Tuesday, December 29, 2009

MySQL Database Corruption post Collation Issues

Now-a-days, most of the web sites use MySQL database to maintain and store their records. However, the need to change the hosting of the web site arises when the user wants to shift to some other server. To do so, the user also needs to transfer the MySQL database from one server to another. The three ways by which the user can shift his/her database to another server are using phpMyAdmin, command line mysql client tools, and other third-party applications. While shifting MySQL database shifting to some other server is an easy task, the process can also result into corruption of database. In such situations, the records stored in the database become inaccessible. For easy access of MySQL database records in these corruption scenarios, you will need to restore the data from an updated backup. But, in case of absence of an updated backup or backup file getting corrupted, you will need to use advanced MySQL Repair application that can repair your database.

Consider a practical case, where create a large MySQL database that also contains some Turkish characters. You transfer your database from a dedicated server to a shared server. However, when the transfer process is complete, your database becomes corrupt. This can be easily identified as the Turkish characters do not display correctly in the database.

Cause:

The root cause for the corruption of your MySQL database could be interrupted or incomplete transfer.

Resolution:

To repair your corrupted MySQL database you will need to use the “Repair” command to perfectly repair your database. The syntax for the command is as follows:

repair table tablename [,tablename1...][options]

While the repair command proves successful in most cases, the command fails to repair when the corruption level is too high. For such severe corruption situations, only an advanced MySQL Database Repair utility can help. Such Repair MySQL Database tools use advanced scanning methods to orderly repair the corrupt database and restore it on user-specified location. With interactive user documentation and interface, the software becomes easily understandable to both technical and non-technical users. The software is absolutely non destructive in nature.

Sunday, December 27, 2009

Table Corruption after running of Flush and Optimize Commands

There are numerous MySQL commands (with different syntax) that help you to systematically maintain your database. Out of the various commands, the two most common MySQL commands are Flush and Optimize. The Flush command reloads or clears all the internal patches used by MySQL. For using the Flush statement, you will need to have the RELOAD privilege. The Optimize command is used to defragment the database file and to reclaim the unused space. While both the commands hold different functionalities, using these commands one after the another can result into corruption of table. In such situations, the data stored in the table becomes inaccessible. For complete accessibility of table records in such situations, a fundamental way is to restore the data from an updated database backup. But if in case, the backup file is unavailable, then you will need to use advanced MySQL Repair to repair the table.

As a practical case, you run the command “Flush tables” and then immediately run “Optimize table” command. After doing so, the table on which the commands are running gets corrupt and the records stored in it become inaccessible.

Cause:

The root cause for table corruption is that these commands do not wait for each other to perform there particular tasks.

Resolution:

An easy way to repair the corrupted tables is to run the below commands:

1.Check the corruption limit of the table using underneath statement:
mysqlcheck [options] dbname tablename [tablename2... ]
2.Repair the corrupt table using below statement:
repair table tablename [,tablename1...][options]

The above steps enable you to repair the table and bring back the table in working state. But if in case, the above steps fail to resolve the corruption, then it means that the table is beyond the capabilities of Repair command. In such scenarios, the only way to repair your table is by using advanced MySQL Database Repair utility.

These Repair MySQL Database applications use powerful scanning and repairing procedures that enable you to repair the table completely. With highly graphical user-documentation, the software is self explanatory and does not require any technical understanding.

Monday, December 21, 2009

MyISAM Table Corrupted due to Improper Indexing

Indexes in MySQL are primarily used to increase the data accessing and retrieval speed of records stored in the database tables. While correct and orderly indexing of data provides the user with lots of benefits, a badly indexed table can result into corruption of tables (primarily when the query is fetching millions of records). Once the table is corrupted, the data stored in it becomes inaccessible. To surmount the effects of table corruption and to access the data stored in the table, you will need to restore the data from an updated backup (mainly maintained on some other storage media). However, in case of backup unavailability or backup falling short to restore, then you will need to search for powerful MySQL Repair software.

As a practical scenario, you have approximately 2 millions rows saved in your MyISAM table. When you run a query to view all the records stored in the table, the table crashes. Once the table crashes, all the records stored in it become inaccessible.

