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Posted to dev@ignite.apache.org by Andrey Kuznetsov <st...@gmail.com> on 2018/10/12 05:29:04 UTC
Re: Critical worker threads liveness checking drawbacks
Igniters,
Now I spot blocking / long-running code arising from
{{GridDhtPartitionsExchangeFuture#init}} calls in partition-exchanger
thread, see [1]. Ideally, all blocking operations along all possible code
paths should be guarded implicitly from critical failure detector to avoid
the thread from being considered blocked. There is a pull request [2] that
provides shallow solution. I didn't change code outside
{{GridDhtPartitionsExchangeFuture}}, otherwise it could be broken by any
upcoming change. Also, I didn't touch the code runnable by threads other
than partition-exchanger. So I have a number of guarded sections that are
wider than they could be, and this potentially hides issues from failure
detector. Does this PR make sense? Or maybe it's better to exclude
partition-exchanger from critical threads registry at all?
[1] https://issues.apache.org/jira/browse/IGNITE-9710
[2] https://github.com/apache/ignite/pull/4962
пт, 28 сент. 2018 г. в 18:56, Maxim Muzafarov <ma...@gmail.com>:
> Andrey, Andrey
>
> > Thanks for being attentive! It's definitely a typo. Could you please
> create
> > an issue?
>
> I've created an issue [1] and prepared PR [2].
> Please, review this change.
>
> [1] https://issues.apache.org/jira/browse/IGNITE-9723
> [2] https://github.com/apache/ignite/pull/4862
>
> On Fri, 28 Sep 2018 at 16:58 Yakov Zhdanov <yz...@apache.org> wrote:
>
> > Config option + mbean access. Does that make sense?
> >
> > Yakov
> >
> > On Fri, Sep 28, 2018, 17:17 Vladimir Ozerov <vo...@gridgain.com>
> wrote:
> >
> > > Then it should be config option.
> > >
> > > пт, 28 сент. 2018 г. в 13:15, Andrey Gura <ag...@apache.org>:
> > >
> > > > Guys,
> > > >
> > > > why we need both config option and system property? I believe one way
> > is
> > > > enough.
> > > > On Fri, Sep 28, 2018 at 12:38 PM Nikolay Izhikov <
> nizhikov@apache.org>
> > > > wrote:
> > > > >
> > > > > Ticket created - https://issues.apache.org/jira/browse/IGNITE-9737
> > > > >
> > > > > Fixed version is 2.7.
> > > > >
> > > > > В Пт, 28/09/2018 в 11:41 +0300, Alexey Goncharuk пишет:
> > > > > > Nikolay, I agree, a user should be able to disable both thread
> > > liveness
> > > > > > check and checkpoint read lock timeout check from config and a
> > system
> > > > > > property.
> > > > > >
> > > > > > пт, 28 сент. 2018 г. в 11:30, Nikolay Izhikov <
> nizhikov@apache.org
> > >:
> > > > > >
> > > > > > > Hello, Igniters.
> > > > > > >
> > > > > > > I found that this feature can't be disabled from config.
> > > > > > > The only way to disable it is from JMX bean.
> > > > > > >
> > > > > > > I think it very dangerous: If we have some corner case or a bug
> > in
> > > > this
> > > > > > > Watch Dog it can make Ignite unusable.
> > > > > > > I propose to implement possibility to disable this feature
> both -
> > > > from
> > > > > > > config and from JVM options.
> > > > > > >
> > > > > > > What do you think?
> > > > > > >
> > > > > > > В Чт, 27/09/2018 в 16:14 +0300, Andrey Kuznetsov пишет:
> > > > > > > > Maxim,
> > > > > > > >
> > > > > > > > Thanks for being attentive! It's definitely a typo. Could you
> > > > please
> > > > > > >
> > > > > > > create
> > > > > > > > an issue?
> > > > > > > >
> > > > > > > > чт, 27 сент. 2018 г. в 16:00, Maxim Muzafarov <
> > > maxmuzaf@gmail.com
> > > > >:
> > > > > > > >
> > > > > > > > > Folks,
> > > > > > > > >
> > > > > > > > > I've found in `GridCachePartitionExchangeManager:2684` [1]
> > > > (master
> > > > > > >
> > > > > > > branch)
> > > > > > > > > exchange future wrapped
> > > > > > > > > with double `blockingSectionEnd` method. Is it correct? I
> > just
> > > > want to
> > > > > > > > > understand this change and
> > > > > > > > > how should I use this in the future.
> > > > > > > > >
> > > > > > > > > Should I file a new issue to fix this? I think here
> > > > > > >
> > > > > > > `blockingSectionBegin`
> > > > > > > > > method should be used.
> > > > > > > > >
> > > > > > > > > -------------
> > > > > > > > > blockingSectionEnd();
> > > > > > > > >
> > > > > > > > > try {
> > > > > > > > > resVer = exchFut.get(exchTimeout,
> TimeUnit.MILLISECONDS);
> > > > > > > > > } finally {
> > > > > > > > > blockingSectionEnd();
> > > > > > > > > }
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > [1]
> > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > >
> > > >
> > >
> >
> https://github.com/apache/ignite/blob/master/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/GridCachePartitionExchangeManager.java#L2684
> > > > > > > > >
> > > > > > > > > On Wed, 26 Sep 2018 at 22:47 Vyacheslav Daradur <
> > > > daradurvs@gmail.com>
> > > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Andrey Gura, thank you for the answer!
> > > > > > > > > >
> > > > > > > > > > I agree that wrapping of 'init' method reduces the profit
> > of
> > > > watchdog
> > > > > > > > > > service in case of PME worker, but in other cases, we
> > should
> > > > wrap all
> > > > > > > > > > possible long sections on GridDhtPartitionExchangeFuture.
> > For
> > > > example
> > > > > > > > > > 'onCacheChangeRequest' method or
> > > > > > > > > > 'cctx.affinity().onCacheChangeRequest' inside because it
> > may
> > > > take
> > > > > > > > > > significant time (reproducer attached).
> > > > > > > > > >
> > > > > > > > > > I only want to point out a possible issue which may allow
> > to
> > > > end-user
> > > > > > > > > > halt the Ignite cluster accidentally.
> > > > > > > > > >
> > > > > > > > > > I'm sure that PME experts know how to fix this issue
> > > properly.
> > > > > > > > > > On Wed, Sep 26, 2018 at 10:28 PM Andrey Gura <
> > > agura@apache.org
> > > > >
> > > > > > >
> > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > Vyacheslav,
> > > > > > > > > > >
> > > > > > > > > > > Exchange worker is strongly tied with
> > > > > > > > > > > GridDhtPartitionExchangeFuture#init and it is ok.
> > Exchange
> > > > worker
> > > > > > >
> > > > > > > also
> > > > > > > > > > > shouldn't be blocked for long time but in reality it
> > > > happens.It
> > > > > > >
> > > > > > > also
> > > > > > > > > > > means that your change doesn't make sense.
> > > > > > > > > > >
> > > > > > > > > > > What actually make sense it is identification of places
> > > which
> > > > > > > > > > > intentionally blocking. May be some places/actions
> should
> > > be
> > > > > > >
> > > > > > > braced by
> > > > > > > > > > > blocking guards.
> > > > > > > > > > >
> > > > > > > > > > > If you have failing tests please make sure that your
> > > > > > >
> > > > > > > failureHandler is
> > > > > > > > > > > NoOpFailureHandler or any other handler with
> > > > ignoreFailureTypes =
> > > > > > > > > > > [CRITICAL_WORKER_BLOCKED].
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > On Wed, Sep 26, 2018 at 9:43 PM Vyacheslav Daradur <
> > > > > > > > >
> > > > > > > > > daradurvs@gmail.com>
> > > > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > Hi Igniters!
> > > > > > > > > > > >
> > > > > > > > > > > > Thank you for this important improvement!
> > > > > > > > > > > >
> > > > > > > > > > > > I've looked through implementation and noticed that
> > > > > > > > > > > > GridDhtPartitionsExchangeFuture#init has not been
> > wrapped
> > > > in
> > > > > > >
> > > > > > > blocked
> > > > > > > > > > > > section. This means it easy to halt the node in case
> of
> > > > > > >
> > > > > > > longrunning
> > > > > > > > > > > > actions during PME, for example when we create a
> cache
> > > with
> > > > > > > > > > > > StoreFactrory which connect to 3rd party DB.
> > > > > > > > > > > >
> > > > > > > > > > > > I'm not sure that it is the right behavior.
> > > > > > > > > > > >
> > > > > > > > > > > > I filled the issue [1] and prepared the PR [2] with
> > > > reproducer
> > > > > > >
> > > > > > > and
> > > > > > > > > >
> > > > > > > > > > possible fix.
> > > > > > > > > > > >
> > > > > > > > > > > > Andrey, could you please look at and confirm that it
> > > makes
> > > > sense?
> > > > > > > > > > > >
> > > > > > > > > > > > [1]
> https://issues.apache.org/jira/browse/IGNITE-9710
> > > > > > > > > > > > [2] https://github.com/apache/ignite/pull/4845
> > > > > > > > > > > > On Mon, Sep 24, 2018 at 9:46 PM Andrey Kuznetsov <
> > > > > > >
> > > > > > > stkuzma@gmail.com>
> > > > > > > > > >
> > > > > > > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > Denis,
> > > > > > > > > > > > >
> > > > > > > > > > > > > I've created the ticket [1] with short description
> of
> > > the
> > > > > > > > > >
> > > > > > > > > > functionality.
> > > > > > > > > > > > >
> > > > > > > > > > > > > [1]
> > https://issues.apache.org/jira/browse/IGNITE-9679
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > пн, 24 сент. 2018 г. в 17:46, Denis Magda <
> > > > dmagda@apache.org>:
> > > > > > > > > > > > >
> > > > > > > > > > > > > > Andrey K. and G.,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks, do we have a documentation ticket
> created?
> > > > Prachi
> > > > > > > > >
> > > > > > > > > (copied)
> > > > > > > > > > can help
> > > > > > > > > > > > > > with the documentation.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > --
> > > > > > > > > > > > > > Denis
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Mon, Sep 24, 2018 at 5:51 AM Andrey Gura <
> > > > > > >
> > > > > > > agura@apache.org>
> > > > > > > > > >
> > > > > > > > > > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Andrey,
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > finally your change is merged to master branch.
> > > > > > >
> > > > > > > Congratulations
> > > > > > > > > >
> > > > > > > > > > and
> > > > > > > > > > > > > > > thank you very much! :)
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > I think that the next step is feature that will
> > > allow
> > > > > > >
> > > > > > > signal
> > > > > > > > > >
> > > > > > > > > > about
> > > > > > > > > > > > > > > blocked threads to the monitoring tools via
> > MXBean.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > I hope you will continue development of this
> > > feature
> > > > and
> > > > > > > > >
> > > > > > > > > provide
> > > > > > > > > > your
> > > > > > > > > > > > > > > vision in new JIRA issue.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Tue, Sep 11, 2018 at 6:54 PM Andrey
> Kuznetsov
> > <
> > > > > > > > > >
> > > > > > > > > > stkuzma@gmail.com>
> > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > David, Maxim!
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Thanks a lot for you ideas. Unfortunately, I
> > > can't
> > > > adopt
> > > > > > >
> > > > > > > all
> > > > > > > > > >
> > > > > > > > > > of them
> > > > > > > > > > > > > > > right
> > > > > > > > > > > > > > > > now: the scope is much broader than the scope
> > of
> > > > the
> > > > > > >
> > > > > > > change I
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > implement.
> > > > > > > > > > > > > > > I
> > > > > > > > > > > > > > > > have had a talk to a group of Ignite
> commiters,
> > > > and we
> > > > > > >
> > > > > > > agreed
> > > > > > > > > >
> > > > > > > > > > to
> > > > > > > > > > > > > > complete
> > > > > > > > > > > > > > > > the change as follows.
> > > > > > > > > > > > > > > > - Blocking instructions in system-critical
> > which
> > > > may
> > > > > > > > >
> > > > > > > > > resonably
> > > > > > > > > > last
> > > > > > > > > > > > > > long
> > > > > > > > > > > > > > > > should be explicitly excluded from the
> > > monitoring.
> > > > > > > > > > > > > > > > - Failure handlers should have a setting to
> > > > suppress some
> > > > > > > > > >
> > > > > > > > > > failures on
> > > > > > > > > > > > > > > > per-failure-type basis.
> > > > > > > > > > > > > > > > According to this I have updated the
> > > > implementation: [1]
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > [1]
> https://github.com/apache/ignite/pull/4089
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > пн, 10 сент. 2018 г. в 22:35, David Harvey <
> > > > > > > > > >
> > > > > > > > > > syssoftsol@gmail.com>:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > When I've done this before,I've needed to
> > find
> > > > the
> > > > > > >
> > > > > > > oldest
> > > > > > > > > >
> > > > > > > > > > thread,
> > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > kill
> > > > > > > > > > > > > > > > > the node running that. From a language
> > > > standpoint,
> > > > > > > > >
> > > > > > > > > Maxim's
> > > > > > > > > > "without
> > > > > > > > > > > > > > > > > progress" better than "heartbeat". For
> > > > example, what
> > > > > > >
> > > > > > > I'm
> > > > > > > > > >
> > > > > > > > > > most
> > > > > > > > > > > > > > > interested
> > > > > > > > > > > > > > > > > in on a distributed system is which thread
> > > > started the
> > > > > > >
> > > > > > > work
> > > > > > > > > >
> > > > > > > > > > it has
> > > > > > > > > > > > > > not
> > > > > > > > > > > > > > > > > completed the earliest, and when did that
> > > thread
> > > > last
> > > > > > >
> > > > > > > make
> > > > > > > > > >
> > > > > > > > > > forward
> > > > > > > > > > > > > > > > > process. You don't want to kill a node
> > > > because a
> > > > > > >
> > > > > > > thread
> > > > > > > > > >
> > > > > > > > > > is
> > > > > > > > > > > > > > waiting
> > > > > > > > > > > > > > > on a
> > > > > > > > > > > > > > > > > lock held by a thread that went off-node
> and
> > > has
> > > > not
> > > > > > > > >
> > > > > > > > > gotten a
> > > > > > > > > > > > > > response.
> > > > > > > > > > > > > > > > > If you don't understand the dependency
> > > > relationships,
> > > > > > >
> > > > > > > you
> > > > > > > > > >
> > > > > > > > > > will make
> > > > > > > > > > > > > > > > > incorrect recovery decisions.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > On Mon, Sep 10, 2018 at 4:08 AM Maxim
> > > Muzafarov <
> > > > > > > > > >
> > > > > > > > > > maxmuzaf@gmail.com>
> > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > I think we should find exact answers to
> > these
> > > > > > >
> > > > > > > questions:
> > > > > > > > > > > > > > > > > > 1. What `critical` issue exactly is?
> > > > > > > > > > > > > > > > > > 2. How can we find critical issues?
> > > > > > > > > > > > > > > > > > 3. How can we handle critical issues?
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > First,
> > > > > > > > > > > > > > > > > > - Ignore uninterruptable actions (e.g.
> > > > > > >
> > > > > > > worker\service
> > > > > > > > > >
> > > > > > > > > > shutdown)
> > > > > > > > > > > > > > > > > > - Long I/O operations (should be a
> > > > configurable
> > > > > > >
> > > > > > > timeout
> > > > > > > > > >
> > > > > > > > > > for each
> > > > > > > > > > > > > > > type of
> > > > > > > > > > > > > > > > > > usage)
> > > > > > > > > > > > > > > > > > - Infinite loops
> > > > > > > > > > > > > > > > > > - Stalled\deadlocked threads (and\or too
> > > many
> > > > parked
> > > > > > > > > >
> > > > > > > > > > threads,
> > > > > > > > > > > > > > > exclude
> > > > > > > > > > > > > > > > > I/O)
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Second,
> > > > > > > > > > > > > > > > > > - The working queue is without progress
> > > (e.g.
> > > > disco,
> > > > > > > > > >
> > > > > > > > > > exchange
> > > > > > > > > > > > > > > queues)
> > > > > > > > > > > > > > > > > > - Work hasn't been completed since the
> > last
> > > > > > >
> > > > > > > heartbeat
> > > > > > > > > >
> > > > > > > > > > (checking
> > > > > > > > > > > > > > > > > > milestones)
> > > > > > > > > > > > > > > > > > - Too many system resources used by a
> > thread
> > > > for the
> > > > > > > > >
> > > > > > > > > long
> > > > > > > > > > period
> > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > time
> > > > > > > > > > > > > > > > > > (allocated memory, CPU)
> > > > > > > > > > > > > > > > > > - Timing fields associated with each
> > thread
> > > > status
> > > > > > > > > >
> > > > > > > > > > exceeded a
> > > > > > > > > > > > > > > maximum
> > > > > > > > > > > > > > > > > time
> > > > > > > > > > > > > > > > > > limit.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Third (not too many options here),
> > > > > > > > > > > > > > > > > > - `log everything` should be the default
> > > > behaviour
> > > > > > >
> > > > > > > in
> > > > > > > > >
> > > > > > > > > all
> > > > > > > > > > these
> > > > > > > > > > > > > > > cases,
> > > > > > > > > > > > > > > > > > since it may be difficult to find the
> cause
> > > > after the
> > > > > > > > > >
> > > > > > > > > > restart.
> > > > > > > > > > > > > > > > > > - Wait some interval of time and kill
> the
> > > > hanging
> > > > > > >
> > > > > > > node
> > > > > > > > > >
> > > > > > > > > > (cluster
> > > > > > > > > > > > > > > should
> > > > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > > configured stable enough)
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Questions,
> > > > > > > > > > > > > > > > > > - Not sure, but can workers miss their
> > > > heartbeat
> > > > > > > > > >
> > > > > > > > > > deadlines if CPU
> > > > > > > > > > > > > > > loads
> > > > > > > > > > > > > > > > > up
> > > > > > > > > > > > > > > > > > to 80%-90%? Bursts of momentary overloads
> > can
> > > > be
> > > > > > > > > > > > > > > > > > expected behaviour as a normal part
> of
> > > > system
> > > > > > > > > >
> > > > > > > > > > operations.
