DROP TABLE IF EXISTS t1, t2; CREATE TABLE t1 (id INT PRIMARY KEY, f0 INT, f1 INT, f2 INT, f3 INT, f4 INT, f5 INT, f6 CHAR(10), f7 CHAR(10), f8 CHAR(10), f9 CHAR(10), fa CHAR(10), fb VARCHAR(30), fc VARCHAR(30), fd VARCHAR(30), fe TEXT(1000), ff TEXT(1000)) ENGINE=XENGINE; ALTER TABLE t1 ADD KEY k0(f0), ADD KEY k1(f1), ADD KEY k2(f2), ADD KEY k3(f3); ALTER TABLE t1 ADD KEY k4(f4), ADD KEY k5(f5), ADD KEY k6(f6), ADD KEY k7(f7) ; ALTER TABLE t1 ADD KEY k8(f8), ADD KEY k9(f9), ADD KEY ka(fa), ADD KEY kb(fb); ALTER TABLE t1 ADD KEY kc(fc), ADD KEY kd(fd), ADD KEY ke(fe(100)), ADD KEY kf(ff(100)); ALTER TABLE t1 ADD KEY k01(f0, f1), ADD KEY k12(f1, f2), ADD KEY k23(f2, f3), ADD KEY k34(f3, f4); ALTER TABLE t1 ADD KEY k45(f4, f5), ADD KEY k56(f5, f6), ADD KEY k67(f6, f7), ADD KEY k78(f7, f8); ALTER TABLE t1 ADD KEY k89(f8, f9), ADD KEY k9a(f9, fa), ADD KEY kab(fa, fb), ADD KEY kbc(fb, fc); ALTER TABLE t1 ADD KEY kcd(fc, fd), ADD KEY kde(fd, fe(100)); ALTER TABLE t1 ADD KEY kef(fe(100), ff(100)), ADD KEY kf0(ff(100), f0); ALTER TABLE t1 ADD KEY k012(f0, f1, f2), ADD KEY k123(f1, f2, f3); ALTER TABLE t1 ADD KEY k234(f2, f3, f4), ADD KEY k345(f3, f4, f5); ALTER TABLE t1 ADD KEY k456(f4, f5, f6), ADD KEY k567(f5, f6, f7); ALTER TABLE t1 ADD KEY k678(f6, f7, f8), ADD KEY k789(f7, f8, f9); ALTER TABLE t1 ADD KEY k89a(f8, f9, fa), ADD KEY k9ab(f9, fa, fb); ALTER TABLE t1 ADD KEY kabc(fa, fb, fc), ADD KEY kbcd(fb, fc, fd); ALTER TABLE t1 ADD KEY kcde(fc, fd, fe(100)), ADD KEY kdef(fd, fe(100), ff(100)); ALTER TABLE t1 ADD KEY kef0(fe(100), ff(100), f0), ADD KEY kf01(ff(100), f0, f1); ALTER TABLE t1 ADD KEY k0123(f0, f1, f2, f3), ADD KEY k1234(f1, f2, f3, f4); ALTER TABLE t1 ADD KEY k2345(f2, f3, f4, f5), ADD KEY k3456(f3, f4, f5, f6); ALTER TABLE t1 ADD KEY k4567(f4, f5, f6, f7), ADD KEY k5678(f5, f6, f7, f8); ALTER TABLE t1 ADD KEY k6789(f6, f7, f8, f9), ADD KEY k789a(f7, f8, f9, fa); ALTER TABLE t1 ADD KEY k89ab(f8, f9, fa, fb), ADD KEY k9abc(f9, fa, fb, fc); ALTER TABLE t1 ADD KEY kabcd(fa, fb, fc, fd), ADD KEY kbcde(fb, fc, fd, fe(100)); ALTER TABLE t1 ADD KEY kcdef(fc, fd, fe(100), ff(100)), ADD KEY kdef0(fd, fe(100), ff(100), f0); ALTER TABLE t1 ADD KEY kef01(fe(100), ff(100), f0, f1); ALTER TABLE t1 ADD KEY kf012(ff(100), f0, f1, f2); ERROR 42000: Too many keys specified; max 64 keys allowed SHOW CREATE TABLE t1; Table Create Table t1 CREATE TABLE `t1` ( `id` int(11) NOT NULL, `f0` int(11) DEFAULT NULL, `f1` int(11) DEFAULT NULL, `f2` int(11) DEFAULT NULL, `f3` int(11) DEFAULT NULL, `f4` int(11) DEFAULT NULL, `f5` int(11) DEFAULT NULL, `f6` char(10) COLLATE utf8mb4_general_ci