Wednesday, February 24, 2010

MySQL Recovery for InnoDB Storage Engine to Fix Tablespace Corruption

Are you encountering assertion failure errors in MySQL database? Are you unable to access your MySQL database due to corrupt InnoDB Tablespace? Such situations occur due to MySQL database corruption. This behavior renders your MySQL database inaccessible. It leads to critical data loss situations and requires you to restore the database from the most recent backup. However, in case the backup isn't updated or you don't have a backup, you are requited to carry out MySQL Repair to gain access of the database.

In a practical scenario, you may encounter the below error message after InnoDB Tablespace corruption:

“InnoDB: Database page corruption on disk or a failed
InnoDB: file read of page 7.
InnoDB: You may have to recover from a backup.
080703 23:46:16 InnoDB: Page dump in ASCII and hex (16384 bytes)”

This problem generally occurs if you are running the MySQL database with InnoDB engine tables and you have crappy hardware, kernel bug, drive bug, power outages or MySQL application bugs. The database crashes with assertion failure. At this point, you need to find the root cause of the problem and Repair MySQL Database by sorting it out.

Cause

There are various things, that, if corrupt may lead to this problem. The most important among them is corruption of the clustered key index. It is quite complicated, as compared to the simple data corruption that can be handled easily using the OPTIMIZE TABLE command. Corruption of any of the database objects may make it impossible for the database to locate and access files or tables.

Resolution

You can try the following things to work around this problem and access your database:

Check the database tables in general operation mode. This method can fix the problem if InnoDB crashes due to Checksum errors.
Run innodb_force_recovery to force InnoDB storage engine to start by preventing the background operations.

If none of the above methods work, you should use MySQL Repair software, to repair and restore damaged MySQL database.

The software Repair MySQL Database database using high-end scanning techniques. They enable you to perform absolute recovery in a quick and easy way as they have simple and rich graphical user interface. With read-only behavior, integrity of your database is always preserved by these software.

MySQL is the most advanced utility that ensures absolute restore of your damaged MySQL database files. The software supports recovery from both InnoDB and MyISAM storage engines. It works well with MySQL 5.x and 4.x.

MySQL Database Related Articles :-
http://www.buzzle.com/articles/tablename-frm-is-locked-against-change-mysql-error-and-recovery.html
http://www.jamespot.com/a/746764-MySQL-Server-crash-after-passing-MySQL-open-file-limit.html

Monday, February 22, 2010

How To Recover Corrupted/Crashed InnoDB Database?

Are you a frequent user of the transaction database characteristic in MySQL? If 'Yes', then you must be quite familiar with the InnoDB storage engine of MySQL. InnoDB offers transaction safe database, along with the BDB, within MySQL environment. However, in some cases, this database engine may get damaged due a number of reasons, and leads to critical data loss situations. At this point, you are required to go for MySQL Repair solutions to get your precious data recovered.

A MySQL user or database administrator would never want bad things to happen, but they do. Sometimes, internal system malfunction, virus infection, human errors, power outages, improper system shutdown, or even operating system malfunction make your MySQL database corrupted or crashed. At this point, it becomes essential to identify the actual cause of the database corruption and perform MySQL Recovery by sorting it out.

How to Find Out Damaged MySQL Database:

All of a sudden, you may encounter query errors on some or all pages of your website. If your MySQL is configured well, you are required to be pretty cautious when you come across the below error message:

ERROR 2006 (HY000): MySQL server has gone away

If the above error occurs repeatedly, further investigation is required. First investigation point for this is the application log. If your installation is standard, you can find the MySQL log file at /var/log/mysqld.log.

The error is related to the below errors. You can run a simple command “OPTIMIZE TABLE tablename” and verify if you experience:

ERROR 1030 (HY000): Got error -1 from storage engine (It means that data has not been recovered from the previous database corruption or crash).
ERROR 1030 (HY000): Got error 28 from storage engine (It means the storage device is full).

If you encounter the first error message, you need to restore your database from the most recent backup. In case the backup is not available, you have to Repair MySQL Database using reliable and effective tools.

The Repair MySQL Database applications ensure complete recovery in all cases of MySQL database corruption as they perform in-depth scan of entire database through high-end scanning techniques. They come equipped with simple and self-descriptive graphical user interface to enable easy recovery, without demanding sound and prior technical skills. These software preserve the integrity of database as they have read-only and non-destructive conduct.