> > > > > > > > > > > > > > > > > > - Why do we decide that critical thread
> > > should
> > > > > > >
> > > > > > > monitor
> > > > > > > > > >
> > > > > > > > > > each other?
> > > > > > > > > > > > > > > For
> > > > > > > > > > > > > > > > > > instance, if all the tasks were blocked
> and
> > > > unable to
> > > > > > > > >
> > > > > > > > > run,
> > > > > > > > > > > > > > > > > > node reset would never occur. As for
> > me,
> > > a
> > > > better
> > > > > > > > > >
> > > > > > > > > > solution is
> > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > use
> > > > > > > > > > > > > > > > > a
> > > > > > > > > > > > > > > > > > separate monitor thread or pool (maybe
> both
> > > > with
> > > > > > >
> > > > > > > software
> > > > > > > > > > > > > > > > > > and hardware checks) that not only
> > checks
> > > > > > >
> > > > > > > heartbeats
> > > > > > > > > >
> > > > > > > > > > but
> > > > > > > > > > > > > > > monitors the
> > > > > > > > > > > > > > > > > > other system as well.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > On Mon, 10 Sep 2018 at 00:07 David
> Harvey <
> > > > > > > > > >
> > > > > > > > > > syssoftsol@gmail.com>
> > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > It would be safer to restart the entire
> > > > cluster
> > > > > > >
> > > > > > > than to
> > > > > > > > > >
> > > > > > > > > > remove
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > last
> > > > > > > > > > > > > > > > > > > node for a cache that should be
> > redundant.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > On Sun, Sep 9, 2018, 4:00 PM Andrey
> Gura
> > <
> > > > > > > > > >
> > > > > > > > > > agura@apache.org>
> > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Hi,
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > I agree with Yakov that we can
> provide
> > > some
> > > > > > >
> > > > > > > option
> > > > > > > > > >
> > > > > > > > > > that manage
> > > > > > > > > > > > > > > worker
> > > > > > > > > > > > > > > > > > > > liveness checker behavior in case of
> > > > observing
> > > > > > >
> > > > > > > that
> > > > > > > > > >
> > > > > > > > > > some worker
> > > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > > > > > blocked too long.
> > > > > > > > > > > > > > > > > > > > At least it will some workaround for
> > > > cases when
> > > > > > >
> > > > > > > node
> > > > > > > > > >
> > > > > > > > > > fails is
> > > > > > > > > > > > > > > too
> > > > > > > > > > > > > > > > > > > > annoying.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Backups count threshold sounds good
> > but I
> > > > don't
> > > > > > > > > >
> > > > > > > > > > understand how
> > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > will
> > > > > > > > > > > > > > > > > > > > help in case of cluster hanging.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > The simplest solution here is alert
> in
> > > > cases of
> > > > > > > > > >
> > > > > > > > > > blocking of
> > > > > > > > > > > > > > some
> > > > > > > > > > > > > > > > > > > > critical worker (we can improve
> > > > WorkersRegistry
> > > > > > >
> > > > > > > for
> > > > > > > > > >
> > > > > > > > > > this
> > > > > > > > > > > > > > purpose
> > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > expose list of blocked workers) and
> > > > optionally
> > > > > > >
> > > > > > > call
> > > > > > > > > >
> > > > > > > > > > system
> > > > > > > > > > > > > > > configured
> > > > > > > > > > > > > > > > > > > > failure processor. BTW, failure
> > processor
> > > > can be
> > > > > > > > > >
> > > > > > > > > > extended in
> > > > > > > > > > > > > > > order to
> > > > > > > > > > > > > > > > > > > > perform any checks (e.g. backup
> count)
> > > and
> > > > decide
> > > > > > > > > >
> > > > > > > > > > whether it
> > > > > > > > > > > > > > > should
> > > > > > > > > > > > > > > > > > > > stop node or not.
> > > > > > > > > > > > > > > > > > > > On Sat, Sep 8, 2018 at 3:42 PM Andrey
> > > > Kuznetsov <
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > stkuzma@gmail.com>
> > > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > David, Yakov, I understand your
> > fears.
> > > > But
> > > > > > >
> > > > > > > liveness
> > > > > > > > > >
> > > > > > > > > > checks
> > > > > > > > > > > > > > deal
> > > > > > > > > > > > > > > > > with
> > > > > > > > > > > > > > > > > > > > > _critical_ conditions, i.e. when
> > such a
> > > > > > >
> > > > > > > condition
> > > > > > > > >
> > > > > > > > > is
> > > > > > > > > > met we
> > > > > > > > > > > > > > > > > conclude
> > > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > > node as totally broken, and there
> is
> > no
> > > > sense
> > > > > > >
> > > > > > > to
> > > > > > > > > >
> > > > > > > > > > keep it
> > > > > > > > > > > > > > alive
> > > > > > > > > > > > > > > > > > > regardless
> > > > > > > > > > > > > > > > > > > > > the data it contains. If we want to
> > > give
> > > > it a
> > > > > > > > > >
> > > > > > > > > > chance, then
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > condition
> > > > > > > > > > > > > > > > > > > > > (long fsync etc.) should not
> > considered
> > > > as
> > > > > > >
> > > > > > > critical
> > > > > > > > > >
> > > > > > > > > > at all.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > сб, 8 сент. 2018 г. в 15:18, Yakov
> > > > Zhdanov <
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > yzhdanov@apache.org>:
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > Agree with David. We need to have
> > an
> > > > > > >
> > > > > > > opporunity
> > > > > > > > > >
> > > > > > > > > > set backups
> > > > > > > > > > > > > > > count
> > > > > > > > > > > > > > > > > > > > threshold
> > > > > > > > > > > > > > > > > > > > > > (at runtime also!) that will not
> > > allow
> > > > any
> > > > > > > > > >
> > > > > > > > > > automatic stop
> > > > > > > > > > > > > > if
> > > > > > > > > > > > > > > > > there
> > > > > > > > > > > > > > > > > > > > will be
> > > > > > > > > > > > > > > > > > > > > > a data loss. Andrey, what do you
> > > think?
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > --Yakov
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > --
> > > > > > > > > > > > > > > > > > > > > Best regards,
> > > > > > > > > > > > > > > > > > > > > Andrey Kuznetsov.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > --
> > > > > > > > > > > > > > > > > > --
> > > > > > > > > > > > > > > > > > Maxim Muzafarov
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > --
> > > > > > > > > > > > > > > > Best regards,
> > > > > > > > > > > > > > > > Andrey Kuznetsov.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > --
> > > > > > > > > > > > > Best regards,
> > > > > > > > > > > > > Andrey Kuznetsov.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > --
> > > > > > > > > > > > Best Regards, Vyacheslav D.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > --
> > > > > > > > > > Best Regards, Vyacheslav D.
> > > > > > > > > >
> > > > > > > > >
> > > > > > > > > --
> > > > > > > > > --
> > > > > > > > > Maxim Muzafarov
> > > > > > > > >
> > > > > > > >
> > > > > > > >
> > > >
> > >
> >
> --
> --
> Maxim Muzafarov
>
--
Best regards,
Andrey Kuznetsov.
Re: Critical worker threads liveness checking drawbacks
Posted by Dmitriy Pavlov <dp...@apache.org>.
Hi,
Sorry for being too formal here, but IGNITE-10003
<https://issues.apache.org/jira/browse/IGNITE-10003> is in progress.
Also, I've tried to find anything related to it in the list. So according
to the list, no one was asking to include.
Sincerely,
Dmitriy Pavlov
ср, 19 дек. 2018 г. в 13:24, Nikolay Izhikov <ni...@apache.org>:
> Hello, Alexey.
>
> No, we don't include this ticket to 2.7.
> Should we?
>
> ср, 19 дек. 2018 г. в 12:55, Alexey Goncharuk <alexey.goncharuk@gmail.com
> >:
>
> > Folks, why did not we include IGNITE-10003 to ignite-2.7 release scope?
> > This causes an Ignite node to be stopped by default when checkpoint read
> > lock acquire times out. I expect a lot of Ignite 2.7 users will be
> affected
> > by this mistake.
> >
> > We should at least update the documentation and make users aware of a
> > workaround.
> >
> > чт, 25 окт. 2018 г. в 16:35, Alexey Goncharuk <
> alexey.goncharuk@gmail.com
> > >:
> >
> > > Andrey,
> > >
> > > I still see that checkpoint read lock acquisition raises a
> > CRITICAL_ERROR,
> > > which by default will shut down local node. As far as I remember, we
> > > decided that by default thread timeout should not trigger node failure.
> > > Now, however, it does, because we ignore SYSTEM_WORKER_BLOCKED events
> in
> > > default configuration.
> > >
> > > Should we introduce another critical failure type
> > > CHECKPOINT_READ_LOCK_BLOCKED or use SYSTEM_WORKER_BLOCKED for
> checkpoint
> > > read lock acquire failure?
> > >
> > > --AG
> > >
> > > пт, 12 окт. 2018 г. в 8:29, Andrey Kuznetsov <st...@gmail.com>:
> > >
> > >> Igniters,
> > >>
> > >> Now I spot blocking / long-running code arising from
> > >> {{GridDhtPartitionsExchangeFuture#init}} calls in partition-exchanger
> > >> thread, see [1]. Ideally, all blocking operations along all possible
> > code
> > >> paths should be guarded implicitly from critical failure detector to
> > avoid
> > >> the thread from being considered blocked. There is a pull request [2]
> > that
> > >> provides shallow solution. I didn't change code outside
> > >> {{GridDhtPartitionsExchangeFuture}}, otherwise it could be broken by
> any
> > >> upcoming change. Also, I didn't touch the code runnable by threads
> other
> > >> than partition-exchanger. So I have a number of guarded sections that
> > are
> > >> wider than they could be, and this potentially hides issues from
> failure
> > >> detector. Does this PR make sense? Or maybe it's better to exclude
> > >> partition-exchanger from critical threads registry at all?
> > >>
> > >> [1] https://issues.apache.org/jira/browse/IGNITE-9710
> > >> [2] https://github.com/apache/ignite/pull/4962
> > >>
> > >>
> > >> пт, 28 сент. 2018 г. в 18:56, Maxim Muzafarov <ma...@gmail.com>:
> > >>
> > >> > Andrey, Andrey
> > >> >
> > >> > > Thanks for being attentive! It's definitely a typo. Could you
> please
> > >> > create
> > >> > > an issue?
> > >> >
> > >> > I've created an issue [1] and prepared PR [2].
> > >> > Please, review this change.
> > >> >
> > >> > [1] https://issues.apache.org/jira/browse/IGNITE-9723
> > >> > [2] https://github.com/apache/ignite/pull/4862
> > >> >
> > >> > On Fri, 28 Sep 2018 at 16:58 Yakov Zhdanov <yz...@apache.org>
> > wrote:
> > >> >
> > >> > > Config option + mbean access. Does that make sense?
> > >> > >
> > >> > > Yakov
> > >> > >
> > >> > > On Fri, Sep 28, 2018, 17:17 Vladimir Ozerov <vozerov@gridgain.com
> >
> > >> > wrote:
> > >> > >
> > >> > > > Then it should be config option.
> > >> > > >
> > >> > > > пт, 28 сент. 2018 г. в 13:15, Andrey Gura <ag...@apache.org>:
> > >> > > >
> > >> > > > > Guys,
> > >> > > > >
> > >> > > > > why we need both config option and system property? I believe
> > one
> > >> way
> > >> > > is
> > >> > > > > enough.
> > >> > > > > On Fri, Sep 28, 2018 at 12:38 PM Nikolay Izhikov <
> > >> > nizhikov@apache.org>
> > >> > > > > wrote:
> > >> > > > > >
> > >> > > > > > Ticket created -
> > >> https://issues.apache.org/jira/browse/IGNITE-9737
> > >> > > > > >
> > >> > > > > > Fixed version is 2.7.
> > >> > > > > >
> > >> > > > > > В Пт, 28/09/2018 в 11:41 +0300, Alexey Goncharuk пишет:
> > >> > > > > > > Nikolay, I agree, a user should be able to disable both
> > thread
> > >> > > > liveness
> > >> > > > > > > check and checkpoint read lock timeout check from config
> > and a
> > >> > > system
> > >> > > > > > > property.
> > >> > > > > > >
> > >> > > > > > > пт, 28 сент. 2018 г. в 11:30, Nikolay Izhikov <
> > >> > nizhikov@apache.org
> > >> > > >:
> > >> > > > > > >
> > >> > > > > > > > Hello, Igniters.
> > >> > > > > > > >
> > >> > > > > > > > I found that this feature can't be disabled from config.
> > >> > > > > > > > The only way to disable it is from JMX bean.
> > >> > > > > > > >
> > >> > > > > > > > I think it very dangerous: If we have some corner case
> or
> > a
> > >> bug
> > >> > > in
> > >> > > > > this
> > >> > > > > > > > Watch Dog it can make Ignite unusable.
> > >> > > > > > > > I propose to implement possibility to disable this
> feature
> > >> > both -
> > >> > > > > from
> > >> > > > > > > > config and from JVM options.
> > >> > > > > > > >
> > >> > > > > > > > What do you think?
> > >> > > > > > > >
> > >> > > > > > > > В Чт, 27/09/2018 в 16:14 +0300, Andrey Kuznetsov пишет:
> > >> > > > > > > > > Maxim,
> > >> > > > > > > > >
> > >> > > > > > > > > Thanks for being attentive! It's definitely a typo.
> > Could
> > >> you
> > >> > > > > please
> > >> > > > > > > >
> > >> > > > > > > > create
> > >> > > > > > > > > an issue?
> > >> > > > > > > > >
> > >> > > > > > > > > чт, 27 сент. 2018 г. в 16:00, Maxim Muzafarov <
> > >> > > > maxmuzaf@gmail.com
> > >> > > > > >:
> > >> > > > > > > > >
> > >> > > > > > > > > > Folks,
> > >> > > > > > > > > >
> > >> > > > > > > > > > I've found in
> `GridCachePartitionExchangeManager:2684`
> > >> [1]
> > >> > > > > (master
> > >> > > > > > > >
> > >> > > > > > > > branch)
> > >> > > > > > > > > > exchange future wrapped
> > >> > > > > > > > > > with double `blockingSectionEnd` method. Is it
> > correct?
> > >> I
> > >> > > just
> > >> > > > > want to
> > >> > > > > > > > > > understand this change and
> > >> > > > > > > > > > how should I use this in the future.
> > >> > > > > > > > > >
> > >> > > > > > > > > > Should I file a new issue to fix this? I think here
> > >> > > > > > > >
> > >> > > > > > > > `blockingSectionBegin`
> > >> > > > > > > > > > method should be used.
> > >> > > > > > > > > >
> > >> > > > > > > > > > -------------
> > >> > > > > > > > > > blockingSectionEnd();
> > >> > > > > > > > > >
> > >> > > > > > > > > > try {
> > >> > > > > > > > > > resVer = exchFut.get(exchTimeout,
> > >> > TimeUnit.MILLISECONDS);
> > >> > > > > > > > > > } finally {
> > >> > > > > > > > > > blockingSectionEnd();
> > >> > > > > > > > > > }
> > >> > > > > > > > > >
> > >> > > > > > > > > >
> > >> > > > > > > > > > [1]
> > >> > > > > > > > > >
> > >> > > > > > > > > >
> > >> > > > > > > >
> > >> > > > > > > >
> > >> > > > >
> > >> > > >
> > >> > >
> > >> >
> > >>
> >
> https://github.com/apache/ignite/blob/master/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/GridCachePartitionExchangeManager.java#L2684
> > >> > > > > > > > > >
> > >> > > > > > > > > > On Wed, 26 Sep 2018 at 22:47 Vyacheslav Daradur <
> > >> > > > > daradurvs@gmail.com>
> > >> > > > > > > > > > wrote:
> > >> > > > > > > > > >
> > >> > > > > > > > > > > Andrey Gura, thank you for the answer!
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > I agree that wrapping of 'init' method reduces the
> > >> profit
> > >> > > of
> > >> > > > > watchdog
> > >> > > > > > > > > > > service in case of PME worker, but in other cases,
> > we
> > >> > > should
> > >> > > > > wrap all
> > >> > > > > > > > > > > possible long sections on
> > >> GridDhtPartitionExchangeFuture.
> > >> > > For
> > >> > > > > example
> > >> > > > > > > > > > > 'onCacheChangeRequest' method or
> > >> > > > > > > > > > > 'cctx.affinity().onCacheChangeRequest' inside
> > because
> > >> it
> > >> > > may
> > >> > > > > take
> > >> > > > > > > > > > > significant time (reproducer attached).
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > I only want to point out a possible issue which
> may
> > >> allow
> > >> > > to
> > >> > > > > end-user
> > >> > > > > > > > > > > halt the Ignite cluster accidentally.
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > I'm sure that PME experts know how to fix this
> issue
> > >> > > > properly.
> > >> > > > > > > > > > > On Wed, Sep 26, 2018 at 10:28 PM Andrey Gura <
> > >> > > > agura@apache.org
> > >> > > > > >
> > >> > > > > > > >
> > >> > > > > > > > wrote:
> > >> > > > > > > > > > > >
> > >> > > > > > > > > > > > Vyacheslav,
> > >> > > > > > > > > > > >
> > >> > > > > > > > > > > > Exchange worker is strongly tied with
> > >> > > > > > > > > > > > GridDhtPartitionExchangeFuture#init and it is
> ok.
> > >> > > Exchange
> > >> > > > > worker
> > >> > > > > > > >
> > >> > > > > > > > also
> > >> > > > > > > > > > > > shouldn't be blocked for long time but in
> reality
> > it
> > >> > > > > happens.It
> > >> > > > > > > >
> > >> > > > > > > > also
> > >> > > > > > > > > > > > means that your change doesn't make sense.