DEFAULT NULL, `f7` char(10) COLLATE utf8mb4_general_ci DEFAULT NULL, `f8` char(10) COLLATE utf8mb4_general_ci DEFAULT NULL, `f9` char(10) COLLATE utf8mb4_general_ci DEFAULT NULL, `fa` char(10) COLLATE utf8mb4_general_ci DEFAULT NULL, `fb` varchar(30) COLLATE utf8mb4_general_ci DEFAULT NULL, `fc` varchar(30) COLLATE utf8mb4_general_ci DEFAULT NULL, `fd` varchar(30) COLLATE utf8mb4_general_ci DEFAULT NULL, `fe` text COLLATE utf8mb4_general_ci, `ff` text COLLATE utf8mb4_general_ci, PRIMARY KEY (`id`), KEY `k0` (`f0`), KEY `k1` (`f1`), KEY `k2` (`f2`), KEY `k3` (`f3`), KEY `k4` (`f4`), KEY `k5` (`f5`), KEY `k6` (`f6`), KEY `k7` (`f7`), KEY `k8` (`f8`), KEY `k9` (`f9`), KEY `ka` (`fa`), KEY `kb` (`fb`), KEY `kc` (`fc`), KEY `kd` (`fd`), KEY `ke` (`fe`(100)), KEY `kf` (`ff`(100)), KEY `k01` (`f0`,`f1`), KEY `k12` (`f1`,`f2`), KEY `k23` (`f2`,`f3`), KEY `k34` (`f3`,`f4`), KEY `k45` (`f4`,`f5`), KEY `k56` (`f5`,`f6`), KEY `k67` (`f6`,`f7`), KEY `k78` (`f7`,`f8`), KEY `k89` (`f8`,`f9`), KEY `k9a` (`f9`,`fa`), KEY `kab` (`fa`,`fb`), KEY `kbc` (`fb`,`fc`), KEY `kcd` (`fc`,`fd`), KEY `kde` (`fd`,`fe`(100)), KEY `kef` (`fe`(100),`ff`(100)), KEY `kf0` (`ff`(100),`f0`), KEY `k012` (`f0`,`f1`,`f2`), KEY `k123` (`f1`,`f2`,`f3`), KEY `k234` (`f2`,`f3`,`f4`), KEY `k345` (`f3`,`f4`,`f5`), KEY `k456` (`f4`,`f5`,`f6`), KEY `k567` (`f5`,`f6`,`f7`), KEY `k678` (`f6`,`f7`,`f8`), KEY `k789` (`f7`,`f8`,`f9`), KEY `k89a` (`f8`,`f9`,`fa`), KEY `k9ab` (`f9`,`fa`,`fb`), KEY `kabc` (`fa`,`fb`,`fc`), KEY `kbcd` (`fb`,`fc`,`fd`), KEY `kcde` (`fc`,`fd`,`fe`(100)), KEY `kdef` (`fd`,`fe`(100),`ff`(100)), KEY `kef0` (`fe`(100),`ff`(100),`f0`), KEY `kf01` (`ff`(100),`f0`,`f1`), KEY `k0123` (`f0`,`f1`,`f2`,`f3`), KEY `k1234` (`f1`,`f2`,`f3`,`f4`), KEY `k2345` (`f2`,`f3`,`f4`,`f5`), KEY `k3456` (`f3`,`f4`,`f5`,`f6`), KEY `k4567` (`f4`,`f5`,`f6`,`f7`), KEY `k5678` (`f5`,`f6`,`f7`,`f8`), KEY `k6789` (`f6`,`f7`,`f8`,`f9`), KEY `k789a` (`f7`,`f8`,`f9`,`fa`), KEY `k89ab` (`f8`,`f9`,`fa`,`fb`), KEY `k9abc` (`f9`,`fa`,`fb`,`fc`), KEY `kabcd` (`fa`,`fb`,`fc`,`fd`), KEY `kbcde` (`fb`,`fc`,`fd`,`fe`(100)), KEY `kcdef` (`fc`,`fd`,`fe`(100),`ff`(100)), KEY `kdef0` (`fd`,`fe`(100),`ff`(100),`f0`), KEY `kef01` (`fe`(100),`ff`(100),`f0`,`f1`) ) ENGINE=XENGINE DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci DROP TABLE t1; CREATE TABLE t1 (id INT PRIMARY KEY, f0 INT, f1 INT, f2 INT, f3 INT, f4 INT, f5 INT, f6 CHAR(10), f7 CHAR(10), f8 CHAR(10), f9 CHAR(10), fa CHAR(10), fb VARCHAR(30), fc VARCHAR(30), fd VARCHAR(30), fe TEXT(1000), ff TEXT(1000)) ENGINE=XENGINE; ALTER TABLE t1 ADD KEY sk1 (f0, f6, fb(10), fe(20)); ALTER