how to repair innodb table in mysql

How to Repair Corrupt InnoDB Table in MySQL?

1. Restart the MySQL Service. Open the Run window by clicking ‘Windows+R’ keys together. ...
2. Force InnoDB Recovery. Enable the innodb_force_recovery option in MySQL my.cnf configuration file to regain access to the MySQL database and its corrupt table.
3. Drop the Corrupt Table. ...
4. Restore the Table
5. Restart MySQL in Normal Mode. ...

Full Answer

How to repair and restore InnoDB tables?

If you find any difficulty while manually repairing InnoDB tables of MySQL database or any of the database components appears missing, you can try MySQL repair software to repair and restore corrupt InnoDB tables. Recovers all the database objects including tables, keys, data types, table properties, triggers, views, etc.

How to fix InnoDB table corrupt in MySQL?

In order to check innodb tables for corruption and to fix it, first of all you need to restart your MySQL service. Doing so will help you to access the MySQL server. Here are the easy steps to do so: At first, press the ‘ Windows+R’ keys at the same time.

How to recover a crashed database in InnoDB?

InnoDB comes with a crash recovery mechanism that helps repair and recover db table from crashes automatically. Also, you can use the ‘Dump and Reload’ method to rebuild one or more corrupted tables.

What's wrong with InnoDB?

We (apparently) had poorly executed of our Solaris MySQL database engine last night. At least some of the InnoDB tables are corrupted, with timestamp out of order errors in the transaction log, and a specific error about the index being corrupted. We know about the tools available for MyISAM table repairs, but cannot find anything for InnoDB.

How repair corrupted MySQL table?

REPAIR TABLE Statement can help you in recovering the table. This statement works for MyISAM, Archive and CSV tables. Command is as follows: REPAIR TABLE tbl_name [, tbl_name]... [QUICK] [EXTENDED] [USE_FRM] Where QUICK: If you use this option then repair table tries to repair only the index file and not the data file.

How do I restore my InnoDB database?

To manually recover your InnoDB tables, you need to follow the below listed steps:Step 1: Bring up your database in recovery mode. ... Step 2: Check which tables are corrupted. ... Step 3: Backup and drop your corrupted tables. ... Step 4: Restart MySQL in normal mode. ... Step 5: Import backup .sql. ... Step 6: Change port.More items...•

Why is InnoDB corrupt?

Most InnoDB corruptions are hardware-related. Corrupted page writes can be caused by power failures or bad memory. The issue also can be caused by using network-attached storage (NAS) and allocating InnoDB databases on it.

How do I reindex a table in MySQL?

Luckily, it's easy for MySQL to optimize index data for MyISAM tables. You can use the OPTIMIZE TABLE command to reindex a table. In doing so, MySQL will reread all the records in the table and reconstruct all of its indexes. The result will be tightly packed indexes with good statistics available.

How do I fix InnoDB corruption?

How to Repair Corrupt InnoDB Table in MySQL?Fix Corrupted InnoDB Table Manually. ... Step 1: Restart the MySQL Service. ... Step 2: Force InnoDB Recovery. ... Step 3: Drop the Corrupt Table. ... Step 4: Restore the Table. ... Step 5: Restart MySQL in Normal Mode.

What is InnoDB crash recovery?

InnoDB Crash Recovery. To recover from an unexpected MySQL server exit, the only requirement is to restart the MySQL server. InnoDB automatically checks the logs and performs a roll-forward of the database to the present.

How do I start MySQL in recovery mode?

It leaves you with corrupted pages in InnoDB tablespace and recovering from that might be problem.Step 1 – Bring up your database in recovery mode: ... Step 2 – Check which tables are corrupted and make a list. ... Step 3 – Backup and drop your corrupted tables. ... Step 4 - Stop the MySQL.More items...•

What is InnoDB engine?

InnoDB is a general-purpose storage engine that balances high reliability and high performance. In MySQL 5.6, InnoDB is the default MySQL storage engine. Unless you have configured a different default storage engine, issuing a CREATE TABLE statement without an ENGINE clause creates an InnoDB table.

What is Mysqld command?

DESCRIPTION. mysqld, also known as MySQL Server, is the main program that does most of the work in a MySQL installation. MySQL Server manages access to the MySQL data directory that contains databases and tables. The data directory is also the default location for other information such as log files and status files.

Which command rebuilds tables into the InnoDB storage system?

If you need to rebuild an InnoDB table because a CHECK TABLE operation indicates that a table upgrade is required, use mysqldump to create a dump file and mysql to reload the file.

What is reindex in MySQL?