> > >> > > > > > > > > > > >
> > >> > > > > > > > > > > > What actually make sense it is identification of
> > >> places
> > >> > > > which
> > >> > > > > > > > > > > > intentionally blocking. May be some
> places/actions
> > >> > should
> > >> > > > be
> > >> > > > > > > >
> > >> > > > > > > > braced by
> > >> > > > > > > > > > > > blocking guards.
> > >> > > > > > > > > > > >
> > >> > > > > > > > > > > > If you have failing tests please make sure that
> > your
> > >> > > > > > > >
> > >> > > > > > > > failureHandler is
> > >> > > > > > > > > > > > NoOpFailureHandler or any other handler with
> > >> > > > > ignoreFailureTypes =
> > >> > > > > > > > > > > > [CRITICAL_WORKER_BLOCKED].
> > >> > > > > > > > > > > >
> > >> > > > > > > > > > > >
> > >> > > > > > > > > > > > On Wed, Sep 26, 2018 at 9:43 PM Vyacheslav
> > Daradur <
> > >> > > > > > > > > >
> > >> > > > > > > > > > daradurvs@gmail.com>
> > >> > > > > > > > > > > wrote:
> > >> > > > > > > > > > > > >
> > >> > > > > > > > > > > > > Hi Igniters!
> > >> > > > > > > > > > > > >
> > >> > > > > > > > > > > > > Thank you for this important improvement!
> > >> > > > > > > > > > > > >
> > >> > > > > > > > > > > > > I've looked through implementation and noticed
> > >> that
> > >> > > > > > > > > > > > > GridDhtPartitionsExchangeFuture#init has not
> > been
> > >> > > wrapped
> > >> > > > > in
> > >> > > > > > > >
> > >> > > > > > > > blocked
> > >> > > > > > > > > > > > > section. This means it easy to halt the node
> in
> > >> case
> > >> > of
> > >> > > > > > > >
> > >> > > > > > > > longrunning
> > >> > > > > > > > > > > > > actions during PME, for example when we
> create a
> > >> > cache
> > >> > > > with
> > >> > > > > > > > > > > > > StoreFactrory which connect to 3rd party DB.
> > >> > > > > > > > > > > > >
> > >> > > > > > > > > > > > > I'm not sure that it is the right behavior.
> > >> > > > > > > > > > > > >
> > >> > > > > > > > > > > > > I filled the issue [1] and prepared the PR [2]
> > >> with
> > >> > > > > reproducer
> > >> > > > > > > >
> > >> > > > > > > > and
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > possible fix.
> > >> > > > > > > > > > > > >
> > >> > > > > > > > > > > > > Andrey, could you please look at and confirm
> > that
> > >> it
> > >> > > > makes
> > >> > > > > sense?
> > >> > > > > > > > > > > > >
> > >> > > > > > > > > > > > > [1]
> > >> > https://issues.apache.org/jira/browse/IGNITE-9710
> > >> > > > > > > > > > > > > [2]
> https://github.com/apache/ignite/pull/4845
> > >> > > > > > > > > > > > > On Mon, Sep 24, 2018 at 9:46 PM Andrey
> > Kuznetsov <
> > >> > > > > > > >
> > >> > > > > > > > stkuzma@gmail.com>
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > wrote:
> > >> > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > Denis,
> > >> > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > I've created the ticket [1] with short
> > >> description
> > >> > of
> > >> > > > the
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > functionality.
> > >> > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > [1]
> > >> > > https://issues.apache.org/jira/browse/IGNITE-9679
> > >> > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > пн, 24 сент. 2018 г. в 17:46, Denis Magda <
> > >> > > > > dmagda@apache.org>:
> > >> > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > Andrey K. and G.,
> > >> > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > Thanks, do we have a documentation ticket
> > >> > created?
> > >> > > > > Prachi
> > >> > > > > > > > > >
> > >> > > > > > > > > > (copied)
> > >> > > > > > > > > > > can help
> > >> > > > > > > > > > > > > > > with the documentation.
> > >> > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > --
> > >> > > > > > > > > > > > > > > Denis
> > >> > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > On Mon, Sep 24, 2018 at 5:51 AM Andrey
> Gura
> > <
> > >> > > > > > > >
> > >> > > > > > > > agura@apache.org>
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > wrote:
> > >> > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > Andrey,
> > >> > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > finally your change is merged to master
> > >> branch.
> > >> > > > > > > >
> > >> > > > > > > > Congratulations
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > and
> > >> > > > > > > > > > > > > > > > thank you very much! :)
> > >> > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > I think that the next step is feature
> that
> > >> will
> > >> > > > allow
> > >> > > > > > > >
> > >> > > > > > > > signal
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > about
> > >> > > > > > > > > > > > > > > > blocked threads to the monitoring tools
> > via
> > >> > > MXBean.
> > >> > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > I hope you will continue development of
> > this
> > >> > > > feature
> > >> > > > > and
> > >> > > > > > > > > >
> > >> > > > > > > > > > provide
> > >> > > > > > > > > > > your
> > >> > > > > > > > > > > > > > > > vision in new JIRA issue.
> > >> > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > On Tue, Sep 11, 2018 at 6:54 PM Andrey
> > >> > Kuznetsov
> > >> > > <
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > stkuzma@gmail.com>
> > >> > > > > > > > > > > > > > > > wrote:
> > >> > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > David, Maxim!
> > >> > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > Thanks a lot for you ideas.
> > >> Unfortunately, I
> > >> > > > can't
> > >> > > > > adopt
> > >> > > > > > > >
> > >> > > > > > > > all
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > of them
> > >> > > > > > > > > > > > > > > > right
> > >> > > > > > > > > > > > > > > > > now: the scope is much broader than
> the
> > >> scope
> > >> > > of
> > >> > > > > the
> > >> > > > > > > >
> > >> > > > > > > > change I
> > >> > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > implement.
> > >> > > > > > > > > > > > > > > > I
> > >> > > > > > > > > > > > > > > > > have had a talk to a group of Ignite
> > >> > commiters,
> > >> > > > > and we
> > >> > > > > > > >
> > >> > > > > > > > agreed
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > to
> > >> > > > > > > > > > > > > > > complete
> > >> > > > > > > > > > > > > > > > > the change as follows.
> > >> > > > > > > > > > > > > > > > > - Blocking instructions in
> > system-critical
> > >> > > which
> > >> > > > > may
> > >> > > > > > > > > >
> > >> > > > > > > > > > resonably
> > >> > > > > > > > > > > last
> > >> > > > > > > > > > > > > > > long
> > >> > > > > > > > > > > > > > > > > should be explicitly excluded from the
> > >> > > > monitoring.
> > >> > > > > > > > > > > > > > > > > - Failure handlers should have a
> setting
> > >> to
> > >> > > > > suppress some
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > failures on
> > >> > > > > > > > > > > > > > > > > per-failure-type basis.
> > >> > > > > > > > > > > > > > > > > According to this I have updated the
> > >> > > > > implementation: [1]
> > >> > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > [1]
> > >> > https://github.com/apache/ignite/pull/4089
> > >> > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > пн, 10 сент. 2018 г. в 22:35, David
> > >> Harvey <
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > syssoftsol@gmail.com>:
> > >> > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > > When I've done this before,I've
> needed
> > >> to
> > >> > > find
> > >> > > > > the
> > >> > > > > > > >
> > >> > > > > > > > oldest
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > thread,
> > >> > > > > > > > > > > > > > > and
> > >> > > > > > > > > > > > > > > > kill
> > >> > > > > > > > > > > > > > > > > > the node running that. From a
> > language
> > >> > > > > standpoint,
> > >> > > > > > > > > >
> > >> > > > > > > > > > Maxim's
> > >> > > > > > > > > > > "without
> > >> > > > > > > > > > > > > > > > > > progress" better than "heartbeat".
> > For
> > >> > > > > example, what
> > >> > > > > > > >
> > >> > > > > > > > I'm
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > most
> > >> > > > > > > > > > > > > > > > interested
> > >> > > > > > > > > > > > > > > > > > in on a distributed system is which
> > >> thread
> > >> > > > > started the
> > >> > > > > > > >
> > >> > > > > > > > work
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > it has
> > >> > > > > > > > > > > > > > > not
> > >> > > > > > > > > > > > > > > > > > completed the earliest, and when did
> > >> that
> > >> > > > thread
> > >> > > > > last
> > >> > > > > > > >
> > >> > > > > > > > make
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > forward
> > >> > > > > > > > > > > > > > > > > > process. You don't want to kill
> a
> > >> node
> > >> > > > > because a
> > >> > > > > > > >
> > >> > > > > > > > thread
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > is
> > >> > > > > > > > > > > > > > > waiting
> > >> > > > > > > > > > > > > > > > on a
> > >> > > > > > > > > > > > > > > > > > lock held by a thread that went
> > off-node
> > >> > and
> > >> > > > has
> > >> > > > > not
> > >> > > > > > > > > >
> > >> > > > > > > > > > gotten a
> > >> > > > > > > > > > > > > > > response.
> > >> > > > > > > > > > > > > > > > > > If you don't understand the
> dependency
> > >> > > > > relationships,
> > >> > > > > > > >
> > >> > > > > > > > you
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > will make
> > >> > > > > > > > > > > > > > > > > > incorrect recovery decisions.
> > >> > > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > > On Mon, Sep 10, 2018 at 4:08 AM
> Maxim
> > >> > > > Muzafarov <
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > maxmuzaf@gmail.com>
> > >> > > > > > > > > > > > > > > > > > wrote:
> > >> > > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > > > I think we should find exact
> answers
> > >> to
> > >> > > these
> > >> > > > > > > >
> > >> > > > > > > > questions:
> > >> > > > > > > > > > > > > > > > > > > 1. What `critical` issue exactly
> > is?
> > >> > > > > > > > > > > > > > > > > > > 2. How can we find critical
> issues?
> > >> > > > > > > > > > > > > > > > > > > 3. How can we handle critical
> > issues?
> > >> > > > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > > > First,
> > >> > > > > > > > > > > > > > > > > > > - Ignore uninterruptable actions
> > >> (e.g.
> > >> > > > > > > >
> > >> > > > > > > > worker\service
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > shutdown)
> > >> > > > > > > > > > > > > > > > > > > - Long I/O operations (should be
> a
> > >> > > > > configurable
> > >> > > > > > > >
> > >> > > > > > > > timeout
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > for each
> > >> > > > > > > > > > > > > > > > type of
> > >> > > > > > > > > > > > > > > > > > > usage)
> > >> > > > > > > > > > > > > > > > > > > - Infinite loops
> > >> > > > > > > > > > > > > > > > > > > - Stalled\deadlocked threads
> > (and\or
> > >> too
> > >> > > > many
> > >> > > > > parked
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > threads,
> > >> > > > > > > > > > > > > > > > exclude
> > >> > > > > > > > > > > > > > > > > > I/O)
> > >> > > > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > > > Second,
> > >> > > > > > > > > > > > > > > > > > > - The working queue is without
> > >> progress
> > >> > > > (e.g.
> > >> > > > > disco,
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > exchange
> > >> > > > > > > > > > > > > > > > queues)
> > >> > > > > > > > > > > > > > > > > > > - Work hasn't been completed
> since
> > >> the
> > >> > > last
> > >> > > > > > > >
> > >> > > > > > > > heartbeat
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > (checking
> > >> > > > > > > > > > > > > > > > > > > milestones)
> > >> > > > > > > > > > > > > > > > > > > - Too many system resources used
> > by a
> > >> > > thread
> > >> > > > > for the
> > >> > > > > > > > > >
> > >> > > > > > > > > > long
> > >> > > > > > > > > > > period
> > >> > > > > > > > > > > > > > > of
> > >> > > > > > > > > > > > > > > > time
> > >> > > > > > > > > > > > > > > > > > > (allocated memory, CPU)
> > >> > > > > > > > > > > > > > > > > > > - Timing fields associated with
> > each
> > >> > > thread
> > >> > > > > status
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > exceeded a
> > >> > > > > > > > > > > > > > > > maximum
> > >> > > > > > > > > > > > > > > > > > time
> > >> > > > > > > > > > > > > > > > > > > limit.
> > >> > > > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > > > Third (not too many options here),
> > >> > > > > > > > > > > > > > > > > > > - `log everything` should be the
> > >> default
> > >> > > > > behaviour
> > >> > > > > > > >
> > >> > > > > > > > in
> > >> > > > > > > > > >
> > >> > > > > > > > > > all
> > >> > > > > > > > > > > these
> > >> > > > > > > > > > > > > > > > cases,
> > >> > > > > > > > > > > > > > > > > > > since it may be difficult to find
> > the
> > >> > cause
> > >> > > > > after the
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > restart.
> > >> > > > > > > > > > > > > > > > > > > - Wait some interval of time and
> > kill
> > >> > the
> > >> > > > > hanging
> > >> > > > > > > >
> > >> > > > > > > > node
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > (cluster
> > >> > > > > > > > > > > > > > > > should
> > >> > > > > > > > > > > > > > > > > > be
> > >> > > > > > > > > > > > > > > > > > > configured stable enough)
> > >> > > > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > > > Questions,
> > >> > > > > > > > > > > > > > > > > > > - Not sure, but can workers miss
> > >> their
> > >> > > > > heartbeat
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > deadlines if CPU
> > >> > > > > > > > > > > > > > > > loads
> > >> > > > > > > > > > > > > > > > > > up
> > >> > > > > > > > > > > > > > > > > > > to 80%-90%? Bursts of momentary
> > >> overloads
> > >> > > can
> > >> > > > > be
> > >> > > > > > > > > > > > > > > > > > > expected behaviour as a normal
> > >> part
> > >> > of
> > >> > > > > system
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > operations.
> > >> > > > > > > > > > > > > > > > > > > - Why do we decide that critical
> > >> thread
> > >> > > > should
> > >> > > > > > > >
> > >> > > > > > > > monitor
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > each other?
> > >> > > > > > > > > > > > > > > > For
> > >> > > > > > > > > > > > > > > > > > > instance, if all the tasks were
> > >> blocked
> > >> > and
> > >> > > > > unable to
> > >> > > > > > > > > >
> > >> > > > > > > > > > run,
> > >> > > > > > > > > > > > > > > > > > > node reset would never occur.
> As
> > >> for
> > >> > > me,
> > >> > > > a
> > >> > > > > better
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > solution is
> > >> > > > > > > > > > > > > > > to
> > >> > > > > > > > > > > > > > > > use
> > >> > > > > > > > > > > > > > > > > > a
> > >> > > > > > > > > > > > > > > > > > > separate monitor thread or pool
> > (maybe
> > >> > both
> > >> > > > > with
> > >> > > > > > > >
> > >> > > > > > > > software
> > >> > > > > > > > > > > > > > > > > > > and hardware checks) that not
> > only
> > >> > > checks
> > >> > > > > > > >
> > >> > > > > > > > heartbeats
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > but
> > >> > > > > > > > > > > > > > > > monitors the
> > >> > > > > > > > > > > > > > > > > > > other system as well.
> > >> > > > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > > > On Mon, 10 Sep 2018 at 00:07 David
> > >> > Harvey <
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > syssoftsol@gmail.com>
> > >> > > > > > > > > > > > > > > > wrote:
> > >> > > > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > > > > It would be safer to restart the
> > >> entire
> > >> > > > > cluster
> > >> > > > > > > >
> > >> > > > > > > > than to
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > remove
> > >> > > > > > > > > > > > > > > the
> > >> > > > > > > > > > > > > > > > last
> > >> > > > > > > > > > > > > > > > > > > > node for a cache that should be
> > >> > > redundant.
> > >> > > > > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > > > > On Sun, Sep 9, 2018, 4:00 PM
> > Andrey
> > >> > Gura
> > >> > > <
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > agura@apache.org>
> > >> > > > > > > > > > > > > > > wrote:
> > >> > > > > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > > > > > Hi,
> > >> > > > > > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > > > > > I agree with Yakov that we can
> > >> > provide
> > >> > > > some
> > >> > > > > > > >
> > >> > > > > > > > option
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > that manage
> > >> > > > > > > > > > > > > > > > worker
> > >> > > > > > > > > > > > > > > > > > > > > liveness checker behavior in
> > case
> > >> of
> > >> > > > > observing
> > >> > > > > > > >
> > >> > > > > > > > that
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > some worker
> > >> > > > > > > > > > > > > > > > is
> > >> > > > > > > > > > > > > > > > > > > > > blocked too long.
> > >> > > > > > > > > > > > > > > > > > > > > At least it will some
> > workaround
> > >> for
> > >> > > > > cases when
> > >> > > > > > > >
> > >> > > > > > > > node
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > fails is
> > >> > > > > > > > > > > > > > > > too
> > >> > > > > > > > > > > > > > > > > > > > > annoying.
> > >> > > > > > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > > > > > Backups count threshold sounds
> > >> good
> > >> > > but I
> > >> > > > > don't
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > understand how
> > >> > > > > > > > > > > > > > > it
> > >> > > > > > > > > > > > > > > > > > will
> > >> > > > > > > > > > > > > > > > > > > > > help in case of cluster
> hanging.
> > >> > > > > > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > > > > > The simplest solution here is
> > >> alert
> > >> > in
> > >> > > > > cases of
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > blocking of
> > >> > > > > > > > > > > > > > > some
> > >> > > > > > > > > > > > > > > > > > > > > critical worker (we can
> improve
> > >> > > > > WorkersRegistry
> > >> > > > > > > >
> > >> > > > > > > > for
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > this
> > >> > > > > > > > > > > > > > > purpose
> > >> > > > > > > > > > > > > > > > and
> > >> > > > > > > > > > > > > > > > > > > > > expose list of blocked
> workers)
> > >> and
> > >> > > > > optionally
> > >> > > > > > > >
> > >> > > > > > > > call
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > system
> > >> > > > > > > > > > > > > > > > configured
> > >> > > > > > > > > > > > > > > > > > > > > failure processor. BTW,
> failure
> > >> > > processor
> > >> > > > > can be
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > extended in
> > >> > > > > > > > > > > > > > > > order to
> > >> > > > > > > > > > > > > > > > > > > > > perform any checks (e.g.
