Causes of Database table corruption: Difference between revisions
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The SwSQL database is based on MySQL and uses the MyISAM engine. MySQL uses three files (*.frm, *.MYI and *.MYD) to represent each table and the engine implements table level locking. | The SwSQL database is based on MySQL and uses the MyISAM engine. MySQL uses three files (*.frm, *.MYI and *.MYD) to represent each table and the engine implements table level locking. This means that when a table is updated no one else can access the table as all of the table files are locked to avoid corruption of the data. | ||
This means that when a table is updated no one else can access the table as all of the table files are locked to avoid corruption of the data. | |||
Table corruption occurs when another application other than the SwSQLServer has already locked either the Data file or the Index file when SwSQL locks the table for update. | Table corruption occurs when another application other than the SwSQLServer has already locked either the Data file or the Index file when SwSQL locks the table for update. | ||
The types of application that will lock the database files are typically either Anti Virus, Backup or the Windows Shadow Copy Service. | The types of application that will lock the database files are typically either Anti Virus, Backup or the Windows Shadow Copy Service. Therefore to avoid table corruption we would advise that the Hornbill folder be added to the exception list of any Anti Virus or Backup software that runs automatically on the server. | ||
Therefore to avoid table corruption we would advise that the Hornbill folder be added to the exception list of any Anti Virus or Backup software that runs automatically on the server. | |||
We would also advise that the Drive that the Supportworks Server is installed on be added to the exception list of the Windows Shadow Copy Service. | We would also advise that the Drive that the Supportworks Server is installed on be added to the exception list of the Windows Shadow Copy Service. | ||
Revision as of 11:45, 16 June 2015
How Virus Scanners, Backup software and the Shadow copy service causes table corruption
The SwSQL database is based on MySQL and uses the MyISAM engine. MySQL uses three files (*.frm, *.MYI and *.MYD) to represent each table and the engine implements table level locking. This means that when a table is updated no one else can access the table as all of the table files are locked to avoid corruption of the data.
Table corruption occurs when another application other than the SwSQLServer has already locked either the Data file or the Index file when SwSQL locks the table for update.
The types of application that will lock the database files are typically either Anti Virus, Backup or the Windows Shadow Copy Service. Therefore to avoid table corruption we would advise that the Hornbill folder be added to the exception list of any Anti Virus or Backup software that runs automatically on the server.
We would also advise that the Drive that the Supportworks Server is installed on be added to the exception list of the Windows Shadow Copy Service.