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java.lang.Objectcom.db4o.tools.Defragment
public class Defragment
defragments a database file.
This class is not part of db4o.jar!
It is delivered as sourcecode in the
path ../com/db4o/tools/
Prerequites:
- The database file may not be
in use.
- All stored classes need to be available.
- If you use yor own special
Db4o translators, they need to be installed before starting Defragment.
Performed tasks:
- Free filespace is removed.
- Deleted IDs are
removed.
- Unavailable classes are removed.
- Unavailable class members are
removed.
- Class indices are restored.
- Previous rename tasks are removed.
Backup:
Defragment creates a backup file with the name [filename].bak. If
a file with this name is already present, Defragment will not run
for safety reasons.
Recommendations:
- Keep the backup copy of your database file.
- Always back up your class files with your database files also.
You will need them to restore the full data of all objects from old database file versions.
- Scan the output log for "Class not available" messages.
You may also run this task programmatically on a scheduled basis.
In this case note that Defragment
modifies db4o
configuration parameters. You may have to restore them for your
application. See the private methods Defragment#configureDb4o() and
Db4o#restoreConfiguration() in the sourcecode of
com.db4o.tools.Defragment.java for the exact changed parameters that
may need to be restored.
Constructor Summary | |
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Defragment()
the main method is the only entry point |
Method Summary | |
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static void |
main(java.lang.String[] args)
the main method that runs Defragment. |
void |
run(java.lang.String filename,
boolean forceBackupDelete)
programmatic interface to run Defragment with a forced delete of a possible old Defragment backup. |
Methods inherited from class java.lang.Object |
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equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public Defragment()
Method Detail |
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public static void main(java.lang.String[] args)
String[]
- a String array of length 1, with the name of the database
file as element 0.public void run(java.lang.String filename, boolean forceBackupDelete)
filename
- the database file.forceBackupDelete
- forces deleting an old backup. Not recommended.
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