> backup
> > >> > count)
> > >> > > > and
> > >> > > > > decide
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > whether it
> > >> > > > > > > > > > > > > > > > should
> > >> > > > > > > > > > > > > > > > > > > > > stop node or not.
> > >> > > > > > > > > > > > > > > > > > > > > On Sat, Sep 8, 2018 at 3:42 PM
> > >> Andrey
> > >> > > > > Kuznetsov <
> > >> > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > stkuzma@gmail.com>
> > >> > > > > > > > > > > > > > > > > > > > wrote:
> > >> > > > > > > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > > > > > > David, Yakov, I understand
> > your
> > >> > > fears.
> > >> > > > > But
> > >> > > > > > > >
> > >> > > > > > > > liveness
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > checks
> > >> > > > > > > > > > > > > > > deal
> > >> > > > > > > > > > > > > > > > > > with
> > >> > > > > > > > > > > > > > > > > > > > > > _critical_ conditions, i.e.
> > when
> > >> > > such a
> > >> > > > > > > >
> > >> > > > > > > > condition
> > >> > > > > > > > > >
> > >> > > > > > > > > > is
> > >> > > > > > > > > > > met we
> > >> > > > > > > > > > > > > > > > > > conclude
> > >> > > > > > > > > > > > > > > > > > > > the
> > >> > > > > > > > > > > > > > > > > > > > > > node as totally broken, and
> > >> there
> > >> > is
> > >> > > no
> > >> > > > > sense
> > >> > > > > > > >
> > >> > > > > > > > to
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > keep it
> > >> > > > > > > > > > > > > > > alive
> > >> > > > > > > > > > > > > > > > > > > > regardless
> > >> > > > > > > > > > > > > > > > > > > > > > the data it contains. If we
> > >> want to
> > >> > > > give
> > >> > > > > it a
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > chance, then
> > >> > > > > > > > > > > > > > > the
> > >> > > > > > > > > > > > > > > > > > > > condition
> > >> > > > > > > > > > > > > > > > > > > > > > (long fsync etc.) should not
> > >> > > considered
> > >> > > > > as
> > >> > > > > > > >
> > >> > > > > > > > critical
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > at all.
> > >> > > > > > > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > > > > > > сб, 8 сент. 2018 г. в 15:18,
> > >> Yakov
> > >> > > > > Zhdanov <
> > >> > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > yzhdanov@apache.org>:
> > >> > > > > > > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > > > > > > > Agree with David. We need
> to
> > >> have
> > >> > > an
> > >> > > > > > > >
> > >> > > > > > > > opporunity
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > set backups
> > >> > > > > > > > > > > > > > > > count
> > >> > > > > > > > > > > > > > > > > > > > > threshold
> > >> > > > > > > > > > > > > > > > > > > > > > > (at runtime also!) that
> will
> > >> not
> > >> > > > allow
> > >> > > > > any
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > automatic stop
> > >> > > > > > > > > > > > > > > if
> > >> > > > > > > > > > > > > > > > > > there
> > >> > > > > > > > > > > > > > > > > > > > > will be
> > >> > > > > > > > > > > > > > > > > > > > > > > a data loss. Andrey, what
> do
> > >> you
> > >> > > > think?
> > >> > > > > > > > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > > > > > > > --Yakov
> > >> > > > > > > > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > > > > > > --
> > >> > > > > > > > > > > > > > > > > > > > > > Best regards,
> > >> > > > > > > > > > > > > > > > > > > > > > Andrey Kuznetsov.
> > >> > > > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > > > --
> > >> > > > > > > > > > > > > > > > > > > --
> > >> > > > > > > > > > > > > > > > > > > Maxim Muzafarov
> > >> > > > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > > > > --
> > >> > > > > > > > > > > > > > > > > Best regards,
> > >> > > > > > > > > > > > > > > > > Andrey Kuznetsov.
> > >> > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > >
> > >> > > > > > > > > > > > > > --
> > >> > > > > > > > > > > > > > Best regards,
> > >> > > > > > > > > > > > > > Andrey Kuznetsov.
> > >> > > > > > > > > > > > >
> > >> > > > > > > > > > > > >
> > >> > > > > > > > > > > > >
> > >> > > > > > > > > > > > > --
> > >> > > > > > > > > > > > > Best Regards, Vyacheslav D.
> > >> > > > > > > > > > >
> > >> > > > > > > > > > >
> > >> > > > > > > > > > >
> > >> > > > > > > > > > > --
> > >> > > > > > > > > > > Best Regards, Vyacheslav D.
> > >> > > > > > > > > > >
> > >> > > > > > > > > >
> > >> > > > > > > > > > --
> > >> > > > > > > > > > --
> > >> > > > > > > > > > Maxim Muzafarov
> > >> > > > > > > > > >
> > >> > > > > > > > >
> > >> > > > > > > > >
> > >> > > > >
> > >> > > >
> > >> > >
> > >> > --
> > >> > --
> > >> > Maxim Muzafarov
> > >> >
> > >>
> > >>
> > >> --
> > >> Best regards,
> > >> Andrey Kuznetsov.
> > >>
> > >
> >
>
Re: Critical worker threads liveness checking drawbacks
Posted by Nikolay Izhikov <ni...@apache.org>.
Hello, Alexey.
No, we don't include this ticket to 2.7.
Should we?
ср, 19 дек. 2018 г. в 12:55, Alexey Goncharuk <al...@gmail.com>:
> Folks, why did not we include IGNITE-10003 to ignite-2.7 release scope?
> This causes an Ignite node to be stopped by default when checkpoint read
> lock acquire times out. I expect a lot of Ignite 2.7 users will be affected
> by this mistake.
>
> We should at least update the documentation and make users aware of a
> workaround.
>
> чт, 25 окт. 2018 г. в 16:35, Alexey Goncharuk <alexey.goncharuk@gmail.com
> >:
>
> > Andrey,
> >
> > I still see that checkpoint read lock acquisition raises a
> CRITICAL_ERROR,
> > which by default will shut down local node. As far as I remember, we
> > decided that by default thread timeout should not trigger node failure.
> > Now, however, it does, because we ignore SYSTEM_WORKER_BLOCKED events in
> > default configuration.
> >
> > Should we introduce another critical failure type
> > CHECKPOINT_READ_LOCK_BLOCKED or use SYSTEM_WORKER_BLOCKED for checkpoint
> > read lock acquire failure?
> >
> > --AG
> >
> > пт, 12 окт. 2018 г. в 8:29, Andrey Kuznetsov <st...@gmail.com>:
> >
> >> Igniters,
> >>
> >> Now I spot blocking / long-running code arising from
> >> {{GridDhtPartitionsExchangeFuture#init}} calls in partition-exchanger
> >> thread, see [1]. Ideally, all blocking operations along all possible
> code
> >> paths should be guarded implicitly from critical failure detector to
> avoid
> >> the thread from being considered blocked. There is a pull request [2]
> that
> >> provides shallow solution. I didn't change code outside
> >> {{GridDhtPartitionsExchangeFuture}}, otherwise it could be broken by any
> >> upcoming change. Also, I didn't touch the code runnable by threads other
> >> than partition-exchanger. So I have a number of guarded sections that
> are
> >> wider than they could be, and this potentially hides issues from failure
> >> detector. Does this PR make sense? Or maybe it's better to exclude
> >> partition-exchanger from critical threads registry at all?
> >>
> >> [1] https://issues.apache.org/jira/browse/IGNITE-9710
> >> [2] https://github.com/apache/ignite/pull/4962
> >>
> >>
> >> пт, 28 сент. 2018 г. в 18:56, Maxim Muzafarov <ma...@gmail.com>:
> >>
> >> > Andrey, Andrey
> >> >
> >> > > Thanks for being attentive! It's definitely a typo. Could you please
> >> > create
> >> > > an issue?
> >> >
> >> > I've created an issue [1] and prepared PR [2].
> >> > Please, review this change.
> >> >
> >> > [1] https://issues.apache.org/jira/browse/IGNITE-9723
> >> > [2] https://github.com/apache/ignite/pull/4862
> >> >
> >> > On Fri, 28 Sep 2018 at 16:58 Yakov Zhdanov <yz...@apache.org>
> wrote:
> >> >
> >> > > Config option + mbean access. Does that make sense?
> >> > >
> >> > > Yakov
> >> > >
> >> > > On Fri, Sep 28, 2018, 17:17 Vladimir Ozerov <vo...@gridgain.com>
> >> > wrote:
> >> > >
> >> > > > Then it should be config option.
> >> > > >
> >> > > > пт, 28 сент. 2018 г. в 13:15, Andrey Gura <ag...@apache.org>:
> >> > > >
> >> > > > > Guys,
> >> > > > >
> >> > > > > why we need both config option and system property? I believe
> one
> >> way
> >> > > is
> >> > > > > enough.
> >> > > > > On Fri, Sep 28, 2018 at 12:38 PM Nikolay Izhikov <
> >> > nizhikov@apache.org>
> >> > > > > wrote:
> >> > > > > >
> >> > > > > > Ticket created -
> >> https://issues.apache.org/jira/browse/IGNITE-9737
> >> > > > > >
> >> > > > > > Fixed version is 2.7.
> >> > > > > >
> >> > > > > > В Пт, 28/09/2018 в 11:41 +0300, Alexey Goncharuk пишет:
> >> > > > > > > Nikolay, I agree, a user should be able to disable both
> thread
> >> > > > liveness
> >> > > > > > > check and checkpoint read lock timeout check from config
> and a
> >> > > system
> >> > > > > > > property.
> >> > > > > > >
> >> > > > > > > пт, 28 сент. 2018 г. в 11:30, Nikolay Izhikov <
> >> > nizhikov@apache.org
> >> > > >:
> >> > > > > > >
> >> > > > > > > > Hello, Igniters.
> >> > > > > > > >
> >> > > > > > > > I found that this feature can't be disabled from config.
> >> > > > > > > > The only way to disable it is from JMX bean.
> >> > > > > > > >
> >> > > > > > > > I think it very dangerous: If we have some corner case or
> a
> >> bug
> >> > > in
> >> > > > > this
> >> > > > > > > > Watch Dog it can make Ignite unusable.
> >> > > > > > > > I propose to implement possibility to disable this feature
> >> > both -
> >> > > > > from
> >> > > > > > > > config and from JVM options.
> >> > > > > > > >
> >> > > > > > > > What do you think?
> >> > > > > > > >
> >> > > > > > > > В Чт, 27/09/2018 в 16:14 +0300, Andrey Kuznetsov пишет:
> >> > > > > > > > > Maxim,
> >> > > > > > > > >
> >> > > > > > > > > Thanks for being attentive! It's definitely a typo.
> Could
> >> you
> >> > > > > please
> >> > > > > > > >
> >> > > > > > > > create
> >> > > > > > > > > an issue?
> >> > > > > > > > >
> >> > > > > > > > > чт, 27 сент. 2018 г. в 16:00, Maxim Muzafarov <
> >> > > > maxmuzaf@gmail.com
> >> > > > > >:
> >> > > > > > > > >
> >> > > > > > > > > > Folks,
> >> > > > > > > > > >
> >> > > > > > > > > > I've found in `GridCachePartitionExchangeManager:2684`
> >> [1]
> >> > > > > (master
> >> > > > > > > >
> >> > > > > > > > branch)
> >> > > > > > > > > > exchange future wrapped
> >> > > > > > > > > > with double `blockingSectionEnd` method. Is it
> correct?
> >> I
> >> > > just
> >> > > > > want to
> >> > > > > > > > > > understand this change and
> >> > > > > > > > > > how should I use this in the future.
> >> > > > > > > > > >
> >> > > > > > > > > > Should I file a new issue to fix this? I think here
> >> > > > > > > >
> >> > > > > > > > `blockingSectionBegin`
> >> > > > > > > > > > method should be used.
> >> > > > > > > > > >
> >> > > > > > > > > > -------------
> >> > > > > > > > > > blockingSectionEnd();
> >> > > > > > > > > >
> >> > > > > > > > > > try {
> >> > > > > > > > > > resVer = exchFut.get(exchTimeout,
> >> > TimeUnit.MILLISECONDS);
> >> > > > > > > > > > } finally {
> >> > > > > > > > > > blockingSectionEnd();
> >> > > > > > > > > > }
> >> > > > > > > > > >
> >> > > > > > > > > >
> >> > > > > > > > > > [1]
> >> > > > > > > > > >
> >> > > > > > > > > >
> >> > > > > > > >
> >> > > > > > > >
> >> > > > >
> >> > > >
> >> > >
> >> >
> >>
> https://github.com/apache/ignite/blob/master/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/GridCachePartitionExchangeManager.java#L2684
> >> > > > > > > > > >
> >> > > > > > > > > > On Wed, 26 Sep 2018 at 22:47 Vyacheslav Daradur <
> >> > > > > daradurvs@gmail.com>
> >> > > > > > > > > > wrote:
> >> > > > > > > > > >
> >> > > > > > > > > > > Andrey Gura, thank you for the answer!
> >> > > > > > > > > > >
> >> > > > > > > > > > > I agree that wrapping of 'init' method reduces the
> >> profit
> >> > > of
> >> > > > > watchdog
> >> > > > > > > > > > > service in case of PME worker, but in other cases,
> we
> >> > > should
> >> > > > > wrap all
> >> > > > > > > > > > > possible long sections on
> >> GridDhtPartitionExchangeFuture.
> >> > > For
> >> > > > > example
> >> > > > > > > > > > > 'onCacheChangeRequest' method or
> >> > > > > > > > > > > 'cctx.affinity().onCacheChangeRequest' inside
> because
> >> it
> >> > > may
> >> > > > > take
> >> > > > > > > > > > > significant time (reproducer attached).
> >> > > > > > > > > > >
> >> > > > > > > > > > > I only want to point out a possible issue which may
> >> allow
> >> > > to
> >> > > > > end-user
> >> > > > > > > > > > > halt the Ignite cluster accidentally.
> >> > > > > > > > > > >
> >> > > > > > > > > > > I'm sure that PME experts know how to fix this issue
> >> > > > properly.
> >> > > > > > > > > > > On Wed, Sep 26, 2018 at 10:28 PM Andrey Gura <
> >> > > > agura@apache.org
> >> > > > > >
> >> > > > > > > >
> >> > > > > > > > wrote:
> >> > > > > > > > > > > >
> >> > > > > > > > > > > > Vyacheslav,
> >> > > > > > > > > > > >
> >> > > > > > > > > > > > Exchange worker is strongly tied with
> >> > > > > > > > > > > > GridDhtPartitionExchangeFuture#init and it is ok.
> >> > > Exchange
> >> > > > > worker
> >> > > > > > > >
> >> > > > > > > > also
> >> > > > > > > > > > > > shouldn't be blocked for long time but in reality
> it
> >> > > > > happens.It
> >> > > > > > > >
> >> > > > > > > > also
> >> > > > > > > > > > > > means that your change doesn't make sense.
> >> > > > > > > > > > > >
> >> > > > > > > > > > > > What actually make sense it is identification of
> >> places
> >> > > > which
> >> > > > > > > > > > > > intentionally blocking. May be some places/actions
> >> > should
> >> > > > be
> >> > > > > > > >
> >> > > > > > > > braced by
> >> > > > > > > > > > > > blocking guards.
> >> > > > > > > > > > > >
> >> > > > > > > > > > > > If you have failing tests please make sure that
> your
> >> > > > > > > >
> >> > > > > > > > failureHandler is
> >> > > > > > > > > > > > NoOpFailureHandler or any other handler with
> >> > > > > ignoreFailureTypes =
> >> > > > > > > > > > > > [CRITICAL_WORKER_BLOCKED].
> >> > > > > > > > > > > >
> >> > > > > > > > > > > >
> >> > > > > > > > > > > > On Wed, Sep 26, 2018 at 9:43 PM Vyacheslav
> Daradur <
> >> > > > > > > > > >
> >> > > > > > > > > > daradurvs@gmail.com>
> >> > > > > > > > > > > wrote:
> >> > > > > > > > > > > > >
> >> > > > > > > > > > > > > Hi Igniters!
> >> > > > > > > > > > > > >
> >> > > > > > > > > > > > > Thank you for this important improvement!
> >> > > > > > > > > > > > >
> >> > > > > > > > > > > > > I've looked through implementation and noticed
> >> that
> >> > > > > > > > > > > > > GridDhtPartitionsExchangeFuture#init has not
> been
> >> > > wrapped
> >> > > > > in
> >> > > > > > > >
> >> > > > > > > > blocked
> >> > > > > > > > > > > > > section. This means it easy to halt the node in
> >> case
> >> > of
> >> > > > > > > >
> >> > > > > > > > longrunning
> >> > > > > > > > > > > > > actions during PME, for example when we create a
> >> > cache
> >> > > > with
> >> > > > > > > > > > > > > StoreFactrory which connect to 3rd party DB.
> >> > > > > > > > > > > > >
> >> > > > > > > > > > > > > I'm not sure that it is the right behavior.
> >> > > > > > > > > > > > >
> >> > > > > > > > > > > > > I filled the issue [1] and prepared the PR [2]
> >> with
> >> > > > > reproducer
> >> > > > > > > >
> >> > > > > > > > and
> >> > > > > > > > > > >
> >> > > > > > > > > > > possible fix.
> >> > > > > > > > > > > > >
> >> > > > > > > > > > > > > Andrey, could you please look at and confirm
> that
> >> it
> >> > > > makes
> >> > > > > sense?
> >> > > > > > > > > > > > >
> >> > > > > > > > > > > > > [1]
> >> > https://issues.apache.org/jira/browse/IGNITE-9710
> >> > > > > > > > > > > > > [2] https://github.com/apache/ignite/pull/4845
> >> > > > > > > > > > > > > On Mon, Sep 24, 2018 at 9:46 PM Andrey
> Kuznetsov <
> >> > > > > > > >
> >> > > > > > > > stkuzma@gmail.com>
> >> > > > > > > > > > >
> >> > > > > > > > > > > wrote:
> >> > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > Denis,
> >> > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > I've created the ticket [1] with short
> >> description
> >> > of
> >> > > > the
> >> > > > > > > > > > >
> >> > > > > > > > > > > functionality.
