MDEV-7049 MySQL#74585 - InnoDB: Failing assertion: *mbmaxlen < 5 in file ha_innodb.cc line 1904

InnoDB limited the maximum number of bytes per character to 4.
But, the filename character set that was introduced in MySQL 5.1
uses up to 5 bytes per character.

To allow InnoDB tables to be created with wider characters, let
us split the mbminmaxlen fields into mbminlen, mbmaxlen, and increase
the limit to 7 bytes per character. This will increase the payload size
of dtype_t and dict_col_t by one bit. The storage size will be unchanged
(54 bits and 77 bits will use the same number of bytes as the
previous sizes 53 and 76 bits).

29 files changed, 176 insertions, 308 deletions

diff --git a/storage/innobase/data/data0type.c b/storage/innobase/data/data0type.c
index 9f855d58adf..c278cc8821e 100644
--- a/storage/innobase/data/data0type.c
+++ b/storage/innobase/data/data0type.c
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2009, Innobase Oy. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -49,8 +50,10 @@ ulint
 dtype_get_at_most_n_mbchars(
 /*========================*/
 	ulint		prtype,		/*!< in: precise type */
-	ulint		mbminmaxlen,	/*!< in: minimum and maximum length of
-					a multi-byte character */
+	ulint		mbminlen,	/*!< in: minimum length of
+					a multi-byte character, in bytes */
+	ulint		mbmaxlen,	/*!< in: maximum length of
+					a multi-byte character, in bytes */
 	ulint		prefix_len,	/*!< in: length of the requested
 					prefix, in characters, multiplied by
 					dtype_get_mbmaxlen(dtype) */
@@ -58,9 +61,6 @@ dtype_get_at_most_n_mbchars(
 	const char*	str)		/*!< in: the string whose prefix
 					length is being determined */
 {
-	ulint	mbminlen = DATA_MBMINLEN(mbminmaxlen);
-	ulint	mbmaxlen = DATA_MBMAXLEN(mbminmaxlen);
-
 	ut_a(data_len != UNIV_SQL_NULL);
 	ut_ad(!mbmaxlen || !(prefix_len % mbmaxlen));
 
diff --git a/storage/innobase/dict/dict0mem.c b/storage/innobase/dict/dict0mem.c
index 87d03eff3c2..e3056df53a5 100644
--- a/storage/innobase/dict/dict0mem.c
+++ b/storage/innobase/dict/dict0mem.c
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2010, Innobase Oy. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -251,7 +252,8 @@ dict_mem_fill_column_struct(
 	column->len = (unsigned int) col_len;
 #ifndef UNIV_HOTBACKUP
         dtype_get_mblen(mtype, prtype, &mbminlen, &mbmaxlen);
-	dict_col_set_mbminmaxlen(column, mbminlen, mbmaxlen);
+	column->mbminlen = mbminlen;
+	column->mbmaxlen = mbmaxlen;
 #endif /* !UNIV_HOTBACKUP */
 }
 
diff --git a/storage/innobase/handler/handler0alter.cc b/storage/innobase/handler/handler0alter.cc
index ecfda6d6264..0ccbb2c3942 100644
--- a/storage/innobase/handler/handler0alter.cc
+++ b/storage/innobase/handler/handler0alter.cc
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 2005, 2013, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -99,8 +100,7 @@ innobase_col_to_mysql(
 #ifdef UNIV_DEBUG
 	case DATA_MYSQL:
 		ut_ad(flen >= len);
-		ut_ad(DATA_MBMAXLEN(col->mbminmaxlen)
-		      >= DATA_MBMINLEN(col->mbminmaxlen));
+		ut_ad(col->mbmaxlen >= col->mbminlen);
 		memcpy(dest, data, len);
 		break;
 
diff --git a/storage/innobase/include/data0type.h b/storage/innobase/include/data0type.h
index 25d68de6646..852e18153c2 100644
--- a/storage/innobase/include/data0type.h
+++ b/storage/innobase/include/data0type.h
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2009, Innobase Oy. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -169,18 +170,7 @@ store the charset-collation number; one byte is left unused, though */
 #define DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE	6
 
 /* Maximum multi-byte character length in bytes, plus 1 */
-#define DATA_MBMAX	5
-
-/* Pack mbminlen, mbmaxlen to mbminmaxlen. */
-#define DATA_MBMINMAXLEN(mbminlen, mbmaxlen)	\
-	((mbmaxlen) * DATA_MBMAX + (mbminlen))
-/* Get mbminlen from mbminmaxlen. Cast the result of UNIV_EXPECT to ulint
-because in GCC it returns a long. */
-#define DATA_MBMINLEN(mbminmaxlen) ((ulint) \
-                                    UNIV_EXPECT(((mbminmaxlen) % DATA_MBMAX), \
-                                                1))
-/* Get mbmaxlen from mbminmaxlen. */
-#define DATA_MBMAXLEN(mbminmaxlen) ((ulint) ((mbminmaxlen) / DATA_MBMAX))
+#define DATA_MBMAX	8
 
 #ifndef UNIV_HOTBACKUP
 /*********************************************************************//**
@@ -201,8 +191,10 @@ ulint
 dtype_get_at_most_n_mbchars(
 /*========================*/
 	ulint		prtype,		/*!< in: precise type */
-	ulint		mbminmaxlen,	/*!< in: minimum and maximum length of
-					a multi-byte character */
+	ulint		mbminlen,	/*!< in: minimum length of
+					a multi-byte character, in bytes */
+	ulint		mbmaxlen,	/*!< in: maximum length of
+					a multi-byte character, in bytes */
 	ulint		prefix_len,	/*!< in: length of the requested
 					prefix, in characters, multiplied by
 					dtype_get_mbmaxlen(dtype) */
@@ -347,19 +339,6 @@ dtype_get_mbmaxlen(
 /*===============*/
 	const dtype_t*	type);	/*!< in: type */
 /*********************************************************************//**
-Sets the minimum and maximum length of a character, in bytes. */
-UNIV_INLINE
-void
-dtype_set_mbminmaxlen(
-/*==================*/
-	dtype_t*	type,		/*!< in/out: type */
-	ulint		mbminlen,	/*!< in: minimum length of a char,
-					in bytes, or 0 if this is not
-					a character type */
-	ulint		mbmaxlen);	/*!< in: maximum length of a char,
-					in bytes, or 0 if this is not
-					a character type */
-/*********************************************************************//**
 Gets the padding character code for the type.
 @return	padding character code, or ULINT_UNDEFINED if no padding specified */
 UNIV_INLINE
@@ -379,7 +358,9 @@ dtype_get_fixed_size_low(
 	ulint	mtype,		/*!< in: main type */
 	ulint	prtype,		/*!< in: precise type */
 	ulint	len,		/*!< in: length */
-	ulint	mbminmaxlen,	/*!< in: minimum and maximum length of a
+	ulint	mbminlen,	/*!< in: minimum length of a
+				multibyte character, in bytes */
+	ulint	mbmaxlen,	/*!< in: maximum length of a
 				multibyte character, in bytes */
 	ulint	comp);		/*!< in: nonzero=ROW_FORMAT=COMPACT  */
 #ifndef UNIV_HOTBACKUP
@@ -393,8 +374,8 @@ dtype_get_min_size_low(
 	ulint	mtype,		/*!< in: main type */
 	ulint	prtype,		/*!< in: precise type */
 	ulint	len,		/*!< in: length */
-	ulint	mbminmaxlen);	/*!< in: minimum and maximum length of a
-				multibyte character */
+	ulint	mbminlen,	/*!< in: minimum length of a character */
+	ulint	mbmaxlen);	/*!< in: maximum length of a character */
 /***********************************************************************//**
 Returns the maximum size of a data type. Note: types in system tables may be
 incomplete and return incorrect information.
@@ -497,11 +478,10 @@ struct dtype_struct{
 					the string, MySQL uses 1 or 2
 					bytes to store the string length) */
 #ifndef UNIV_HOTBACKUP
-	unsigned	mbminmaxlen:5;	/*!< minimum and maximum length of a
-					character, in bytes;
-					DATA_MBMINMAXLEN(mbminlen,mbmaxlen);
-					mbminlen=DATA_MBMINLEN(mbminmaxlen);
-					mbmaxlen=DATA_MBMINLEN(mbminmaxlen) */
+	unsigned	mbminlen:3;	/*!< minimum length of a character,
+					in bytes */
+	unsigned	mbmaxlen:3;	/*!< maximum length of a character,
+					in bytes */
 #endif /* !UNIV_HOTBACKUP */
 };
 
