RBR replication works incorrectly for 'BINARY' type

[sougou]

Overview of the Issue

MySQL pads binary columns with zeroes. Here's an example script that shows the problem:

mysql> create table d(id int, val binary(5), primary key(id));
Query OK, 0 rows affected (0.02 sec)

mysql> insert into d values(1, 'a');
Query OK, 1 row affected (0.01 sec)

mysql> select * from d where val='a';
Empty set (0.00 sec)

mysql> select * from d where val='a\0\0\0\0';
+----+-------+
| id | val   |
+----+-------+
|  1 | a     |
+----+-------+
1 row in set (0.00 sec)

When a row like this goes through our binlog streamer, DMLs get generated as val='a', and that does not match the target row. This fails filtered replication.

Reproduction Steps

Create a table like the above, start running a split clone, and perform a DML that changes any row on that table. The filtered replication will fail to affect the target row.

[sougou]

@alainjobart Let's discuss this when you have the time.

[sougou]

Did some binlog mining:

mysql> create table sbt(id int, val char(5), primary key(id));
Query OK, 0 rows affected (0.03 sec)

mysql> insert into sbt values(1, 'a');
Query OK, 1 row affected (0.02 sec)

mysql> update sbt set val='b' where id = 1;
Query OK, 1 row affected (0.01 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update sbt set val='cc' where id = 1;
Query OK, 1 row affected (0.02 sec)
Rows matched: 1  Changed: 1  Warnings: 0

Char codes:

'a'=0x61
'b'=0x62
'c'=0x63

For first update ('a'->'b'):

mysql.binlogEvent{0xaa, 0x2f, 0xa, 0x5b, 0x1f, 0x96, 0xe9, 0xf5, 0x40, 0x32, 0x0, 0x0, 0x0, 0x48, 0xf, 0x0, 0x0, 0x0, 0x0, 0x72, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x0, 0x2, 0x0, 0x2, 0xff, 0xff, 0xfc, 0x1, 0x0, 0x0, 0x0, 0x1, 0x61, 0xfc, 0x1, 0x0, 0x0, 0x0, 0x1, 0x62, 0xe4, 0xbf, 0x63, 0x5a}

For second update ('b'->'cc'):

mysql.binlogEvent{0x5e, 0x33, 0xa, 0x5b, 0x1f, 0x96, 0xe9, 0xf5, 0x40, 0x33, 0x0, 0x0, 0x0, 0x6c, 0x10, 0x0, 0x0, 0x0, 0x0, 0x72, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x0, 0x2, 0x0, 0x2, 0xff, 0xff, 0xfc, 0x1, 0x0, 0x0, 0x0, 0x1, 0x62, 0xfc, 0x1, 0x0, 0x0, 0x0, 0x2, 0x63, 0x63, 0xd6, 0xf1, 0xdf, 0x54}

MySQL does not supply all bytes of a column. So, we have to add the padding before putting those in the where clause.