[#MDEV-26612] Two different ways to start MariaDB service can cause data corruption

These two ways are not equal: first way is defined (probably) by post-install scripts, the second - by file from the package /etc/init.d/mysql

The data corruption can happen if we start first `service mysqld start` and then try to restart with `service mariadb ....`

sudo service mysqld start; sudo service mariadb start

echo 'CREATE DATABASE test1' | sudo mysql

echo 'CREATE TABLE t1 (i INT)' | sudo mysql test1

echo 'INSERT INTO t1 VALUES(1)' | sudo mysql test1

mkdir -p /var/tmp/backup/preupgrade_backup

sudo mariabackup --backup --user=root --target-dir=/var/tmp/backup/preupgrade_backup

[00] 2021-09-15 17:15:01 Connecting to MySQL server host: localhost, user: root, password: not set, port: not set, socket: not set

[00] 2021-09-15 17:15:01 Using server version 10.3.31-MariaDB

mariabackup based on MariaDB server 10.3.31-MariaDB Linux (x86_64)

[00] 2021-09-15 17:15:01 uses posix_fadvise().

[00] 2021-09-15 17:15:01 cd to /var/lib/mysql/

[00] 2021-09-15 17:15:01 open files limit requested 0, set to 1024

[00] 2021-09-15 17:15:01 mariabackup: using the following InnoDB configuration:

[00] 2021-09-15 17:15:01 innodb_data_home_dir =

[00] 2021-09-15 17:15:01 innodb_data_file_path = ibdata1:12M:autoextend

[00] 2021-09-15 17:15:01 innodb_log_group_home_dir = ./

[00] 2021-09-15 17:15:01 InnoDB: Using Linux native AIO

2021-09-15 17:15:01 0 [Note] InnoDB: Number of pools: 1

[00] 2021-09-15 17:15:01 mariabackup: Generating a list of tablespaces

2021-09-15 17:15:01 0 [Warning] InnoDB: Allocated tablespace ID 1 for mysql/innodb_table_stats, old maximum was 0

Skipping db: ./#rocksdb

2021-09-15 17:15:01 0 [ERROR] InnoDB: ############### CORRUPT LOG RECORD FOUND ##################

2021-09-15 17:15:01 0 [Note] InnoDB: Log record type 116, page 0:1. Log parsing proceeded successfully up to 1625479. Previous log record type 128, is multi 0 Recv offset 0, prev 0

2021-09-15 17:15:01 0 [Note] InnoDB: Hex dump starting 0 bytes before and ending 100 bytes after the corrupted record:

 len 100; hex 74657374312f74312e69626400370500000f2e2f74657374312f74312e696264001f3b0500020500001808040500002605040500002a00040500002e04040500003200040500003621040500003a00040500003e000405000042f0ffffffff0205000046; asc test1/t1.ibd 7    ./test1/t1.ibd  ;            &     *     .     2     6!    :     >     B         F;

2021-09-15 17:15:01 0 [Note] InnoDB: Set innodb_force_recovery to ignore this error.

[00] 2021-09-15 17:15:01 Error: copying the log failed

[00] FATAL ERROR: 2021-09-15 17:15:01 xtrabackup_copy_logfile() failed: corrupt log.

[MDEV-26612] Two different ways to start MariaDB service can cause data corruption Created: 2021-09-15 Updated: 2022-03-13 Resolved: 2022-03-13
Status:	Closed
Project:	MariaDB Server
Component/s:	Packaging
Affects Version/s:	10.2, 10.3
Fix Version/s:	10.2.41, 10.3.32, 10.4.22, 10.5.13, 10.6.5

[MDEV-26612] Two different ways to start MariaDB service can cause data corruption Created: 2021-09-15 Updated: 2022-03-13 Resolved: 2022-03-13