diff --git a/storage/innobase/include/data0type.ic b/storage/innobase/include/data0type.ic
index 515b6b249ef..2b4ae7bcf54 100644
--- a/storage/innobase/include/data0type.ic
+++ b/storage/innobase/include/data0type.ic
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2012, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -101,27 +102,6 @@ dtype_get_mblen(
 }
 
 /*********************************************************************//**
-Sets the minimum and maximum length of a character, in bytes. */
-UNIV_INLINE
-void
-dtype_set_mbminmaxlen(
-/*==================*/
-	dtype_t*	type,		/*!< in/out: type */
-	ulint		mbminlen,	/*!< in: minimum length of a char,
-					in bytes, or 0 if this is not
-					a character type */
-	ulint		mbmaxlen)	/*!< in: maximum length of a char,
-					in bytes, or 0 if this is not
-					a character type */
-{
-	ut_ad(mbminlen < DATA_MBMAX);
-	ut_ad(mbmaxlen < DATA_MBMAX);
-	ut_ad(mbminlen <= mbmaxlen);
-
-	type->mbminmaxlen = DATA_MBMINMAXLEN(mbminlen, mbmaxlen);
-}
-
-/*********************************************************************//**
 Compute the mbminlen and mbmaxlen members of a data type structure. */
 UNIV_INLINE
 void
@@ -133,7 +113,8 @@ dtype_set_mblen(
 	ulint	mbmaxlen;
 
 	dtype_get_mblen(type->mtype, type->prtype, &mbminlen, &mbmaxlen);
-	dtype_set_mbminmaxlen(type, mbminlen, mbmaxlen);
+	type->mbminlen = mbminlen;
+	type->mbmaxlen = mbmaxlen;
 
 	ut_ad(dtype_validate(type));
 }
@@ -229,8 +210,7 @@ dtype_get_mbminlen(
 /*===============*/
 	const dtype_t*	type)	/*!< in: type */
 {
-	ut_ad(type);
-	return(DATA_MBMINLEN(type->mbminmaxlen));
+	return type->mbminlen;
 }
 /*********************************************************************//**
 Gets the maximum length of a character, in bytes.
@@ -242,8 +222,7 @@ dtype_get_mbmaxlen(
 /*===============*/
 	const dtype_t*	type)	/*!< in: type */
 {
-	ut_ad(type);
-	return(DATA_MBMAXLEN(type->mbminmaxlen));
+	return type->mbmaxlen;
 }
 
 /*********************************************************************//**
@@ -424,8 +403,10 @@ dtype_get_fixed_size_low(
 	ulint	mtype,		/*!< in: main type */
 	ulint	prtype,		/*!< in: precise type */
 	ulint	len,		/*!< in: length */
-	ulint	mbminmaxlen,	/*!< in: minimum and maximum length of
-				a multibyte character, in bytes */
+	ulint	mbminlen,	/*!< in: minimum length of a
+				multibyte character, in bytes */
+	ulint	mbmaxlen,	/*!< in: maximum length of a
+				multibyte character, in bytes */
 	ulint	comp)		/*!< in: nonzero=ROW_FORMAT=COMPACT  */
 {
 	switch (mtype) {
@@ -466,11 +447,10 @@ dtype_get_fixed_size_low(
 				dtype_get_charset_coll(prtype),
 				&i_mbminlen, &i_mbmaxlen);
 
-			ut_ad(DATA_MBMINMAXLEN(i_mbminlen, i_mbmaxlen)
-			      == mbminmaxlen);
+			ut_ad(i_mbminlen == mbminlen);
+			ut_ad(i_mbmaxlen == mbmaxlen);
 #endif /* UNIV_DEBUG */
-			if (DATA_MBMINLEN(mbminmaxlen)
-			    == DATA_MBMAXLEN(mbminmaxlen)) {
+			if (mbminlen == mbmaxlen) {
 				return(len);
 			}
 		}
@@ -502,8 +482,8 @@ dtype_get_min_size_low(
 	ulint	mtype,		/*!< in: main type */
 	ulint	prtype,		/*!< in: precise type */
 	ulint	len,		/*!< in: length */
-	ulint	mbminmaxlen)	/*!< in: minimum and maximum length of a
-				multi-byte character */
+	ulint	mbminlen,	/*!< in: minimum length of a character */
+	ulint	mbmaxlen)	/*!< in: maximum length of a character */
 {
 	switch (mtype) {
 	case DATA_SYS:
@@ -533,9 +513,6 @@ dtype_get_min_size_low(
 		if (prtype & DATA_BINARY_TYPE) {
 			return(len);
 		} else {
-			ulint	mbminlen = DATA_MBMINLEN(mbminmaxlen);
-			ulint	mbmaxlen = DATA_MBMAXLEN(mbminmaxlen);
-
 			if (mbminlen == mbmaxlen) {
 				return(len);
 			}
@@ -606,9 +583,9 @@ dtype_get_sql_null_size(
 {
 #ifndef UNIV_HOTBACKUP
 	return(dtype_get_fixed_size_low(type->mtype, type->prtype, type->len,
-					type->mbminmaxlen, comp));
+					type->mbminlen, type->mbmaxlen, comp));
 #else /* !UNIV_HOTBACKUP */
 	return(dtype_get_fixed_size_low(type->mtype, type->prtype, type->len,
-					0, 0));
+					0, 0, 0));
 #endif /* !UNIV_HOTBACKUP */
 }
diff --git a/storage/innobase/include/dict0dict.h b/storage/innobase/include/dict0dict.h
index bb1119b3c19..4d6fd4a9b1e 100644
--- a/storage/innobase/include/dict0dict.h
+++ b/storage/innobase/include/dict0dict.h
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2014, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -119,17 +120,6 @@ dict_col_get_mbmaxlen(
 /*==================*/
 	const dict_col_t*	col);	/*!< in: column */
 /*********************************************************************//**
-Sets the minimum and maximum number of bytes per character. */
-UNIV_INLINE
-void
-dict_col_set_mbminmaxlen(
-/*=====================*/
-	dict_col_t*	col,		/*!< in/out: column */
-	ulint		mbminlen,	/*!< in: minimum multi-byte
-					character size, in bytes */
-	ulint		mbmaxlen);	/*!< in: minimum multi-byte
-					character size, in bytes */
-/*********************************************************************//**
 Gets the column data type. */
 UNIV_INLINE
 void
diff --git a/storage/innobase/include/dict0dict.ic b/storage/innobase/include/dict0dict.ic
index dbc3ce99ab0..c17826548e4 100644
--- a/storage/innobase/include/dict0dict.ic
+++ b/storage/innobase/include/dict0dict.ic
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2014, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -38,7 +39,7 @@ dict_col_get_mbminlen(
 /*==================*/
 	const dict_col_t*	col)	/*!< in: column */
 {
-	return(DATA_MBMINLEN(col->mbminmaxlen));
+	return col->mbminlen;
 }
 /*********************************************************************//**
 Gets the maximum number of bytes per character.
@@ -49,25 +50,7 @@ dict_col_get_mbmaxlen(
 /*==================*/
 	const dict_col_t*	col)	/*!< in: column */
 {
-	return(DATA_MBMAXLEN(col->mbminmaxlen));
-}
-/*********************************************************************//**
-Sets the minimum and maximum number of bytes per character. */
-UNIV_INLINE
-void
-dict_col_set_mbminmaxlen(
-/*=====================*/
-	dict_col_t*	col,		/*!< in/out: column */
-	ulint		mbminlen,	/*!< in: minimum multi-byte
-					character size, in bytes */
-	ulint		mbmaxlen)	/*!< in: minimum multi-byte
-					character size, in bytes */
-{
-	ut_ad(mbminlen < DATA_MBMAX);
-	ut_ad(mbmaxlen < DATA_MBMAX);
-	ut_ad(mbminlen <= mbmaxlen);
-
-	col->mbminmaxlen = DATA_MBMINMAXLEN(mbminlen, mbmaxlen);
+	return col->mbmaxlen;
 }
 /*********************************************************************//**
 Gets the column data type. */
@@ -83,7 +66,8 @@ dict_col_copy_type(
 	type->mtype = col->mtype;
 	type->prtype = col->prtype;
 	type->len = col->len;
-	type->mbminmaxlen = col->mbminmaxlen;
+	type->mbminlen = col->mbminlen;
+	type->mbmaxlen = col->mbmaxlen;
 }
 #endif /* !UNIV_HOTBACKUP */
 
