Check for duplicate index (port from mysql)

(pre fts)

25 files changed, 418 insertions, 14 deletions

diff --git a/mysql-test/r/alter_table.result b/mysql-test/r/alter_table.result
index c16f68dda3f..d1df0aced63 100644
--- a/mysql-test/r/alter_table.result
+++ b/mysql-test/r/alter_table.result
@@ -1442,13 +1442,19 @@ affected rows: 0
 info: Records: 0  Duplicates: 0  Warnings: 0
 ALTER TABLE t1 ADD INDEX i2(b), ALGORITHM= DEFAULT;
 affected rows: 0
-info: Records: 0  Duplicates: 0  Warnings: 0
+info: Records: 0  Duplicates: 0  Warnings: 1
+Warnings:
+Note	1831	Duplicate index 'i2' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 ALTER TABLE t1 ADD INDEX i3(b), ALGORITHM= COPY;
 affected rows: 2
-info: Records: 2  Duplicates: 0  Warnings: 0
+info: Records: 2  Duplicates: 0  Warnings: 1
+Warnings:
+Note	1831	Duplicate index 'i3' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 ALTER TABLE t1 ADD INDEX i4(b), ALGORITHM= INPLACE;
 affected rows: 0
-info: Records: 0  Duplicates: 0  Warnings: 0
+info: Records: 0  Duplicates: 0  Warnings: 1
+Warnings:
+Note	1831	Duplicate index 'i4' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 ALTER TABLE t1 ADD INDEX i5(b), ALGORITHM= INVALID;
 ERROR HY000: Unknown ALGORITHM 'INVALID'
 ALTER TABLE m1 ENABLE KEYS;
@@ -1471,13 +1477,19 @@ affected rows: 2
 info: Records: 2  Duplicates: 0  Warnings: 0
 ALTER TABLE t1 ADD INDEX i2(b), ALGORITHM= DEFAULT;
 affected rows: 2
-info: Records: 2  Duplicates: 0  Warnings: 0
+info: Records: 2  Duplicates: 0  Warnings: 1
+Warnings:
+Note	1831	Duplicate index 'i2' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 ALTER TABLE t1 ADD INDEX i3(b), ALGORITHM= COPY;
 affected rows: 2
-info: Records: 2  Duplicates: 0  Warnings: 0
+info: Records: 2  Duplicates: 0  Warnings: 1
+Warnings:
+Note	1831	Duplicate index 'i3' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 ALTER TABLE t1 ADD INDEX i4(b), ALGORITHM= INPLACE;
 affected rows: 0
-info: Records: 0  Duplicates: 0  Warnings: 0
+info: Records: 0  Duplicates: 0  Warnings: 1
+Warnings:
+Note	1831	Duplicate index 'i4' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 SET SESSION old_alter_table= 0;
 affected rows: 0
 ALTER TABLE t1 DROP INDEX i1, DROP INDEX i2, DROP INDEX i3, DROP INDEX i4;
@@ -1497,13 +1509,19 @@ affected rows: 0
 info: Records: 0  Duplicates: 0  Warnings: 0
 ALTER TABLE t1 ADD INDEX i2(b), LOCK= NONE;
 affected rows: 0
-info: Records: 0  Duplicates: 0  Warnings: 0
+info: Records: 0  Duplicates: 0  Warnings: 1
+Warnings:
+Note	1831	Duplicate index 'i2' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 ALTER TABLE t1 ADD INDEX i3(b), LOCK= SHARED;
 affected rows: 0
-info: Records: 0  Duplicates: 0  Warnings: 0
+info: Records: 0  Duplicates: 0  Warnings: 1
+Warnings:
+Note	1831	Duplicate index 'i3' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 ALTER TABLE t1 ADD INDEX i4(b), LOCK= EXCLUSIVE;
 affected rows: 0
-info: Records: 0  Duplicates: 0  Warnings: 0
+info: Records: 0  Duplicates: 0  Warnings: 1
+Warnings:
+Note	1831	Duplicate index 'i4' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 ALTER TABLE t1 ADD INDEX i5(b), LOCK= INVALID;
 ERROR HY000: Unknown LOCK type 'INVALID'
 ALTER TABLE m1 ENABLE KEYS, LOCK= DEFAULT;
@@ -1521,18 +1539,26 @@ affected rows: 0
 info: Records: 0  Duplicates: 0  Warnings: 0
 ALTER TABLE t1 ADD INDEX i2(b), ALGORITHM= INPLACE, LOCK= SHARED;
 affected rows: 0
-info: Records: 0  Duplicates: 0  Warnings: 0
+info: Records: 0  Duplicates: 0  Warnings: 1
+Warnings:
+Note	1831	Duplicate index 'i2' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 ALTER TABLE t1 ADD INDEX i3(b), ALGORITHM= INPLACE, LOCK= EXCLUSIVE;
 affected rows: 0
-info: Records: 0  Duplicates: 0  Warnings: 0
+info: Records: 0  Duplicates: 0  Warnings: 1
+Warnings:
+Note	1831	Duplicate index 'i3' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 ALTER TABLE t1 ADD INDEX i4(b), ALGORITHM= COPY, LOCK= NONE;
 ERROR 0A000: LOCK=NONE is not supported. Reason: COPY algorithm requires a lock. Try LOCK=SHARED.
