maria-discuss team mailing list archive

[bapt x <baptx.is@xxxxxxxxx>]

You said "This step is not necessary when upgrading to MariaDB 10.2.5 or
later." and in my case, I was upgrading to mariadb-server 10.3.17, so I
guess I should not need "set global innodb_fast_shutdown=0;"?
Can someone reproduce the issue with Ubuntu 19.04 on VirtualBox?

On Wed, 16 Oct 2019 at 11:05, Gordan Bobic <gordan.bobic@xxxxxxxxx> wrote:

> I'm not sure if you accidentally omitted it, but the part I was referring
> to is documented here:
>
> https://mariadb.com/kb/en/library/upgrading-from-mariadb-101-to-mariadb-102/
>
> Specifically:
> Set innodb_fast_shutdown
> <https://mariadb.com/kb/en/xtradbinnodb-server-system-variables/#innodb_fast_shutdown>
>  to 0. It can be changed dynamically with SET GLOBAL
> <https://mariadb.com/kb/en/set/#global-session>. For example:
> SET GLOBAL innodb_fast_shutdown=0;
>
>    - This step is not necessary when upgrading to MariaDB 10.2.5
>    <https://mariadb.com/kb/en/mariadb-1025-release-notes/> or later.
>
>
> Can you confirm this is reproducible if you:
>
> MariaDB> set global innodb_fast_shutdown=0;
> # systemctl stop mariadb
> # rm /var/lib/mysql/ib_logfile*
>
> and then do the package upgrade and restart?
>
> Can you back up the full data set (or snapshot it)?
> If so, remove the ib_logfile* files and see if that lets you start up
> mysqld? Failing that, you may have to crank up innodb_force_recover=6
> (because this is level to avoid redo log replay), and then mysqldump the
> data. You will lose any recent transactions that haven't made it from the
> transaction log to the tablespaces.
>
>
>
> On Wed, Oct 16, 2019 at 9:46 AM bapt x <baptx.is@xxxxxxxxx> wrote:
>
>> @Andrei all the error messages I found were included in my original
>> email, let me know how I can provide additional information if no one can
>> reproduce the problem.
>> I forgot to include maria-discuss@xxxxxxxxxxxxxxxxxxx, you can see my
>> reply below.
>>
>> ---------- Forwarded message ---------
>> From: bapt x <baptx.is@xxxxxxxxx>
>> Date: Wed, 16 Oct 2019 at 10:35
>> Subject: Re: [Maria-discuss] database corrupted when switching from MySQL
>> to MariaDB on Ubuntu 19.04
>> To: Gordan Bobic <gordan.bobic@xxxxxxxxx>
>>
>>
>> Thanks for the information. It looks like I did everything properly since
>> I was able to reproduce the problem several times with a clean install of
>> Ubuntu 19.04 on VirtualBox. I think if someone else tries the steps I
>> explained, he can reproduce the problem. Now it would be nice to know if
>> there is a way to recover the data. If MariaDB was able to corrupt the
>> data, there should be a way to reverse engineer the process and restore the
>> data. Maybe a developer that knows well MariaDB upgrade system has a
>> solution.
>>
>> On Wed, 16 Oct 2019 at 10:23, Gordan Bobic <gordan.bobic@xxxxxxxxx>
>> wrote:
>>
>>> I don't know if it is recoverable but it sounds like you missed the step
>>> of always needing a full, clean shutdown between upgrades with
>>> innodb_fast_shutdown=0. Then you can delete ib_logfile*, and upgrade.
>>>
>>> On Wed, 16 Oct 2019, 09:19 bapt x, <baptx.is@xxxxxxxxx> wrote:
>>>
>>>> Hello,
>>>>
>>>> On Ubuntu 19.04, which uses packages mariadb-server 10.3.17 and
>>>> mysql-server 5.7.27, I noticed that if I wanted to switch from MySQL to
>>>> MariaDB, the database is corrupted and there is a complete data loss
>>>> even if I switch back to MySQL.
>>>> In the previous version of Ubuntu, switching from MySQL to MariaDB did
>>>> not manage to import data automatically (unlike Debian) but at least it
>>>> created a backup of the data in /var/lib/mysql-5.7/ folder which is not
>>>> done anymore.
>>>>
>>>> Here is the error message I saw during install when trying to use the
>>>> database corrupted by MariaDB and switching back to MySQL:
>>>> "MySQL has been frozen to prevent damage to your system. Please see
>>>> /etc/mysql/FROZEN for help."
>>>>
>>>> And in /var/log/mysql/error.log:
>>>> "[ERROR] InnoDB: Unsupported redo log format. The redo log was created
>>>> with MariaDB 10.3.17. Please follow the instructions athttp://dev.mysql.com/doc/refman/5.7/en/upgrading-downgrading.html";
>>>>
>>>> I was able to reproduce the issue with a clean installation of Ubuntu
>>>> 19.04 in VirtualBox.
>>>>
>>>> Do you know where the problem comes from and if it is possible to fix
>>>> the binary data from */var/lib/mysql/* to make it work with either MySQL
>>>> or MariaDB?
>>>> It looks like MariaDB tried to convert the data ("[ERROR] InnoDB:
>>>> Unsupported redo log format") but now it fails with both MySQL and MariaDB.
>>>> Is it possible to revert the changes done by MariaDB to make the data
>>>> work again with MySQL? (and then do a proper backup with mysqldump)
>>>>
>>>> Thanks.
>>>>
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>>> _______________________________________________
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