> >> > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > [1]
> >> > > https://issues.apache.org/jira/browse/IGNITE-9679
> >> > > > > > > > > > > > > >
> >> > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > пн, 24 сент. 2018 г. в 17:46, Denis Magda <
> >> > > > > dmagda@apache.org>:
> >> > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > Andrey K. and G.,
> >> > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > Thanks, do we have a documentation ticket
> >> > created?
> >> > > > > Prachi
> >> > > > > > > > > >
> >> > > > > > > > > > (copied)
> >> > > > > > > > > > > can help
> >> > > > > > > > > > > > > > > with the documentation.
> >> > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > --
> >> > > > > > > > > > > > > > > Denis
> >> > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > On Mon, Sep 24, 2018 at 5:51 AM Andrey Gura
> <
> >> > > > > > > >
> >> > > > > > > > agura@apache.org>
> >> > > > > > > > > > >
> >> > > > > > > > > > > wrote:
> >> > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > Andrey,
> >> > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > finally your change is merged to master
> >> branch.
> >> > > > > > > >
> >> > > > > > > > Congratulations
> >> > > > > > > > > > >
> >> > > > > > > > > > > and
> >> > > > > > > > > > > > > > > > thank you very much! :)
> >> > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > I think that the next step is feature that
> >> will
> >> > > > allow
> >> > > > > > > >
> >> > > > > > > > signal
> >> > > > > > > > > > >
> >> > > > > > > > > > > about
> >> > > > > > > > > > > > > > > > blocked threads to the monitoring tools
> via
> >> > > MXBean.
> >> > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > I hope you will continue development of
> this
> >> > > > feature
> >> > > > > and
> >> > > > > > > > > >
> >> > > > > > > > > > provide
> >> > > > > > > > > > > your
> >> > > > > > > > > > > > > > > > vision in new JIRA issue.
> >> > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > On Tue, Sep 11, 2018 at 6:54 PM Andrey
> >> > Kuznetsov
> >> > > <
> >> > > > > > > > > > >
> >> > > > > > > > > > > stkuzma@gmail.com>
> >> > > > > > > > > > > > > > > > wrote:
> >> > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > David, Maxim!
> >> > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > Thanks a lot for you ideas.
> >> Unfortunately, I
> >> > > > can't
> >> > > > > adopt
> >> > > > > > > >
> >> > > > > > > > all
> >> > > > > > > > > > >
> >> > > > > > > > > > > of them
> >> > > > > > > > > > > > > > > > right
> >> > > > > > > > > > > > > > > > > now: the scope is much broader than the
> >> scope
> >> > > of
> >> > > > > the
> >> > > > > > > >
> >> > > > > > > > change I
> >> > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > implement.
> >> > > > > > > > > > > > > > > > I
> >> > > > > > > > > > > > > > > > > have had a talk to a group of Ignite
> >> > commiters,
> >> > > > > and we
> >> > > > > > > >
> >> > > > > > > > agreed
> >> > > > > > > > > > >
> >> > > > > > > > > > > to
> >> > > > > > > > > > > > > > > complete
> >> > > > > > > > > > > > > > > > > the change as follows.
> >> > > > > > > > > > > > > > > > > - Blocking instructions in
> system-critical
> >> > > which
> >> > > > > may
> >> > > > > > > > > >
> >> > > > > > > > > > resonably
> >> > > > > > > > > > > last
> >> > > > > > > > > > > > > > > long
> >> > > > > > > > > > > > > > > > > should be explicitly excluded from the
> >> > > > monitoring.
> >> > > > > > > > > > > > > > > > > - Failure handlers should have a setting
> >> to
> >> > > > > suppress some
> >> > > > > > > > > > >
> >> > > > > > > > > > > failures on
> >> > > > > > > > > > > > > > > > > per-failure-type basis.
> >> > > > > > > > > > > > > > > > > According to this I have updated the
> >> > > > > implementation: [1]
> >> > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > [1]
> >> > https://github.com/apache/ignite/pull/4089
> >> > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > пн, 10 сент. 2018 г. в 22:35, David
> >> Harvey <
> >> > > > > > > > > > >
> >> > > > > > > > > > > syssoftsol@gmail.com>:
> >> > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > > When I've done this before,I've needed
> >> to
> >> > > find
> >> > > > > the
> >> > > > > > > >
> >> > > > > > > > oldest
> >> > > > > > > > > > >
> >> > > > > > > > > > > thread,
> >> > > > > > > > > > > > > > > and
> >> > > > > > > > > > > > > > > > kill
> >> > > > > > > > > > > > > > > > > > the node running that. From a
> language
> >> > > > > standpoint,
> >> > > > > > > > > >
> >> > > > > > > > > > Maxim's
> >> > > > > > > > > > > "without
> >> > > > > > > > > > > > > > > > > > progress" better than "heartbeat".
> For
> >> > > > > example, what
> >> > > > > > > >
> >> > > > > > > > I'm
> >> > > > > > > > > > >
> >> > > > > > > > > > > most
> >> > > > > > > > > > > > > > > > interested
> >> > > > > > > > > > > > > > > > > > in on a distributed system is which
> >> thread
> >> > > > > started the
> >> > > > > > > >
> >> > > > > > > > work
> >> > > > > > > > > > >
> >> > > > > > > > > > > it has
> >> > > > > > > > > > > > > > > not
> >> > > > > > > > > > > > > > > > > > completed the earliest, and when did
> >> that
> >> > > > thread
> >> > > > > last
> >> > > > > > > >
> >> > > > > > > > make
> >> > > > > > > > > > >
> >> > > > > > > > > > > forward
> >> > > > > > > > > > > > > > > > > > process. You don't want to kill a
> >> node
> >> > > > > because a
> >> > > > > > > >
> >> > > > > > > > thread
> >> > > > > > > > > > >
> >> > > > > > > > > > > is
> >> > > > > > > > > > > > > > > waiting
> >> > > > > > > > > > > > > > > > on a
> >> > > > > > > > > > > > > > > > > > lock held by a thread that went
> off-node
> >> > and
> >> > > > has
> >> > > > > not
> >> > > > > > > > > >
> >> > > > > > > > > > gotten a
> >> > > > > > > > > > > > > > > response.
> >> > > > > > > > > > > > > > > > > > If you don't understand the dependency
> >> > > > > relationships,
> >> > > > > > > >
> >> > > > > > > > you
> >> > > > > > > > > > >
> >> > > > > > > > > > > will make
> >> > > > > > > > > > > > > > > > > > incorrect recovery decisions.
> >> > > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > > On Mon, Sep 10, 2018 at 4:08 AM Maxim
> >> > > > Muzafarov <
> >> > > > > > > > > > >
> >> > > > > > > > > > > maxmuzaf@gmail.com>
> >> > > > > > > > > > > > > > > > > > wrote:
> >> > > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > > > I think we should find exact answers
> >> to
> >> > > these
> >> > > > > > > >
> >> > > > > > > > questions:
> >> > > > > > > > > > > > > > > > > > > 1. What `critical` issue exactly
> is?
> >> > > > > > > > > > > > > > > > > > > 2. How can we find critical issues?
> >> > > > > > > > > > > > > > > > > > > 3. How can we handle critical
> issues?
> >> > > > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > > > First,
> >> > > > > > > > > > > > > > > > > > > - Ignore uninterruptable actions
> >> (e.g.
> >> > > > > > > >
> >> > > > > > > > worker\service
> >> > > > > > > > > > >
> >> > > > > > > > > > > shutdown)
> >> > > > > > > > > > > > > > > > > > > - Long I/O operations (should be a
> >> > > > > configurable
> >> > > > > > > >
> >> > > > > > > > timeout
> >> > > > > > > > > > >
> >> > > > > > > > > > > for each
> >> > > > > > > > > > > > > > > > type of
> >> > > > > > > > > > > > > > > > > > > usage)
> >> > > > > > > > > > > > > > > > > > > - Infinite loops
> >> > > > > > > > > > > > > > > > > > > - Stalled\deadlocked threads
> (and\or
> >> too
> >> > > > many
> >> > > > > parked
> >> > > > > > > > > > >
> >> > > > > > > > > > > threads,
> >> > > > > > > > > > > > > > > > exclude
> >> > > > > > > > > > > > > > > > > > I/O)
> >> > > > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > > > Second,
> >> > > > > > > > > > > > > > > > > > > - The working queue is without
> >> progress
> >> > > > (e.g.
> >> > > > > disco,
> >> > > > > > > > > > >
> >> > > > > > > > > > > exchange
> >> > > > > > > > > > > > > > > > queues)
> >> > > > > > > > > > > > > > > > > > > - Work hasn't been completed since
> >> the
> >> > > last
> >> > > > > > > >
> >> > > > > > > > heartbeat
> >> > > > > > > > > > >
> >> > > > > > > > > > > (checking
> >> > > > > > > > > > > > > > > > > > > milestones)
> >> > > > > > > > > > > > > > > > > > > - Too many system resources used
> by a
> >> > > thread
> >> > > > > for the
> >> > > > > > > > > >
> >> > > > > > > > > > long
> >> > > > > > > > > > > period
> >> > > > > > > > > > > > > > > of
> >> > > > > > > > > > > > > > > > time
> >> > > > > > > > > > > > > > > > > > > (allocated memory, CPU)
> >> > > > > > > > > > > > > > > > > > > - Timing fields associated with
> each
> >> > > thread
> >> > > > > status
> >> > > > > > > > > > >
> >> > > > > > > > > > > exceeded a
> >> > > > > > > > > > > > > > > > maximum
> >> > > > > > > > > > > > > > > > > > time
> >> > > > > > > > > > > > > > > > > > > limit.
> >> > > > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > > > Third (not too many options here),
> >> > > > > > > > > > > > > > > > > > > - `log everything` should be the
> >> default
> >> > > > > behaviour
> >> > > > > > > >
> >> > > > > > > > in
> >> > > > > > > > > >
> >> > > > > > > > > > all
> >> > > > > > > > > > > these
> >> > > > > > > > > > > > > > > > cases,
> >> > > > > > > > > > > > > > > > > > > since it may be difficult to find
> the
> >> > cause
> >> > > > > after the
> >> > > > > > > > > > >
> >> > > > > > > > > > > restart.
> >> > > > > > > > > > > > > > > > > > > - Wait some interval of time and
> kill
> >> > the
> >> > > > > hanging
> >> > > > > > > >
> >> > > > > > > > node
> >> > > > > > > > > > >
> >> > > > > > > > > > > (cluster
> >> > > > > > > > > > > > > > > > should
> >> > > > > > > > > > > > > > > > > > be
> >> > > > > > > > > > > > > > > > > > > configured stable enough)
> >> > > > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > > > Questions,
> >> > > > > > > > > > > > > > > > > > > - Not sure, but can workers miss
> >> their
> >> > > > > heartbeat
> >> > > > > > > > > > >
> >> > > > > > > > > > > deadlines if CPU
> >> > > > > > > > > > > > > > > > loads
> >> > > > > > > > > > > > > > > > > > up
> >> > > > > > > > > > > > > > > > > > > to 80%-90%? Bursts of momentary
> >> overloads
> >> > > can
> >> > > > > be
> >> > > > > > > > > > > > > > > > > > > expected behaviour as a normal
> >> part
> >> > of
> >> > > > > system
> >> > > > > > > > > > >
> >> > > > > > > > > > > operations.
> >> > > > > > > > > > > > > > > > > > > - Why do we decide that critical
> >> thread
> >> > > > should
> >> > > > > > > >
> >> > > > > > > > monitor
> >> > > > > > > > > > >
> >> > > > > > > > > > > each other?
> >> > > > > > > > > > > > > > > > For
> >> > > > > > > > > > > > > > > > > > > instance, if all the tasks were
> >> blocked
> >> > and
> >> > > > > unable to
> >> > > > > > > > > >
> >> > > > > > > > > > run,
> >> > > > > > > > > > > > > > > > > > > node reset would never occur. As
> >> for
> >> > > me,
> >> > > > a
> >> > > > > better
> >> > > > > > > > > > >
> >> > > > > > > > > > > solution is
> >> > > > > > > > > > > > > > > to
> >> > > > > > > > > > > > > > > > use
> >> > > > > > > > > > > > > > > > > > a
> >> > > > > > > > > > > > > > > > > > > separate monitor thread or pool
> (maybe
> >> > both
> >> > > > > with
> >> > > > > > > >
> >> > > > > > > > software
> >> > > > > > > > > > > > > > > > > > > and hardware checks) that not
> only
> >> > > checks
> >> > > > > > > >
> >> > > > > > > > heartbeats
> >> > > > > > > > > > >
> >> > > > > > > > > > > but
> >> > > > > > > > > > > > > > > > monitors the
> >> > > > > > > > > > > > > > > > > > > other system as well.
> >> > > > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > > > On Mon, 10 Sep 2018 at 00:07 David
> >> > Harvey <
> >> > > > > > > > > > >
> >> > > > > > > > > > > syssoftsol@gmail.com>
> >> > > > > > > > > > > > > > > > wrote:
> >> > > > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > > > > It would be safer to restart the
> >> entire
> >> > > > > cluster
> >> > > > > > > >
> >> > > > > > > > than to
> >> > > > > > > > > > >
> >> > > > > > > > > > > remove
> >> > > > > > > > > > > > > > > the
> >> > > > > > > > > > > > > > > > last
> >> > > > > > > > > > > > > > > > > > > > node for a cache that should be
> >> > > redundant.
> >> > > > > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > > > > On Sun, Sep 9, 2018, 4:00 PM
> Andrey
> >> > Gura
> >> > > <
> >> > > > > > > > > > >
> >> > > > > > > > > > > agura@apache.org>
> >> > > > > > > > > > > > > > > wrote:
> >> > > > > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > > > > > Hi,
> >> > > > > > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > > > > > I agree with Yakov that we can
> >> > provide
> >> > > > some
> >> > > > > > > >
> >> > > > > > > > option
> >> > > > > > > > > > >
> >> > > > > > > > > > > that manage
> >> > > > > > > > > > > > > > > > worker
> >> > > > > > > > > > > > > > > > > > > > > liveness checker behavior in
> case
> >> of
> >> > > > > observing
> >> > > > > > > >
> >> > > > > > > > that
> >> > > > > > > > > > >
> >> > > > > > > > > > > some worker
> >> > > > > > > > > > > > > > > > is
> >> > > > > > > > > > > > > > > > > > > > > blocked too long.
> >> > > > > > > > > > > > > > > > > > > > > At least it will some
> workaround
> >> for
> >> > > > > cases when
> >> > > > > > > >
> >> > > > > > > > node
> >> > > > > > > > > > >
> >> > > > > > > > > > > fails is
> >> > > > > > > > > > > > > > > > too
> >> > > > > > > > > > > > > > > > > > > > > annoying.
> >> > > > > > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > > > > > Backups count threshold sounds
> >> good
> >> > > but I
> >> > > > > don't
> >> > > > > > > > > > >
> >> > > > > > > > > > > understand how
> >> > > > > > > > > > > > > > > it
> >> > > > > > > > > > > > > > > > > > will
> >> > > > > > > > > > > > > > > > > > > > > help in case of cluster hanging.
> >> > > > > > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > > > > > The simplest solution here is
> >> alert
> >> > in
> >> > > > > cases of
> >> > > > > > > > > > >
> >> > > > > > > > > > > blocking of
> >> > > > > > > > > > > > > > > some
> >> > > > > > > > > > > > > > > > > > > > > critical worker (we can improve
> >> > > > > WorkersRegistry
> >> > > > > > > >
> >> > > > > > > > for
> >> > > > > > > > > > >
> >> > > > > > > > > > > this
> >> > > > > > > > > > > > > > > purpose
> >> > > > > > > > > > > > > > > > and
> >> > > > > > > > > > > > > > > > > > > > > expose list of blocked workers)
> >> and
> >> > > > > optionally
> >> > > > > > > >
> >> > > > > > > > call
> >> > > > > > > > > > >
> >> > > > > > > > > > > system
> >> > > > > > > > > > > > > > > > configured
> >> > > > > > > > > > > > > > > > > > > > > failure processor. BTW, failure
> >> > > processor
> >> > > > > can be
> >> > > > > > > > > > >
> >> > > > > > > > > > > extended in
> >> > > > > > > > > > > > > > > > order to
> >> > > > > > > > > > > > > > > > > > > > > perform any checks (e.g. backup
> >> > count)
> >> > > > and
> >> > > > > decide
> >> > > > > > > > > > >
> >> > > > > > > > > > > whether it
> >> > > > > > > > > > > > > > > > should
> >> > > > > > > > > > > > > > > > > > > > > stop node or not.
> >> > > > > > > > > > > > > > > > > > > > > On Sat, Sep 8, 2018 at 3:42 PM
> >> Andrey
> >> > > > > Kuznetsov <
> >> > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > stkuzma@gmail.com>
> >> > > > > > > > > > > > > > > > > > > > wrote:
> >> > > > > > > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > > > > > > David, Yakov, I understand
> your
> >> > > fears.
> >> > > > > But
> >> > > > > > > >
> >> > > > > > > > liveness
> >> > > > > > > > > > >
> >> > > > > > > > > > > checks
> >> > > > > > > > > > > > > > > deal
> >> > > > > > > > > > > > > > > > > > with
> >> > > > > > > > > > > > > > > > > > > > > > _critical_ conditions, i.e.
