[2.2.1] Magento Database Backup Command Fails (Fix included)

[azeemism]

The magento backup command fails under magento 2.2.1. There was no such issue under magento 2.1.8. They are no errors in the database log.

Preconditions

1. Magento composer install

www-data@skynet:~/example.com/magento/2.x/2.x$ php bin/magento -V
Magento CLI version 2.2.1

2. Using MariaDB

root@skynet:~/.admin/scripts# dpkg -l | grep mariadb
ii  libmariadbclient18                   10.1.30+maria-1~jessie               amd64        MariaDB database client library
ii  mariadb-client                       10.1.30+maria-1~jessie               all          MariaDB database client (metapackage depending on the latest version)
ii  mariadb-client-10.1                  10.1.30+maria-1~jessie               amd64        MariaDB database client binaries
ii  mariadb-client-core-10.1             10.1.30+maria-1~jessie               amd64        MariaDB database core client binaries
ii  mariadb-common                       10.1.30+maria-1~jessie               all          MariaDB database common files (e.g. /etc/mysql/conf.d/mariadb.cnf)
ii  mariadb-server                       10.1.30+maria-1~jessie               all          MariaDB database server (metapackage depending on the latest version)
ii  mariadb-server-10.1                  10.1.30+maria-1~jessie               amd64        MariaDB database server binaries
ii  mariadb-server-core-10.1             10.1.30+maria-1~jessie               amd64        MariaDB database core server files

root@skynet:~/.admin/scripts# dpkg -l | grep mysql
ii  dovecot-mysql                        1:2.2.13-12~deb8u3                   amd64        secure POP3/IMAP server - MySQL support
ii  libclass-dbi-mysql-perl              1.00-3                               all          extensions to Class::DBI for MySQL
ii  libdbd-mysql-perl                    4.028-2+deb8u2                       amd64        Perl5 database interface to the MySQL database
ii  libmysqlclient18                     10.1.30+maria-1~jessie               amd64        Virtual package to satisfy external depends
ii  libqt4-sql-mysql:amd64               4:4.8.6+git64-g5dc8b2b+dfsg-3+deb8u1 amd64        Qt 4 MySQL database driver
ii  libtime-piece-mysql-perl             0.06-2                               all          module adding MySQL-specific methods to Time::Piece
ii  mariadb-common                       10.1.30+maria-1~jessie               all          MariaDB database common files (e.g. /etc/mysql/conf.d/mariadb.cnf)
ii  mysql-common                         10.1.30+maria-1~jessie               all          MariaDB database common files (e.g. /etc/mysql/my.cnf)
ii  php5-mysqlnd                         5.6.30+dfsg-0+deb8u1                 amd64        MySQL module for php5 (Native Driver)
ii  php7.0-mysql                         7.0.26-1~dotdeb+8.2                  amd64        MySQL module for PHP
ii  postfix-mysql                        2.11.3-1+deb8u2                      amd64        MySQL map support for Postfix
ii  roundcube-mysql                      1.2.3+dfsg.1-4+deb9u1                all          metapackage providing MySQL dependencies for RoundCube