MySQL is an excellent solution to repair and restore damaged MySQL database in all cases. It supports both InnoDB and MyISAM storage engines of MySQL. The software works well with MySQL 5.x and 4.x.

Related Aricles :-

http://www.salvationdata.co.uk/articles/serverrecovery/Cannot%20Add%20Events%20to%20Scheduler%20in%20MySQL.html
http://www.salvationdata.co.uk/articles/serverrecovery/Found%20key%20at%20pageltpage%20numbergtthat%20points%20MySQL%20Error.html

Thursday, February 18, 2010

Error 145 Occurs while accessing Merge Table

A 'merge table' in MySQL is primarily a collection of MyISAM tables. These tables are identical and can be used as single table. A database user can create a merge table by specifying a Union operator between the used MyISAM tables. The user can also apply all kinds of operations, such as, select, insert, update, and delete on the merge table. Just like any other table, these tables can also be corrupted due to various internal and external reasons. In most cases the user encounters an error message after merge table corruption. This message does not allows the user to access the records saved in the merge table. To access the records after merge table corruption, the user needs to restore data from updated table backup. But, if the user has not maintained any backup, then the merge table needs to be repaired using advanced third-party MySQL Repair application.

Consider a practical case, where you have a large merge table containing thousands of records. However, due to a server crash, the table gets corrupted. Now, when you attempt to access the records saved in that particular merge table, you receive an error message:

“ERROR 1016 (HY000): Can't open file: 'merge_employee.MRG' (errno: 145)”

On viewing the server error log, you find the following message:

“060601 21:42:20 [ERROR] /usr/sbin/mysqld: Can't open file: 'mailer_mailsent.MRG' (errno: 145)”

After this error message appears, the data saved in the merge table gets inaccessible.

Resolution:

To resolve the above error message and to access the table data, follow the below mentioned measures:

1.Run Check table command to identify the level of corruption.
2.Run Repair table command to repair the table.

If the problem persists and the table remains corrupt even after following the above steps, then you will need to search for a powerful MySQL Database Repair application to repair the corrupt table. A Repair MySQL Database utility uses latest repairing procedures to comprehensively repair the corrupt table. The tool ensures risk-free repair of tables that allow even a layman to perform MySQL table repair.

MySQL fulfills all the requirements of being the finest MySQL Repair application. The read-only repair tool repairs almost all database components created in MyISAM and InnoDB storage engines. The software is designed for Windows 7, Vista, XP, 2003 and 2000 operating systems. It supports MySQL 5.x and 4.x.

Source Taken From :- http://www.articlesengine.com/Article/Error-145-Occurs-while-accessing-Merge-Table/507466/1

Sunday, February 14, 2010

Fixing “Unknown Table” Error post MySQL database corruption

InnoDB database engine saves all the data in the form of pages, linked in a B-tree structure. The pages in the B-tree structure are arranged in a way that each page has it entry in its Index node. These pages contain actual data stored in the InnoDB tables. Since these tables are updated very frequently, it requires special treatment to handle the B-tree structure. Corruption in this structure can occur due to various reasons like, MySQLD improper shutdown, virus attack, operating system malfunction, and human errors. In such situations, the data saved in the InnoDB table becomes inaccessible. To access the data after InnoDB corruption, a simple way is to restore the data from an updated backup. However, inaccessibility of table backup or backup falling short of restoring the required data, requires an advanced third-party MySQL Repair application.

As a practical case, you encounter the underneath error message while trying to access the InnoDB table:

“#1051 - Unknown table 'table name'”
'table name' is the name of the table which is corrupted

The above error message appears every time you attempt to access that table. It does not allow you to access the records saved in the table.

Cause:

The reason behind the above error message is corruption/damage in InnoDB table.

Resolution:

To isolate the above error message and to access the table records, use the below command:

“ innodb_force_recovery = 4 ”

The above command works in most cases. It comprehensively repairs the corrupted table and allows
makes all the records accessible. However, if the above command fails to repair the table and the above
error message persists, then you will need to use a powerful MySQL Repair application.

A Repair MySQL Database repair tool is a third-party application that scans the table by employing high-end scanning algorithms. The repair application is built with interactive user-documentation that makes even an novice user to understand and perform the repair process. These tools are completely non-destructive in nature as the repairing is performed without modifying the original data.

Stellar Phoenix Database Recovery For MySQL, a powerful application used world-wide by most of the MySQL database users, ensures complete repair of tables created in MyISAM or InnoDB storage engines. The MySQL Repair tool is designed for MySQL 5.x and 4.x. It is compatible with Windows 7, Vista, XP, 2003 and 2000 operating systems.

