INTO t1(a, b) VALUES(2, 2); connection con1; ERROR HY000: Lock wait timeout exceeded; try restarting transaction SET DEBUG_SYNC = 'now SIGNAL s3'; disconnect con1; connection default; SET DEBUG_SYNC = 'RESET'; ALTER TABLE t1 ADD KEY(b); INSERT INTO t1(a, b) VALUES(3, 3); SELECT * FROM t1; a b c 1 1 2 2 2 3 3 3 4 CHECK TABLE t1; Table Op Msg_type Msg_text test.t1 check status OK DROP TABLE t1;