TABLE t1 ADD UNIQUE KEY uk1(f1, f7, fc(10), ff(20)); ALTER TABLE t1 ADD COLUMN f16 TEXT(1000), ADD KEY sk2 (f0, f1, f2, f3, f4, f5, f6, f7, f8, f9, fa, fb(10), fc(10), fd(10), fe(20), ff(20), f16(20)); ERROR 42000: Too many key parts specified; max 16 parts allowed ALTER TABLE t1 ADD COLUMN f16 TEXT(1000), ADD UNIQUE KEY uk2 (f0, f1, f2, f3, f4, f5, f6, f7, f8, f9, fa, fb(10), fc(10), fd(10), fe(20), ff(20), f16(20)); ERROR 42000: Too many key parts specified; max 16 parts allowed ALTER TABLE t1 DROP PRIMARY KEY, ADD PRIMARY KEY(id, f0, f1, f2, f3, f4, f5, f6, f7, f8, f9, fa, fb(10), fc(10), fd(10), fe(20), ff(20)); ERROR 42000: Too many key parts specified; max 16 parts allowed ALTER TABLE t1 ADD KEY sk2 (f0, f1, f2, f3, f4, f5, f6, f7, f8, f9, fa, fb(10), fc(10), fd(10), fe(20), ff(20)); ALTER TABLE t1 ADD UNIQUE KEY uk2 (f0, f1, f2, f3, f4, f5, f6, f7, f8, f9, fa, fb(10), fc(10), fd(10), fe(20), ff(20)); ALTER TABLE t1 DROP PRIMARY KEY, ADD PRIMARY KEY(id, f0, f1, f2, f3, f4, f5, f6, f7, f8, f9, fa, fb(10), fc(10), fd(10), fe(20)); SHOW CREATE TABLE t1; Table Create Table t1 CREATE TABLE `t1` ( `id` int(11) NOT NULL, `f0` int(11) NOT NULL, `f1` int(11) NOT NULL, `f2` int(11) NOT NULL, `f3` int(11) NOT NULL, `f4` int(11) NOT NULL, `f5` int(11) NOT NULL, `f6` char(10) COLLATE utf8mb4_general_ci NOT NULL, `f7` char(10) COLLATE utf8mb4_general_ci NOT NULL, `f8` char(10) COLLATE utf8mb4_general_ci NOT NULL, `f9` char(10) COLLATE utf8mb4_general_ci NOT NULL, `fa` char(10) COLLATE utf8mb4_general_ci NOT NULL, `fb` varchar(30) COLLATE utf8mb4_general_ci NOT NULL, `fc` varchar(30) COLLATE utf8mb4_general_ci NOT NULL, `fd` varchar(30) COLLATE utf8mb4_general_ci NOT NULL, `fe` text COLLATE utf8mb4_general_ci NOT NULL, `ff` text COLLATE utf8mb4_general_ci, PRIMARY KEY (`id`,`f0`,`f1`,`f2`,`f3`,`f4`,`f5`,`f6`,`f7`,`f8`,`f9`,`fa`,`fb`(10),`fc`(10),`fd`(10),`fe`(20)), UNIQUE KEY `uk1` (`f1`,`f7`,`fc`(10),`ff`(20)), UNIQUE KEY `uk2` (`f0`,`f1`,`f2`,`f3`,`f4`,`f5`,`f6`,`f7`,`f8`,`f9`,`fa`,`fb`(10),`fc`(10),`fd`(10),`fe`(20),`ff`(20)), KEY `sk1` (`f0`,`f6`,`fb`(10),`fe`(20)), KEY `sk2` (`f0`,`f1`,`f2`,`f3`,`f4`,`f5`,`f6`,`f7`,`f8`,`f9`,`fa`,`fb`(10),`fc`(10),`fd`(10),`fe`(20),`ff`(20)) ) ENGINE=XENGINE DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci DROP TABLE t1; CREATE TABLE t1 (pk INT PRIMARY KEY, a INT, c CHAR(8)) ENGINE=xengine; INSERT INTO t1 VALUES (1,1,'a'),(2,5,'z'); ALTER TABLE t1 PARTITION BY HASH(id) PARTITIONS 8; ERROR 42000: The storage engine for the table doesn't support native partitioning ALTER TABLE t1 ADD COLUMN c2 INT GENERATED ALWAYS AS (c1 + 1); ERROR