Amazon RDS Point-In-Time restore fails – wp_wfBlocks7 issue

Hi @managedhostingpartners,

The column and information that AWS referenced is a binary column storing values for IP addresses. The default value is all zeroes (16 characters in this case for either IPv4 or IPv6 values).

The wp_wfBlocks7 table is going to be created using the default engine for your database, so you may want to double-check whether or not it’s using MyISAM. As noted by michael-sqlbot in the serverfault thread:

The MyISAM storage engine does not support reliable recovery and can result in lost or corrupt data when MySQL is restarted after a recovery, preventing Point-In-Time restore or snapshot restore from working as intended.

Let us know if you have any further questions!

Hi there,

it is not created as MyISAM.

The way it is set up now, it won’t support point in time recovery on RDS, is there no other way to default this column?

Jochen

Here is also a quick test of default values for binary columns on MySQL 5.7.21. It seems Binary columns are already defaulted to \0

mysql> create table btest (t varchar(10) not null,bcol binary not null);
Query OK, 0 rows affected (0.01 sec)

mysql> show create table btest;
+-------+---------------------------------------------------------------------------------------------------------------------+
| Table | Create Table                                                                                                        |
+-------+---------------------------------------------------------------------------------------------------------------------+
| btest | CREATE TABLE <code>btest</code> (
  <code>t</code> varchar(10) NOT NULL,
  <code>bcol</code> binary(1) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
+-------+---------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> insert into btest (t) values ('a');
Query OK, 1 row affected, 1 warning (0.00 sec)

mysql> select * from btest where bcol = "\0";
+---+------+
| t | bcol |
+---+------+
| a |      |
+---+------+
1 row in set (0.00 sec)

Hi @managedhostingpartners,

I had Quality Assurance take a look at this issue, and when they tested your table and insert they triggered “ERROR 1364 (HY000): Field ‘bcol’ doesn’t have a default value”, which may point to a configuration difference where instead you just saw a warning. Beyond that, we’re not seeing anything that points to Wordfence, as we aren’t seeing any other reports of this or similar issues. We don’t recommend changing the column default as this could break future updates to Wordfence and wouldn’t be supported.

Since the failure seems to be around their restore process taking a valid table definition, exporting it, and re-importing its own output, it may be worth investigating on their end whether something is going on with how they’re handling and interpreting binary data through that process.

Ok, could you have a look at the response from Amazon Web Services here: https://serverfault.com/a/917563/81774

I wonder why the default is set as

\^@\^@\^@\^@\^@\^@\^@\^@\^@\^@\^@\^@\^@\^@\^@\^@

instead of

\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0

Jochen

Hi there,

have you had any further thoughts on the default setting of this field and why it is not usiung a simpler format?

Jochen