 ALTER TABLE t1 ADD INDEX i5(b), ALGORITHM= COPY, LOCK= SHARED;
 affected rows: 2
-info: Records: 2  Duplicates: 0  Warnings: 0
+info: Records: 2  Duplicates: 0  Warnings: 1
+Warnings:
+Note	1831	Duplicate index 'i5' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 ALTER TABLE t1 ADD INDEX i6(b), ALGORITHM= COPY, LOCK= EXCLUSIVE;
 affected rows: 2
-info: Records: 2  Duplicates: 0  Warnings: 0
+info: Records: 2  Duplicates: 0  Warnings: 1
+Warnings:
+Note	1831	Duplicate index 'i6' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 ALTER TABLE m1 ENABLE KEYS, ALGORITHM= INPLACE, LOCK= NONE;
 ERROR 0A000: LOCK=NONE/SHARED is not supported for this operation. Try LOCK=EXCLUSIVE.
 ALTER TABLE m1 ENABLE KEYS, ALGORITHM= INPLACE, LOCK= SHARED;
diff --git a/mysql-test/r/check.result b/mysql-test/r/check.result
index ac9c7bca9d7..0ac42272c4f 100644
--- a/mysql-test/r/check.result
+++ b/mysql-test/r/check.result
@@ -1,6 +1,10 @@
 drop table if exists t1,t2;
 drop view if exists v1;
 create table t1(n int not null, key(n), key(n), key(n), key(n));
+Warnings:
+Note	1831	Duplicate index 'n_2' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'n_3' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'n_4' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 check table t1 extended;
 insert into t1 values (200000);
 Table	Op	Msg_type	Msg_text
diff --git a/mysql-test/r/constraints.result b/mysql-test/r/constraints.result
index 3821a18b072..3bec2c3e16d 100644
--- a/mysql-test/r/constraints.result
+++ b/mysql-test/r/constraints.result
@@ -17,7 +17,11 @@ drop table t1;
 create table t1 (a int null);
 alter table t1 add constraint constraint_1 unique (a);
 alter table t1 add constraint unique key_1(a);
+Warnings:
+Note	1831	Duplicate index 'key_1' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 alter table t1 add constraint constraint_2 unique key_2(a);
+Warnings:
+Note	1831	Duplicate index 'key_2' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
diff --git a/mysql-test/r/create.result b/mysql-test/r/create.result
index 4768af0176c..ab9cddb2c06 100644
--- a/mysql-test/r/create.result
+++ b/mysql-test/r/create.result
@@ -179,6 +179,37 @@ DROP TABLE IF EXISTS t2;
 Warnings:
 Note	1051	Unknown table 'test.t2'
 create table t1 (a int not null, b int, primary key(a), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b), key (b));
+Warnings:
+Note	1831	Duplicate index 'b_2' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_3' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_4' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_5' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_6' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_7' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_8' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_9' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_10' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_11' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_12' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_13' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_14' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_15' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_16' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_17' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_18' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_19' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_20' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_21' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_22' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_23' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_24' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_25' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_26' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_27' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_28' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_29' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_30' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_31' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
@@ -1012,6 +1043,70 @@ c1,c2,c3,c4,c5,c6,c7,c8,c9,c10,c11,c12,c13,c14,c15,c16),
 key a064_long_123456789_123456789_123456789_123456789_123456789_1234 (
 c1,c2,c3,c4,c5,c6,c7,c8,c9,c10,c11,c12,c13,c14,c15,c16)
 );
+Warnings:
+Note	1831	Duplicate index 'a002_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a003_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a004_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a005_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a006_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a007_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a008_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a009_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a010_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a011_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a012_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a013_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a014_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a015_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a016_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a017_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a018_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a019_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a020_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a021_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a022_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a023_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a024_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a025_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a026_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a027_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a028_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a029_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a030_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a031_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a032_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a033_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a034_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a035_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a036_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a037_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a038_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a039_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a040_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a041_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a042_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a043_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a044_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a045_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a046_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a047_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a048_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a049_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a050_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a051_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a052_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a053_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a054_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a055_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a056_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a057_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a058_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a059_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a060_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a061_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a062_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a063_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a064_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
@@ -1313,6 +1408,70 @@ add key a063_long_123456789_123456789_123456789_123456789_123456789_1234 (
 c1,c2,c3,c4,c5,c6,c7,c8,c9,c10,c11,c12,c13,c14,c15,c16),
 add key a064_long_123456789_123456789_123456789_123456789_123456789_1234 (
 c1,c2,c3,c4,c5,c6,c7,c8,c9,c10,c11,c12,c13,c14,c15,c16);
+Warnings:
+Note	1831	Duplicate index 'a002_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a003_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a004_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a005_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a006_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a007_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a008_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a009_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a010_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a011_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a012_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a013_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a014_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a015_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a016_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a017_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a018_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a019_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a020_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a021_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a022_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a023_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a024_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a025_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a026_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a027_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a028_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a029_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a030_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a031_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a032_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a033_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a034_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a035_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a036_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a037_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a038_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a039_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a040_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a041_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a042_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a043_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a044_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a045_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a046_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a047_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a048_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a049_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a050_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a051_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a052_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a053_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a054_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a055_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a056_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a057_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a058_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a059_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a060_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a061_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a062_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a063_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a064_long_123456789_123456789_123456789_123456789_123456789_1234' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
diff --git a/mysql-test/r/explain.result b/mysql-test/r/explain.result
index 919e29f185e..4c67ab5693a 100644
--- a/mysql-test/r/explain.result
+++ b/mysql-test/r/explain.result
@@ -98,6 +98,46 @@ KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
 KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
 KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
 KEY(b),KEY(b),KEY(b),KEY(b),KEY(b));
+Warnings:
+Note	1831	Duplicate index 'b_2' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_3' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_4' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_5' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_6' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_7' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_8' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_9' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_10' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_11' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_12' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_13' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_14' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_15' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_16' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_17' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_18' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_19' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_20' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_21' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_22' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_23' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_24' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_25' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_26' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_27' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_28' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_29' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_30' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_31' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_32' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_33' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_34' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_35' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_36' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_37' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_38' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_39' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'b_40' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
 INSERT INTO t2 VALUES (),(),();
 EXPLAIN SELECT 1 FROM
 (SELECT 1 FROM t2,t1 WHERE b < c GROUP BY 1 LIMIT 1) AS d2;
diff --git a/mysql-test/r/index_merge_myisam.result b/mysql-test/r/index_merge_myisam.result
index e771d48b6d2..1db3eb50bd2 100644
--- a/mysql-test/r/index_merge_myisam.result
+++ b/mysql-test/r/index_merge_myisam.result
@@ -223,6 +223,8 @@ index i1b (key1b, key1a),
 index i2_1(key2, key2_1),
 index i2_2(key2, key2_1)
 );
+Warnings:
+Note	1831	Duplicate index 'i2_2' defined on the table 'test.t4'. This is deprecated and will be disallowed in a future release.