@@ -105,7 +89,8 @@ dict_col_type_assert_equal(
 	ut_ad(col->prtype == type->prtype);
 	ut_ad(col->len == type->len);
 # ifndef UNIV_HOTBACKUP
-	ut_ad(col->mbminmaxlen == type->mbminmaxlen);
+	ut_ad(col->mbminlen == type->mbminlen);
+	ut_ad(col->mbmaxlen == type->mbmaxlen);
 # endif /* !UNIV_HOTBACKUP */
 
 	return(TRUE);
@@ -123,7 +108,7 @@ dict_col_get_min_size(
 	const dict_col_t*	col)	/*!< in: column */
 {
 	return(dtype_get_min_size_low(col->mtype, col->prtype, col->len,
-				      col->mbminmaxlen));
+				      col->mbminlen, col->mbmaxlen));
 }
 /***********************************************************************//**
 Returns the maximum size of the column.
@@ -148,7 +133,7 @@ dict_col_get_fixed_size(
 	ulint			comp)	/*!< in: nonzero=ROW_FORMAT=COMPACT  */
 {
 	return(dtype_get_fixed_size_low(col->mtype, col->prtype, col->len,
-					col->mbminmaxlen, comp));
+					col->mbminlen, col->mbmaxlen, comp));
 }
 /***********************************************************************//**
 Returns the ROW_FORMAT=REDUNDANT stored SQL NULL size of a column.
diff --git a/storage/innobase/include/dict0mem.h b/storage/innobase/include/dict0mem.h
index 1b12c8303bb..e807d0fcbea 100644
--- a/storage/innobase/include/dict0mem.h
+++ b/storage/innobase/include/dict0mem.h
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2014, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -294,11 +295,10 @@ struct dict_col_struct{
 					the string, MySQL uses 1 or 2
 					bytes to store the string length) */
 
-	unsigned	mbminmaxlen:5;	/*!< minimum and maximum length of a
-					character, in bytes;
-					DATA_MBMINMAXLEN(mbminlen,mbmaxlen);
-					mbminlen=DATA_MBMINLEN(mbminmaxlen);
-					mbmaxlen=DATA_MBMINLEN(mbminmaxlen) */
+	unsigned	mbminlen:3;	/*!< minimum length of a
+					character, in bytes */
+	unsigned	mbmaxlen:3;	/*!< maximum length of a
+					character, in bytes */
 	/*----------------------*/
 	/* End of definitions copied from dtype_t */
 	/* @} */
diff --git a/storage/innobase/rem/rem0rec.c b/storage/innobase/rem/rem0rec.c
index 7f435a92489..779a2a0867d 100644
--- a/storage/innobase/rem/rem0rec.c
+++ b/storage/innobase/rem/rem0rec.c
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1994, 2011, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -845,13 +846,10 @@ rec_get_converted_size_comp_prefix_low(
 
 		if (fixed_len) {
 #ifdef UNIV_DEBUG
-			ulint	mbminlen = DATA_MBMINLEN(col->mbminmaxlen);
-			ulint	mbmaxlen = DATA_MBMAXLEN(col->mbminmaxlen);
-
 			ut_ad(len <= fixed_len);
 
-			ut_ad(!mbmaxlen || len >= mbminlen
-			      * (fixed_len / mbmaxlen));
+			ut_ad(!col->mbmaxlen || len >= col->mbminlen
+			      * (fixed_len / col->mbmaxlen));
 
 			/* dict_index_add_col() should guarantee this */
 			ut_ad(!field->prefix_len
@@ -1237,14 +1235,10 @@ rec_convert_dtuple_to_rec_comp(
 		it is 128 or more, or when the field is stored externally. */
 		if (fixed_len) {
 #ifdef UNIV_DEBUG
-			ulint	mbminlen = DATA_MBMINLEN(
-				ifield->col->mbminmaxlen);
-			ulint	mbmaxlen = DATA_MBMAXLEN(
-				ifield->col->mbminmaxlen);
-
 			ut_ad(len <= fixed_len);
-			ut_ad(!mbmaxlen || len >= mbminlen
-			      * (fixed_len / mbmaxlen));
+			ut_ad(!ifield->col->mbmaxlen
+			      || len >= ifield->col->mbminlen
+			      * (fixed_len / ifield->col->mbmaxlen));
 			ut_ad(!dfield_is_ext(field));
 #endif /* UNIV_DEBUG */
 		} else if (dfield_is_ext(field)) {
diff --git a/storage/innobase/row/row0ins.c b/storage/innobase/row/row0ins.c
index ec3815ed8cd..93628d9261c 100644
--- a/storage/innobase/row/row0ins.c
+++ b/storage/innobase/row/row0ins.c
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2014, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -527,7 +528,8 @@ row_ins_cascade_calc_update_vec(
 
