Details
Major Description
Server can be started in two ways:
service mariadb start
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and
serivce mysqld start
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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 ....`
As example:
sudo service mysqld start; sudo service mariadb start
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echo 'CREATE DATABASE test1' | sudo mysql
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echo 'CREATE TABLE t1 (i INT)' | sudo mysql test1
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echo 'INSERT INTO t1 VALUES(1)' | sudo mysql test1
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mkdir -p /var/tmp/backup/preupgrade_backup
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sudo mariabackup --backup --user=root --target-dir=/var/tmp/backup/preupgrade_backup
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results in:
[00] 2021-09-15 17:15:01 Connecting to MySQL server host: localhost, user: root, password: not set, port: not set, socket: not set
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[00] 2021-09-15 17:15:01 Using server version 10.3.31-MariaDB
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mariabackup based on MariaDB server 10.3.31-MariaDB Linux (x86_64)
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[00] 2021-09-15 17:15:01 uses posix_fadvise().
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[00] 2021-09-15 17:15:01 cd to /var/lib/mysql/
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[00] 2021-09-15 17:15:01 open files limit requested 0, set to 1024
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[00] 2021-09-15 17:15:01 mariabackup: using the following InnoDB configuration:
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[00] 2021-09-15 17:15:01 innodb_data_home_dir =
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[00] 2021-09-15 17:15:01 innodb_data_file_path = ibdata1:12M:autoextend
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[00] 2021-09-15 17:15:01 innodb_log_group_home_dir = ./
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[00] 2021-09-15 17:15:01 InnoDB: Using Linux native AIO
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2021-09-15 17:15:01 0 [Note] InnoDB: Number of pools: 1
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[00] 2021-09-15 17:15:01 mariabackup: Generating a list of tablespaces
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2021-09-15 17:15:01 0 [Warning] InnoDB: Allocated tablespace ID 1 for mysql/innodb_table_stats, old maximum was 0
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Skipping db: ./#rocksdb
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2021-09-15 17:15:01 0 [ERROR] InnoDB: ############### CORRUPT LOG RECORD FOUND ##################
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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
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2021-09-15 17:15:01 0 [Note] InnoDB: Hex dump starting 0 bytes before and ending 100 bytes after the corrupted record:
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len 100; hex 74657374312f74312e69626400370500000f2e2f74657374312f74312e696264001f3b0500020500001808040500002605040500002a00040500002e04040500003200040500003621040500003a00040500003e000405000042f0ffffffff0205000046; asc test1/t1.ibd 7 ./test1/t1.ibd ; & * . 2 6! : > B F;
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2021-09-15 17:15:01 0 [Note] InnoDB: Set innodb_force_recovery to ignore this error.
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[00] 2021-09-15 17:15:01 Error: copying the log failed
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[00] FATAL ERROR: 2021-09-15 17:15:01 xtrabackup_copy_logfile() failed: corrupt log.
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Attachments
Activity
debians are not affected because they use different /etc/init.d/mysql script
the fix is 23bfbba97959dbeba2e7f1d7046d04dbf911cbc4
I didn't see any problems with that, but requested review just to make sure it will not create another issues
the fix is pushed.
tturenko, could you please take a look at possibly remaining issues I described above?
The root cause of InnoDB corruption is the lack of protection against double-start, it is discussed in
MDEV-24393and is out of the scope of this issue.The question here is why mariadb service and mysql service run the server in a different way, the latter uses the init script with mysqld_safe (ATTN: I think it's mysql, not mysqld, but please double check).
Please check from the code/history whether it's intentional, and if not, it probably needs to be fixed.