Cause:

The root cause for table corruption is that table is badly indexed.

Note: In most cases of MyISAM table corruption, you encounter an error message.

Resolution:

The error message and the MySQL database corruption can be resolved by following the underneath steps:
1.You will need to check the limit till the table is corrupted by using below command:
mysqlcheck [options] dbname tablename [tablename2... ]
2.Next, repair the table using the underneath command:
repair table tablename [,tablename1...][options]

The above two steps repair the corrupt MyISAM table in most corruption scenarios. However, there might be situations where the table does not repair, then it means that it is severely corrupted. To repair the table in such situations, you will need to opt for effective MySQL Database Repair software.

A third-party MySQL Repair tool is an easy to understand repair application that systematically repairs MySQL database tables with ease. Such tools use advanced scanning methods to scan and repair the corrupt table. In addition, these applications provide safe repair by not deleting or modifying the original content.

Saturday, December 19, 2009

MySQL Table corruption post Migration to MySQL5

With the newer versions of MySQL coming into the market, it becomes obvious for the database users to migrate to the new version. Migration primarily allows you to use the additional functionalities of the new version. Few additional functionalities could be increased speed and security. While migration allows you with numerous benefits, it might also result in corruption of database. Once the database is corrupted, it becomes unmountable making its records inaccessible. In such situations, an updated database backup acts as a boon and allows you to restore the database components. However, there are many occasions where the users either forgets to create a database backup or backup falls short to restore the required data. For such scenarios, only an advanced MySQL Repair software can help.

As a practical case, you migrated your MySQL database from MySQL 4.1 to MySQL5. After doing so, when you attempt to access the records stored in your tables, you receive the below error message:

“wikidb.archive1
Error : Table 'wikidb.archive1' doesn't exist
error : Corrupt
wikidb.categorylinks1
Error : Table 'wikidb.categorylinks1' doesn't exist
error : Corrupt
wikidb.externallinks1
Error : Table 'wikidb.externallinks1' doesn't exist
error : Corrupt
wikidb.filearchive1
Error : Table 'wikidb.filearchive1' doesn't exist
error : Corrupt”

The error message clearly indicates corruption of MySQL tables.

Cause:

Migration can result into MySQL database corruption under following circumstances:

Incomplete migration
Compatibility Issues

Resolution:

To resolve the above error message and to access the data stored in tables, you will need to follow the below steps:

1.Check the extent of table corruption using mysqlcheck [options] dbname tablename [tablename2... ] command.
2.Repair the table using repair table tablename [,tablename1...][options] command.

The overhead steps confirm complete repair in most of the table corruption scenarios. However, if the above steps fail to solve the purpose, then you will need to use advanced MySQL Repair application. Such Repair MySQL Database tools use extensive scanning methods to repair corrupt database objects in most cases. Their interactive user interface makes them easy to understand and implement. In addition, these tools neither delete or modify the original data stored in the database.

Tuesday, December 8, 2009

MySQL Server crash after passing MySQL open file limit

The file descriptor limit in Windows operating system restricts simultaneous opening of the files to a defined limit of 2048. The limit further causes severe performance issues for a busy MySQL server, because the table cache value needs to be greater than 2048. In most of these scenarios, MySQL server crashes resulting in corruption of MySQL database. In addition, the database becomes unmountable and its records inaccessible. To access your database records in such scenarios, you will need to restore the data from a valid and complete database backup. But if in case, your database is not available or backup file is corrupted, an advanced third-party MySQL Repair application always helps by performing a complete repair.

As a practical instance, your MySQL Server is already running busy and when you attempt to open some more tables, your server crashes displaying the below error message:

“080726 6:06:11 [ERROR] Error in accept: Too many open files
080726 6:08:16 [ERROR] /home/sbester/mysql/5.1/mysql-5.1.28-linux-i686/bin/mysqld: Can't
open file: './test/t1_tmp.frm' (errno: 24)
080726 6:08:17 [ERROR] /home/sbester/mysql/5.1/mysql-5.1.28-linux-i686/bin/mysqld: Can't
open file: './test/t_@002d123.frm' (errno: 24)....”
Your MySQL server shuts down expectedly after the above error message.