 insert into t4 select key1,key1,key1 div 10, key1 % 10, key1 % 10, key1 from t0;
 select * from t4 where key1a = 3 or key1b = 4;
 key1a	key1b	key2	key2_1	key2_2	key3
diff --git a/mysql-test/r/innodb_icp.result b/mysql-test/r/innodb_icp.result
index 07c75986392..5e9e6d647f8 100644
--- a/mysql-test/r/innodb_icp.result
+++ b/mysql-test/r/innodb_icp.result
@@ -711,6 +711,9 @@ a INT PRIMARY KEY NOT NULL AUTO_INCREMENT,
 b INT, c INT, d DATE NOT NULL, e VARCHAR(1),
 KEY (c), KEY (d), KEY k2(b), KEY k3(b), KEY k4(b)
 );
+Warnings:
+Note	1831	Duplicate index 'k3' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'k4' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 INSERT INTO t1 (b,c,d,e) VALUES
 (6,5,'2006-05-25','y'),(1,5,'2008-01-23','t'),
 (6,5,'2007-06-18','d'),(4,5,'1900-01-01','r'),
diff --git a/mysql-test/r/innodb_mysql_sync.result b/mysql-test/r/innodb_mysql_sync.result
index 2164b936938..0fecadf6de5 100644
--- a/mysql-test/r/innodb_mysql_sync.result
+++ b/mysql-test/r/innodb_mysql_sync.result
@@ -304,6 +304,8 @@ ERROR HY000: Lock wait timeout exceeded; try restarting transaction
 SET DEBUG_SYNC= 'now SIGNAL continue3';
 # Connection default
 # Reaping ALTER TABLE ...
+Warnings:
+Note	1831	Duplicate index 'i2' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 SET DEBUG_SYNC= 'RESET';
 DELETE FROM t1 WHERE a= 3;
 #
@@ -352,6 +354,8 @@ ERROR HY000: Lock wait timeout exceeded; try restarting transaction
 SET DEBUG_SYNC= 'now SIGNAL continue4';
 # Connection default
 # Reaping ALTER TABLE ...
+Warnings:
+Note	1831	Duplicate index 'i4' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 SET DEBUG_SYNC= 'RESET';
 DROP TABLE t1;
 SET DEBUG_SYNC= 'RESET';
diff --git a/mysql-test/r/key.result b/mysql-test/r/key.result
index cb21e5e8134..2479308a2c4 100644
--- a/mysql-test/r/key.result
+++ b/mysql-test/r/key.result
@@ -427,6 +427,8 @@ unique i4 (c4),
 index i5 (c1, c2, c3, c4),
 primary key (c2, c3),
 index (c2, c4));
+Warnings:
+Note	1831	Duplicate index 'i1' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
@@ -445,12 +447,18 @@ t1	CREATE TABLE `t1` (
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 alter table t1 drop index c1;
 alter table t1 add index (c1);
+Warnings:
+Note	1831	Duplicate index 'c1' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 alter table t1 add index (c1);
+Warnings:
+Note	1831	Duplicate index 'c1_2' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 alter table t1 drop index i3;
 alter table t1 add index i3 (c3);
 alter table t1 drop index i2, drop index i4;
 alter table t1 add index i2 (c2), add index i4 (c4);
 alter table t1 drop index i2, drop index i4, add index i6 (c2, c4);
+Warnings:
+Note	1831	Duplicate index 'i6' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 alter table t1 add index i2 (c2), add index i4 (c4), drop index i6;
 alter table t1 drop index i2, drop index i4, add unique i4 (c4);
 alter table t1 add index i2 (c2), drop index i4, add index i4 (c4);
diff --git a/mysql-test/r/mix2_myisam.result b/mysql-test/r/mix2_myisam.result
index 6f90555325b..e824db8928a 100644
--- a/mysql-test/r/mix2_myisam.result
+++ b/mysql-test/r/mix2_myisam.result
@@ -256,6 +256,8 @@ user_id	name	phone	ref_email	detail
 drop table t1;
 CREATE TABLE t1 (a int not null, b int not null,c int not null,
 key(a),primary key(a,b), unique(c),key(a),unique(b)) ENGINE = MyISAM;
+Warnings:
+Note	1831	Duplicate index 'a_2' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 show index from t1;
 Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
 t1	0	PRIMARY	1	a	A	#	NULL	NULL		BTREE		
@@ -1547,6 +1549,8 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 alter table t1 add unique(v);
 ERROR 23000: Duplicate entry '{ ' for key 'v_2'
 alter table t1 add key(v);
+Warnings:
+Note	1831	Duplicate index 'v_2' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 select concat('*',v,'*',c,'*',t,'*') as qq from t1 where v='a';
 qq
 *a*a*a*
diff --git a/mysql-test/r/mrr_icp_extra.result b/mysql-test/r/mrr_icp_extra.result
index f7adcfb19fd..855ac4beab5 100644
--- a/mysql-test/r/mrr_icp_extra.result
+++ b/mysql-test/r/mrr_icp_extra.result
