[
https://issues.apache.org/jira/browse/DERBY-4741?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12924571#action_12924571
]
Dag H. Wanvik commented on DERBY-4741:
--------------------------------------
Hi Lily, thanks for test driving the patch :) I really appreciate your help
looking at this work. Having another set of eyes on this is good, the change
are a bit cross cutting and affect much existing code, so it's good to have
someone double checking the changes. Two comments:
- if the mailjdbc test still deadlocks, I doubt it can be due to this patch,
since it doesn't really change any behavior, it just installs the machinery for
the behavior changes to come in later patches, as you presumed.
- the difference is EmbedBlob with local initial null is just some cruft from
an experiment I did with trying to place restoreIntrFlagIfSeen in a finally
block. This didn't work out since, error handling may close the connection and
with it the lcc, so the check would happen too late. (The current method is to
check before return and in the error handling code itself). I'll revert that
change, thanks for noticing.
My main concern with this patch currently is to verify that I have found all
the ways control can return to the user app after Derby code has had control,
and possibly set the interrupt status flag. A case in point is the Blob methods
that don't require a connection, e.g. EmbedBlob#getBytes if the lob is
materialized, we call control.read: if we see an interrupt inside the read, the
flag would get stored in a thread local variable, since there is no lcc, so
I'll I need to add a call to no-args version of restoreIntrFlagIfSeen() there.
> 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-a-01-api-interruptstatus.diff,
> derby-4741-a-01-api-interruptstatus.stat,
> derby-4741-all+lenient+resurrect.diff, derby-4741-all+lenient+resurrect.stat,
> 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.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
