Thomas J. Taylor wrote:
Hello everyone,
I'm having a bit of trouble with a Derby 10.1.1.0 database. My ultimate
question is how do I recover from ERROR XSDB4 - I have been searching
through the manuals and have yet to find information about crash recovery.
Any help is appreciated.
Thomas
And now, the details...
Previously, I reported getting ERROR 25502 (cannot change read-only data)
through a JDBC connection. This computer has three Derby 10.1.1.0 databases
(MyDB-1, MyDB-2, MyDB-3). I would receive ERROR 25502 when accessing MyDB-1
or MyDB-2 through JDBC. The ERROR 25502 would crash the system before
getting to MyDB-3.
After further testing on the computer with IJ, I am able to READ, CREATE,
INSERT, UPDATE, and DROP data from MyDB-1 and MyDB-2, but when I try to
access MyDB-3 through IJ, I now get ERROR XJ040 "Failed to start database
C:\db\MyDB-3" (see IJ TEST below).
----- START IJ TEST -----
C:\Program Files\Java\jre1.5.0_04\bin\java -classpath
derby-10.1.1.0.jar;derbytools-10.1.1.0.jar -Dij.protocol=jdbc:derby:
-Dij.database=C:\DB\MyDB-3 -Dij.driver=org.apache.derby.jdbc.EmbeddedDriver
org.apache.derby.tools.ij Read_Test.sql
SELECT * FROM MyTable;
ERROR XJ040: Failed to start database 'C:\DB\MyDB-3', see the next exception
for details.
ERROR XSDB4: Page Page(2,Container(0, 3392)) is at version 906, the log file
contains change version 1,325, either there are log records of this page
missing, or this page did not get written out to disk properly.
----- END IJ TEST -----
Between the JDBC ERROR 25502 problem and the IJ ERROR XJ040 problem, I had
the computer administrator delete DB.LCK from MyDB-1, MyDB-2, and MyDB-3;
and confirm that Windows WRITE access was allowed on all databases.
Thomas J. Taylor wrote:
= = SNIP = = =
This error means that the database is corrupted. The only recourse is
to recover the data from backup.
This kind of corruption is most often caused by double booting the
database. The file db.lck is an internal management file used to
prevent double booting and should never to modified / deleted manually
lest corruption occur. I suspect either two instances of your program
or IJ and your program accessed MyDB-3 at the same time. The second
embedded connection, not finding a db.lck file, will create it's own
data cache and cause the transaction logfile to be processed and
cleared. The first connection will continue working from it's data
cache thinking that it's work in progress is safely logged but, in fact,
it was rolled back by connection 2. Both will write logpages with their
own version sequence until the log records need to be read - I suspect
Derby will crash at this point and the next boot attempt will produce
the error you are experiencing.
Can the database be rebuilt?