@@ -350,6 +350,8 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 alter table t1 add unique(v);
 ERROR 23000: Duplicate entry '{ ' for key 'v_2'
 alter table t1 add key(v);
+Warnings:
+Note	1831	Duplicate index 'v_2' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 select concat('*',v,'*',c,'*',t,'*') as qq from t1 where v='a';
 qq
 *a*a*a*
diff --git a/mysql-test/r/myisam.result b/mysql-test/r/myisam.result
index 5b0dbbf6957..3a6fa9a4673 100644
--- a/mysql-test/r/myisam.result
+++ b/mysql-test/r/myisam.result
@@ -1242,6 +1242,8 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 alter table t1 add unique(v);
 ERROR 23000: Duplicate entry '{ ' for key 'v_2'
 alter table t1 add key(v);
+Warnings:
+Note	1831	Duplicate index 'v_2' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 select concat('*',v,'*',c,'*',t,'*') as qq from t1 where v='a';
 qq
 *a*a*a*
@@ -2439,6 +2441,9 @@ DROP TABLE t1;
 SET myisam_repair_threads=2;
 SET myisam_sort_buffer_size=4096;
 CREATE TABLE t1(a CHAR(255), KEY(a), KEY(a), KEY(a));
+Warnings:
+Note	1831	Duplicate index 'a_2' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a_3' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 INSERT INTO t1 VALUES (0),(1),(2),(3),(4),(5),(6),(7),(8),(9),(0),(1),(2),(3);
 REPAIR TABLE t1;
 Table	Op	Msg_type	Msg_text
diff --git a/mysql-test/r/myisam_icp.result b/mysql-test/r/myisam_icp.result
index 2c157102270..49cba60320d 100644
--- a/mysql-test/r/myisam_icp.result
+++ b/mysql-test/r/myisam_icp.result
@@ -715,6 +715,9 @@ a INT PRIMARY KEY NOT NULL AUTO_INCREMENT,
 b INT, c INT, d DATE NOT NULL, e VARCHAR(1),
 KEY (c), KEY (d), KEY k2(b), KEY k3(b), KEY k4(b)
 );
+Warnings:
+Note	1831	Duplicate index 'k3' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'k4' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 INSERT INTO t1 (b,c,d,e) VALUES
 (6,5,'2006-05-25','y'),(1,5,'2008-01-23','t'),
 (6,5,'2007-06-18','d'),(4,5,'1900-01-01','r'),
diff --git a/mysql-test/r/partition.result b/mysql-test/r/partition.result
index f2429c09149..24567f5cd72 100644
--- a/mysql-test/r/partition.result
+++ b/mysql-test/r/partition.result
@@ -299,6 +299,8 @@ insert into t1 select * from t1;
 create index i on t1 (a);
 ERROR 42000: Duplicate key name 'i'
 create index i2 on t1 (a);
+Warnings:
+Note	1831	Duplicate index 'i2' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 drop table t1;
 CREATE TABLE t1 (a INT, FOREIGN KEY (a) REFERENCES t0 (a))
 ENGINE=MyISAM
diff --git a/mysql-test/r/partition_innodb.result b/mysql-test/r/partition_innodb.result
index 2d35fe0bf07..f627cdcfb7b 100644
--- a/mysql-test/r/partition_innodb.result
+++ b/mysql-test/r/partition_innodb.result
@@ -597,6 +597,8 @@ b INT,
 c INT,
 PRIMARY KEY (c,a), KEY (a),KEY (a)
 ) ENGINE=INNODB PARTITION BY KEY () PARTITIONS 2;
+Warnings:
+Note	1831	Duplicate index 'a_2' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 INSERT INTO t1 VALUES (1,5,1),(2,4,1),(3,3,1),(4,2,1),(5,1,1);
 UPDATE t1 SET b = 0, c=1 WHERE a <=>0;
 SELECT * FROM t1;
diff --git a/mysql-test/r/type_ranges.result b/mysql-test/r/type_ranges.result
index d99c2363d62..5992b1347f3 100644
--- a/mysql-test/r/type_ranges.result
+++ b/mysql-test/r/type_ranges.result
@@ -85,7 +85,11 @@ t1	1	options	1	options	A	NULL	NULL	NULL		BTREE
 t1	1	options	2	flags	A	NULL	NULL	NULL		BTREE		
 CREATE UNIQUE INDEX test on t1 ( auto ) ;
 CREATE INDEX test2 on t1 ( ulonglong,ulong) ;
+Warnings:
+Note	1831	Duplicate index 'test2' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 CREATE INDEX test3 on t1 ( medium ) ;
+Warnings:
+Note	1831	Duplicate index 'test3' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 DROP INDEX test ON t1;
 insert into t1 values (10, 1,1,1,1,1,1,1,1,1,1,1,1,1,NULL,0,0,0,1,1,1,1,'one','one');
 insert into t1 values (NULL,2,2,2,2,2,2,2,2,2,2,2,2,2,NULL,NULL,NULL,NULL,NULL,NULL,2,2,'two','two,one');
@@ -303,6 +307,8 @@ c2	int(11)	NULL	YES		NULL		#
 const	int(1)	NULL	NO		0		#	
 drop table t1,t2,t3;
 create table t1 ( myfield INT NOT NULL, UNIQUE INDEX (myfield), unique (myfield), index(myfield));
+Warnings:
+Note	1831	Duplicate index 'myfield_2' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 drop table t1;
 create table t1 ( id integer unsigned not null primary key );
 create table t2 ( id integer unsigned not null primary key );
diff --git a/mysql-test/suite/innodb/r/innodb-index.result b/mysql-test/suite/innodb/r/innodb-index.result
index d9242e8ee33..d3c12ee2828 100644
--- a/mysql-test/suite/innodb/r/innodb-index.result
+++ b/mysql-test/suite/innodb/r/innodb-index.result
@@ -62,7 +62,9 @@ t1	CREATE TABLE `t1` (
 ) ENGINE=InnoDB DEFAULT CHARSET=latin1
 alter table t1 add unique index (c), add index (d);
 affected rows: 0
-info: Records: 0  Duplicates: 0  Warnings: 0
+info: Records: 0  Duplicates: 0  Warnings: 1
+Warnings:
+Note	1831	Duplicate index 'd' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
diff --git a/mysql-test/suite/innodb/r/innodb.result b/mysql-test/suite/innodb/r/innodb.result
index c67a200d513..7d255e794c0 100644
--- a/mysql-test/suite/innodb/r/innodb.result
+++ b/mysql-test/suite/innodb/r/innodb.result
@@ -404,6 +404,8 @@ user_id	name	phone	ref_email	detail
 drop table t1;
 CREATE TABLE t1 (a int not null, b int not null,c int not null,
 key(a),primary key(a,b), unique(c),key(a),unique(b));
+Warnings:
+Note	1831	Duplicate index 'a_2' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 show index from t1;
 Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
 t1	0	PRIMARY	1	a	A	#	NULL	NULL		BTREE		
@@ -1442,6 +1444,8 @@ t2	CREATE TABLE `t2` (
   CONSTRAINT `t1_id_fk` FOREIGN KEY (`id`) REFERENCES `t1` (`id`)
 ) ENGINE=InnoDB DEFAULT CHARSET=latin1
 create index id2 on t2 (id);
+Warnings:
+Note	1831	Duplicate index 'id2' defined on the table 'test.t2'. This is deprecated and will be disallowed in a future release.
 show create table t2;
 Table	Create Table
 t2	CREATE TABLE `t2` (
@@ -1850,6 +1854,8 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 alter table t1 add unique(v);
 ERROR 23000: Duplicate entry '{ ' for key 'v_2'
 alter table t1 add key(v);
+Warnings:
+Note	1831	Duplicate index 'v_2' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 select concat('*',v,'*',c,'*',t,'*') as qq from t1 where v='a';
 qq
 *a*a*a*
diff --git a/mysql-test/suite/innodb/r/innodb_bug51378.result b/mysql-test/suite/innodb/r/innodb_bug51378.result
index a3ca73c16a9..a2a9bcad564 100644
--- a/mysql-test/suite/innodb/r/innodb_bug51378.result
+++ b/mysql-test/suite/innodb/r/innodb_bug51378.result
@@ -4,6 +4,8 @@ col2 blob not null,
 col3 time not null) engine = innodb;
 create unique index idx on bug51378(col1, col2(31));
 alter table bug51378 add unique index idx2(col1, col2(31));
+Warnings:
+Note	1831	Duplicate index 'idx2' defined on the table 'test.bug51378'. This is deprecated and will be disallowed in a future release.
 create unique index idx3 on bug51378(col1, col3);
 SHOW CREATE TABLE bug51378;
 Table	Create Table
diff --git a/mysql-test/suite/innodb/r/innodb_index_large_prefix.result b/mysql-test/suite/innodb/r/innodb_index_large_prefix.result
index 330ade923b3..b610d1ed7b8 100644
--- a/mysql-test/suite/innodb/r/innodb_index_large_prefix.result
+++ b/mysql-test/suite/innodb/r/innodb_index_large_prefix.result
@@ -192,8 +192,11 @@ show warnings;
 Level	Code	Message
 Warning	1071	Specified key was too long; max key length is 3072 bytes
 create index idx3 on worklog5743_8(a2(3072));
+Warnings:
+Note	1831	Duplicate index 'idx3' defined on the table 'test.worklog5743_8'. This is deprecated and will be disallowed in a future release.
 show warnings;
 Level	Code	Message
+Note	1831	Duplicate index 'idx3' defined on the table 'test.worklog5743_8'. This is deprecated and will be disallowed in a future release.
 create index idx4 on worklog5743_8(a1, a2(3069));
 ERROR 42000: Specified key was too long; max key length is 3072 bytes
 show warnings;
@@ -225,8 +228,11 @@ show warnings;
 Level	Code	Message
 Warning	1071	Specified key was too long; max key length is 3072 bytes
 create index idx3 on worklog5743_16(a2(3072));
+Warnings:
+Note	1831	Duplicate index 'idx3' defined on the table 'test.worklog5743_16'. This is deprecated and will be disallowed in a future release.