Resource Taken From :- http://www.articlesengine.com/Article/Fixing--Unknown-Table--Error-post-MySQL-database-corruption/503221/1

Wednesday, February 10, 2010

Resolving “No MySQL pid file found” Error Message

MySQL database corruption mostly results into displaying of an error message at the time of mounting the database. For detailed reason of the MySQL database corruption, you can view the MySQL error log. In most cases of log description, a solution is also mentioned along with the cause of the error. If the solution works, then you can continue working on your database. However, if the solution is not provided or fails to resolve the error message, then an ideal way is to restore the data from an updated backup. But if in case, the backup file is not available or backup falls short to restore the required data, then you will need to use advanced MySQL Repair application to repair the corrupted database.

Consider a practical case, where the underneath error message pops up when you attempt to mount your MySQL database:

“No MySQL pid file found”

On viewing the MySQL error log, below information is displayed:

“InnoDB: Page may be an update undo log page. Page may be an index page where index id is 0 40
InnoDB: (index `PRIMARY` of table `piprd/Broadcast`) database page corruption on disk or a failed
InnoDB: file read of page 2280. You may have to recover from a backup.
InnoDB: It is also possible that your operating system has corrupted its own file cache and
InnoDB: rebooting your computer removes the error.
InnoDB: If the corrupt page is an index page you can also try to fix the corruption
InnoDB: by dumping, dropping, and reimporting the corrupt table. You can use CHECK
InnoDB: TABLE to scan your table for corruption”

The error log clearly states that the database is corrupted. Few reasons for corruption could be operating system corruption (also mentioned in error message), MySQLD improper shutdown, and virus attack.

Resolution:

To resolve the above error message and to access the database components, you will need to look for efficient Repair MySQL Database software. A MySQL Repair tool should only be purchased only after the testing its demo version.

Stellar Phoenix Database Recovery For MySQL is a powerful repair tool whose demo version allows you to preview all the repairable InnoDB and MyISAM database components. Compatible with MySQL 5.x and 4.x, the MySQL Repair utility supports Windows 7, Vista, XP, 2003 and 2000 operating systems. The tool is completely non-destructive.

Resource Taken From :- http://www.articlesengine.com/Article/Resolving--No-MySQL-pid-file-found--Error-Message/502384/1

Wednesday, February 3, 2010

Repair MySQL table with damaged Index


MySQL database table can be corrupted due to to various reasons, one of them being the damage of Index. A table index, usually created at the time of creation of table, is a set of pointers that point towards particular rows in a table. A table Index in MySQL is primarily used to improve the performance of the database by increasing the speed of your MySQL queries. MySQL table, once corrupted due to any reason, makes the records saved in it inaccessible. In such cases, the records can be easily accessed by restoration from an updated backup. However, if the backup does not restore the required table records, then it is of no use. A better way to overcome such table corruption scenarios is by repairing the table by using an advanced Repair MySQL Database application.

To illustrate the above scenario, picture a case where you encounter the below error message when you try to access your MySQL table:

“[Incorrect file format 'TABLENAME']”

After the above table error message pops up, the data saved in your MySQL table becomes inaccessible.

Cause:

The fundamental reason for the occurrence of the above error message is corruption of your MySQL table due to damage of its index.

Resolution:

The above table error message can be resolved within phpMyAdmin. To do so, you will need to follow the below steps:

1.Login into phpMyAdmin by entering your User name and Password.
2.Select the corrupted MySQL database table.
3.Enter the below code for the database table:
repair table employee use_frm;

The above steps resolve the above problem in most cases. However, if the above steps fail, then you will need to use an advanced MySQL Database Repair application to repair your table.

A third-party MySQL Repair utility is a complete solution to repair corrupt MySQL table, irrespective of their reason of damage. The repair utility uses powerful repairing methods – developed by database repair experts – to repair almost all MySQL database components. It can be downloaded from the Internet and allows even a novice user to perform the repair.

MySQL is a powerful application used by most of the MySQL database users to repair their database components. With repair of both MyISAM or InnoDB tables, the software is compatible with MySQL 5.x and 4.x. The MySQL Repair utility supports Windows 7, Vista, XP, 2003 and 2000.

Resource Taken From :- http://www.articleblast.com/Computers_and_Internet/Programming/Repair_MySQL_table_with_damaged_Index/