4. Using PHP7

root@skynet:~/.admin/scripts# dpkg -l | grep php7
rc  libapache2-mod-php7.0                7.0.14-1~dotdeb+8.1                  amd64        server-side, HTML-embedded scripting language (Apache 2 module)
ii  php7.0                               7.0.26-1~dotdeb+8.2                  all          server-side, HTML-embedded scripting language (metapackage)
ii  php7.0-bcmath                        7.0.26-1~dotdeb+8.2                  amd64        Bcmath module for PHP
ii  php7.0-cli                           7.0.26-1~dotdeb+8.2                  amd64        command-line interpreter for the PHP scripting language
ii  php7.0-common                        7.0.26-1~dotdeb+8.2                  amd64        documentation, examples and common module for PHP
ii  php7.0-curl                          7.0.26-1~dotdeb+8.2                  amd64        CURL module for PHP
ii  php7.0-dev                           7.0.26-1~dotdeb+8.2                  amd64        Files for PHP7.0 module development
ii  php7.0-fpm                           7.0.26-1~dotdeb+8.2                  amd64        server-side, HTML-embedded scripting language (FPM-CGI binary)
ii  php7.0-gd                            7.0.26-1~dotdeb+8.2                  amd64        GD module for PHP
ii  php7.0-igbinary                      2.0.1-1~dotdeb+8.1                   amd64        igbinary serializer for PHP
ii  php7.0-imagick                       3.4.3-1~dotdeb+8.1                   amd64        Provides a wrapper to the ImageMagick library
ii  php7.0-intl                          7.0.26-1~dotdeb+8.2                  amd64        Internationalisation module for PHP
ii  php7.0-json                          7.0.26-1~dotdeb+8.2                  amd64        JSON module for PHP
ii  php7.0-mbstring                      7.0.26-1~dotdeb+8.2                  amd64        MBSTRING module for PHP
ii  php7.0-mcrypt                        7.0.26-1~dotdeb+8.2                  amd64        libmcrypt module for PHP
ii  php7.0-mysql                         7.0.26-1~dotdeb+8.2                  amd64        MySQL module for PHP
ii  php7.0-opcache                       7.0.26-1~dotdeb+8.2                  amd64        Zend OpCache module for PHP
ii  php7.0-pspell                        7.0.26-1~dotdeb+8.2                  amd64        pspell module for PHP
ii  php7.0-readline                      7.0.26-1~dotdeb+8.2                  amd64        readline module for PHP
ii  php7.0-redis                         3.1.3-1~dotdeb+8.1                   amd64        PHP extension for interfacing with Redis
ii  php7.0-soap                          7.0.26-1~dotdeb+8.2                  amd64        SOAP module for PHP
ii  php7.0-xml                           7.0.26-1~dotdeb+8.2                  amd64        DOM, SimpleXML, WDDX, XML, and XSL module for PHP
ii  php7.0-xmlrpc                        7.0.26-1~dotdeb+8.2                  amd64        XMLRPC-EPI module for PHP
ii  php7.0-xsl                           7.0.26-1~dotdeb+8.2                  all          XSL module for PHP (dummy)
ii  php7.0-zip                           7.0.26-1~dotdeb+8.2                  amd64        Zip module for PHP

5. OS

root@skynet:~/.admin/scripts# uname -a
Linux skynet 3.16.0-4-amd64 #1 SMP Debian 3.16.51-2 (2017-12-03) x86_64 GNU/Linux

6. composer.json

{
    "name": "magento/project-community-edition",
    "description": "eCommerce Platform for Growth (Community Edition)",
    "type": "project",
    "version": "2.1.1",
    "license": [
        "OSL-3.0",
        "AFL-3.0"
    ],
    "require": {
        "magento/product-community-edition": "2.2.1",
        "composer/composer": "@alpha",
        "magento/magento-composer-installer": "^0.1.12",
        "geoip2/geoip2": "^2.4",
        "webshopapps/module-matrixrate": "^20.1"
    },
    "require-dev": {
        "phpunit/phpunit": "4.1.0",
        "squizlabs/php_codesniffer": "1.5.3",
        "phpmd/phpmd": "@stable",
        "pdepend/pdepend": "2.2.2",
        "fabpot/php-cs-fixer": "~1.2",
        "lusitanian/oauth": "~0.3 <=0.7.0",
        "sebastian/phpcpd": "2.0.0"
    },
    "config": {
        "use-include-path": true
    },
    "autoload": {
        "psr-4": {
            "Magento\\Framework\\": "lib/internal/Magento/Framework/",
            "Magento\\Setup\\": "setup/src/Magento/Setup/",
            "Magento\\": "app/code/Magento/"
        },
        "psr-0": {
            "": "app/code/"
        },
        "files": [
            "app/etc/NonComposerComponentRegistration.php"
        ]
    },
    "autoload-dev": {
        "psr-4": {
            "Magento\\Sniffs\\": "dev/tests/static/framework/Magento/Sniffs/",
            "Magento\\Tools\\": "dev/tools/Magento/Tools/",
            "Magento\\Tools\\Sanity\\": "dev/build/publication/sanity/Magento/Tools/Sanity/",
            "Magento\\TestFramework\\Inspection\\": "dev/tests/static/framework/Magento/TestFramework/Inspection/",
            "Magento\\TestFramework\\Utility\\": "dev/tests/static/framework/Magento/TestFramework/Utility/"
        }
    },
    "minimum-stability": "alpha",
    "prefer-stable": true,
    "repositories": [
        {
            "type": "composer",
            "url": "https://repo.magento.com/"
        }
    ],
    "extra": {
        "magento-force": "override"
    }
}

Steps to reproduce

1. php bin/magento setup:backup --code --media --db
2. php bin/magento setup:backup --db

Expected result

1. [SUCCESS]: DB backup completed successfully.