 				if (!dfield_is_null(&ufield->new_val)
 				    && dtype_get_at_most_n_mbchars(
-					col->prtype, col->mbminmaxlen,
+					col->prtype,
+					col->mbminlen, col->mbmaxlen,
 					col->len,
 					ufield_len,
 					dfield_get_data(&ufield->new_val))
@@ -2312,7 +2314,7 @@ row_ins_index_entry_set_vals(
 				= dict_field_get_col(ind_field);
 
 			len = dtype_get_at_most_n_mbchars(
-				col->prtype, col->mbminmaxlen,
+				col->prtype, col->mbminlen, col->mbmaxlen,
 				ind_field->prefix_len,
 				len, dfield_get_data(row_field));
 
diff --git a/storage/innobase/row/row0merge.c b/storage/innobase/row/row0merge.c
index a393254d145..22ba78a1ef3 100644
--- a/storage/innobase/row/row0merge.c
+++ b/storage/innobase/row/row0merge.c
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1995, 2013, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -339,7 +340,7 @@ row_merge_buf_add(
 		if (ifield->prefix_len) {
 			len = dtype_get_at_most_n_mbchars(
 				col->prtype,
-				col->mbminmaxlen,
+				col->mbminlen, col->mbmaxlen,
 				ifield->prefix_len,
 				len, dfield_get_data(field));
 			dfield_set_len(field, len);
@@ -349,8 +350,7 @@ row_merge_buf_add(
 
 		fixed_len = ifield->fixed_len;
 		if (fixed_len && !dict_table_is_comp(index->table)
-		    && DATA_MBMINLEN(col->mbminmaxlen)
-		    != DATA_MBMAXLEN(col->mbminmaxlen)) {
+		    && col->mbminlen != col->mbmaxlen) {
 			/* CHAR in ROW_FORMAT=REDUNDANT is always
 			fixed-length, but in the temporary file it is
 			variable-length for variable-length character
@@ -360,14 +360,11 @@ row_merge_buf_add(
 
 		if (fixed_len) {
 #ifdef UNIV_DEBUG
-			ulint	mbminlen = DATA_MBMINLEN(col->mbminmaxlen);
-			ulint	mbmaxlen = DATA_MBMAXLEN(col->mbminmaxlen);
-
 			/* len should be between size calcualted base on
 			mbmaxlen and mbminlen */
 			ut_ad(len <= fixed_len);
-			ut_ad(!mbmaxlen || len >= mbminlen
-			      * (fixed_len / mbmaxlen));
+			ut_ad(!col->mbmaxlen || len >= col->mbminlen
+			      * (fixed_len / col->mbmaxlen));
 
 			ut_ad(!dfield_is_ext(field));
 #endif /* UNIV_DEBUG */
diff --git a/storage/innobase/row/row0row.c b/storage/innobase/row/row0row.c
index c15e2bbf739..bacdcbfaac0 100644
--- a/storage/innobase/row/row0row.c
+++ b/storage/innobase/row/row0row.c
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2012, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -164,7 +165,7 @@ row_build_index_entry(
 		/* If a column prefix index, take only the prefix. */
 		if (ind_field->prefix_len) {
 			len = dtype_get_at_most_n_mbchars(
-				col->prtype, col->mbminmaxlen,
+				col->prtype, col->mbminlen, col->mbmaxlen,
 				ind_field->prefix_len, len,
 				dfield_get_data(dfield));
 			dfield_set_len(dfield, len);
@@ -546,7 +547,8 @@ row_build_row_ref(
 				dfield_set_len(dfield,
 					       dtype_get_at_most_n_mbchars(
 						       dtype->prtype,
-						       dtype->mbminmaxlen,
+						       dtype->mbminlen,
+						       dtype->mbmaxlen,
 						       clust_col_prefix_len,
 						       len, (char*) field));
 			}
@@ -660,7 +662,8 @@ notfound:
 				dfield_set_len(dfield,
 					       dtype_get_at_most_n_mbchars(
 						       dtype->prtype,
-						       dtype->mbminmaxlen,
+						       dtype->mbminlen,
+						       dtype->mbmaxlen,
 						       clust_col_prefix_len,
 						       len, (char*) field));
 			}
diff --git a/storage/innobase/row/row0sel.c b/storage/innobase/row/row0sel.c
index d697fef3f52..e6525489a52 100644
--- a/storage/innobase/row/row0sel.c
+++ b/storage/innobase/row/row0sel.c
@@ -2,6 +2,7 @@
 
 Copyright (c) 1997, 2013, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2008, Google Inc.
+Copyright (c) 2018, MariaDB Corporation.
 
 Portions of this file contain modifications contributed and copyrighted by
 Google, Inc. Those modifications are gratefully acknowledged and are described
@@ -90,8 +91,10 @@ row_sel_sec_rec_is_for_blob(
 /*========================*/
 	ulint		mtype,		/*!< in: main type */
 	ulint		prtype,		/*!< in: precise type */
-	ulint		mbminmaxlen,	/*!< in: minimum and maximum length of
-					a multi-byte character */
+	ulint		mbminlen,	/*!< in: minimum length of
+					a character, in bytes */
+	ulint		mbmaxlen,	/*!< in: maximum length of
+					a character, in bytes */
 	const byte*	clust_field,	/*!< in: the locally stored part of
 					the clustered index column, including
 					the BLOB pointer; the clustered
@@ -141,7 +144,7 @@ row_sel_sec_rec_is_for_blob(
 		return(FALSE);
 	}
 
-	len = dtype_get_at_most_n_mbchars(prtype, mbminmaxlen,
+	len = dtype_get_at_most_n_mbchars(prtype, mbminlen, mbmaxlen,
 					  prefix_len, len, (const char*) buf);
 
 	return(!cmp_data_data(mtype, prtype, buf, len, sec_field, sec_len));
@@ -225,14 +228,14 @@ row_sel_sec_rec_is_for_clust_rec(
 			}
 
 			len = dtype_get_at_most_n_mbchars(
-				col->prtype, col->mbminmaxlen,
+				col->prtype, col->mbminlen, col->mbmaxlen,
 				ifield->prefix_len, len, (char*) clust_field);
 
 			if (rec_offs_nth_extern(clust_offs, clust_pos)
 			    && len < sec_len) {
 				if (!row_sel_sec_rec_is_for_blob(
 					    col->mtype, col->prtype,
-					    col->mbminmaxlen,
+					    col->mbminlen, col->mbmaxlen,
 					    clust_field, clust_len,
 					    sec_field, sec_len,
 					    ifield->prefix_len,
diff --git a/storage/innobase/row/row0upd.c b/storage/innobase/row/row0upd.c
index 25fe6f09c4e..35a989a75c4 100644
--- a/storage/innobase/row/row0upd.c
+++ b/storage/innobase/row/row0upd.c
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2014, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -990,7 +991,7 @@ row_upd_index_replace_new_col_val(
 		}
 
 		len = dtype_get_at_most_n_mbchars(col->prtype,
-						  col->mbminmaxlen,
+						  col->mbminlen, col->mbmaxlen,
 						  field->prefix_len, len,
 						  (const char*) data);
 