 show warnings;
 Level	Code	Message
+Note	1831	Duplicate index 'idx3' defined on the table 'test.worklog5743_16'. This is deprecated and will be disallowed in a future release.
 create index idx4 on worklog5743_16(a1, a2(3069));
 ERROR 42000: Specified key was too long; max key length is 3072 bytes
 show warnings;
@@ -455,6 +461,8 @@ create index idx1 on worklog5743(a(3073));
 Warnings:
 Warning	1071	Specified key was too long; max key length is 3072 bytes
 create index idx2 on worklog5743(a(3072));
+Warnings:
+Note	1831	Duplicate index 'idx2' defined on the table 'test.worklog5743'. This is deprecated and will be disallowed in a future release.
 show create table worklog5743;
 Table	Create Table
 worklog5743	CREATE TABLE `worklog5743` (
diff --git a/mysql-test/suite/maria/icp.result b/mysql-test/suite/maria/icp.result
index 9552580bb88..28b6418d6cf 100644
--- a/mysql-test/suite/maria/icp.result
+++ b/mysql-test/suite/maria/icp.result
@@ -717,6 +717,9 @@ a INT PRIMARY KEY NOT NULL AUTO_INCREMENT,
 b INT, c INT, d DATE NOT NULL, e VARCHAR(1),
 KEY (c), KEY (d), KEY k2(b), KEY k3(b), KEY k4(b)
 );
+Warnings:
+Note	1831	Duplicate index 'k3' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'k4' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 INSERT INTO t1 (b,c,d,e) VALUES
 (6,5,'2006-05-25','y'),(1,5,'2008-01-23','t'),
 (6,5,'2007-06-18','d'),(4,5,'1900-01-01','r'),
diff --git a/mysql-test/suite/maria/maria.result b/mysql-test/suite/maria/maria.result
index 914c9568ea4..77da9813559 100644
--- a/mysql-test/suite/maria/maria.result
+++ b/mysql-test/suite/maria/maria.result
@@ -1131,6 +1131,8 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 alter table t1 add unique(v);
 ERROR 23000: Duplicate entry '{ ' for key 'v_2'
 alter table t1 add key(v);
+Warnings:
+Note	1831	Duplicate index 'v_2' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 select concat('*',v,'*',c,'*',t,'*') as qq from t1 where v='a';
 qq
 *a*a*a*
@@ -2686,6 +2688,9 @@ drop table t1;
 SET aria_repair_threads=2;
 SET aria_sort_buffer_size=8192;
 CREATE TABLE t1(a CHAR(255), KEY(a), KEY(a), KEY(a));
+Warnings:
+Note	1831	Duplicate index 'a_2' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
+Note	1831	Duplicate index 'a_3' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
 INSERT INTO t1 VALUES (0),(1),(2),(3),(4),(5),(6),(7),(8),(9),(0),(1),(2),(3);
 REPAIR TABLE t1;
 Table	Op	Msg_type	Msg_text
diff --git a/mysql-test/suite/optimizer_unfixed_bugs/r/bug45221.result b/mysql-test/suite/optimizer_unfixed_bugs/r/bug45221.result
index 45e502ca5a4..3668df4c2f0 100644
--- a/mysql-test/suite/optimizer_unfixed_bugs/r/bug45221.result
+++ b/mysql-test/suite/optimizer_unfixed_bugs/r/bug45221.result
@@ -7,6 +7,8 @@ PRIMARY KEY (`pk`),
 KEY `int_key` (`int_key`),
 KEY `varchar_key` (`int_key`)
 ) ENGINE=MyISAM AUTO_INCREMENT=30 DEFAULT CHARSET=latin1;
+Warnings:
+Note	1831	Duplicate index 'varchar_key' defined on the table 'test.CC'. This is deprecated and will be disallowed in a future release.
 INSERT INTO `CC` VALUES (10,8,NULL,'2002-02-26 06:14:37'),(11,9,'2006-06-14','1900-01-01 00:00:00'),(12,9,'2002-09-12','2006-12-03 09:37:26'),(13,186,'2005-02-15','2008-05-26 12:27:10'),(14,NULL,NULL,'2004-12-14 16:37:30'),(15,2,'2008-11-04','2003-02-11 21:19:41'),(16,3,'2004-09-04','2009-10-18 02:27:49'),(17,0,'2006-06-05','2000-09-26 07:45:57'),(18,133,'1900-01-01',NULL),(19,1,'1900-01-01','2005-11-10 12:40:29'),(20,8,'1900-01-01','2009-04-25 00:00:00'),(21,5,'2005-01-13','2002-11-27 00:00:00'),(22,5,'2006-05-21','2004-01-26 20:32:32'),(23,8,'2003-09-08','2007-10-26 11:41:40'),(24,6,'2006-12-23','2005-10-07 00:00:00'),(25,51,'2006-10-15','2000-07-15 05:00:34'),(26,4,'2005-04-06','2000-04-03 16:33:32'),(27,7,'2008-04-07',NULL),(28,6,'2006-10-10','2001-04-25 01:26:12'),(29,4,'1900-01-01','2000-12-27 00:00:00');
 CREATE TABLE `C` (
 `pk` int(11) NOT NULL AUTO_INCREMENT,
@@ -17,6 +19,8 @@ PRIMARY KEY (`pk`),
 KEY `int_key` (`int_key`),
 KEY `varchar_key` (`int_key`)
 ) ENGINE=MyISAM AUTO_INCREMENT=21 DEFAULT CHARSET=latin1;
+Warnings:
+Note	1831	Duplicate index 'varchar_key' defined on the table 'test.C'. This is deprecated and will be disallowed in a future release.