HY000: 'Specified storage engine' is not supported for generated columns. ALTER TABLE t1 ADD COLUMN c3 INT GENERATED ALWAYS AS (c1 + 2) STORED; ERROR HY000: 'Specified storage engine' is not supported for generated columns. ALTER TABLE t1 ADD SPATIAL INDEX spi(c1); ERROR HY000: The used table type doesn't support SPATIAL indexes CREATE TABLE t2(id INT AUTO_INCREMENT PRIMARY KEY, name CHAR(10)) ENGINE=XENGINE; ALTER TABLE t1 ADD COLUMN fk1 INT NOT NULL, ADD FOREIGN KEY(fk1) REFERENCES t2(id); ERROR 42000: XEngine currently doesn't support foreign key constraints DROP TABLE t2; ALTER TABLE t1 ADD COLUMN c3 INT DEFAULT 1; CREATE INDEX btr_key USING BTREE on t1(c3); Warnings: Note 3502 This storage engine does not support the BTREE index algorithm, storage engine default was used instead. DROP INDEX btr_key ON t1; CREATE INDEX hsh_key USING HASH on t1(c3); Warnings: Note 3502 This storage engine does not support the HASH index algorithm, storage engine default was used instead. DROP INDEX hsh_key ON t1; ALTER TABLE t1 DROP COLUMN c3; SHOW CREATE TABLE t1; Table Create Table t1 CREATE TABLE `t1` ( `pk` int(11) NOT NULL, `a` int(11) DEFAULT NULL, `c` char(8) COLLATE utf8mb4_general_ci DEFAULT NULL, PRIMARY KEY (`pk`) ) ENGINE=XENGINE DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci ALTER TABLE t1 ADD COLUMN b INT; SHOW CREATE TABLE t1; Table Create Table t1 CREATE TABLE `t1` ( `pk` int(11) NOT NULL, `a` int(11) DEFAULT NULL, `c` char(8) COLLATE utf8mb4_general_ci DEFAULT NULL, `b` int(11) DEFAULT NULL, PRIMARY KEY (`pk`) ) ENGINE=XENGINE DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci ALTER TABLE t1 ALTER COLUMN a SET DEFAULT '0'; SHOW CREATE TABLE t1; Table Create Table t1 CREATE TABLE `t1` ( `pk` int(11) NOT NULL, `a` int(11) DEFAULT '0', `c` char(8) COLLATE utf8mb4_general_ci DEFAULT NULL, `b` int(11) DEFAULT NULL, PRIMARY KEY (`pk`) ) ENGINE=XENGINE DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci ALTER TABLE t1 ALTER a DROP DEFAULT; SHOW CREATE TABLE t1; Table Create Table t1 CREATE TABLE `t1` ( `pk` int(11) NOT NULL, `a` int(11), `c` char(8) COLLATE utf8mb4_general_ci DEFAULT NULL, `b` int(11) DEFAULT NULL, PRIMARY KEY (`pk`) ) ENGINE=XENGINE DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci ALTER TABLE t1 CHANGE COLUMN b b1 CHAR(8) FIRST; SHOW CREATE TABLE t1; Table Create Table t1 CREATE TABLE `t1` ( `b1` char(8) COLLATE utf8mb4_general_ci DEFAULT NULL, `pk` int(11) NOT NULL, `a` int(11), `c` char(8) COLLATE utf8mb4_general_ci DEFAULT NULL, PRIMARY KEY (`pk`) ) ENGINE=XENGINE DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci ALTER