diff --git a/storage/xtradb/data/data0type.c b/storage/xtradb/data/data0type.c
index 9f855d58adf..c278cc8821e 100644
--- a/storage/xtradb/data/data0type.c
+++ b/storage/xtradb/data/data0type.c
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2009, Innobase Oy. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -49,8 +50,10 @@ ulint
 dtype_get_at_most_n_mbchars(
 /*========================*/
 	ulint		prtype,		/*!< in: precise type */
-	ulint		mbminmaxlen,	/*!< in: minimum and maximum length of
-					a multi-byte character */
+	ulint		mbminlen,	/*!< in: minimum length of
+					a multi-byte character, in bytes */
+	ulint		mbmaxlen,	/*!< in: maximum length of
+					a multi-byte character, in bytes */
 	ulint		prefix_len,	/*!< in: length of the requested
 					prefix, in characters, multiplied by
 					dtype_get_mbmaxlen(dtype) */
@@ -58,9 +61,6 @@ dtype_get_at_most_n_mbchars(
 	const char*	str)		/*!< in: the string whose prefix
 					length is being determined */
 {
-	ulint	mbminlen = DATA_MBMINLEN(mbminmaxlen);
-	ulint	mbmaxlen = DATA_MBMAXLEN(mbminmaxlen);
-
 	ut_a(data_len != UNIV_SQL_NULL);
 	ut_ad(!mbmaxlen || !(prefix_len % mbmaxlen));
 
diff --git a/storage/xtradb/dict/dict0mem.c b/storage/xtradb/dict/dict0mem.c
index 18917a30ff6..253d766d5b3 100644
--- a/storage/xtradb/dict/dict0mem.c
+++ b/storage/xtradb/dict/dict0mem.c
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2010, Innobase Oy. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -254,7 +255,8 @@ dict_mem_fill_column_struct(
 	column->len = (unsigned int) col_len;
 #ifndef UNIV_HOTBACKUP
         dtype_get_mblen(mtype, prtype, &mbminlen, &mbmaxlen);
-	dict_col_set_mbminmaxlen(column, mbminlen, mbmaxlen);
+	column->mbminlen = mbminlen;
+	column->mbmaxlen = mbmaxlen;
 #endif /* !UNIV_HOTBACKUP */
 }
 
diff --git a/storage/xtradb/handler/ha_innodb.cc b/storage/xtradb/handler/ha_innodb.cc
index 00f345d4bc1..a17ab44f49d 100644
--- a/storage/xtradb/handler/ha_innodb.cc
+++ b/storage/xtradb/handler/ha_innodb.cc
@@ -5800,8 +5800,8 @@ build_template_field(
 	}
 
 	templ->charset = dtype_get_charset_coll(col->prtype);
-	templ->mbminlen = DATA_MBMINLEN(col->mbminmaxlen);
-	templ->mbmaxlen = DATA_MBMAXLEN(col->mbminmaxlen);
+	templ->mbminlen = col->mbminlen;
+	templ->mbmaxlen = col->mbmaxlen;
 	templ->is_unsigned = col->prtype & DATA_UNSIGNED;
 
 	if (!dict_index_is_clust(index)
diff --git a/storage/xtradb/handler/handler0alter.cc b/storage/xtradb/handler/handler0alter.cc
index 82902db8412..70ff556e98d 100644
--- a/storage/xtradb/handler/handler0alter.cc
+++ b/storage/xtradb/handler/handler0alter.cc
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 2005, 2013, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -100,8 +101,7 @@ innobase_col_to_mysql(
 #ifdef UNIV_DEBUG
 	case DATA_MYSQL:
 		ut_ad(flen >= len);
-		ut_ad(DATA_MBMAXLEN(col->mbminmaxlen)
-		      >= DATA_MBMINLEN(col->mbminmaxlen));
+		ut_ad(col->mbmaxlen >= col->mbminlen);
 		memcpy(dest, data, len);
 		break;
 
diff --git a/storage/xtradb/include/data0type.h b/storage/xtradb/include/data0type.h
index 25d68de6646..852e18153c2 100644
--- a/storage/xtradb/include/data0type.h
+++ b/storage/xtradb/include/data0type.h
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2009, Innobase Oy. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -169,18 +170,7 @@ store the charset-collation number; one byte is left unused, though */
 #define DATA_NEW_ORDER_NULL_TYPE_BUF_SIZE	6
 
 /* Maximum multi-byte character length in bytes, plus 1 */
-#define DATA_MBMAX	5
-
-/* Pack mbminlen, mbmaxlen to mbminmaxlen. */
-#define DATA_MBMINMAXLEN(mbminlen, mbmaxlen)	\
-	((mbmaxlen) * DATA_MBMAX + (mbminlen))
-/* Get mbminlen from mbminmaxlen. Cast the result of UNIV_EXPECT to ulint
-because in GCC it returns a long. */
-#define DATA_MBMINLEN(mbminmaxlen) ((ulint) \
-                                    UNIV_EXPECT(((mbminmaxlen) % DATA_MBMAX), \
-                                                1))
-/* Get mbmaxlen from mbminmaxlen. */
-#define DATA_MBMAXLEN(mbminmaxlen) ((ulint) ((mbminmaxlen) / DATA_MBMAX))
+#define DATA_MBMAX	8
 
 #ifndef UNIV_HOTBACKUP
 /*********************************************************************//**
@@ -201,8 +191,10 @@ ulint
 dtype_get_at_most_n_mbchars(
 /*========================*/
 	ulint		prtype,		/*!< in: precise type */
-	ulint		mbminmaxlen,	/*!< in: minimum and maximum length of
-					a multi-byte character */
+	ulint		mbminlen,	/*!< in: minimum length of
+					a multi-byte character, in bytes */
+	ulint		mbmaxlen,	/*!< in: maximum length of
+					a multi-byte character, in bytes */
 	ulint		prefix_len,	/*!< in: length of the requested
 					prefix, in characters, multiplied by
 					dtype_get_mbmaxlen(dtype) */
@@ -347,19 +339,6 @@ dtype_get_mbmaxlen(
 /*===============*/
 	const dtype_t*	type);	/*!< in: type */
 /*********************************************************************//**
-Sets the minimum and maximum length of a character, in bytes. */
-UNIV_INLINE
-void
-dtype_set_mbminmaxlen(
-/*==================*/
-	dtype_t*	type,		/*!< in/out: type */
-	ulint		mbminlen,	/*!< in: minimum length of a char,
-					in bytes, or 0 if this is not
-					a character type */
-	ulint		mbmaxlen);	/*!< in: maximum length of a char,
-					in bytes, or 0 if this is not
-					a character type */
-/*********************************************************************//**
 Gets the padding character code for the type.
 @return	padding character code, or ULINT_UNDEFINED if no padding specified */
 UNIV_INLINE
@@ -379,7 +358,9 @@ dtype_get_fixed_size_low(
 	ulint	mtype,		/*!< in: main type */
 	ulint	prtype,		/*!< in: precise type */
 	ulint	len,		/*!< in: length */
-	ulint	mbminmaxlen,	/*!< in: minimum and maximum length of a
+	ulint	mbminlen,	/*!< in: minimum length of a
+				multibyte character, in bytes */
+	ulint	mbmaxlen,	/*!< in: maximum length of a
 				multibyte character, in bytes */
 	ulint	comp);		/*!< in: nonzero=ROW_FORMAT=COMPACT  */
 #ifndef UNIV_HOTBACKUP
@@ -393,8 +374,8 @@ dtype_get_min_size_low(
 	ulint	mtype,		/*!< in: main type */
 	ulint	prtype,		/*!< in: precise type */
 	ulint	len,		/*!< in: length */
-	ulint	mbminmaxlen);	/*!< in: minimum and maximum length of a
-				multibyte character */
+	ulint	mbminlen,	/*!< in: minimum length of a character */
+	ulint	mbmaxlen);	/*!< in: maximum length of a character */
 /***********************************************************************//**
 Returns the maximum size of a data type. Note: types in system tables may be
 incomplete and return incorrect information.
@@ -497,11 +478,10 @@ struct dtype_struct{
 					the string, MySQL uses 1 or 2
 					bytes to store the string length) */
 #ifndef UNIV_HOTBACKUP
-	unsigned	mbminmaxlen:5;	/*!< minimum and maximum length of a
-					character, in bytes;
-					DATA_MBMINMAXLEN(mbminlen,mbmaxlen);
-					mbminlen=DATA_MBMINLEN(mbminmaxlen);
-					mbmaxlen=DATA_MBMINLEN(mbminmaxlen) */
+	unsigned	mbminlen:3;	/*!< minimum length of a character,
+					in bytes */
+	unsigned	mbmaxlen:3;	/*!< maximum length of a character,
+					in bytes */
 #endif /* !UNIV_HOTBACKUP */
 };
 
