Do you happen to know why it works on windows? Is the file lock
behavior different, or is the old windows-only locking method
automatically kicking in?
Suresh Thalamati (JIRA) wrote:
[ http://issues.apache.org/jira/browse/DERBY-700?page=comments#action_12363492 ]
Suresh Thalamati commented on DERBY-700:
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After doing bit of testing realized checking for OverlappingFileLockException does not work. This exception is reliable only if the same file channel instance is used., With multiple class loaders
I don't know how it is possible to have a sigle file channel object.
On Linux , one can acquire the lock on the same region using diferent file channels on the same file.
Realated info from the java docs:
java.nio.channel.FileLock
,On some systems, closing a channel releases all locks held by the Java virtual machine on the underlying file regardless of whether the locks were acquired via that channel or via another channel open on the same file. It is strongly recommended that, within a program, a unique channel be used to acquire all locks on any given file.
Derby does not prevent dual boot of database from different classloaders on
Linux
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Key: DERBY-700
URL: http://issues.apache.org/jira/browse/DERBY-700
Project: Derby
Type: Bug
Components: Store
Versions: 10.1.2.1
Environment: ava -version
java version "1.4.2_08"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_08-b03)
Java HotSpot(TM) Client VM (build 1.4.2_08-b03, mixed mode)
Reporter: Kathey Marsden
Attachments: DualBootRepro.java, DualBootRepro2.zip
Derby does not prevent dual boot from two different classloaders on Linux.
To reproduce run the program DualBootRepro with no derby jars in your
classpath. The program assumes derby.jar is in 10.1.2.1/derby.jar, you can
change the location by changing the DERBY_LIB_DIR variable.
On Linux the output is:
$java -cp . DualBootRepro
Loading derby from file:10.1.2.1/derby.jar
10.1.2.1/derby.jar
Booted database in loader [EMAIL PROTECTED]
FAIL: Booted database in 2nd loader [EMAIL PROTECTED]
On Windows I get the expected output.
$ java -cp . DualBootRepro
Loading derby from file:10.1.2.1/derby.jar
10.1.2.1/derby.jar
Booted database in loader [EMAIL PROTECTED]
PASS: Expected exception for dualboot:Another instance of Derby may have
already booted the database D:\marsden\repro\dualboot\mydb.
