all,
I use mysqldump to backup mysql cluster data with 10 million lines data daily. Recently, our cluster is crashed after a update, then we restore the .sql file generated by mysqldump. When restoring the database, we got key duplication errors/problem, and then I use "-f" to force the restore process. And finally, the restore process completed and all tables is back. Some tables are smaller, we think that is because the duplicate lines are ignored.
But recently, we find some data is missing, it seems that some duplicated data dose not restored correctly.
May I know whether there is a nice way to avoid this in restore process or how to check whether we have duplication before mysqldump?
Couple of suggestions - take a look at the errors that are generated when not using the force option and see if you can figure out how to fix the root cause. Using the force option allows the restore to continue after the error but the failed rows will still be lost.
Is there a reason why you're using mysqldump rather than the backup command within ndb_mgm - which is an online operation? If using the native Cluster (on-line!) backup then you use the ndb_restore command to restore your data.
Related
I accidentally dropped a database which I used for my web application, and it is in MySQL. Browsing through the internet I found out that to recover you need to have binary logs enabled. Read that binary logs records only changes in tables, so what it has to do with recovering a db. Upon executing the command "show binary logs;" console shows me "Error Code: 1381. You are not using binary logging". I am a newbie to MySQL, so is it possible to recover it without my binary logging enabled PLUS I have not made any real backup for the db. Going through the MySQL "my.cnf" file found that InnoDB is default enabled, can it help me recover.
If I cannot recover, please mention the steps to be carried out next time creating a new db to ensure that I could recover even if it has been accidentally deleted.
I think it can't be recovered. In case of this case, you can do the following when creating a new db:
open the binary log by add the following:
log-bin=/data/mysqlbinlog/mysql-bin
binlog-format=mixed (or row)
create a slave db.
Good luck for you.
I have a question regarding to mysql DB backup:
1.AT 8.00.00 AM ,I do backup Database by using mysqldump command.It somtime takes 5 second to finish.
2.While database backup is inprogress(At 8.00.01 AM ), someone make some changes to DB
Will backup version containt data changes of step 2 ?
I have goolge but not found explaination yet.Pls help me !
Percona provides a free tool for this purpose called xtrabackup.
For InnoDB tables MySQL uses log files to store DML commands, so that commands can be rolled back and some other things.
You can backup your database (in a non locking way), and after you created the backup you can apply the logs, so that you have a backup which holds the database status when the backup is finished. Don't know the commands without looking them up now, sorry, you'll have to have a look into the documentation.
It depends on your mysqldump command and which table the dump is on at the time of the update:
If you used the --single-transaction option, then, no, it will not contain the late change.
If you did not use that option then:
if the table being updated has not been dumped yet, then yes it will have the change.
If the table being updated has been dumped already, then no it won't have the change.
Chances are, you don't want that change in your backup, because you would like your backup to be consistent to a point in time. Here is some more discussion about all those kinds of things:
How to obtain a correct dump using mysqldump and single-transaction when DDL is used at the same time?
I understand I need to fully backup the log file before I do anything.
But, once I do that, what would happen if I followed the procedure for detaching the database and then deleting the log file and then recreating it?
This could be quick way of shrinking database log file because sp_attach_db will automatically create a new log file of the original size specified with the database creation.
And also detach procedure is safe as SQL Server ensure that server is cleanly detaching database files which means
1. No incomplete transactions are in the database
2. Memory has no dirty pages for DB
After I ran the transaction log backup twice and ran the shrink command all is good in the world.
Thanks
Once you delete and recreate the log file, it will create the t-log from no knowledge of the DB state and you may encounter data lost.
Good day to you.
I used my MySQL server with "innodb_file_per_table" option, and now server is crashed. I want to recover this server using this way:
Uninstall old MySQL
Install new MySQL
Add "innodb_file_per_table" in MySQL configuration
Copy databases folders (only my, not mysql) from old MySQL/data to new MySQL/data
In every folder I have two files, .frm and .ibd, and looks like this files have all data from my databases tables.
But, after copying, tables in this databases didn't work: when I try to open some table, I get error: Table xxx doesn't exist in engine.
I tried REPAIR command, but it isn't helpful.
If you know how to finish my way of repair — please help.
...I know that I need to copy ibdata1 also, but it looks so dead for recovery, so I try way that I try.
REPAIR command won't help with InnoDB.
If you're lucky enough the best you can do is:
1. Start MySQL with innodb_force_recovery=4 (try 5, 6 values if InnoDB fails to start). Make sure innodb_purge_threads=0.
2. Dump the database with mysqldump tool. Yes, it may be slow, but there is no other choice.
3. Create new empty InnoDB table space and reload the dump.
If MySQL fails to start with innodb_force_recovery=6, then recovery from backups is the only option. Well, you can fetch records from *.ibd files, but this is tedious job - google data recovery tool from percona
UPDATE: Data recovery toolkit moved to GitHub
You need to copy everything, not only the data folder
For example, without the ibdata file, mysql don't know where the tables are stored.
https://serverfault.com/questions/487159/what-is-the-ibdata1-file-in-my-var-lib-mysql-directory
I have a production MySQL server that I need to dump a database out of. The problem is that whenever I make this dump, it generates the View information first. When I try to restore this backup, it errors immediately as the tables that back it don't exist yet.
Is there any quick fix to this issue? I'm dumping the database via PHPMyAdmin.
Thanks!
Rob
phpmyadmin generates incorrect backups (no table locks or REPEATABLE READ isolation level), so for serious backups you should really use mysqldump. It is also much, much faster.