[EMAIL PROTECTED] wrote:
Hi,
I use Derby in my product which is personal finance manager written in Java. The app is standalone and has derby as embedded
database which of course starts together with an app.
The version of derby.jar (from manifest) is:
Bundle-Name: Apache Derby 10.1
Bundle-Version: 10.1.1000000.208786
and I use embedded driver from the same jar:
org.apache.derby.jdbc.EmbeddedDriver
Now. I have a serious problem. The application is used by many users, and from time to time the database gets corrupted. I do
not know what way. I have never such a corrupt on my desktop (I use my app as a user as well). I can maybe suppose that users
are doing something wrong, or the other way that I do.
Anyway, after db files are corrupted, the data is lost. I don't know how to get them back. Are there any diagnostic tools for
Derby? I don't see any.
Well this is sample fragment from stacktrace from JDBC trying to open corrupted
db:
(...)
Page Page(3,Container(0, 976)) is at version 755, the log file contains change version 5 564, either there are log records of
this page missing, or this page did not get written out to disk properly.
ERROR XSDB4: Page Page(3,Container(0, 976)) is at
version 755, the log file contains change version 5 564, either there are log records of this page missing, or this page did
not get written out to disk properly.
at org.apache.derby.iapi.error.StandardException.newException(Unknown
Source)
at
org.apache.derby.impl.store.raw.data.PageBasicOperation.needsRedo(Unknown
Source)
at org.apache.derby.impl.store.raw.log.FileLogger.redo(Unknown Source)
at org.apache.derby.impl.store.raw.log.LogToFile.recover(Unknown Source)
at org.apache.derby.impl.store.raw.RawStore.boot(Unknown Source)
at org.apache.derby.impl.services.monitor.BaseMonitor.boot(Unknown
Source)
at org.apache.derby.impl.services.monitor.TopService.bootModule(Unknown
Source)
at
org.apache.derby.impl.services.monitor.BaseMonitor.startModule(Unknown Source)
at
org.apache.derby.iapi.services.monitor.Monitor.bootServiceModule(Unknown Source)
at org.apache.derby.impl.store.access.RAMAccessManager.boot(Unknown
Source)
at org.apache.derby.impl.services.monitor.BaseMonitor.boot(Unknown
Source)
at org.apache.derby.impl.services.monitor.TopService.bootModule(Unknown
Source)
at
org.apache.derby.impl.services.monitor.BaseMonitor.startModule(Unknown Source)
at
org.apache.derby.iapi.services.monitor.Monitor.bootServiceModule(Unknown Source)
at org.apache.derby.impl.db.BasicDatabase.bootStore(Unknown Source)
at org.apache.derby.impl.db.BasicDatabase.boot(Unknown Source)
at org.apache.derby.impl.services.monitor.BaseMonitor.boot(Unknown
Source)
at org.apache.derby.impl.services.monitor.TopService.bootModule(Unknown
Source)
at
org.apache.derby.impl.services.monitor.BaseMonitor.bootService(Unknown Source)
at
org.apache.derby.impl.services.monitor.BaseMonitor.startProviderService(Unknown
Source)
at
org.apache.derby.impl.services.monitor.BaseMonitor.findProviderAndStartService(Unknown
Source)
at
org.apache.derby.impl.services.monitor.BaseMonitor.startPersistentService(Unknown
Source)
at
org.apache.derby.impl.services.monitor.BaseMonitor.startPersistentService(Unknown
Source)
at
org.apache.derby.iapi.services.monitor.Monitor.startPersistentService(Unknown
Source)
at org.apache.derby.impl.jdbc.EmbedConnection.bootDatabase(Unknown
Source)
at org.apache.derby.impl.jdbc.EmbedConnection.<init>(Unknown Source)
at org.apache.derby.impl.jdbc.EmbedConnection30.<init>(Unknown Source)
at org.apache.derby.jdbc.Driver30.getNewEmbedConnection(Unknown Source)
at org.apache.derby.jdbc.InternalDriver.connect(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
(...)
Now I have the questions:
1. How can I diagnose the bug? Do you have any idea what way can I reproduce it
or something?
2. Is it possible to restore lost data from such corrupted file?
3. Is there possibility that db gets corrupted for example where app is closed wrong way (for example there is power off) -
it should not I suppose?
4. Are there any tools that could help me to look at the problem closely?
Thanks.
Maciek
-------------------------------------------------------------------
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What Knut suggestes could cause this error and would hardware problems
related to I/O but the most common cause of this type of problem is
double booting the database. Take care that two instances of the
application are not started at the same time. I believe that double
booting is more likely to be a problem on Unix / Linux platforms and
when using an older JVM. What JVM are you using?
When using older JVMs, double-booting problems can be minimized by
setting the property |derby.database.forceDatabaseLock=true|. One
side-effect of setting |forceDatabaseLock| is that the existence of the
database lock file (db.lck) will always prevent a database from booting.
When a database is not properly shutdown (for example, a crash or an
abort) an 'orphan' database lock file will be left. When
|forceDatabaseLock| is set, this orphan file will need to be removed
manually.
