Fix for bug#19236 bad COLUMNS.CHARACTER_MAXIMUM_LENGHT and CHARACTER_OCTET_LENGTH

mysql-test/r/information_schema.result

@@ -1091,3 +1091,11 @@ group by column_type order by num;
 column_type	group_concat(table_schema, '.', table_name)	num
 varchar(20)	information_schema.COLUMNS	1
 varchar(7)	information_schema.ROUTINES,information_schema.VIEWS	2
+create table t1(f1 char(1) not null, f2 char(9) not null)
+default character set utf8;
+select CHARACTER_MAXIMUM_LENGTH, CHARACTER_OCTET_LENGTH from
+information_schema.columns where table_schema='test' and table_name = 't1';
+CHARACTER_MAXIMUM_LENGTH	CHARACTER_OCTET_LENGTH
+1	3
+9	27
+drop table t1;

mysql-test/r/join.result

@@ -700,8 +700,8 @@ ERROR 42S22: Unknown column 't1.b' in 'on clause'
 select * from information_schema.statistics join information_schema.columns
 using(table_name,column_name) where table_name='user';
 TABLE_NAME	COLUMN_NAME	TABLE_CATALOG	TABLE_SCHEMA	NON_UNIQUE	INDEX_SCHEMA	INDEX_NAME	SEQ_IN_INDEX	COLLATION	CARDINALITY	SUB_PART	PACKED	NULLABLE	INDEX_TYPE	COMMENT	TABLE_CATALOG	TABLE_SCHEMA	ORDINAL_POSITION	COLUMN_DEFAULT	IS_NULLABLE	DATA_TYPE	CHARACTER_MAXIMUM_LENGTH	CHARACTER_OCTET_LENGTH	NUMERIC_PRECISION	NUMERIC_SCALE	CHARACTER_SET_NAME	COLLATION_NAME	COLUMN_TYPE	COLUMN_KEY	EXTRA	PRIVILEGES	COLUMN_COMMENT
-user	Host	NULL	mysql	0	mysql	PRIMARY	1	A	NULL	NULL	NULL		BTREE		NULL	mysql	1		NO	char	20	60	NULL	NULL	utf8	utf8_bin	char(60)	PRI		select,insert,update,references	
-user	User	NULL	mysql	0	mysql	PRIMARY	2	A	5	NULL	NULL		BTREE		NULL	mysql	2		NO	char	5	16	NULL	NULL	utf8	utf8_bin	char(16)	PRI		select,insert,update,references	
+user	Host	NULL	mysql	0	mysql	PRIMARY	1	A	NULL	NULL	NULL		BTREE		NULL	mysql	1		NO	char	60	180	NULL	NULL	utf8	utf8_bin	char(60)	PRI		select,insert,update,references	
+user	User	NULL	mysql	0	mysql	PRIMARY	2	A	5	NULL	NULL		BTREE		NULL	mysql	2		NO	char	16	48	NULL	NULL	utf8	utf8_bin	char(16)	PRI		select,insert,update,references	
 drop table t1;
 drop table t2;
 drop table t3;

mysql-test/t/information_schema.test

@@ -802,3 +802,12 @@ from information_schema.columns where
 table_schema='information_schema' and
 (column_type = 'varchar(7)' or column_type = 'varchar(20)')
 group by column_type order by num;
+
+#
+# Bug#19236 bad COLUMNS.CHARACTER_MAXIMUM_LENGHT and CHARACTER_OCTET_LENGTH
+#
+create table t1(f1 char(1) not null, f2 char(9) not null)
+default character set utf8;
+select CHARACTER_MAXIMUM_LENGTH, CHARACTER_OCTET_LENGTH from
+information_schema.columns where table_schema='test' and table_name = 't1';
+drop table t1;

sql/sql_show.cc

@@ -2662,7 +2662,7 @@ static int get_schema_column_record(THD *thd, struct st_table_list *tables,
         field->real_type() == MYSQL_TYPE_STRING)     // For binary type
     {
       uint32 octet_max_length= field->max_length();
-      if (octet_max_length != (uint32) 4294967295U)
+      if (is_blob && octet_max_length != (uint32) 4294967295U)
         octet_max_length /= field->charset()->mbmaxlen;
       longlong char_max_len= is_blob ? 
         (longlong) octet_max_length / field->charset()->mbminlen :