> when
> >> > > such a
> >> > > > > > > >
> >> > > > > > > > condition
> >> > > > > > > > > >
> >> > > > > > > > > > is
> >> > > > > > > > > > > met we
> >> > > > > > > > > > > > > > > > > > conclude
> >> > > > > > > > > > > > > > > > > > > > the
> >> > > > > > > > > > > > > > > > > > > > > > node as totally broken, and
> >> there
> >> > is
> >> > > no
> >> > > > > sense
> >> > > > > > > >
> >> > > > > > > > to
> >> > > > > > > > > > >
> >> > > > > > > > > > > keep it
> >> > > > > > > > > > > > > > > alive
> >> > > > > > > > > > > > > > > > > > > > regardless
> >> > > > > > > > > > > > > > > > > > > > > > the data it contains. If we
> >> want to
> >> > > > give
> >> > > > > it a
> >> > > > > > > > > > >
> >> > > > > > > > > > > chance, then
> >> > > > > > > > > > > > > > > the
> >> > > > > > > > > > > > > > > > > > > > condition
> >> > > > > > > > > > > > > > > > > > > > > > (long fsync etc.) should not
> >> > > considered
> >> > > > > as
> >> > > > > > > >
> >> > > > > > > > critical
> >> > > > > > > > > > >
> >> > > > > > > > > > > at all.
> >> > > > > > > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > > > > > > сб, 8 сент. 2018 г. в 15:18,
> >> Yakov
> >> > > > > Zhdanov <
> >> > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > yzhdanov@apache.org>:
> >> > > > > > > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > > > > > > > Agree with David. We need to
> >> have
> >> > > an
> >> > > > > > > >
> >> > > > > > > > opporunity
> >> > > > > > > > > > >
> >> > > > > > > > > > > set backups
> >> > > > > > > > > > > > > > > > count
> >> > > > > > > > > > > > > > > > > > > > > threshold
> >> > > > > > > > > > > > > > > > > > > > > > > (at runtime also!) that will
> >> not
> >> > > > allow
> >> > > > > any
> >> > > > > > > > > > >
> >> > > > > > > > > > > automatic stop
> >> > > > > > > > > > > > > > > if
> >> > > > > > > > > > > > > > > > > > there
> >> > > > > > > > > > > > > > > > > > > > > will be
> >> > > > > > > > > > > > > > > > > > > > > > > a data loss. Andrey, what do
> >> you
> >> > > > think?
> >> > > > > > > > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > > > > > > > --Yakov
> >> > > > > > > > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > > > > > > --
> >> > > > > > > > > > > > > > > > > > > > > > Best regards,
> >> > > > > > > > > > > > > > > > > > > > > > Andrey Kuznetsov.
> >> > > > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > > > --
> >> > > > > > > > > > > > > > > > > > > --
> >> > > > > > > > > > > > > > > > > > > Maxim Muzafarov
> >> > > > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > > > > --
> >> > > > > > > > > > > > > > > > > Best regards,
> >> > > > > > > > > > > > > > > > > Andrey Kuznetsov.
> >> > > > > > > > > > > > > >
> >> > > > > > > > > > > > > >
> >> > > > > > > > > > > > > > --
> >> > > > > > > > > > > > > > Best regards,
> >> > > > > > > > > > > > > > Andrey Kuznetsov.
> >> > > > > > > > > > > > >
> >> > > > > > > > > > > > >
> >> > > > > > > > > > > > >
> >> > > > > > > > > > > > > --
> >> > > > > > > > > > > > > Best Regards, Vyacheslav D.
> >> > > > > > > > > > >
> >> > > > > > > > > > >
> >> > > > > > > > > > >
> >> > > > > > > > > > > --
> >> > > > > > > > > > > Best Regards, Vyacheslav D.
> >> > > > > > > > > > >
> >> > > > > > > > > >
> >> > > > > > > > > > --
> >> > > > > > > > > > --
> >> > > > > > > > > > Maxim Muzafarov
> >> > > > > > > > > >
> >> > > > > > > > >
> >> > > > > > > > >
> >> > > > >
> >> > > >
> >> > >
> >> > --
> >> > --
> >> > Maxim Muzafarov
> >> >
> >>
> >>
> >> --
> >> Best regards,
> >> Andrey Kuznetsov.
> >>
> >
>
Re: Critical worker threads liveness checking drawbacks
Posted by Alexey Goncharuk <al...@gmail.com>.
Folks, why did not we include IGNITE-10003 to ignite-2.7 release scope?
This causes an Ignite node to be stopped by default when checkpoint read
lock acquire times out. I expect a lot of Ignite 2.7 users will be affected
by this mistake.
We should at least update the documentation and make users aware of a
workaround.
чт, 25 окт. 2018 г. в 16:35, Alexey Goncharuk <al...@gmail.com>:
> Andrey,
>
> I still see that checkpoint read lock acquisition raises a CRITICAL_ERROR,
> which by default will shut down local node. As far as I remember, we
> decided that by default thread timeout should not trigger node failure.
> Now, however, it does, because we ignore SYSTEM_WORKER_BLOCKED events in
> default configuration.
>
> Should we introduce another critical failure type
> CHECKPOINT_READ_LOCK_BLOCKED or use SYSTEM_WORKER_BLOCKED for checkpoint
> read lock acquire failure?
>
> --AG
>
> пт, 12 окт. 2018 г. в 8:29, Andrey Kuznetsov <st...@gmail.com>:
>
>> Igniters,
>>
>> Now I spot blocking / long-running code arising from
>> {{GridDhtPartitionsExchangeFuture#init}} calls in partition-exchanger
>> thread, see [1]. Ideally, all blocking operations along all possible code
>> paths should be guarded implicitly from critical failure detector to avoid
>> the thread from being considered blocked. There is a pull request [2] that
>> provides shallow solution. I didn't change code outside
>> {{GridDhtPartitionsExchangeFuture}}, otherwise it could be broken by any
>> upcoming change. Also, I didn't touch the code runnable by threads other
>> than partition-exchanger. So I have a number of guarded sections that are
>> wider than they could be, and this potentially hides issues from failure
>> detector. Does this PR make sense? Or maybe it's better to exclude
>> partition-exchanger from critical threads registry at all?
>>
>> [1] https://issues.apache.org/jira/browse/IGNITE-9710
>> [2] https://github.com/apache/ignite/pull/4962
>>
>>
>> пт, 28 сент. 2018 г. в 18:56, Maxim Muzafarov <ma...@gmail.com>:
>>
>> > Andrey, Andrey
>> >
>> > > Thanks for being attentive! It's definitely a typo. Could you please
>> > create
>> > > an issue?
>> >
>> > I've created an issue [1] and prepared PR [2].
>> > Please, review this change.
>> >
>> > [1] https://issues.apache.org/jira/browse/IGNITE-9723
>> > [2] https://github.com/apache/ignite/pull/4862
>> >
>> > On Fri, 28 Sep 2018 at 16:58 Yakov Zhdanov <yz...@apache.org> wrote:
>> >
>> > > Config option + mbean access. Does that make sense?
>> > >
>> > > Yakov
>> > >
>> > > On Fri, Sep 28, 2018, 17:17 Vladimir Ozerov <vo...@gridgain.com>
>> > wrote:
>> > >
>> > > > Then it should be config option.
>> > > >
>> > > > пт, 28 сент. 2018 г. в 13:15, Andrey Gura <ag...@apache.org>:
>> > > >
>> > > > > Guys,
>> > > > >
>> > > > > why we need both config option and system property? I believe one
>> way
>> > > is
>> > > > > enough.
>> > > > > On Fri, Sep 28, 2018 at 12:38 PM Nikolay Izhikov <
>> > nizhikov@apache.org>
>> > > > > wrote:
>> > > > > >
>> > > > > > Ticket created -
>> https://issues.apache.org/jira/browse/IGNITE-9737
>> > > > > >
>> > > > > > Fixed version is 2.7.
>> > > > > >
>> > > > > > В Пт, 28/09/2018 в 11:41 +0300, Alexey Goncharuk пишет:
>> > > > > > > Nikolay, I agree, a user should be able to disable both thread
>> > > > liveness
>> > > > > > > check and checkpoint read lock timeout check from config and a
>> > > system
>> > > > > > > property.
>> > > > > > >
>> > > > > > > пт, 28 сент. 2018 г. в 11:30, Nikolay Izhikov <
>> > nizhikov@apache.org
>> > > >:
>> > > > > > >
>> > > > > > > > Hello, Igniters.
>> > > > > > > >
>> > > > > > > > I found that this feature can't be disabled from config.
>> > > > > > > > The only way to disable it is from JMX bean.
>> > > > > > > >
>> > > > > > > > I think it very dangerous: If we have some corner case or a
>> bug
>> > > in
>> > > > > this
>> > > > > > > > Watch Dog it can make Ignite unusable.
>> > > > > > > > I propose to implement possibility to disable this feature
>> > both -
>> > > > > from
>> > > > > > > > config and from JVM options.
>> > > > > > > >
>> > > > > > > > What do you think?
>> > > > > > > >
>> > > > > > > > В Чт, 27/09/2018 в 16:14 +0300, Andrey Kuznetsov пишет:
>> > > > > > > > > Maxim,
>> > > > > > > > >
>> > > > > > > > > Thanks for being attentive! It's definitely a typo. Could
>> you
>> > > > > please
>> > > > > > > >
>> > > > > > > > create
>> > > > > > > > > an issue?
>> > > > > > > > >
>> > > > > > > > > чт, 27 сент. 2018 г. в 16:00, Maxim Muzafarov <
>> > > > maxmuzaf@gmail.com
>> > > > > >:
>> > > > > > > > >
>> > > > > > > > > > Folks,
>> > > > > > > > > >
>> > > > > > > > > > I've found in `GridCachePartitionExchangeManager:2684`
>> [1]
>> > > > > (master
>> > > > > > > >
>> > > > > > > > branch)
>> > > > > > > > > > exchange future wrapped
>> > > > > > > > > > with double `blockingSectionEnd` method. Is it correct?
>> I
>> > > just
>> > > > > want to
>> > > > > > > > > > understand this change and
>> > > > > > > > > > how should I use this in the future.
>> > > > > > > > > >
>> > > > > > > > > > Should I file a new issue to fix this? I think here
>> > > > > > > >
>> > > > > > > > `blockingSectionBegin`
>> > > > > > > > > > method should be used.
>> > > > > > > > > >
>> > > > > > > > > > -------------
>> > > > > > > > > > blockingSectionEnd();
>> > > > > > > > > >
>> > > > > > > > > > try {
>> > > > > > > > > > resVer = exchFut.get(exchTimeout,
>> > TimeUnit.MILLISECONDS);
>> > > > > > > > > > } finally {
>> > > > > > > > > > blockingSectionEnd();
>> > > > > > > > > > }
>> > > > > > > > > >
>> > > > > > > > > >
>> > > > > > > > > > [1]
>> > > > > > > > > >
>> > > > > > > > > >
>> > > > > > > >
>> > > > > > > >
>> > > > >
>> > > >
>> > >
>> >
>> https://github.com/apache/ignite/blob/master/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/GridCachePartitionExchangeManager.java#L2684
>> > > > > > > > > >
>> > > > > > > > > > On Wed, 26 Sep 2018 at 22:47 Vyacheslav Daradur <
>> > > > > daradurvs@gmail.com>
>> > > > > > > > > > wrote:
>> > > > > > > > > >
>> > > > > > > > > > > Andrey Gura, thank you for the answer!
>> > > > > > > > > > >
>> > > > > > > > > > > I agree that wrapping of 'init' method reduces the
>> profit
>> > > of
>> > > > > watchdog
>> > > > > > > > > > > service in case of PME worker, but in other cases, we
>> > > should
>> > > > > wrap all
>> > > > > > > > > > > possible long sections on
>> GridDhtPartitionExchangeFuture.
>> > > For
>> > > > > example
>> > > > > > > > > > > 'onCacheChangeRequest' method or
>> > > > > > > > > > > 'cctx.affinity().onCacheChangeRequest' inside because
>> it
>> > > may
>> > > > > take
>> > > > > > > > > > > significant time (reproducer attached).
>> > > > > > > > > > >
>> > > > > > > > > > > I only want to point out a possible issue which may
>> allow
>> > > to
>> > > > > end-user
>> > > > > > > > > > > halt the Ignite cluster accidentally.
>> > > > > > > > > > >
>> > > > > > > > > > > I'm sure that PME experts know how to fix this issue
>> > > > properly.
>> > > > > > > > > > > On Wed, Sep 26, 2018 at 10:28 PM Andrey Gura <
>> > > > agura@apache.org
>> > > > > >
>> > > > > > > >
>> > > > > > > > wrote:
>> > > > > > > > > > > >
>> > > > > > > > > > > > Vyacheslav,
>> > > > > > > > > > > >
>> > > > > > > > > > > > Exchange worker is strongly tied with
>> > > > > > > > > > > > GridDhtPartitionExchangeFuture#init and it is ok.
>> > > Exchange
>> > > > > worker
>> > > > > > > >
>> > > > > > > > also
>> > > > > > > > > > > > shouldn't be blocked for long time but in reality it
>> > > > > happens.It
>> > > > > > > >
>> > > > > > > > also
>> > > > > > > > > > > > means that your change doesn't make sense.
>> > > > > > > > > > > >
>> > > > > > > > > > > > What actually make sense it is identification of
>> places
>> > > > which
>> > > > > > > > > > > > intentionally blocking. May be some places/actions
>> > should
>> > > > be
>> > > > > > > >
>> > > > > > > > braced by
>> > > > > > > > > > > > blocking guards.
>> > > > > > > > > > > >
>> > > > > > > > > > > > If you have failing tests please make sure that your
>> > > > > > > >
>> > > > > > > > failureHandler is
>> > > > > > > > > > > > NoOpFailureHandler or any other handler with
>> > > > > ignoreFailureTypes =
>> > > > > > > > > > > > [CRITICAL_WORKER_BLOCKED].
>> > > > > > > > > > > >
>> > > > > > > > > > > >
>> > > > > > > > > > > > On Wed, Sep 26, 2018 at 9:43 PM Vyacheslav Daradur <
>> > > > > > > > > >
>> > > > > > > > > > daradurvs@gmail.com>
>> > > > > > > > > > > wrote:
>> > > > > > > > > > > > >
>> > > > > > > > > > > > > Hi Igniters!
>> > > > > > > > > > > > >
>> > > > > > > > > > > > > Thank you for this important improvement!
>> > > > > > > > > > > > >
>> > > > > > > > > > > > > I've looked through implementation and noticed
>> that
>> > > > > > > > > > > > > GridDhtPartitionsExchangeFuture#init has not been
>> > > wrapped
>> > > > > in
>> > > > > > > >
>> > > > > > > > blocked
>> > > > > > > > > > > > > section. This means it easy to halt the node in
>> case
>> > of
>> > > > > > > >
>> > > > > > > > longrunning
>> > > > > > > > > > > > > actions during PME, for example when we create a
>> > cache
>> > > > with
>> > > > > > > > > > > > > StoreFactrory which connect to 3rd party DB.
>> > > > > > > > > > > > >
>> > > > > > > > > > > > > I'm not sure that it is the right behavior.
>> > > > > > > > > > > > >
>> > > > > > > > > > > > > I filled the issue [1] and prepared the PR [2]
>> with
>> > > > > reproducer
>> > > > > > > >
>> > > > > > > > and
>> > > > > > > > > > >
>> > > > > > > > > > > possible fix.
>> > > > > > > > > > > > >
>> > > > > > > > > > > > > Andrey, could you please look at and confirm that
>> it
>> > > > makes
>> > > > > sense?
>> > > > > > > > > > > > >
>> > > > > > > > > > > > > [1]
>> > https://issues.apache.org/jira/browse/IGNITE-9710
>> > > > > > > > > > > > > [2] https://github.com/apache/ignite/pull/4845
>> > > > > > > > > > > > > On Mon, Sep 24, 2018 at 9:46 PM Andrey Kuznetsov <
>> > > > > > > >
>> > > > > > > > stkuzma@gmail.com>
>> > > > > > > > > > >
>> > > > > > > > > > > wrote:
>> > > > > > > > > > > > > >
>> > > > > > > > > > > > > > Denis,
>> > > > > > > > > > > > > >
>> > > > > > > > > > > > > > I've created the ticket [1] with short
>> description
>> > of
>> > > > the
>> > > > > > > > > > >
>> > > > > > > > > > > functionality.
>> > > > > > > > > > > > > >
>> > > > > > > > > > > > > > [1]
>> > > https://issues.apache.org/jira/browse/IGNITE-9679
>> > > > > > > > > > > > > >
>> > > > > > > > > > > > > >
>> > > > > > > > > > > > > > пн, 24 сент. 2018 г. в 17:46, Denis Magda <
>> > > > > dmagda@apache.org>:
>> > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > Andrey K. and G.,
>> > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > Thanks, do we have a documentation ticket
>> > created?
>> > > > > Prachi
>> > > > > > > > > >
>> > > > > > > > > > (copied)
>> > > > > > > > > > > can help
>> > > > > > > > > > > > > > > with the documentation.
>> > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > --
>> > > > > > > > > > > > > > > Denis
>> > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > On Mon, Sep 24, 2018 at 5:51 AM Andrey Gura <
>> > > > > > > >
>> > > > > > > > agura@apache.org>
>> > > > > > > > > > >
>> > > > > > > > > > > wrote:
>> > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > Andrey,
>> > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > finally your change is merged to master
>> branch.
>> > > > > > > >
>> > > > > > > > Congratulations
>> > > > > > > > > > >
>> > > > > > > > > > > and
>> > > > > > > > > > > > > > > > thank you very much! :)
>> > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > I think that the next step is feature that
>> will
>> > > > allow
>> > > > > > > >
>> > > > > > > > signal
>> > > > > > > > > > >
>> > > > > > > > > > > about
>> > > > > > > > > > > > > > > > blocked threads to the monitoring tools via
>> > > MXBean.
>> > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > I hope you will continue development of this
>> > > > feature
>> > > > > and
>> > > > > > > > > >
>> > > > > > > > > > provide
>> > > > > > > > > > > your
>> > > > > > > > > > > > > > > > vision in new JIRA issue.
>> > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > On Tue, Sep 11, 2018 at 6:54 PM Andrey
>> > Kuznetsov
>> > > <
>> > > > > > > > > > >
>> > > > > > > > > > > stkuzma@gmail.com>
>> > > > > > > > > > > > > > > > wrote:
>> > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > David, Maxim!
>> > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > Thanks a lot for you ideas.
>> Unfortunately, I
>> > > > can't
>> > > > > adopt
>> > > > > > > >
>> > > > > > > > all
>> > > > > > > > > > >
>> > > > > > > > > > > of them
>> > > > > > > > > > > > > > > > right
>> > > > > > > > > > > > > > > > > now: the scope is much broader than the
>> scope
>> > > of
>> > > > > the
>> > > > > > > >
>> > > > > > > > change I
>> > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > implement.
>> > > > > > > > > > > > > > > > I
>> > > > > > > > > > > > > > > > > have had a talk to a group of Ignite
>> > commiters,
>> > > > > and we
>> > > > > > > >
>> > > > > > > > agreed
>> > > > > > > > > > >
>> > > > > > > > > > > to
>> > > > > > > > > > > > > > > complete
>> > > > > > > > > > > > > > > > > the change as follows.
>> > > > > > > > > > > > > > > > > - Blocking instructions in system-critical
>> > > which
>> > > > > may
>> > > > > > > > > >
>> > > > > > > > > > resonably
>> > > > > > > > > > > last
>> > > > > > > > > > > > > > > long
>> > > > > > > > > > > > > > > > > should be explicitly excluded from the
>> > > > monitoring.
>> > > > > > > > > > > > > > > > > - Failure handlers should have a setting
>> to
>> > > > > suppress some
>> > > > > > > > > > >
>> > > > > > > > > > > failures on
>> > > > > > > > > > > > > > > > > per-failure-type basis.
>> > > > > > > > > > > > > > > > > According to this I have updated the
>> > > > > implementation: [1]
>> > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > [1]
>> > https://github.com/apache/ignite/pull/4089
>> > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > пн, 10 сент. 2018 г. в 22:35, David
>> Harvey <
>> > > > > > > > > > >
>> > > > > > > > > > > syssoftsol@gmail.com>:
>> > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > > When I've done this before,I've needed
>> to
>> > > find
>> > > > > the
>> > > > > > > >
>> > > > > > > > oldest
>> > > > > > > > > > >
>> > > > > > > > > > > thread,
>> > > > > > > > > > > > > > > and
>> > > > > > > > > > > > > > > > kill
>> > > > > > > > > > > > > > > > > > the node running that. From a language
>> > > > > standpoint,
>> > > > > > > > > >
>> > > > > > > > > > Maxim's
>> > > > > > > > > > > "without
>> > > > > > > > > > > > > > > > > > progress" better than "heartbeat". For
>> > > > > example, what
>> > > > > > > >
>> > > > > > > > I'm
>> > > > > > > > > > >
>> > > > > > > > > > > most
>> > > > > > > > > > > > > > > > interested
>> > > > > > > > > > > > > > > > > > in on a distributed system is which
>> thread
>> > > > > started the
>> > > > > > > >
>> > > > > > > > work
>> > > > > > > > > > >
>> > > > > > > > > > > it has
>> > > > > > > > > > > > > > > not
>> > > > > > > > > > > > > > > > > > completed the earliest, and when did
>> that
>> > > > thread
>> > > > > last
>> > > > > > > >
>> > > > > > > > make
>> > > > > > > > > > >
>> > > > > > > > > > > forward
>> > > > > > > > > > > > > > > > > > process. You don't want to kill a
>> node
>> > > > > because a
>> > > > > > > >
>> > > > > > > > thread
>> > > > > > > > > > >
>> > > > > > > > > > > is
>> > > > > > > > > > > > > > > waiting
>> > > > > > > > > > > > > > > > on a
>> > > > > > > > > > > > > > > > > > lock held by a thread that went off-node
>> > and
>> > > > has
>> > > > > not
>> > > > > > > > > >
>> > > > > > > > > > gotten a
>> > > > > > > > > > > > > > > response.
>> > > > > > > > > > > > > > > > > > If you don't understand the dependency
>> > > > > relationships,
>> > > > > > > >
>> > > > > > > > you
>> > > > > > > > > > >
>> > > > > > > > > > > will make
>> > > > > > > > > > > > > > > > > > incorrect recovery decisions.
>> > > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > > On Mon, Sep 10, 2018 at 4:08 AM Maxim
>> > > > Muzafarov <
>> > > > > > > > > > >
>> > > > > > > > > > > maxmuzaf@gmail.com>
>> > > > > > > > > > > > > > > > > > wrote:
>> > > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > > > I think we should find exact answers
>> to
>> > > these
>> > > > > > > >
>> > > > > > > > questions:
>> > > > > > > > > > > > > > > > > > > 1. What `critical` issue exactly is?
>> > > > > > > > > > > > > > > > > > > 2. How can we find critical issues?
>> > > > > > > > > > > > > > > > > > > 3. How can we handle critical issues?
>> > > > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > > > First,
>> > > > > > > > > > > > > > > > > > > - Ignore uninterruptable actions
>> (e.g.
>> > > > > > > >
>> > > > > > > > worker\service
>> > > > > > > > > > >
>> > > > > > > > > > > shutdown)
>> > > > > > > > > > > > > > > > > > > - Long I/O operations (should be a
>> > > > > configurable
>> > > > > > > >
>> > > > > > > > timeout
>> > > > > > > > > > >
>> > > > > > > > > > > for each
>> > > > > > > > > > > > > > > > type of
>> > > > > > > > > > > > > > > > > > > usage)
>> > > > > > > > > > > > > > > > > > > - Infinite loops
>> > > > > > > > > > > > > > > > > > > - Stalled\deadlocked threads (and\or
>> too
>> > > > many
>> > > > > parked
>> > > > > > > > > > >
>> > > > > > > > > > > threads,
>> > > > > > > > > > > > > > > > exclude
>> > > > > > > > > > > > > > > > > > I/O)
>> > > > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > > > Second,
>> > > > > > > > > > > > > > > > > > > - The working queue is without
>> progress
>> > > > (e.g.
>> > > > > disco,
>> > > > > > > > > > >
>> > > > > > > > > > > exchange
>> > > > > > > > > > > > > > > > queues)
>> > > > > > > > > > > > > > > > > > > - Work hasn't been completed since
>> the
>> > > last
>> > > > > > > >
>> > > > > > > > heartbeat
>> > > > > > > > > > >
>> > > > > > > > > > > (checking
>> > > > > > > > > > > > > > > > > > > milestones)
>> > > > > > > > > > > > > > > > > > > - Too many system resources used by a
>> > > thread
>> > > > > for the
>> > > > > > > > > >
>> > > > > > > > > > long
>> > > > > > > > > > > period
>> > > > > > > > > > > > > > > of
>> > > > > > > > > > > > > > > > time
>> > > > > > > > > > > > > > > > > > > (allocated memory, CPU)
>> > > > > > > > > > > > > > > > > > > - Timing fields associated with each
>> > > thread
>> > > > > status
>> > > > > > > > > > >
>> > > > > > > > > > > exceeded a
>> > > > > > > > > > > > > > > > maximum
>> > > > > > > > > > > > > > > > > > time
>> > > > > > > > > > > > > > > > > > > limit.
>> > > > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > > > Third (not too many options here),
>> > > > > > > > > > > > > > > > > > > - `log everything` should be the
>> default
>> > > > > behaviour
>> > > > > > > >
>> > > > > > > > in
>> > > > > > > > > >
>> > > > > > > > > > all
>> > > > > > > > > > > these
>> > > > > > > > > > > > > > > > cases,
>> > > > > > > > > > > > > > > > > > > since it may be difficult to find the
>> > cause
>> > > > > after the
>> > > > > > > > > > >
>> > > > > > > > > > > restart.
>> > > > > > > > > > > > > > > > > > > - Wait some interval of time and kill
>> > the
>> > > > > hanging
>> > > > > > > >
>> > > > > > > > node
>> > > > > > > > > > >
>> > > > > > > > > > > (cluster
>> > > > > > > > > > > > > > > > should
>> > > > > > > > > > > > > > > > > > be
>> > > > > > > > > > > > > > > > > > > configured stable enough)
>> > > > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > > > Questions,
>> > > > > > > > > > > > > > > > > > > - Not sure, but can workers miss
>> their
>> > > > > heartbeat
>> > > > > > > > > > >
>> > > > > > > > > > > deadlines if CPU
>> > > > > > > > > > > > > > > > loads
>> > > > > > > > > > > > > > > > > > up
>> > > > > > > > > > > > > > > > > > > to 80%-90%? Bursts of momentary
>> overloads
>> > > can
>> > > > > be
>> > > > > > > > > > > > > > > > > > > expected behaviour as a normal
>> part
>> > of
>> > > > > system
>> > > > > > > > > > >
>> > > > > > > > > > > operations.
>> > > > > > > > > > > > > > > > > > > - Why do we decide that critical
>> thread
>> > > > should
>> > > > > > > >
>> > > > > > > > monitor
>> > > > > > > > > > >
>> > > > > > > > > > > each other?
>> > > > > > > > > > > > > > > > For
>> > > > > > > > > > > > > > > > > > > instance, if all the tasks were
>> blocked
>> > and
>> > > > > unable to
>> > > > > > > > > >
>> > > > > > > > > > run,
>> > > > > > > > > > > > > > > > > > > node reset would never occur. As
>> for
>> > > me,
>> > > > a
>> > > > > better
>> > > > > > > > > > >
>> > > > > > > > > > > solution is
>> > > > > > > > > > > > > > > to
>> > > > > > > > > > > > > > > > use
>> > > > > > > > > > > > > > > > > > a
>> > > > > > > > > > > > > > > > > > > separate monitor thread or pool (maybe
>> > both
>> > > > > with
>> > > > > > > >
>> > > > > > > > software
>> > > > > > > > > > > > > > > > > > > and hardware checks) that not only
>> > > checks
>> > > > > > > >
>> > > > > > > > heartbeats
>> > > > > > > > > > >
>> > > > > > > > > > > but
>> > > > > > > > > > > > > > > > monitors the
>> > > > > > > > > > > > > > > > > > > other system as well.
>> > > > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > > > On Mon, 10 Sep 2018 at 00:07 David
>> > Harvey <
>> > > > > > > > > > >
>> > > > > > > > > > > syssoftsol@gmail.com>
>> > > > > > > > > > > > > > > > wrote:
>> > > > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > > > > It would be safer to restart the
>> entire
>> > > > > cluster
>> > > > > > > >
>> > > > > > > > than to
>> > > > > > > > > > >
>> > > > > > > > > > > remove
>> > > > > > > > > > > > > > > the
>> > > > > > > > > > > > > > > > last
>> > > > > > > > > > > > > > > > > > > > node for a cache that should be
>> > > redundant.
>> > > > > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > > > > On Sun, Sep 9, 2018, 4:00 PM Andrey
>> > Gura
>> > > <
>> > > > > > > > > > >
>> > > > > > > > > > > agura@apache.org>
>> > > > > > > > > > > > > > > wrote:
>> > > > > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > > > > > Hi,
>> > > > > > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > > > > > I agree with Yakov that we can
>> > provide
>> > > > some
>> > > > > > > >
>> > > > > > > > option
>> > > > > > > > > > >
>> > > > > > > > > > > that manage
>> > > > > > > > > > > > > > > > worker
>> > > > > > > > > > > > > > > > > > > > > liveness checker behavior in case
>> of
>> > > > > observing
>> > > > > > > >
>> > > > > > > > that
>> > > > > > > > > > >
>> > > > > > > > > > > some worker
>> > > > > > > > > > > > > > > > is
>> > > > > > > > > > > > > > > > > > > > > blocked too long.
>> > > > > > > > > > > > > > > > > > > > > At least it will some workaround
>> for
>> > > > > cases when
>> > > > > > > >
>> > > > > > > > node
>> > > > > > > > > > >
>> > > > > > > > > > > fails is
>> > > > > > > > > > > > > > > > too
>> > > > > > > > > > > > > > > > > > > > > annoying.
>> > > > > > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > > > > > Backups count threshold sounds
>> good
>> > > but I
>> > > > > don't
>> > > > > > > > > > >
>> > > > > > > > > > > understand how
>> > > > > > > > > > > > > > > it
>> > > > > > > > > > > > > > > > > > will
>> > > > > > > > > > > > > > > > > > > > > help in case of cluster hanging.
>> > > > > > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > > > > > The simplest solution here is
>> alert
>> > in
>> > > > > cases of
>> > > > > > > > > > >
>> > > > > > > > > > > blocking of
>> > > > > > > > > > > > > > > some
>> > > > > > > > > > > > > > > > > > > > > critical worker (we can improve
>> > > > > WorkersRegistry
>> > > > > > > >
>> > > > > > > > for
>> > > > > > > > > > >
>> > > > > > > > > > > this
>> > > > > > > > > > > > > > > purpose
>> > > > > > > > > > > > > > > > and
>> > > > > > > > > > > > > > > > > > > > > expose list of blocked workers)
>> and
>> > > > > optionally
>> > > > > > > >
>> > > > > > > > call
>> > > > > > > > > > >
>> > > > > > > > > > > system
>> > > > > > > > > > > > > > > > configured
>> > > > > > > > > > > > > > > > > > > > > failure processor. BTW, failure
>> > > processor
>> > > > > can be
>> > > > > > > > > > >
>> > > > > > > > > > > extended in
>> > > > > > > > > > > > > > > > order to
>> > > > > > > > > > > > > > > > > > > > > perform any checks (e.g. backup
>> > count)
>> > > > and
>> > > > > decide
>> > > > > > > > > > >
>> > > > > > > > > > > whether it
>> > > > > > > > > > > > > > > > should
>> > > > > > > > > > > > > > > > > > > > > stop node or not.
>> > > > > > > > > > > > > > > > > > > > > On Sat, Sep 8, 2018 at 3:42 PM
>> Andrey
>> > > > > Kuznetsov <
>> > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > stkuzma@gmail.com>
>> > > > > > > > > > > > > > > > > > > > wrote:
>> > > > > > > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > > > > > > David, Yakov, I understand your
>> > > fears.
>> > > > > But
>> > > > > > > >
>> > > > > > > > liveness
>> > > > > > > > > > >
>> > > > > > > > > > > checks
>> > > > > > > > > > > > > > > deal
>> > > > > > > > > > > > > > > > > > with
>> > > > > > > > > > > > > > > > > > > > > > _critical_ conditions, i.e. when
>> > > such a
>> > > > > > > >
>> > > > > > > > condition
>> > > > > > > > > >
>> > > > > > > > > > is
>> > > > > > > > > > > met we
>> > > > > > > > > > > > > > > > > > conclude
>> > > > > > > > > > > > > > > > > > > > the
>> > > > > > > > > > > > > > > > > > > > > > node as totally broken, and
>> there
>> > is
>> > > no
>> > > > > sense
>> > > > > > > >
>> > > > > > > > to
>> > > > > > > > > > >
>> > > > > > > > > > > keep it
>> > > > > > > > > > > > > > > alive
>> > > > > > > > > > > > > > > > > > > > regardless
>> > > > > > > > > > > > > > > > > > > > > > the data it contains. If we
>> want to
>> > > > give
>> > > > > it a
>> > > > > > > > > > >
>> > > > > > > > > > > chance, then
>> > > > > > > > > > > > > > > the
>> > > > > > > > > > > > > > > > > > > > condition
>> > > > > > > > > > > > > > > > > > > > > > (long fsync etc.) should not
>> > > considered
>> > > > > as
>> > > > > > > >
>> > > > > > > > critical
>> > > > > > > > > > >
>> > > > > > > > > > > at all.
>> > > > > > > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > > > > > > сб, 8 сент. 2018 г. в 15:18,
>> Yakov
>> > > > > Zhdanov <
>> > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > yzhdanov@apache.org>:
>> > > > > > > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > > > > > > > Agree with David. We need to
>> have
>> > > an
>> > > > > > > >
>> > > > > > > > opporunity
>> > > > > > > > > > >
>> > > > > > > > > > > set backups
>> > > > > > > > > > > > > > > > count
>> > > > > > > > > > > > > > > > > > > > > threshold
>> > > > > > > > > > > > > > > > > > > > > > > (at runtime also!) that will
>> not
>> > > > allow
>> > > > > any
>> > > > > > > > > > >
>> > > > > > > > > > > automatic stop
>> > > > > > > > > > > > > > > if
>> > > > > > > > > > > > > > > > > > there
>> > > > > > > > > > > > > > > > > > > > > will be
>> > > > > > > > > > > > > > > > > > > > > > > a data loss. Andrey, what do
>> you
>> > > > think?
>> > > > > > > > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > > > > > > > --Yakov
>> > > > > > > > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > > > > > > --
>> > > > > > > > > > > > > > > > > > > > > > Best regards,
>> > > > > > > > > > > > > > > > > > > > > > Andrey Kuznetsov.
>> > > > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > > > --
>> > > > > > > > > > > > > > > > > > > --
>> > > > > > > > > > > > > > > > > > > Maxim Muzafarov
>> > > > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > >
>> > > > > > > > > > > > > > > > > --
>> > > > > > > > > > > > > > > > > Best regards,
>> > > > > > > > > > > > > > > > > Andrey Kuznetsov.
>> > > > > > > > > > > > > >
>> > > > > > > > > > > > > >
>> > > > > > > > > > > > > > --
>> > > > > > > > > > > > > > Best regards,
>> > > > > > > > > > > > > > Andrey Kuznetsov.
>> > > > > > > > > > > > >
>> > > > > > > > > > > > >
>> > > > > > > > > > > > >
>> > > > > > > > > > > > > --
>> > > > > > > > > > > > > Best Regards, Vyacheslav D.
>> > > > > > > > > > >
>> > > > > > > > > > >
>> > > > > > > > > > >
>> > > > > > > > > > > --
>> > > > > > > > > > > Best Regards, Vyacheslav D.
