diff --git a/include/my_base.h b/include/my_base.h
index 7016766ce58..d045251778f 100644
--- a/include/my_base.h
+++ b/include/my_base.h
@@ -272,8 +272,8 @@ enum ha_base_keytype {
 #define HA_GENERATED_KEY	8192U	/* Automatically generated key */
 
         /* The combination of the above can be used for key type comparison. */
-#define HA_KEYFLAG_MASK (HA_NOSAME | HA_PACK_KEY | HA_AUTO_KEY | \
-                         HA_BINARY_PACK_KEY | HA_FULLTEXT | HA_UNIQUE_CHECK | \
+#define HA_KEYFLAG_MASK (HA_NOSAME | HA_AUTO_KEY | \
+                         HA_FULLTEXT | HA_UNIQUE_CHECK | \
                          HA_SPATIAL | HA_NULL_ARE_EQUAL | HA_GENERATED_KEY)
 
 /*
diff --git a/mysql-test/main/alter_table_upgrade_aria.result b/mysql-test/main/alter_table_upgrade_aria.result
new file mode 100644
index 00000000000..10afd128649
--- /dev/null
+++ b/mysql-test/main/alter_table_upgrade_aria.result
@@ -0,0 +1,53 @@
+#
+# Start of 10.4 tests
+#
+#
+# MDEV-29481 mariadb-upgrade prints confusing statement
+#
+SET @debug_key_flags=NULL;
+SET default_storage_engine=ARIA;
+CREATE PROCEDURE debug_show_key_flags()
+BEGIN
+IF @debug_key_flags IS TRUE
+THEN
+FLUSH TABLES;
+-- Wrap SET into EXECUTE IMMEDIATE to avoid
+-- parse time "Unknown system variable" errors in release builds.
+EXECUTE IMMEDIATE "SET debug_dbug='+d,key'";
+SELECT * FROM t1 LIMIT 0;
+EXECUTE IMMEDIATE "SET debug_dbug=''";
+END IF;
+END;
+$$
+SHOW CREATE TABLE t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `d` double(18,7) DEFAULT NULL,
+  KEY `d` (`d`)
+) ENGINE=Aria DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci PAGE_CHECKSUM=1
+CHECK TABLE t1 FOR UPGRADE;
+Table	Op	Msg_type	Msg_text
+test.t1	check	status	OK
+DROP TABLE t1;
+CALL debug_show_key_flags();
+ALTER TABLE t1 MODIFY d DOUBLE DEFAULT 10, ALGORITHM=INSTANT;
+CALL debug_show_key_flags();
+DROP TABLE t1;
+CALL debug_show_key_flags();
+ALTER TABLE t1 MODIFY d DOUBLE DEFAULT 10, ALGORITHM=NOCOPY;
+CALL debug_show_key_flags();
+DROP TABLE t1;
+CALL debug_show_key_flags();
+REPAIR TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	repair	status	OK
+CALL debug_show_key_flags();
+DROP TABLE t1;
+CALL debug_show_key_flags();
+ALTER TABLE t1 FORCE;
+CALL debug_show_key_flags();
+DROP TABLE t1;
+DROP PROCEDURE debug_show_key_flags;
+#
+# End of 10.4 tests
+#
diff --git a/mysql-test/main/alter_table_upgrade_aria.test b/mysql-test/main/alter_table_upgrade_aria.test
new file mode 100644
index 00000000000..5b87095f515
--- /dev/null
+++ b/mysql-test/main/alter_table_upgrade_aria.test
@@ -0,0 +1,21 @@
+--source include/have_aria.inc
+
+--echo #
+--echo # Start of 10.4 tests
+--echo #
+
+--echo #
+--echo # MDEV-29481 mariadb-upgrade prints confusing statement
+--echo #
+
+let $table= std_data/mysql_upgrade/mdev29481_100104_aria;
+let $EXT_DAT= MAD;
+let $EXT_IDX= MAI;
+SET @debug_key_flags=NULL;
+SET default_storage_engine=ARIA;
+--source alter_table_upgrade_mdev29481_myisam_aria.inc
+
+
+--echo #
+--echo # End of 10.4 tests
+--echo #
diff --git a/mysql-test/main/alter_table_upgrade_mdev29481_myisam_aria.inc b/mysql-test/main/alter_table_upgrade_mdev29481_myisam_aria.inc
new file mode 100644
index 00000000000..0a8759eccdd
--- /dev/null
+++ b/mysql-test/main/alter_table_upgrade_mdev29481_myisam_aria.inc
@@ -0,0 +1,59 @@
+let $datadir=`select @@datadir`;
+
+DELIMITER $$;
+CREATE PROCEDURE debug_show_key_flags()
+BEGIN
+  IF @debug_key_flags IS TRUE
+  THEN
+    FLUSH TABLES;
+    -- Wrap SET into EXECUTE IMMEDIATE to avoid
+    -- parse time "Unknown system variable" errors in release builds.