MySQL REINDEX denotes the re-indexing process to rebuild the indexes on a database if the database is corrupted or needs repair to optimize the tables and fetch the rows using indexes properly using phpMyAdmin.

How do I force an index in MySQL?

The syntax of the force index is given below.SELECT * FROM table_name. FORCE INDEX (index_list) WHERE condition;CREATE DATABASE test_db;USE test_db;

How do you fix ibdata1?

You can try restoring backup to recover the ibdata1 file data. If you don't have the backup, try to dump, drop, and recreate corrupted databases....Method 1 – Recover InnoDB Database ManuallyOpen the MySQL configuration file (my. cnf) on your server.Locate [mysqld] in the my. ... Add the following line in [mysqld] section:

How do I read a .frm file in MySQL?

Step by Step Guides to Open . frm fileInstall MySQL Repair Tool.Click on the Browse button to Open MySQL Database . frm file.Now, after scanning, explore the selected FRM file with details.Click on Save MySQL Data and choose the saving mode and click on the OK button.Now save recovered .

What is the use of ibdata1 file in MySQL?

The file ibdata1 is the system tablespace for the InnoDB infrastructure. You can separate Data and Index Pages from ibdata1 by enabling innodb_file_per_table . This will cause any newly created InnoDB table to store data and index pages in an external .

How to fix InnoDB corruption?

Different methods to repair InnoDB tables. 1. You can use the dump-and-reload method; that is, first you create a dump file, and then just reload it and thus fix InnoDB corruption. Here's what it looks like: Using the dump-and-reload method . 2.

Is the lock table statement used in SQL?

The lock tables statement is preferably not used, and the select ... for update syntax is quite acceptable for unlocking rows that need to be updated in order to get exclusive write access to the rowset. 6.

Can InnoDB tables be corrupted?

Fortunately, InnoDB tables do not get corrupted so often, yet unforeseen situations can occur, such as power surges, corruption of MySQL databases, etc. In any case, you can’t avoid dealing with such a situation, since usually tables contain quite important information.

How to check if MySQL is working?

Restart the MySQL Service, to check if you can access the server, by performing the following: Open the Run window by clicking ‘Windows+R’ keys together. Type msc and hit Enter. From the Services window, look for MySQL Service and right-click on it, and then click restart.

What happens when an InnoDB table is corrupted?

When an InnoDB table gets corrupted, the data within it becomes unreadable and inaccessible. And, an attempt to read from a corrupted table can cause the MySQL Server to crash.

Why is InnoDB used?

Starting from MySQL 5.5 version, InnoDB is used as the default storage engine for all the new tables in a MySQL database. The great thing about InnoDB is that it supports crash recovery. Thus, it cannot get corrupted easily, but when it does, it may happen due to MySQL Server crash after a reboot, hardware failure or bugs in ...

How to access MySQL server?

Restart the MySQL Service, to check if you can access the server, by performing the following: 1 Open the Run window by clicking ‘Windows+R’ keys together. 2 Type msc and hit Enter. 3 From the Services window, look for MySQL Service and right-click on it, and then click restart.

What does InnoDB_force_recovery mean?

Using ‘innodb_force_recovery’ value greater than 4 to regain access to the database can lead to data corruption. Also, in cases of severe corruption, you may fail to restart your MySQL server. You can overcome these limitations of manually repairing the corrupt table of MySQL database by using specialized MySQL repair software such as Stellar Repair for MySQL.

Do you need to repair InnoDB?

You will rarely need to repair InnoDB tables , as the storage engine helps perform crash recovery that can fix most issues once the server gets restarted. However, there may arise a situation where you will need to manually rebuild or repair a corrupt table. Here’s how you can do it:

Initial response

The first priority is to isolate the database, and to get a backup. For this, stop the web server (which will deny any more new database transactions), and block external access to port 3306 (if you have allowed remote access). Using the “mysqladmin” utility, ensure that there are no more transactions running.

Restoring the databases

Once you have a reliable database dump, drop the corrupt databases, and remove the recovery settings from /etc/my.cnf.

How to be prepared

Server crashes can happen due to a variety of reasons like hardware failure, high server load etc. So, it is possible that InnoDB can get corrupted at any such instance. As explained above, we can use recovery mode to get back the databases, but it might not always be successful.

How to restart MySQL?

Solution #1: Restart MySQL Service 1 Now, in a Services, simply search for the MySQL Service & make right-click on it 2 In this step, you have to click on stop , restart or start

Why is MySQL shutting down?

A MySQL server gets stops in the middle of writing process. The machine, on which MySQL is running, is shut down suddenly. Because of the hardware failure.