TABLE t1 CHANGE b1 b INT AFTER c; SHOW CREATE TABLE t1; Table Create Table t1 CREATE TABLE `t1` ( `pk` int(11) NOT NULL, `a` int(11), `c` char(8) COLLATE utf8mb4_general_ci DEFAULT NULL, `b` int(11) DEFAULT NULL, PRIMARY KEY (`pk`) ) ENGINE=XENGINE DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci ALTER TABLE t1 CHANGE b b CHAR(8); SHOW CREATE TABLE t1; Table Create Table t1 CREATE TABLE `t1` ( `pk` int(11) NOT NULL, `a` int(11), `c` char(8) COLLATE utf8mb4_general_ci DEFAULT NULL, `b` char(8) COLLATE utf8mb4_general_ci DEFAULT NULL, PRIMARY KEY (`pk`) ) ENGINE=XENGINE DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci ALTER TABLE t1 MODIFY COLUMN b INT; SHOW CREATE TABLE t1; Table Create Table t1 CREATE TABLE `t1` ( `pk` int(11) NOT NULL, `a` int(11), `c` char(8) COLLATE utf8mb4_general_ci DEFAULT NULL, `b` int(11) DEFAULT NULL, PRIMARY KEY (`pk`) ) ENGINE=XENGINE DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci ALTER TABLE t1 MODIFY COLUMN b CHAR(8) FIRST; SHOW CREATE TABLE t1; Table Create Table t1 CREATE TABLE `t1` ( `b` char(8) COLLATE utf8mb4_general_ci DEFAULT NULL, `pk` int(11) NOT NULL, `a` int(11), `c` char(8) COLLATE utf8mb4_general_ci DEFAULT NULL, PRIMARY KEY (`pk`) ) ENGINE=XENGINE DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci ALTER TABLE t1 MODIFY COLUMN b INT AFTER a; SHOW CREATE TABLE t1; Table Create Table t1 CREATE TABLE `t1` ( `pk` int(11) NOT NULL, `a` int(11), `b` int(11) DEFAULT NULL, `c` char(8) COLLATE utf8mb4_general_ci DEFAULT NULL, PRIMARY KEY (`pk`) ) ENGINE=XENGINE DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci ALTER TABLE t1 DROP COLUMN b; SHOW CREATE TABLE t1; Table Create Table t1 CREATE TABLE `t1` ( `pk` int(11) NOT NULL, `a` int(11), `c` char(8) COLLATE utf8mb4_general_ci DEFAULT NULL, PRIMARY KEY (`pk`) ) ENGINE=XENGINE DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci ALTER TABLE t1 RENAME TO t2; SHOW CREATE TABLE t1; ERROR 42S02: Table 'test.t1' doesn't exist SHOW CREATE TABLE t2; Table Create Table t2 CREATE TABLE `t2` ( `pk` int(11) NOT NULL, `a` int(11), `c` char(8) COLLATE utf8mb4_general_ci DEFAULT NULL, PRIMARY KEY (`pk`) ) ENGINE=XENGINE DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci DROP TABLE t2; CREATE TABLE t1 (pk INT PRIMARY KEY, a INT, b INT) ENGINE=xengine; INSERT INTO t1 VALUES (1,1,5),(2,2,2),(3,4,3); SHOW CREATE TABLE t1; Table Create Table t1 CREATE TABLE `t1` ( `pk` int(11) NOT NULL, `a` int(11) DEFAULT NULL, `b` int(11) DEFAULT NULL, PRIMARY KEY (`pk`) ) ENGINE=XENGINE DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci ALTER TABLE t1 ORDER BY b ASC, a