 INSERT INTO `C` VALUES (1,2,NULL,'2004-10-11 18:13:16'),(2,9,'2001-09-19',NULL),(3,3,'2004-09-12','1900-01-01 00:00:00'),(4,9,NULL,'2009-07-25 00:00:00'),(5,NULL,'2002-07-19',NULL),(6,9,'2002-12-16','2008-07-27 00:00:00'),(7,3,'2006-02-08','2002-11-13 16:37:31'),(8,8,'2006-08-28','1900-01-01 00:00:00'),(9,8,'2001-04-14','2003-12-10 00:00:00'),(10,53,'2000-01-05','2001-12-21 22:38:22'),(11,0,'2003-12-06','2008-12-13 23:16:44'),(12,5,'1900-01-01','2005-08-15 12:39:41'),(13,166,'2002-11-27',NULL),(14,3,NULL,'2006-09-11 12:06:14'),(15,0,'2003-05-27','2007-12-15 12:39:34'),(16,1,'2005-05-03','2005-08-09 00:00:00'),(17,9,'2001-04-18','2001-09-02 22:50:02'),(18,5,'2005-12-27','2005-12-16 22:58:11'),(19,6,'2004-08-20','2007-04-19 00:19:53'),(20,2,'1900-01-01','1900-01-01 00:00:00');
 SELECT `pk`  
 FROM C OUTR  
@@ -72,6 +76,8 @@ KEY `int_key` (`int_key`),
 KEY `datetime_key` (`datetime_key`),
 KEY `varchar_key` (`int_key`)
 ) ENGINE=MyISAM AUTO_INCREMENT=30 DEFAULT CHARSET=latin1;
+Warnings:
+Note	1831	Duplicate index 'varchar_key' defined on the table 'test.CC'. This is deprecated and will be disallowed in a future release.
 INSERT INTO `CC` VALUES (10,7,8,NULL,'2002-02-26 06:14:37','2002-02-26 06:14:37'),(11,1,9,'2006-06-14','1900-01-01 00:00:00','1900-01-01 00:00:00'),(12,5,9,'2002-09-12','2006-12-03 09:37:26','2006-12-03 09:37:26'),(13,3,186,'2005-02-15','2008-05-26 12:27:10','2008-05-26 12:27:10'),(14,6,NULL,NULL,'2004-12-14 16:37:30','2004-12-14 16:37:30'),(15,92,2,'2008-11-04','2003-02-11 21:19:41','2003-02-11 21:19:41'),(16,7,3,'2004-09-04','2009-10-18 02:27:49','2009-10-18 02:27:49'),(17,NULL,0,'2006-06-05','2000-09-26 07:45:57','2000-09-26 07:45:57'),(18,3,133,'1900-01-01',NULL,NULL),(19,5,1,'1900-01-01','2005-11-10 12:40:29','2005-11-10 12:40:29'),(20,1,8,'1900-01-01','2009-04-25 00:00:00','2009-04-25 00:00:00'),(21,2,5,'2005-01-13','2002-11-27 00:00:00','2002-11-27 00:00:00'),(22,NULL,5,'2006-05-21','2004-01-26 20:32:32','2004-01-26 20:32:32'),(23,1,8,'2003-09-08','2007-10-26 11:41:40','2007-10-26 11:41:40'),(24,0,6,'2006-12-23','2005-10-07 00:00:00','2005-10-07 00:00:00'),(25,210,51,'2006-10-15','2000-07-15 05:00:34','2000-07-15 05:00:34'),(26,8,4,'2005-04-06','2000-04-03 16:33:32','2000-04-03 16:33:32'),(27,7,7,'2008-04-07',NULL,NULL),(28,5,6,'2006-10-10','2001-04-25 01:26:12','2001-04-25 01:26:12'),(29,NULL,4,'1900-01-01','2000-12-27 00:00:00','2000-12-27 00:00:00');
 CREATE TABLE `C` (
 `pk` int(11) NOT NULL AUTO_INCREMENT,
@@ -85,6 +91,8 @@ KEY `int_key` (`int_key`),
 KEY `datetime_key` (`datetime_key`),
 KEY `varchar_key` (`int_key`)
 ) ENGINE=MyISAM AUTO_INCREMENT=21 DEFAULT CHARSET=latin1;
+Warnings:
+Note	1831	Duplicate index 'varchar_key' defined on the table 'test.C'. This is deprecated and will be disallowed in a future release.