Actual result

www-data@skynet:~/example.com/magento/2.x/2.x$ php bin/magento setup:backup --code --media --db

Enabling maintenance mode
Code backup is starting...
Code backup filename: 1514213089_filesystem_code.tgz (The archive can be uncompressed with 7-Zip on Windows systems)
Code backup path: /var/www/example.com/magento/2.x/2.x/var/backups/1514213089_filesystem_code.tgz
[SUCCESS]: Code backup completed successfully.
Media backup is starting...
Media backup filename: 1514213089_filesystem_media.tgz (The archive can be uncompressed with 7-Zip on Windows systems)
Media backup path: /var/www/example.com/magento/2.x/2.x/var/backups/1514213089_filesystem_media.tgz
[SUCCESS]: Media backup completed successfully.
DB backup is starting...
Warning: Division by zero in /var/www/example.com/magento/2.x/2.x/vendor/magento/module-backup/Model/Db.php on line 157
Disabling maintenance mode
PHP Fatal error:  Uncaught Exception: User Error: Some transactions have not been committed or rolled back in /var/www/example.com/magento/2.x/2.x/vendor/magento/framework/DB/Adapter/Pdo/Mysql.php on line 3864 in /var/www/example.com/magento/2.x/2.x/vendor/magento/framework/App/ErrorHandler.php:61
Stack trace:
#0 [internal function]: Magento\Framework\App\ErrorHandler->handler(256, 'Some transactio...', '/var/www/vitami...', 3864, Array)
#1 /var/www/example.com/magento/2.x/2.x/vendor/magento/framework/DB/Adapter/Pdo/Mysql.php(3864): trigger_error('Some transactio...', 256)
#2 [internal function]: Magento\Framework\DB\Adapter\Pdo\Mysql->__destruct()
#3 {main}
  thrown in /var/www/example.com/magento/2.x/2.x/vendor/magento/framework/App/ErrorHandler.php on line 61

[azeemism]

Possible fix mentioned by ChrisK on Feb 8 at 6:51
https://magento.stackexchange.com/questions/141087/warning-division-by-zero-in-var-www-magento-vendor-magento-module-backup-model

Looks like the db dump crashed while trying to add rows for or around "importexport_importdata" table

A quick glance it looks like a small issue with not checking for a non-zero denominator.

The code/file in question is: https://github.com/magento/magento2/blob/2.2/app/code/Magento/Backup/Model/Db.php#L157

ChrisK indicated that he managed to fix the issue by overriding/localing the file and modifying the line

$limit = floor(self::BUFFER_LENGTH / $tableStatus->getAvgRowLength());

to

$limit = floor(self::BUFFER_LENGTH / max($tableStatus->getAvgRowLength(), 1));

And keeping the rest intact

[azeemism]

The Database backup completes successfully after making the change:

www-data@skynet:~/example.com/magento/2.x/2.x$ nano /var/www/vitaminwebstore.com/magento/2.x/2.x/vendor/magento/module-backup/Model/Db.php

Replace Line 157:
$limit = floor(self::BUFFER_LENGTH / $tableStatus->getAvgRowLength());

With:
$limit = floor(self::BUFFER_LENGTH / max($tableStatus->getAvgRowLength(), 1));

www-data@skynet:~/example.com/magento/2.x/2.x$ php bin/magento setup:backup --db

Enabling maintenance mode
DB backup is starting...
DB backup filename: 1514217168_db.sql
DB backup path: /var/www/example.com/magento/2.x/2.x/var/backups/1514217168_db.sql
[SUCCESS]: DB backup completed successfully.
Disabling maintenance mode

Please update the code/file with this fix: https://github.com/magento/magento2/blob/2.2/app/code/Magento/Backup/Model/Db.php#L157

[PieterCappelle]

@azeemism Could you create PR please? Thanks!

[azeemism]

Hi @PieterCappelle , I have never created a PR before. I am not sure how to create one.

[jagritijoshi]

I am fixing this issue as per @azeemism and creating a pull request #mm18in

[ishakhsuvarov]

Hi @azeemism. Thank you for your report.
The issue has been fixed in #13066 by @jagritijoshi in 2.2-develop branch
Related commit(s):

• bc434c1

The fix will be available with the upcoming patch release.

[magento-engcom-team]

Hi @azeemism. Thank you for your report.
The issue has been fixed in magento-engcom/magento2ce#1302 by @magento-engcom-team in 2.3-develop branch
Related commit(s):

• 176b9f0
• ab50437
• 6a527a8
• a0cb9e2
• 6e6c7d2
• 1d45a06
• 1fdee00
• 727f9b3
• f842883
• 5474264
• ba1d05a
• 6fb29ac
• be2840d
• 17da65c
• ded8aa9
• 818cccd

The fix will be available with the upcoming patch release.