+    EXECUTE IMMEDIATE "SET debug_dbug='+d,key'";
+    SELECT * FROM t1 LIMIT 0;
+    EXECUTE IMMEDIATE "SET debug_dbug=''";
+  END IF;
+END;
+$$
+DELIMITER ;$$
+
+
+copy_file $table.frm $datadir/test/t1.frm;
+copy_file $table.$EXT_DAT $datadir/test/t1.$EXT_DAT;
+copy_file $table.$EXT_IDX $datadir/test/t1.$EXT_IDX;
+SHOW CREATE TABLE t1;
+CHECK TABLE t1 FOR UPGRADE;
+DROP TABLE t1;
+
+copy_file $table.frm $datadir/test/t1.frm;
+copy_file $table.$EXT_DAT $datadir/test/t1.$EXT_DAT;
+copy_file $table.$EXT_IDX $datadir/test/t1.$EXT_IDX;
+CALL debug_show_key_flags();
+ALTER TABLE t1 MODIFY d DOUBLE DEFAULT 10, ALGORITHM=INSTANT;
+CALL debug_show_key_flags();
+DROP TABLE t1;
+
+copy_file $table.frm $datadir/test/t1.frm;
+copy_file $table.$EXT_DAT $datadir/test/t1.$EXT_DAT;
+copy_file $table.$EXT_IDX $datadir/test/t1.$EXT_IDX;
+CALL debug_show_key_flags();
+ALTER TABLE t1 MODIFY d DOUBLE DEFAULT 10, ALGORITHM=NOCOPY;
+CALL debug_show_key_flags();
+DROP TABLE t1;
+
+copy_file $table.frm $datadir/test/t1.frm;
+copy_file $table.$EXT_DAT $datadir/test/t1.$EXT_DAT;
+copy_file $table.$EXT_IDX $datadir/test/t1.$EXT_IDX;
+CALL debug_show_key_flags();
+REPAIR TABLE t1;
+CALL debug_show_key_flags();
+DROP TABLE t1;
+
+copy_file $table.frm $datadir/test/t1.frm;
+copy_file $table.$EXT_DAT $datadir/test/t1.$EXT_DAT;
+copy_file $table.$EXT_IDX $datadir/test/t1.$EXT_IDX;
+CALL debug_show_key_flags();
+ALTER TABLE t1 FORCE;
+CALL debug_show_key_flags();
+DROP TABLE t1;
+
+DROP PROCEDURE debug_show_key_flags;
diff --git a/mysql-test/main/alter_table_upgrade_myisam.result b/mysql-test/main/alter_table_upgrade_myisam.result
new file mode 100644
index 00000000000..06bd1b70a0a
--- /dev/null
+++ b/mysql-test/main/alter_table_upgrade_myisam.result
@@ -0,0 +1,52 @@
+#
+# Start of 10.4 tests
+#
+#
+# MDEV-29481 mariadb-upgrade prints confusing statement
+#
+SET @debug_key_flags=NULL;
+CREATE PROCEDURE debug_show_key_flags()
+BEGIN
+IF @debug_key_flags IS TRUE
+THEN
+FLUSH TABLES;
+-- Wrap SET into EXECUTE IMMEDIATE to avoid
+-- parse time "Unknown system variable" errors in release builds.