 INSERT INTO `C` VALUES (1,NULL,2,NULL,'2004-10-11 18:13:16','2004-10-11 18:13:16'),(2,7,9,'2001-09-19',NULL,NULL),(3,9,3,'2004-09-12','1900-01-01 00:00:00','1900-01-01 00:00:00'),(4,7,9,NULL,'2009-07-25 00:00:00','2009-07-25 00:00:00'),(5,4,NULL,'2002-07-19',NULL,NULL),(6,2,9,'2002-12-16','2008-07-27 00:00:00','2008-07-27 00:00:00'),(7,6,3,'2006-02-08','2002-11-13 16:37:31','2002-11-13 16:37:31'),(8,8,8,'2006-08-28','1900-01-01 00:00:00','1900-01-01 00:00:00'),(9,NULL,8,'2001-04-14','2003-12-10 00:00:00','2003-12-10 00:00:00'),(10,5,53,'2000-01-05','2001-12-21 22:38:22','2001-12-21 22:38:22'),(11,NULL,0,'2003-12-06','2008-12-13 23:16:44','2008-12-13 23:16:44'),(12,6,5,'1900-01-01','2005-08-15 12:39:41','2005-08-15 12:39:41'),(13,188,166,'2002-11-27',NULL,NULL),(14,2,3,NULL,'2006-09-11 12:06:14','2006-09-11 12:06:14'),(15,1,0,'2003-05-27','2007-12-15 12:39:34','2007-12-15 12:39:34'),(16,1,1,'2005-05-03','2005-08-09 00:00:00','2005-08-09 00:00:00'),(17,0,9,'2001-04-18','2001-09-02 22:50:02','2001-09-02 22:50:02'),(18,9,5,'2005-12-27','2005-12-16 22:58:11','2005-12-16 22:58:11'),(19,NULL,6,'2004-08-20','2007-04-19 00:19:53','2007-04-19 00:19:53'),(20,4,2,'1900-01-01','1900-01-01 00:00:00','1900-01-01 00:00:00');
 SELECT OUTR . `pk` AS X 
 FROM C AS OUTR 
diff --git a/mysql-test/suite/rpl/r/rpl_sp.result b/mysql-test/suite/rpl/r/rpl_sp.result
index a91a9ff6ebe..8ca72672073 100644
--- a/mysql-test/suite/rpl/r/rpl_sp.result
+++ b/mysql-test/suite/rpl/r/rpl_sp.result
@@ -252,6 +252,8 @@ return 0;
 end
 delete from t2;
 alter table t2 add unique (a);
+Warnings:
+Note	1831	Duplicate index 'a_2' defined on the table 'mysqltest1.t2'. This is deprecated and will be disallowed in a future release.
 drop function fn1;
 create function fn1(x int)
 returns int
diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index 0f535c81d69..f1c6d85c659 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -3042,6 +3042,90 @@ void promote_first_timestamp_column(List<Create_field> *column_definitions)
 }
 
 
+/**
+  Check if there is a duplicate key. Report a warning for every duplicate key.
+
+  @param thd              Thread context.
+  @param key              Key to be checked.
+  @param key_info         Key meta-data info.
+  @param key_list         List of existing keys.
+*/
+static void check_duplicate_key(THD *thd,
+                                Key *key, KEY *key_info,
+                                List<Key> *key_list)
+{
+  /*
+    We only check for duplicate indexes if it is requested and the
+    key is not auto-generated.
+
+    Check is requested if the key was explicitly created or altered
+    by the user (unless it's a foreign key).
+  */
+  if (!key->key_create_info.check_for_duplicate_indexes || key->generated)
+    return;
+
+  List_iterator<Key> key_list_iterator(*key_list);
+  List_iterator<Key_part_spec> key_column_iterator(key->columns);
+  Key *k;
+
+  while ((k= key_list_iterator++))
+  {
+    // Looking for a similar key...
+
+    if (k == key)
+      break;
+
+    if (k->generated ||
+        (key->type != k->type) ||
+        (key->key_create_info.algorithm != k->key_create_info.algorithm) ||
+        (key->columns.elements != k->columns.elements))
+    {
+      // Keys are different.
+      continue;
+    }
+
+    /*
+      Keys 'key' and 'k' might be identical.
+      Check that the keys have identical columns in the same order.
+    */
+
+    List_iterator<Key_part_spec> k_column_iterator(k->columns);
+
+    bool all_columns_are_identical= true;
+
+    key_column_iterator.rewind();
+
+    for (uint i= 0; i < key->columns.elements; ++i)
+    {
+      Key_part_spec *c1= key_column_iterator++;
+      Key_part_spec *c2= k_column_iterator++;
+
+      DBUG_ASSERT(c1 && c2);
+
+      if (my_strcasecmp(system_charset_info,
+                        c1->field_name.str, c2->field_name.str) ||
+          (c1->length != c2->length))
+      {
+        all_columns_are_identical= false;
+        break;
+      }
+    }
+
+    // Report a warning if we have two identical keys.
+
+    if (all_columns_are_identical)
+    {
+      push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE,
+                          ER_DUP_INDEX, ER(ER_DUP_INDEX),
+                          key_info->name,
+                          thd->lex->query_tables->db,
+                          thd->lex->query_tables->table_name);
+      break;
+    }
+  }
+}
+
+
 /*
   Preparation for table creation
 
@@ -3958,8 +4042,12 @@ mysql_prepare_create_table(THD *thd, HA_CREATE_INFO *create_info,
       key_info->comment.str= key->key_create_info.comment.str;
     }
 
+    // Check if a duplicate index is defined.
+    check_duplicate_key(thd, key, key_info, &alter_info->key_list);
+
     key_info++;
   }
+
   if (!unique_key && !primary_key &&
       (file->ha_table_flags() & HA_REQUIRE_PRIMARY_KEY))
   {
@@ -7019,6 +7107,12 @@ mysql_prepare_alter_table(THD *thd, TABLE *table,
       if (key_info->flags & HA_USES_COMMENT)
         key_create_info.comment= key_info->comment;
 
+      /*
+        We're refreshing an already existing index. Since the index is not
+        modified, there is no need to check for duplicate indexes again.
+      */
+      key_create_info.check_for_duplicate_indexes= false;
+
       if (key_info->flags & HA_SPATIAL)
         key_type= Key::SPATIAL;
       else if (key_info->flags & HA_NOSAME)