MDEV-11320: MariaRocks: rocksdb.type_text_indexes fails

Backport the fix for BUG#81810 from facebook/mysql-5.6 tree.
Added the original testcase.

rocksdb.type_text_indexes still fails due to another problem.

mysql-test/r/ctype_collate.result

@@ -719,3 +719,38 @@ DROP FUNCTION getText;
 DROP DATABASE test1;
 USE test;
 SET NAMES latin1;
+#
+# MDEV-11320, MySQL BUG#81810: Inconsistent sort order for blob/text between InnoDB and filesort
+#
+CREATE TABLE t1 (
+b LONGTEXT CHARACTER SET "latin1" COLLATE "latin1_bin",
+KEY b (b(32))
+);
+INSERT INTO t1 (b) VALUES ('a'), (_binary 0x1), (_binary 0x0), ('');
+drop table t1;
+CREATE TABLE t1 (
+b LONGTEXT CHARACTER SET "latin1" COLLATE "latin1_bin",
+PRIMARY KEY b (b(32))
+);
+INSERT INTO t1 (b) VALUES ('a'), (_binary 0x1), (_binary 0x0), ('');
+explain 
+select hex(b) from t1 force index (PRIMARY) where b<'zzz';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	range	PRIMARY	PRIMARY	34	NULL	4	Using where
+select hex(b) from t1 force index (PRIMARY) where b<'zzz';
+hex(b)
+00
+01
+
+61
+explain
+select hex(b) from t1 where b<'zzz' order by b;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	4	Using where; Using filesort
+select hex(b) from t1 where b<'zzz' order by b;
+hex(b)
+00
+01
+
+61
+drop table t1;

mysql-test/r/myisam.result

@@ -1108,8 +1108,8 @@ length(c1)	c1
 0	
 SELECT DISTINCT length(c1), c1 FROM t1 ORDER BY c1;
 length(c1)	c1
-0	
 2		A
+0	
 2	 B
 DROP TABLE t1;
 End of 4.1 tests

mysql-test/t/ctype_collate.test

@@ -308,3 +308,34 @@ DROP FUNCTION getText;
 DROP DATABASE test1;
 USE test;
 SET NAMES latin1;
+
+--echo #
+--echo # MDEV-11320, MySQL BUG#81810: Inconsistent sort order for blob/text between InnoDB and filesort
+--echo #
+
+CREATE TABLE t1 (
+  b LONGTEXT CHARACTER SET "latin1" COLLATE "latin1_bin",
+  KEY b (b(32))
+);
+INSERT INTO t1 (b) VALUES ('a'), (_binary 0x1), (_binary 0x0), ('');
+
+
+drop table t1;
+
+CREATE TABLE t1 (
+  b LONGTEXT CHARACTER SET "latin1" COLLATE "latin1_bin",
+  PRIMARY KEY b (b(32))
+);
+
+INSERT INTO t1 (b) VALUES ('a'), (_binary 0x1), (_binary 0x0), ('');
+
+explain 
+select hex(b) from t1 force index (PRIMARY) where b<'zzz';
+select hex(b) from t1 force index (PRIMARY) where b<'zzz';
+
+explain
+select hex(b) from t1 where b<'zzz' order by b;
+select hex(b) from t1 where b<'zzz' order by b;
+
+drop table t1;
+

sql/field.cc

@@ -8259,7 +8259,7 @@ void Field_blob::sort_string(uchar *to,uint length)
   uchar *blob;
   uint blob_length=get_length();
 
-  if (!blob_length)
+  if (!blob_length && field_charset->pad_char == 0)
     bzero(to,length);
   else
   {