+EXECUTE IMMEDIATE "SET debug_dbug='+d,key'";
+SELECT * FROM t1 LIMIT 0;
+EXECUTE IMMEDIATE "SET debug_dbug=''";
+END IF;
+END;
+$$
+SHOW CREATE TABLE t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `d` double(18,7) DEFAULT NULL,
+  KEY `d` (`d`)
+) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
+CHECK TABLE t1 FOR UPGRADE;
+Table	Op	Msg_type	Msg_text
+test.t1	check	status	OK
+DROP TABLE t1;
+CALL debug_show_key_flags();
+ALTER TABLE t1 MODIFY d DOUBLE DEFAULT 10, ALGORITHM=INSTANT;
+CALL debug_show_key_flags();
+DROP TABLE t1;
+CALL debug_show_key_flags();
+ALTER TABLE t1 MODIFY d DOUBLE DEFAULT 10, ALGORITHM=NOCOPY;
+CALL debug_show_key_flags();
+DROP TABLE t1;
+CALL debug_show_key_flags();
+REPAIR TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	repair	status	OK
+CALL debug_show_key_flags();
+DROP TABLE t1;
+CALL debug_show_key_flags();
+ALTER TABLE t1 FORCE;
+CALL debug_show_key_flags();
+DROP TABLE t1;
+DROP PROCEDURE debug_show_key_flags;
+#
+# End of 10.4 tests
+#
diff --git a/mysql-test/main/alter_table_upgrade_myisam.test b/mysql-test/main/alter_table_upgrade_myisam.test
new file mode 100644
index 00000000000..251ca3e3555
--- /dev/null
+++ b/mysql-test/main/alter_table_upgrade_myisam.test
@@ -0,0 +1,17 @@
+--echo #
+--echo # Start of 10.4 tests
+--echo #
+
+--echo #
+--echo # MDEV-29481 mariadb-upgrade prints confusing statement
+--echo #
+
+let $table= std_data/mysql_upgrade/mdev29481_100104_myisam;
+let $EXT_DAT= MYD;
+let $EXT_IDX= MYI;
+SET @debug_key_flags=NULL;
+--source alter_table_upgrade_mdev29481_myisam_aria.inc
+
+--echo #
+--echo # End of 10.4 tests
+--echo #
diff --git a/mysql-test/main/alter_table_upgrade_myisam_debug.result b/mysql-test/main/alter_table_upgrade_myisam_debug.result
new file mode 100644
index 00000000000..ed135585d9d
--- /dev/null
+++ b/mysql-test/main/alter_table_upgrade_myisam_debug.result
@@ -0,0 +1,92 @@
+#
+# Start of 10.4 tests
+#
+#
+# MDEV-29481 mariadb-upgrade prints confusing statement
+#
+SET @debug_key_flags=TRUE;
+CREATE PROCEDURE debug_show_key_flags()
+BEGIN
+IF @debug_key_flags IS TRUE
+THEN
+FLUSH TABLES;
+-- Wrap SET into EXECUTE IMMEDIATE to avoid
+-- parse time "Unknown system variable" errors in release builds.