DESC, pk DESC; Warnings: Warning 1105 ORDER BY ignored as there is a user-defined clustered index in the table 't1' SHOW CREATE TABLE t1; Table Create Table t1 CREATE TABLE `t1` ( `pk` int(11) NOT NULL, `a` int(11) DEFAULT NULL, `b` int(11) DEFAULT NULL, PRIMARY KEY (`pk`) ) ENGINE=XENGINE DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci SELECT * FROM t1; pk a b 1 1 5 2 2 2 3 4 3 DROP TABLE t1; CREATE TABLE t1 (pk INT PRIMARY KEY, a INT, b CHAR(8), c CHAR(8)) ENGINE=xengine CHARACTER SET latin1 COLLATE latin1_general_cs; INSERT INTO t1 VALUES (1,5,'z','t'); SHOW CREATE TABLE t1; Table Create Table t1 CREATE TABLE `t1` ( `pk` int(11) NOT NULL, `a` int(11) DEFAULT NULL, `b` char(8) COLLATE latin1_general_cs DEFAULT NULL, `c` char(8) COLLATE latin1_general_cs DEFAULT NULL, PRIMARY KEY (`pk`) ) ENGINE=XENGINE DEFAULT CHARSET=latin1 COLLATE=latin1_general_cs ALTER TABLE t1 CONVERT TO CHARACTER SET utf8; Warnings: Warning 3719 'utf8' is currently an alias for the character set UTF8MB3, but will be an alias for UTF8MB4 in a future release. Please consider using UTF8MB4 in order to be unambiguous. SHOW CREATE TABLE t1; Table Create Table t1 CREATE TABLE `t1` ( `pk` int(11) NOT NULL, `a` int(11) DEFAULT NULL, `b` char(8) DEFAULT NULL, `c` char(8) DEFAULT NULL, PRIMARY KEY (`pk`) ) ENGINE=XENGINE DEFAULT CHARSET=utf8 ALTER TABLE t1 DEFAULT CHARACTER SET = latin1 COLLATE latin1_general_ci; SHOW CREATE TABLE t1; Table Create Table t1 CREATE TABLE `t1` ( `pk` int(11) NOT NULL, `a` int(11) DEFAULT NULL, `b` char(8) CHARACTER SET utf8 DEFAULT NULL, `c` char(8) CHARACTER SET utf8 DEFAULT NULL, PRIMARY KEY (`pk`) ) ENGINE=XENGINE DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci ALTER TABLE t1 FORCE; SHOW CREATE TABLE t1; Table Create Table t1 CREATE TABLE `t1` ( `pk` int(11) NOT NULL, `a` int(11) DEFAULT NULL, `b` char(8) CHARACTER SET utf8 DEFAULT NULL, `c` char(8) CHARACTER SET utf8 DEFAULT NULL, PRIMARY KEY (`pk`) ) ENGINE=XENGINE DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci DROP TABLE t1; CREATE TABLE `t1` ( `col1` int(11) NOT NULL, `col2` int(11) NOT NULL, `col3` int(11) DEFAULT NULL, `col4` int(11) DEFAULT NULL, `col5` text, `col6` blob, PRIMARY KEY (col5(10))); Warnings: Warning 1681 Integer display width is deprecated and will be removed in a future release. Warning 1681 Integer display width is deprecated and will be removed in a future release. Warning 1681 Integer display width is deprecated and will be removed in a future release. Warning 1681 Integer display width is deprecated and will be removed in a future release. insert into t1 