diff --git a/storage/xtradb/include/data0type.ic b/storage/xtradb/include/data0type.ic
index 5848e5d6548..0688b162387 100644
--- a/storage/xtradb/include/data0type.ic
+++ b/storage/xtradb/include/data0type.ic
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2012, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -101,27 +102,6 @@ dtype_get_mblen(
 }
 
 /*********************************************************************//**
-Sets the minimum and maximum length of a character, in bytes. */
-UNIV_INLINE
-void
-dtype_set_mbminmaxlen(
-/*==================*/
-	dtype_t*	type,		/*!< in/out: type */
-	ulint		mbminlen,	/*!< in: minimum length of a char,
-					in bytes, or 0 if this is not
-					a character type */
-	ulint		mbmaxlen)	/*!< in: maximum length of a char,
-					in bytes, or 0 if this is not
-					a character type */
-{
-	ut_ad(mbminlen < DATA_MBMAX);
-	ut_ad(mbmaxlen < DATA_MBMAX);
-	ut_ad(mbminlen <= mbmaxlen);
-
-	type->mbminmaxlen = DATA_MBMINMAXLEN(mbminlen, mbmaxlen);
-}
-
-/*********************************************************************//**
 Compute the mbminlen and mbmaxlen members of a data type structure. */
 UNIV_INLINE
 void
@@ -133,7 +113,8 @@ dtype_set_mblen(
 	ulint	mbmaxlen;
 
 	dtype_get_mblen(type->mtype, type->prtype, &mbminlen, &mbmaxlen);
-	dtype_set_mbminmaxlen(type, mbminlen, mbmaxlen);
+	type->mbminlen = mbminlen;
+	type->mbmaxlen = mbmaxlen;
 
 	ut_ad(dtype_validate(type));
 }
@@ -229,8 +210,7 @@ dtype_get_mbminlen(
 /*===============*/
 	const dtype_t*	type)	/*!< in: type */
 {
-	ut_ad(type);
-	return(DATA_MBMINLEN(type->mbminmaxlen));
+	return type->mbminlen;
 }
 /*********************************************************************//**
 Gets the maximum length of a character, in bytes.
@@ -242,8 +222,7 @@ dtype_get_mbmaxlen(
 /*===============*/
 	const dtype_t*	type)	/*!< in: type */
 {
-	ut_ad(type);
-	return(DATA_MBMAXLEN(type->mbminmaxlen));
+	return type->mbmaxlen;
 }
 
 /*********************************************************************//**
@@ -424,8 +403,10 @@ dtype_get_fixed_size_low(
 	ulint	mtype,		/*!< in: main type */
 	ulint	prtype,		/*!< in: precise type */
 	ulint	len,		/*!< in: length */
-	ulint	mbminmaxlen,	/*!< in: minimum and maximum length of
-				a multibyte character, in bytes */
+	ulint	mbminlen,	/*!< in: minimum length of a
+				multibyte character, in bytes */
+	ulint	mbmaxlen,	/*!< in: maximum length of a
+				multibyte character, in bytes */
 	ulint	comp)		/*!< in: nonzero=ROW_FORMAT=COMPACT  */
 {
 	switch (mtype) {
@@ -466,11 +447,10 @@ dtype_get_fixed_size_low(
 				dtype_get_charset_coll(prtype),
 				&i_mbminlen, &i_mbmaxlen);
 
-			ut_ad(DATA_MBMINMAXLEN(i_mbminlen, i_mbmaxlen)
-			      == mbminmaxlen);
+			ut_ad(i_mbminlen == mbminlen);
+			ut_ad(i_mbmaxlen == mbmaxlen);
 #endif /* UNIV_DEBUG */
-			if (DATA_MBMINLEN(mbminmaxlen)
-			    == DATA_MBMAXLEN(mbminmaxlen)) {
+			if (mbminlen == mbmaxlen) {
 				return(len);
 			}
 		}
@@ -502,8 +482,8 @@ dtype_get_min_size_low(
 	ulint	mtype,		/*!< in: main type */
 	ulint	prtype,		/*!< in: precise type */
 	ulint	len,		/*!< in: length */
-	ulint	mbminmaxlen)	/*!< in: minimum and maximum length of a
-				multi-byte character */
+	ulint	mbminlen,	/*!< in: minimum length of a character */
+	ulint	mbmaxlen)	/*!< in: maximum length of a character */
 {
 	switch (mtype) {
 	case DATA_SYS:
@@ -533,9 +513,6 @@ dtype_get_min_size_low(
 		if (prtype & DATA_BINARY_TYPE) {
 			return(len);
 		} else {
-			ulint	mbminlen = DATA_MBMINLEN(mbminmaxlen);
-			ulint	mbmaxlen = DATA_MBMAXLEN(mbminmaxlen);
-
 			if (mbminlen == mbmaxlen) {
 				return(len);
 			}
@@ -606,9 +583,9 @@ dtype_get_sql_null_size(
 {
 #ifndef UNIV_HOTBACKUP
 	return(dtype_get_fixed_size_low(type->mtype, type->prtype, type->len,
-					type->mbminmaxlen, comp));
+					type->mbminlen, type->mbmaxlen, comp));
 #else /* !UNIV_HOTBACKUP */
 	return(dtype_get_fixed_size_low(type->mtype, type->prtype, type->len,
-					0, 0));
+					0, 0, 0));
 #endif /* !UNIV_HOTBACKUP */
 }
diff --git a/storage/xtradb/include/dict0dict.h b/storage/xtradb/include/dict0dict.h
index d8c8e39b1bf..9f39a0b3e05 100644
--- a/storage/xtradb/include/dict0dict.h
+++ b/storage/xtradb/include/dict0dict.h
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2014, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -119,17 +120,6 @@ dict_col_get_mbmaxlen(
 /*==================*/
 	const dict_col_t*	col);	/*!< in: column */
 /*********************************************************************//**
-Sets the minimum and maximum number of bytes per character. */
-UNIV_INLINE
-void
-dict_col_set_mbminmaxlen(
-/*=====================*/
-	dict_col_t*	col,		/*!< in/out: column */
-	ulint		mbminlen,	/*!< in: minimum multi-byte
-					character size, in bytes */
-	ulint		mbmaxlen);	/*!< in: minimum multi-byte
-					character size, in bytes */
-/*********************************************************************//**
 Gets the column data type. */
 UNIV_INLINE
 void
diff --git a/storage/xtradb/include/dict0dict.ic b/storage/xtradb/include/dict0dict.ic
index 3410c945a80..3631dc38d81 100644
--- a/storage/xtradb/include/dict0dict.ic
+++ b/storage/xtradb/include/dict0dict.ic
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2014, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -38,7 +39,7 @@ dict_col_get_mbminlen(
 /*==================*/
 	const dict_col_t*	col)	/*!< in: column */
 {
-	return(DATA_MBMINLEN(col->mbminmaxlen));
+	return col->mbminlen;
 }
 /*********************************************************************//**
 Gets the maximum number of bytes per character.
@@ -49,25 +50,7 @@ dict_col_get_mbmaxlen(
 /*==================*/
 	const dict_col_t*	col)	/*!< in: column */
 {
-	return(DATA_MBMAXLEN(col->mbminmaxlen));
-}
-/*********************************************************************//**
-Sets the minimum and maximum number of bytes per character. */
-UNIV_INLINE
-void
-dict_col_set_mbminmaxlen(
-/*=====================*/
-	dict_col_t*	col,		/*!< in/out: column */
-	ulint		mbminlen,	/*!< in: minimum multi-byte
-					character size, in bytes */
-	ulint		mbmaxlen)	/*!< in: minimum multi-byte
-					character size, in bytes */
-{
-	ut_ad(mbminlen < DATA_MBMAX);
-	ut_ad(mbmaxlen < DATA_MBMAX);
-	ut_ad(mbminlen <= mbmaxlen);
-
-	col->mbminmaxlen = DATA_MBMINMAXLEN(mbminlen, mbmaxlen);
+	return col->mbmaxlen;
 }
 /*********************************************************************//**
 Gets the column data type. */
@@ -83,7 +66,8 @@ dict_col_copy_type(
 	type->mtype = col->mtype;
 	type->prtype = col->prtype;
 	type->len = col->len;
-	type->mbminmaxlen = col->mbminmaxlen;
+	type->mbminlen = col->mbminlen;
+	type->mbmaxlen = col->mbmaxlen;
 }
 #endif /* !UNIV_HOTBACKUP */
 