+EXECUTE IMMEDIATE "SET debug_dbug='+d,key'";
+SELECT * FROM t1 LIMIT 0;
+EXECUTE IMMEDIATE "SET debug_dbug=''";
+END IF;
+END;
+$$
+SHOW CREATE TABLE t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `d` double(18,7) DEFAULT NULL,
+  KEY `d` (`d`)
+) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
+CHECK TABLE t1 FOR UPGRADE;
+Table	Op	Msg_type	Msg_text
+test.t1	check	status	OK
+DROP TABLE t1;
+CALL debug_show_key_flags();
+d
+Warnings:
+Note	1105	DBUG: ha_myisam::open: name=`d` flags=00000068 (HA_NULL_PART_KEY|HA_BINARY_PACK_KEY|HA_VAR_LENGTH_KEY)
+Note	1105	DBUG:   seg[0].type=6 DOUBLE
+Note	1105	DBUG:   seg[0].flag=00000850 (HA_CAN_MEMCMP|HA_SWAP_KEY|HA_NULL_PART)
+ALTER TABLE t1 MODIFY d DOUBLE DEFAULT 10, ALGORITHM=INSTANT;
+CALL debug_show_key_flags();
+d
+Warnings:
+Note	1105	DBUG: ha_myisam::open: name=`d` flags=00000068 (HA_NULL_PART_KEY|HA_BINARY_PACK_KEY|HA_VAR_LENGTH_KEY)
+Note	1105	DBUG:   seg[0].type=6 DOUBLE
+Note	1105	DBUG:   seg[0].flag=00000850 (HA_CAN_MEMCMP|HA_SWAP_KEY|HA_NULL_PART)
+DROP TABLE t1;
+CALL debug_show_key_flags();
+d
+Warnings:
+Note	1105	DBUG: ha_myisam::open: name=`d` flags=00000068 (HA_NULL_PART_KEY|HA_BINARY_PACK_KEY|HA_VAR_LENGTH_KEY)
+Note	1105	DBUG:   seg[0].type=6 DOUBLE
+Note	1105	DBUG:   seg[0].flag=00000850 (HA_CAN_MEMCMP|HA_SWAP_KEY|HA_NULL_PART)
+ALTER TABLE t1 MODIFY d DOUBLE DEFAULT 10, ALGORITHM=NOCOPY;
+CALL debug_show_key_flags();
+d
+Warnings:
+Note	1105	DBUG: ha_myisam::open: name=`d` flags=00000068 (HA_NULL_PART_KEY|HA_BINARY_PACK_KEY|HA_VAR_LENGTH_KEY)
+Note	1105	DBUG:   seg[0].type=6 DOUBLE
+Note	1105	DBUG:   seg[0].flag=00000850 (HA_CAN_MEMCMP|HA_SWAP_KEY|HA_NULL_PART)
+DROP TABLE t1;
+CALL debug_show_key_flags();
+d
+Warnings:
+Note	1105	DBUG: ha_myisam::open: name=`d` flags=00000068 (HA_NULL_PART_KEY|HA_BINARY_PACK_KEY|HA_VAR_LENGTH_KEY)
+Note	1105	DBUG:   seg[0].type=6 DOUBLE
+Note	1105	DBUG:   seg[0].flag=00000850 (HA_CAN_MEMCMP|HA_SWAP_KEY|HA_NULL_PART)
+REPAIR TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	repair	status	OK
+CALL debug_show_key_flags();
+d
+Warnings:
+Note	1105	DBUG: ha_myisam::open: name=`d` flags=00000068 (HA_NULL_PART_KEY|HA_BINARY_PACK_KEY|HA_VAR_LENGTH_KEY)
+Note	1105	DBUG:   seg[0].type=6 DOUBLE
+Note	1105	DBUG:   seg[0].flag=00000850 (HA_CAN_MEMCMP|HA_SWAP_KEY|HA_NULL_PART)
+DROP TABLE t1;
+CALL debug_show_key_flags();
+d
+Warnings:
+Note	1105	DBUG: ha_myisam::open: name=`d` flags=00000068 (HA_NULL_PART_KEY|HA_BINARY_PACK_KEY|HA_VAR_LENGTH_KEY)
+Note	1105	DBUG:   seg[0].type=6 DOUBLE
+Note	1105	DBUG:   seg[0].flag=00000850 (HA_CAN_MEMCMP|HA_SWAP_KEY|HA_NULL_PART)
+ALTER TABLE t1 FORCE;
+CALL debug_show_key_flags();
+d
+Warnings:
+Note	1105	DBUG: ha_myisam::open: name=`d` flags=00000048 (HA_NULL_PART_KEY|HA_VAR_LENGTH_KEY)
+Note	1105	DBUG:   seg[0].type=6 DOUBLE
+Note	1105	DBUG:   seg[0].flag=00000850 (HA_CAN_MEMCMP|HA_SWAP_KEY|HA_NULL_PART)
+DROP TABLE t1;
+DROP PROCEDURE debug_show_key_flags;
+#
+# End of 10.4 tests
+#
diff --git a/mysql-test/main/alter_table_upgrade_myisam_debug.test b/mysql-test/main/alter_table_upgrade_myisam_debug.test
new file mode 100644
index 00000000000..8e26bcd2453
--- /dev/null
+++ b/mysql-test/main/alter_table_upgrade_myisam_debug.test
@@ -0,0 +1,19 @@
+--source include/have_debug.inc
+
+--echo #
+--echo # Start of 10.4 tests
+--echo #
+
+--echo #
+--echo # MDEV-29481 mariadb-upgrade prints confusing statement
+--echo #
+
+let $table= std_data/mysql_upgrade/mdev29481_100104_myisam;
+let $EXT_DAT= MYD;
+let $EXT_IDX= MYI;
+SET @debug_key_flags=TRUE;
+--source alter_table_upgrade_mdev29481_myisam_aria.inc
+
+--echo #
+--echo # End of 10.4 tests
+--echo #
diff --git a/mysql-test/std_data/mysql_upgrade/mdev29481_100104_aria.MAD b/mysql-test/std_data/mysql_upgrade/mdev29481_100104_aria.MAD
new file mode 100644
index 00000000000..3dcc005ec0d
Binary files /dev/null and b/mysql-test/std_data/mysql_upgrade/mdev29481_100104_aria.MAD differ
diff --git a/mysql-test/std_data/mysql_upgrade/mdev29481_100104_aria.MAI b/mysql-test/std_data/mysql_upgrade/mdev29481_100104_aria.MAI
new file mode 100644
index 00000000000..d11da43bf2b
Binary files /dev/null and b/mysql-test/std_data/mysql_upgrade/mdev29481_100104_aria.MAI differ
diff --git a/mysql-test/std_data/mysql_upgrade/mdev29481_100104_aria.frm b/mysql-test/std_data/mysql_upgrade/mdev29481_100104_aria.frm
new file mode 100644
index 00000000000..81d7672c405
Binary files /dev/null and b/mysql-test/std_data/mysql_upgrade/mdev29481_100104_aria.frm differ
diff --git a/mysql-test/std_data/mysql_upgrade/mdev29481_100104_innodb.frm b/mysql-test/std_data/mysql_upgrade/mdev29481_100104_innodb.frm
new file mode 100644
index 00000000000..3ff86d1dca1
Binary files /dev/null and b/mysql-test/std_data/mysql_upgrade/mdev29481_100104_innodb.frm differ
diff --git a/mysql-test/std_data/mysql_upgrade/mdev29481_100104_myisam.MYD b/mysql-test/std_data/mysql_upgrade/mdev29481_100104_myisam.MYD
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/mysql-test/std_data/mysql_upgrade/mdev29481_100104_myisam.MYI b/mysql-test/std_data/mysql_upgrade/mdev29481_100104_myisam.MYI
new file mode 100644
index 00000000000..d36f27ac0cf
Binary files /dev/null and b/mysql-test/std_data/mysql_upgrade/mdev29481_100104_myisam.MYI differ
diff --git a/mysql-test/std_data/mysql_upgrade/mdev29481_100104_myisam.frm b/mysql-test/std_data/mysql_upgrade/mdev29481_100104_myisam.frm