values(1,1,1,1,'a','a'); insert into t1 values(1,1,1,1,'b','a'); alter table t1 add index idx1(col3); alter table t1 drop index idx1, add unique index idx2(col2); ERROR 23000: Duplicate entry '1' for key 'idx2' insert into t1 values(1,1,1,1,'c','b'); select * from t1; col1 col2 col3 col4 col5 col6 1 1 1 1 a a 1 1 1 1 b a 1 1 1 1 c b drop table t1; CREATE TABLE T1(COL1 INT, COL2 INT, COL3 INT); INSERT INTO T1 VALUES(1,1,1); INSERT INTO T1 VALUES(1,2,1); INSERT INTO T1 VALUES(1,3,1); set session debug= "+d,after_inplace_populate_sk"; ALTER TABLE T1 ADD INDEX IDX_C1(COL1);; select sleep(2); sleep(2) 0 delete from T1 where col2=2; show create table T1; Table Create Table T1 CREATE TABLE `T1` ( `COL1` int(11) DEFAULT NULL, `COL2` int(11) DEFAULT NULL, `COL3` int(11) DEFAULT NULL, KEY `IDX_C1` (`COL1`) ) ENGINE=XENGINE DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci select col1 from T1 force index(idx_c1); col1 1 1 select * from T1; COL1 COL2 COL3 1 1 1 1 3 1 set session debug= "-d,after_inplace_populate_sk"; drop table T1; CREATE TABLE `t1` ( `col4` text NOT NULL, `col1` int(11) NOT NULL, `col3` int(11) DEFAULT NULL, `col2` int(11) DEFAULT NULL, `extra` int(11) DEFAULT NULL, PRIMARY KEY (`col4`(10),`col1`) ) ENGINE=XENGINE DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci; Warnings: Warning 1681 Integer display width is deprecated and will be removed in a future release. Warning 1681 Integer display width is deprecated and will be removed in a future release. Warning 1681 Integer display width is deprecated and will be removed in a future release. Warning 1681 Integer display width is deprecated and will be removed in a future release. truncate table t1; insert into t1 values('3333333333333333333333333',4,4,4,null); insert into t1 values('4444444444444444444444444',4,4,3,null); select * from t1; col4 col1 col3 col2 extra 3333333333333333333333333 4 4 4 NULL 4444444444444444444444444 4 4 3 NULL set session debug= "+d,sleep_after_index_base_creation"; ALTER TABLE t1 ADD UNIQUE INDEX uidx(col2);; select sleep(2); sleep(2) 0 UPDATE t1 SET col2 = 4 LIMIT 2; ERROR 23000: Duplicate entry '4' for key 'uidx' show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `col4` text NOT NULL, `col1` int(11) NOT NULL, `col3` int(11) DEFAULT NULL, `col2` int(11) DEFAULT NULL, `extra` int(11) DEFAULT NULL, PRIMARY KEY (`col4`(10),`col1`) ) ENGINE=XENGINE DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci select * from t1; col4 col1 col3 col2 extra 3333333333333333333333333 4 4 4 NULL 4444444444444444444444444 4 4 4 NULL set session debug= "-d,after_inplace_populate_sk"; drop table t1;