Note: In most cases of improper shutdown of MySQL server, your database becomes corrupt and inaccessible.

To prevent database corruption caused due to above reason, you should exceed the default open file limit to 16384 or more by using max-open-files directive in MySQL. For repairing your corrupted database, you should follow the below steps:

1.Use the below command to check the level of corruption:
mysqlcheck [options] dbname tablename [tablename2... ].
2.Repair your database using the below command:
repair table tablename [,tablename1...][options]

The above resolution proves successful in repairing your database after all logical crash scenarios. But the possibilities of failure of the above method also do exist. In such situations, you will need to use advanced MySQL Database Repair application. Such MySQL Recovery tools perform comprehensive repair after by incorporating intensive scanning and repair techniques.

Monday, December 7, 2009

“Error Signal 11” at MySQL Server Startup

Error message at the startup of MySQLD (MySQL Server) primarily occurs when the database is corrupted or damaged. Few main factors responsible for MySQL database corruption are improper MySQLD shutdown, concurrent modification of same database component, and software bugs. Two major outcomes that you might encounter after database corruption are unmountability of database and inaccessibility of records. To surmount both these hazards and easily access the database records, a standard way is to restore it from an updated database backup. However, in case of database backup unavailable, the only alternative left is to repair your database using powerful MySQL Repair application.

Consider a scenario, where you encounter the below error message when you attempt to start MySQLD:

“MySQL got signal 11”

After the above error signal appears, MySQLD shuts down automatically and then restarts on its own, resulting in improper shutdown of your MySQLD.

Note: If the above scenario occurs several times in a single day, the probability of severe database corruption increase manifold.

Cause:

The root cause for the occurrence of the above error message is hitting of MySQLD with a bug.

Resolution:

If your database gets corrupted due to improper shutdown of MySQLD, then you can repair your database using below steps:

You will need to check the level of corruption by running the underneath command:
mysqlcheck [options] dbname tablename [tablename2... ].
After determining the level of corruption, you will need to use the below command to repair your database:
repair table tablename [,tablename1...][options]

The above steps prove successful in repairing the corrupted database in most of the corruption scenarios. However, if the above error message persists even after following the above steps, then it means that database is badly corrupted and requires a powerful third-party MySQL Recovery software.

Such MySQL Repair tools provide comprehensive database repair by throughly scanning the database using high-end scanning methods. With highly interactive user-interface and to-the-point documentation, these software are self-explanatory without any technical knowledge. Moreover, these utilities are non-destructive in nature and perform recovery without making any modifications in original file.

Saturday, December 5, 2009

Upgradation to 5.1.28 results in MySQL Database Corruption

Upgradation to a new version of MySQL database server allows you to remove all the bugs in the previous version. It also enables you to improve the server performance, security, and retrieval results. While upgradation allows you with numerous benefits, it can also result in corruption or damage of your database. In such situations, your database becomes unmountable and its records inaccessible. To successfully access your database records, an ideal way is to restore your database from an updated backup. However, there have been thousands of case studies where the user has either not created any backup or its backup file has been corrupted or damaged due to various internal or external factors. For such corruption scenarios, you will need to repair your database by using advanced MySQL Repair software.

Consider a practical scenario, where you upgraded your system from 5.0.27 to 5.1.28 on Windows Vista operating system. However, when the upgradataion is complete and you attempt to access your database components, they become inaccessible. Furthermore, you also encounter an error message stating that your tables have been corrupted.

Cause:

Few main causes for the corruption of tables are discussed below:

Improper upgradataion
Incomplete upgradation

Resolution:

To resolve the above error message and to access your database records, you will need to follow the below steps:

1.Downgrade to the previous version of MySQL database server.
2.Restore data from an updated backup.
The above resolution proves successful in most of corruption scenarios. The resolution only fails to perform when you have not created any database backup or the backup is corrupted. In such circumstances, the only way left to repair your database and to access the records is by using a powerful third-party MySQL Database Repair application.

Such MySQL Recovery applications use intensive scanning techniques to repair and restore all MySQL database components. With highly graphical user-interface, these tools are easy to understand without any former technical understanding. These non-destructive applications provide safe repair by not making any changes in the original database file.