new file mode 100644
index 00000000000..afffafabbb1
Binary files /dev/null and b/mysql-test/std_data/mysql_upgrade/mdev29481_100104_myisam.frm differ
diff --git a/mysql-test/suite/innodb/r/alter_table_upgrade.result b/mysql-test/suite/innodb/r/alter_table_upgrade.result
new file mode 100644
index 00000000000..eebabd561ca
--- /dev/null
+++ b/mysql-test/suite/innodb/r/alter_table_upgrade.result
@@ -0,0 +1,36 @@
+#
+# Start of 10.4 tests
+#
+#
+# MDEV-29481 mariadb-upgrade prints confusing statement
+#
+CREATE TABLE pet4 (
+build_time double(18,7) DEFAULT NULL,
+KEY idx1 (build_time)) ENGINE=InnoDB;
+FLUSH TABLES;
+SHOW CREATE TABLE pet4;
+Table	Create Table
+pet4	CREATE TABLE `pet4` (
+  `build_time` double(18,7) DEFAULT NULL,
+  KEY `idx1` (`build_time`)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_general_ci
+CHECK TABLE pet4 FOR UPGRADE;
+Table	Op	Msg_type	Msg_text
+test.pet4	check	status	OK
+ALTER TABLE pet4 ADD i1 INTEGER, ALGORITHM=INSTANT;
+DROP TABLE pet4;
+CREATE TABLE pet4 (
+build_time double(18,7) DEFAULT NULL,
+KEY idx1 (build_time)) ENGINE=InnoDB;
+FLUSH TABLES;
+SHOW CREATE TABLE pet4;
+Table	Create Table
+pet4	CREATE TABLE `pet4` (
+  `build_time` double(18,7) DEFAULT NULL,
+  KEY `idx1` (`build_time`)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_general_ci
+ALTER TABLE pet4 ADD i1 INTEGER, ALGORITHM=NOCOPY;
+DROP TABLE pet4;
+#
+# End of 10.4 tests
+#
diff --git a/mysql-test/suite/innodb/t/alter_table_upgrade.test b/mysql-test/suite/innodb/t/alter_table_upgrade.test
new file mode 100644
index 00000000000..cd058aeee3c
--- /dev/null
+++ b/mysql-test/suite/innodb/t/alter_table_upgrade.test
@@ -0,0 +1,36 @@
+--source include/have_innodb.inc
+
+let $datadir=`select @@datadir`;
+
+--echo #
+--echo # Start of 10.4 tests
+--echo #
+
+--echo #
+--echo # MDEV-29481 mariadb-upgrade prints confusing statement
+--echo #
+
+CREATE TABLE pet4 (
+  build_time double(18,7) DEFAULT NULL,
+  KEY idx1 (build_time)) ENGINE=InnoDB;
+FLUSH TABLES;
+remove_file $datadir/test/pet4.frm;
+copy_file std_data/mysql_upgrade/mdev29481_100104_innodb.frm $datadir/test/pet4.frm;
+SHOW CREATE TABLE pet4;
+CHECK TABLE pet4 FOR UPGRADE;
+ALTER TABLE pet4 ADD i1 INTEGER, ALGORITHM=INSTANT;
+DROP TABLE pet4;
+
+CREATE TABLE pet4 (
+  build_time double(18,7) DEFAULT NULL,
+  KEY idx1 (build_time)) ENGINE=InnoDB;
+FLUSH TABLES;
+remove_file $datadir/test/pet4.frm;
+copy_file std_data/mysql_upgrade/mdev29481_100104_innodb.frm $datadir/test/pet4.frm;
+SHOW CREATE TABLE pet4;
+ALTER TABLE pet4 ADD i1 INTEGER, ALGORITHM=NOCOPY;
+DROP TABLE pet4;
+
+--echo #
+--echo # End of 10.4 tests
+--echo #