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https://issues.apache.org/jira/browse/DERBY-4741?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12922716#action_12922716
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Dag H. Wanvik commented on DERBY-4741:
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I feel pretty confident the main approach will improve things by now, so I'll
upload a final version of the experimental patch, and the start producing
incremental patches for commit roughly in the following order:
a) hooks in the APIs to resurrect interrupt flags before we return to the
user's app on the basis of info collected during operation, the new util class
InterruptStatus, which is a collection of methods to save away and resurrect
interrupt flags, and throw an interrupt SQLexception. I intend to *not* throw
any exception if the API method ran to completion, just resurrect the flag.
b) the modified RAFContainer4 stuff for reading and writing db cache pages
safely with NIO.
c) the modified DirRandomAccessFile4 stuff + log retries for safe operation of
log writing
d) stop execution if intr seen within a batch, when checking query timeout, and
when seeing intr while waiting for locks
e) make undo safe
f) time permitting, make boot and recovery interrupt safe.
Please let me know if there any objections or suggestions to this plan! Whether
all this gets ready for 10.7 is a possible issue, but hopefully we should not
behave worse the before at any step.
> Make Derby work reliably in the presence of thread interrupts
> -------------------------------------------------------------
>
> Key: DERBY-4741
> URL: https://issues.apache.org/jira/browse/DERBY-4741
> Project: Derby
> Issue Type: Bug
> Components: Store
> Affects Versions: 10.2.1.6, 10.2.2.0, 10.3.1.4, 10.3.2.1, 10.3.3.0,
> 10.4.1.3, 10.4.2.0, 10.5.1.1, 10.5.2.0, 10.5.3.0, 10.6.1.0
> Reporter: Dag H. Wanvik
> Assignee: Dag H. Wanvik
> Attachments: derby-4741-nio-container+log+waits+locks+throws.diff,
> derby-4741-nio-container+log+waits+locks+throws.stat,
> derby-4741-nio-container+log+waits+locks-2.diff,
> derby-4741-nio-container+log+waits+locks-2.stat,
> derby-4741-nio-container+log+waits+locks.diff,
> derby-4741-nio-container+log+waits+locks.stat,
> derby-4741-nio-container+log+waits.diff,
> derby-4741-nio-container+log+waits.stat, derby-4741-nio-container+log.diff,
> derby-4741-nio-container+log.stat, derby-4741-nio-container-2.diff,
> derby-4741-nio-container-2.log, derby-4741-nio-container-2.stat,
> derby-4741-nio-container-2b.diff, derby-4741-nio-container-2b.stat,
> derby.log, derby.log, MicroAPITest.java, xsbt0.log.gz
>
>
> When not executing on a small device VM, Derby has been using the Java NIO
> classes java.nio.clannel.* for file io.
> If thread is interrupted while executing blocking IO operations in NIO, the
> ClosedByInterruptException will get thrown. Unfortunately, Derby isn't
> current architected to retry and complete such operations (before passing on
> the interrupt), so the Derby database can be left in an inconsistent state
> and we therefore have to return a database level error. This means the
> applications can no longer access the database without a shutdown and reboot
> including a recovery.
> It would be nice if Derby could somehow detect and finish IO operations
> underway when thread interrupts happen before passing the exception on to the
> application. Derby embedded is sometimes embedded in applications that use
> Thread.interrupt to stop threads.
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