@@ -105,7 +89,8 @@ dict_col_type_assert_equal(
 	ut_ad(col->prtype == type->prtype);
 	ut_ad(col->len == type->len);
 # ifndef UNIV_HOTBACKUP
-	ut_ad(col->mbminmaxlen == type->mbminmaxlen);
+	ut_ad(col->mbminlen == type->mbminlen);
+	ut_ad(col->mbmaxlen == type->mbmaxlen);
 # endif /* !UNIV_HOTBACKUP */
 
 	return(TRUE);
@@ -123,7 +108,7 @@ dict_col_get_min_size(
 	const dict_col_t*	col)	/*!< in: column */
 {
 	return(dtype_get_min_size_low(col->mtype, col->prtype, col->len,
-				      col->mbminmaxlen));
+				      col->mbminlen, col->mbmaxlen));
 }
 /***********************************************************************//**
 Returns the maximum size of the column.
@@ -148,7 +133,7 @@ dict_col_get_fixed_size(
 	ulint			comp)	/*!< in: nonzero=ROW_FORMAT=COMPACT  */
 {
 	return(dtype_get_fixed_size_low(col->mtype, col->prtype, col->len,
-					col->mbminmaxlen, comp));
+					col->mbminlen, col->mbmaxlen, comp));
 }
 /***********************************************************************//**
 Returns the ROW_FORMAT=REDUNDANT stored SQL NULL size of a column.
diff --git a/storage/xtradb/include/dict0mem.h b/storage/xtradb/include/dict0mem.h
index 07ecc42f045..bd4cbddd591 100644
--- a/storage/xtradb/include/dict0mem.h
+++ b/storage/xtradb/include/dict0mem.h
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2014, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -294,11 +295,10 @@ struct dict_col_struct{
 					the string, MySQL uses 1 or 2
 					bytes to store the string length) */
 
-	unsigned	mbminmaxlen:5;	/*!< minimum and maximum length of a
-					character, in bytes;
-					DATA_MBMINMAXLEN(mbminlen,mbmaxlen);
-					mbminlen=DATA_MBMINLEN(mbminmaxlen);
-					mbmaxlen=DATA_MBMINLEN(mbminmaxlen) */
+	unsigned	mbminlen:3;	/*!< minimum length of a
+					character, in bytes */
+	unsigned	mbmaxlen:3;	/*!< maximum length of a
+					character, in bytes */
 	/*----------------------*/
 	/* End of definitions copied from dtype_t */
 	/* @} */
diff --git a/storage/xtradb/rem/rem0rec.c b/storage/xtradb/rem/rem0rec.c
index a43085fe89e..a7126f526e8 100644
--- a/storage/xtradb/rem/rem0rec.c
+++ b/storage/xtradb/rem/rem0rec.c
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1994, 2011, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -845,13 +846,10 @@ rec_get_converted_size_comp_prefix_low(
 
 		if (fixed_len) {
 #ifdef UNIV_DEBUG
-			ulint	mbminlen = DATA_MBMINLEN(col->mbminmaxlen);
-			ulint	mbmaxlen = DATA_MBMAXLEN(col->mbminmaxlen);
-
 			ut_ad(len <= fixed_len);
 
-			ut_ad(!mbmaxlen || len >= mbminlen
-			      * (fixed_len / mbmaxlen));
+			ut_ad(!col->mbmaxlen || len >= col->mbminlen
+			      * (fixed_len / col->mbmaxlen));
 
 			/* dict_index_add_col() should guarantee this */
 			ut_ad(!field->prefix_len
@@ -1237,14 +1235,10 @@ rec_convert_dtuple_to_rec_comp(
 		it is 128 or more, or when the field is stored externally. */
 		if (fixed_len) {
 #ifdef UNIV_DEBUG
-			ulint	mbminlen = DATA_MBMINLEN(
-				ifield->col->mbminmaxlen);
-			ulint	mbmaxlen = DATA_MBMAXLEN(
-				ifield->col->mbminmaxlen);
-
 			ut_ad(len <= fixed_len);
-			ut_ad(!mbmaxlen || len >= mbminlen
-			      * (fixed_len / mbmaxlen));
+			ut_ad(!ifield->col->mbmaxlen
+			      || len >= ifield->col->mbminlen
+			      * (fixed_len / ifield->col->mbmaxlen));
 			ut_ad(!dfield_is_ext(field));
 #endif /* UNIV_DEBUG */
 		} else if (dfield_is_ext(field)) {
diff --git a/storage/xtradb/row/row0ins.c b/storage/xtradb/row/row0ins.c
index e6c92080e41..0e3c1d38897 100644
--- a/storage/xtradb/row/row0ins.c
+++ b/storage/xtradb/row/row0ins.c
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2014, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -528,7 +529,8 @@ row_ins_cascade_calc_update_vec(
 
 				if (!dfield_is_null(&ufield->new_val)
 				    && dtype_get_at_most_n_mbchars(
-					col->prtype, col->mbminmaxlen,
+					col->prtype,
+					col->mbminlen, col->mbmaxlen,
 					col->len,
 					ufield_len,
 					dfield_get_data(&ufield->new_val))
@@ -2353,7 +2355,7 @@ row_ins_index_entry_set_vals(
 				= dict_field_get_col(ind_field);
 
 			len = dtype_get_at_most_n_mbchars(
-				col->prtype, col->mbminmaxlen,
+				col->prtype, col->mbminlen, col->mbmaxlen,
 				ind_field->prefix_len,
 				len, dfield_get_data(row_field));
 
diff --git a/storage/xtradb/row/row0merge.c b/storage/xtradb/row/row0merge.c
index 00a7decdce6..0d0b0e402d3 100644
--- a/storage/xtradb/row/row0merge.c
+++ b/storage/xtradb/row/row0merge.c
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1995, 2013, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -350,7 +351,7 @@ row_merge_buf_add(
 		if (ifield->prefix_len) {
 			len = dtype_get_at_most_n_mbchars(
 				col->prtype,
-				col->mbminmaxlen,
+				col->mbminlen, col->mbmaxlen,
 				ifield->prefix_len,
 				len, dfield_get_data(field));
 			dfield_set_len(field, len);
@@ -360,8 +361,7 @@ row_merge_buf_add(
 
 		fixed_len = ifield->fixed_len;
 		if (fixed_len && !dict_table_is_comp(index->table)
-		    && DATA_MBMINLEN(col->mbminmaxlen)
-		    != DATA_MBMAXLEN(col->mbminmaxlen)) {
+		    && col->mbminlen != col->mbmaxlen) {
 			/* CHAR in ROW_FORMAT=REDUNDANT is always
 			fixed-length, but in the temporary file it is
 			variable-length for variable-length character
@@ -371,14 +371,11 @@ row_merge_buf_add(
 
 		if (fixed_len) {
 #ifdef UNIV_DEBUG
-			ulint	mbminlen = DATA_MBMINLEN(col->mbminmaxlen);
-			ulint	mbmaxlen = DATA_MBMAXLEN(col->mbminmaxlen);
-
 			/* len should be between size calcualted base on
 			mbmaxlen and mbminlen */
 			ut_ad(len <= fixed_len);
-			ut_ad(!mbmaxlen || len >= mbminlen
-			      * (fixed_len / mbmaxlen));
+			ut_ad(!col->mbmaxlen || len >= col->mbminlen
+			      * (fixed_len / col->mbmaxlen));
 
 			ut_ad(!dfield_is_ext(field));
 #endif /* UNIV_DEBUG */
diff --git a/storage/xtradb/row/row0row.c b/storage/xtradb/row/row0row.c
index 2c33bdc4b15..0c1c1da3b2b 100644
--- a/storage/xtradb/row/row0row.c
+++ b/storage/xtradb/row/row0row.c
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2012, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -164,7 +165,7 @@ row_build_index_entry(
 		/* If a column prefix index, take only the prefix. */
 		if (ind_field->prefix_len) {
 			len = dtype_get_at_most_n_mbchars(
-				col->prtype, col->mbminmaxlen,
+				col->prtype, col->mbminlen, col->mbmaxlen,
 				ind_field->prefix_len, len,
 				dfield_get_data(dfield));
 			dfield_set_len(dfield, len);
@@ -562,7 +563,8 @@ row_build_row_ref(
 				dfield_set_len(dfield,
 					       dtype_get_at_most_n_mbchars(
 						       dtype->prtype,
-						       dtype->mbminmaxlen,
+						       dtype->mbminlen,
+						       dtype->mbmaxlen,
 						       clust_col_prefix_len,
 						       len, (char*) field));
 			}
@@ -676,7 +678,8 @@ notfound:
 				dfield_set_len(dfield,
 					       dtype_get_at_most_n_mbchars(
 						       dtype->prtype,
-						       dtype->mbminmaxlen,
+						       dtype->mbminlen,
+						       dtype->mbmaxlen,
 						       clust_col_prefix_len,
 						       len, (char*) field));
 			}
diff --git a/storage/xtradb/row/row0sel.c b/storage/xtradb/row/row0sel.c
index 69b364600b2..54a76ca06c6 100644
--- a/storage/xtradb/row/row0sel.c
+++ b/storage/xtradb/row/row0sel.c
@@ -2,6 +2,7 @@
 
 Copyright (c) 1997, 2013, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2008, Google Inc.
+Copyright (c) 2018, MariaDB Corporation.
 
 Portions of this file contain modifications contributed and copyrighted by
 Google, Inc. Those modifications are gratefully acknowledged and are described
@@ -92,8 +93,10 @@ row_sel_sec_rec_is_for_blob(
 /*========================*/
 	ulint		mtype,		/*!< in: main type */
 	ulint		prtype,		/*!< in: precise type */
-	ulint		mbminmaxlen,	/*!< in: minimum and maximum length of
-					a multi-byte character */
+	ulint		mbminlen,	/*!< in: minimum length of
+					a character, in bytes */
+	ulint		mbmaxlen,	/*!< in: maximum length of
+					a character, in bytes */
 	const byte*	clust_field,	/*!< in: the locally stored part of
 					the clustered index column, including
 					the BLOB pointer; the clustered
@@ -143,7 +146,7 @@ row_sel_sec_rec_is_for_blob(
 		return(FALSE);
 	}
 
-	len = dtype_get_at_most_n_mbchars(prtype, mbminmaxlen,
+	len = dtype_get_at_most_n_mbchars(prtype, mbminlen, mbmaxlen,
 					  prefix_len, len, (const char*) buf);
 
 	return(!cmp_data_data(mtype, prtype, buf, len, sec_field, sec_len));
@@ -227,14 +230,14 @@ row_sel_sec_rec_is_for_clust_rec(
 			}
 
 			len = dtype_get_at_most_n_mbchars(
-				col->prtype, col->mbminmaxlen,
+				col->prtype, col->mbminlen, col->mbmaxlen,
 				ifield->prefix_len, len, (char*) clust_field);
 
 			if (rec_offs_nth_extern(clust_offs, clust_pos)
 			    && len < sec_len) {
 				if (!row_sel_sec_rec_is_for_blob(
 					    col->mtype, col->prtype,
-					    col->mbminmaxlen,
+					    col->mbminlen, col->mbmaxlen,
 					    clust_field, clust_len,
 					    sec_field, sec_len,
 					    ifield->prefix_len,
diff --git a/storage/xtradb/row/row0upd.c b/storage/xtradb/row/row0upd.c
index c5c2ca5ee8a..c829a5a6744 100644
--- a/storage/xtradb/row/row0upd.c
+++ b/storage/xtradb/row/row0upd.c
@@ -1,6 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1996, 2014, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -1008,7 +1009,7 @@ row_upd_index_replace_new_col_val(
 		}
 
 		len = dtype_get_at_most_n_mbchars(col->prtype,
-						  col->mbminmaxlen,
+						  col->mbminlen, col->mbmaxlen,
 						  field->prefix_len, len,
 						  (const char*) data);