>> > > > > > > > > > >
>> > > > > > > > > >
>> > > > > > > > > > --
>> > > > > > > > > > --
>> > > > > > > > > > Maxim Muzafarov
>> > > > > > > > > >
>> > > > > > > > >
>> > > > > > > > >
>> > > > >
>> > > >
>> > >
>> > --
>> > --
>> > Maxim Muzafarov
>> >
>>
>>
>> --
>> Best regards,
>> Andrey Kuznetsov.
>>
>
Re: Critical worker threads liveness checking drawbacks
Posted by Alexey Goncharuk <al...@gmail.com>.
Andrey,
I still see that checkpoint read lock acquisition raises a CRITICAL_ERROR,
which by default will shut down local node. As far as I remember, we
decided that by default thread timeout should not trigger node failure.
Now, however, it does, because we ignore SYSTEM_WORKER_BLOCKED events in
default configuration.
Should we introduce another critical failure type
CHECKPOINT_READ_LOCK_BLOCKED or use SYSTEM_WORKER_BLOCKED for checkpoint
read lock acquire failure?
--AG
пт, 12 окт. 2018 г. в 8:29, Andrey Kuznetsov <st...@gmail.com>:
> Igniters,
>
> Now I spot blocking / long-running code arising from
> {{GridDhtPartitionsExchangeFuture#init}} calls in partition-exchanger
> thread, see [1]. Ideally, all blocking operations along all possible code
> paths should be guarded implicitly from critical failure detector to avoid
> the thread from being considered blocked. There is a pull request [2] that
> provides shallow solution. I didn't change code outside
> {{GridDhtPartitionsExchangeFuture}}, otherwise it could be broken by any
> upcoming change. Also, I didn't touch the code runnable by threads other
> than partition-exchanger. So I have a number of guarded sections that are
> wider than they could be, and this potentially hides issues from failure
> detector. Does this PR make sense? Or maybe it's better to exclude
> partition-exchanger from critical threads registry at all?
>
> [1] https://issues.apache.org/jira/browse/IGNITE-9710
> [2] https://github.com/apache/ignite/pull/4962
>
>
> пт, 28 сент. 2018 г. в 18:56, Maxim Muzafarov <ma...@gmail.com>:
>
> > Andrey, Andrey
> >
> > > Thanks for being attentive! It's definitely a typo. Could you please
> > create
> > > an issue?
> >
> > I've created an issue [1] and prepared PR [2].
> > Please, review this change.
> >
> > [1] https://issues.apache.org/jira/browse/IGNITE-9723
> > [2] https://github.com/apache/ignite/pull/4862
> >
> > On Fri, 28 Sep 2018 at 16:58 Yakov Zhdanov <yz...@apache.org> wrote:
> >
> > > Config option + mbean access. Does that make sense?
> > >
> > > Yakov
> > >
> > > On Fri, Sep 28, 2018, 17:17 Vladimir Ozerov <vo...@gridgain.com>
> > wrote:
> > >
> > > > Then it should be config option.
> > > >
> > > > пт, 28 сент. 2018 г. в 13:15, Andrey Gura <ag...@apache.org>:
> > > >
> > > > > Guys,
> > > > >
> > > > > why we need both config option and system property? I believe one
> way
> > > is
> > > > > enough.
> > > > > On Fri, Sep 28, 2018 at 12:38 PM Nikolay Izhikov <
> > nizhikov@apache.org>
> > > > > wrote:
> > > > > >
> > > > > > Ticket created -
> https://issues.apache.org/jira/browse/IGNITE-9737
> > > > > >
> > > > > > Fixed version is 2.7.
> > > > > >
> > > > > > В Пт, 28/09/2018 в 11:41 +0300, Alexey Goncharuk пишет:
> > > > > > > Nikolay, I agree, a user should be able to disable both thread
> > > > liveness
> > > > > > > check and checkpoint read lock timeout check from config and a
> > > system
> > > > > > > property.
> > > > > > >
> > > > > > > пт, 28 сент. 2018 г. в 11:30, Nikolay Izhikov <
> > nizhikov@apache.org
> > > >:
> > > > > > >
> > > > > > > > Hello, Igniters.
> > > > > > > >
> > > > > > > > I found that this feature can't be disabled from config.
> > > > > > > > The only way to disable it is from JMX bean.
> > > > > > > >
> > > > > > > > I think it very dangerous: If we have some corner case or a
> bug
> > > in
> > > > > this
> > > > > > > > Watch Dog it can make Ignite unusable.
> > > > > > > > I propose to implement possibility to disable this feature
> > both -
> > > > > from
> > > > > > > > config and from JVM options.
> > > > > > > >
> > > > > > > > What do you think?
> > > > > > > >
> > > > > > > > В Чт, 27/09/2018 в 16:14 +0300, Andrey Kuznetsov пишет:
> > > > > > > > > Maxim,
> > > > > > > > >
> > > > > > > > > Thanks for being attentive! It's definitely a typo. Could
> you
> > > > > please
> > > > > > > >
> > > > > > > > create
> > > > > > > > > an issue?
> > > > > > > > >
> > > > > > > > > чт, 27 сент. 2018 г. в 16:00, Maxim Muzafarov <
> > > > maxmuzaf@gmail.com
> > > > > >:
> > > > > > > > >
> > > > > > > > > > Folks,
> > > > > > > > > >
> > > > > > > > > > I've found in `GridCachePartitionExchangeManager:2684`
> [1]
> > > > > (master
> > > > > > > >
> > > > > > > > branch)
> > > > > > > > > > exchange future wrapped
> > > > > > > > > > with double `blockingSectionEnd` method. Is it correct? I
> > > just
> > > > > want to
> > > > > > > > > > understand this change and
> > > > > > > > > > how should I use this in the future.
> > > > > > > > > >
> > > > > > > > > > Should I file a new issue to fix this? I think here
> > > > > > > >
> > > > > > > > `blockingSectionBegin`
> > > > > > > > > > method should be used.
> > > > > > > > > >
> > > > > > > > > > -------------
> > > > > > > > > > blockingSectionEnd();
> > > > > > > > > >
> > > > > > > > > > try {
> > > > > > > > > > resVer = exchFut.get(exchTimeout,
> > TimeUnit.MILLISECONDS);
> > > > > > > > > > } finally {
> > > > > > > > > > blockingSectionEnd();
> > > > > > > > > > }
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > [1]
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > >
> > > >
> > >
> >
> https://github.com/apache/ignite/blob/master/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/GridCachePartitionExchangeManager.java#L2684
> > > > > > > > > >
> > > > > > > > > > On Wed, 26 Sep 2018 at 22:47 Vyacheslav Daradur <
> > > > > daradurvs@gmail.com>
> > > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > > Andrey Gura, thank you for the answer!
> > > > > > > > > > >
> > > > > > > > > > > I agree that wrapping of 'init' method reduces the
> profit
> > > of
> > > > > watchdog
> > > > > > > > > > > service in case of PME worker, but in other cases, we
> > > should
> > > > > wrap all
> > > > > > > > > > > possible long sections on
> GridDhtPartitionExchangeFuture.
> > > For
> > > > > example
> > > > > > > > > > > 'onCacheChangeRequest' method or
> > > > > > > > > > > 'cctx.affinity().onCacheChangeRequest' inside because
> it
> > > may
> > > > > take
> > > > > > > > > > > significant time (reproducer attached).
> > > > > > > > > > >
> > > > > > > > > > > I only want to point out a possible issue which may
> allow
> > > to
> > > > > end-user
> > > > > > > > > > > halt the Ignite cluster accidentally.
> > > > > > > > > > >
> > > > > > > > > > > I'm sure that PME experts know how to fix this issue
> > > > properly.
> > > > > > > > > > > On Wed, Sep 26, 2018 at 10:28 PM Andrey Gura <
> > > > agura@apache.org
> > > > > >
> > > > > > > >
> > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > Vyacheslav,
> > > > > > > > > > > >
> > > > > > > > > > > > Exchange worker is strongly tied with
> > > > > > > > > > > > GridDhtPartitionExchangeFuture#init and it is ok.
> > > Exchange
> > > > > worker
> > > > > > > >
> > > > > > > > also
> > > > > > > > > > > > shouldn't be blocked for long time but in reality it
> > > > > happens.It
> > > > > > > >
> > > > > > > > also
> > > > > > > > > > > > means that your change doesn't make sense.
> > > > > > > > > > > >
> > > > > > > > > > > > What actually make sense it is identification of
> places
> > > > which
> > > > > > > > > > > > intentionally blocking. May be some places/actions
> > should
> > > > be
> > > > > > > >
> > > > > > > > braced by
> > > > > > > > > > > > blocking guards.
> > > > > > > > > > > >
> > > > > > > > > > > > If you have failing tests please make sure that your
> > > > > > > >
> > > > > > > > failureHandler is
> > > > > > > > > > > > NoOpFailureHandler or any other handler with
> > > > > ignoreFailureTypes =
> > > > > > > > > > > > [CRITICAL_WORKER_BLOCKED].
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > On Wed, Sep 26, 2018 at 9:43 PM Vyacheslav Daradur <
> > > > > > > > > >
> > > > > > > > > > daradurvs@gmail.com>
> > > > > > > > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > Hi Igniters!
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thank you for this important improvement!
> > > > > > > > > > > > >
> > > > > > > > > > > > > I've looked through implementation and noticed that
> > > > > > > > > > > > > GridDhtPartitionsExchangeFuture#init has not been
> > > wrapped
> > > > > in
> > > > > > > >
> > > > > > > > blocked
> > > > > > > > > > > > > section. This means it easy to halt the node in
> case
> > of
> > > > > > > >
> > > > > > > > longrunning
> > > > > > > > > > > > > actions during PME, for example when we create a
> > cache
> > > > with
> > > > > > > > > > > > > StoreFactrory which connect to 3rd party DB.
> > > > > > > > > > > > >
> > > > > > > > > > > > > I'm not sure that it is the right behavior.
> > > > > > > > > > > > >
> > > > > > > > > > > > > I filled the issue [1] and prepared the PR [2] with
> > > > > reproducer
> > > > > > > >
> > > > > > > > and
> > > > > > > > > > >
> > > > > > > > > > > possible fix.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Andrey, could you please look at and confirm that
> it
> > > > makes
> > > > > sense?
> > > > > > > > > > > > >
> > > > > > > > > > > > > [1]
> > https://issues.apache.org/jira/browse/IGNITE-9710
> > > > > > > > > > > > > [2] https://github.com/apache/ignite/pull/4845
> > > > > > > > > > > > > On Mon, Sep 24, 2018 at 9:46 PM Andrey Kuznetsov <
> > > > > > > >
> > > > > > > > stkuzma@gmail.com>
> > > > > > > > > > >
> > > > > > > > > > > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Denis,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > I've created the ticket [1] with short
> description
> > of
> > > > the
> > > > > > > > > > >
> > > > > > > > > > > functionality.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > [1]
> > > https://issues.apache.org/jira/browse/IGNITE-9679
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > пн, 24 сент. 2018 г. в 17:46, Denis Magda <
> > > > > dmagda@apache.org>:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Andrey K. and G.,
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks, do we have a documentation ticket
> > created?
> > > > > Prachi
> > > > > > > > > >
> > > > > > > > > > (copied)
> > > > > > > > > > > can help
> > > > > > > > > > > > > > > with the documentation.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > --
> > > > > > > > > > > > > > > Denis
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Mon, Sep 24, 2018 at 5:51 AM Andrey Gura <
> > > > > > > >
> > > > > > > > agura@apache.org>
> > > > > > > > > > >
> > > > > > > > > > > wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Andrey,
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > finally your change is merged to master
> branch.
> > > > > > > >
> > > > > > > > Congratulations
> > > > > > > > > > >
> > > > > > > > > > > and
> > > > > > > > > > > > > > > > thank you very much! :)
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > I think that the next step is feature that
> will
> > > > allow
> > > > > > > >
> > > > > > > > signal
> > > > > > > > > > >
> > > > > > > > > > > about
> > > > > > > > > > > > > > > > blocked threads to the monitoring tools via
> > > MXBean.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > I hope you will continue development of this
> > > > feature
> > > > > and
> > > > > > > > > >
> > > > > > > > > > provide
> > > > > > > > > > > your
> > > > > > > > > > > > > > > > vision in new JIRA issue.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > On Tue, Sep 11, 2018 at 6:54 PM Andrey
> > Kuznetsov
> > > <
> > > > > > > > > > >
> > > > > > > > > > > stkuzma@gmail.com>
> > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > David, Maxim!
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Thanks a lot for you ideas. Unfortunately,
> I
> > > > can't
> > > > > adopt
> > > > > > > >
> > > > > > > > all
> > > > > > > > > > >
> > > > > > > > > > > of them
> > > > > > > > > > > > > > > > right
> > > > > > > > > > > > > > > > > now: the scope is much broader than the
> scope
> > > of
> > > > > the
> > > > > > > >
> > > > > > > > change I
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > implement.
> > > > > > > > > > > > > > > > I
> > > > > > > > > > > > > > > > > have had a talk to a group of Ignite
> > commiters,
> > > > > and we
> > > > > > > >
> > > > > > > > agreed
> > > > > > > > > > >
> > > > > > > > > > > to
> > > > > > > > > > > > > > > complete
> > > > > > > > > > > > > > > > > the change as follows.
> > > > > > > > > > > > > > > > > - Blocking instructions in system-critical
> > > which
> > > > > may
> > > > > > > > > >
> > > > > > > > > > resonably
> > > > > > > > > > > last
> > > > > > > > > > > > > > > long
> > > > > > > > > > > > > > > > > should be explicitly excluded from the
> > > > monitoring.
> > > > > > > > > > > > > > > > > - Failure handlers should have a setting to
> > > > > suppress some
> > > > > > > > > > >
> > > > > > > > > > > failures on
> > > > > > > > > > > > > > > > > per-failure-type basis.
> > > > > > > > > > > > > > > > > According to this I have updated the
> > > > > implementation: [1]
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > [1]
> > https://github.com/apache/ignite/pull/4089
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > пн, 10 сент. 2018 г. в 22:35, David Harvey
> <
> > > > > > > > > > >
> > > > > > > > > > > syssoftsol@gmail.com>:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > When I've done this before,I've needed to
> > > find
> > > > > the
> > > > > > > >
> > > > > > > > oldest
> > > > > > > > > > >
> > > > > > > > > > > thread,
> > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > kill
> > > > > > > > > > > > > > > > > > the node running that. From a language
> > > > > standpoint,
> > > > > > > > > >
> > > > > > > > > > Maxim's
> > > > > > > > > > > "without
> > > > > > > > > > > > > > > > > > progress" better than "heartbeat". For
> > > > > example, what
> > > > > > > >
> > > > > > > > I'm
> > > > > > > > > > >
> > > > > > > > > > > most
> > > > > > > > > > > > > > > > interested
> > > > > > > > > > > > > > > > > > in on a distributed system is which
> thread
> > > > > started the
> > > > > > > >
> > > > > > > > work
> > > > > > > > > > >
> > > > > > > > > > > it has
> > > > > > > > > > > > > > > not
> > > > > > > > > > > > > > > > > > completed the earliest, and when did that
> > > > thread
> > > > > last
> > > > > > > >
> > > > > > > > make
> > > > > > > > > > >
> > > > > > > > > > > forward
> > > > > > > > > > > > > > > > > > process. You don't want to kill a
> node
> > > > > because a
> > > > > > > >
> > > > > > > > thread
> > > > > > > > > > >
> > > > > > > > > > > is
> > > > > > > > > > > > > > > waiting
> > > > > > > > > > > > > > > > on a
> > > > > > > > > > > > > > > > > > lock held by a thread that went off-node
> > and
> > > > has
> > > > > not
> > > > > > > > > >
> > > > > > > > > > gotten a
> > > > > > > > > > > > > > > response.
> > > > > > > > > > > > > > > > > > If you don't understand the dependency
> > > > > relationships,
> > > > > > > >
> > > > > > > > you
> > > > > > > > > > >
> > > > > > > > > > > will make
> > > > > > > > > > > > > > > > > > incorrect recovery decisions.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > On Mon, Sep 10, 2018 at 4:08 AM Maxim
> > > > Muzafarov <
> > > > > > > > > > >
> > > > > > > > > > > maxmuzaf@gmail.com>
> > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > I think we should find exact answers to
> > > these
> > > > > > > >
> > > > > > > > questions:
> > > > > > > > > > > > > > > > > > > 1. What `critical` issue exactly is?
> > > > > > > > > > > > > > > > > > > 2. How can we find critical issues?
> > > > > > > > > > > > > > > > > > > 3. How can we handle critical issues?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > First,
> > > > > > > > > > > > > > > > > > > - Ignore uninterruptable actions (e.g.
> > > > > > > >
> > > > > > > > worker\service
> > > > > > > > > > >
> > > > > > > > > > > shutdown)
> > > > > > > > > > > > > > > > > > > - Long I/O operations (should be a
> > > > > configurable
> > > > > > > >
> > > > > > > > timeout
> > > > > > > > > > >
> > > > > > > > > > > for each
> > > > > > > > > > > > > > > > type of
> > > > > > > > > > > > > > > > > > > usage)
> > > > > > > > > > > > > > > > > > > - Infinite loops
> > > > > > > > > > > > > > > > > > > - Stalled\deadlocked threads (and\or
> too
> > > > many
> > > > > parked
> > > > > > > > > > >
> > > > > > > > > > > threads,
> > > > > > > > > > > > > > > > exclude
> > > > > > > > > > > > > > > > > > I/O)
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Second,
> > > > > > > > > > > > > > > > > > > - The working queue is without
> progress
> > > > (e.g.
> > > > > disco,
> > > > > > > > > > >
> > > > > > > > > > > exchange
> > > > > > > > > > > > > > > > queues)
> > > > > > > > > > > > > > > > > > > - Work hasn't been completed since the
> > > last
> > > > > > > >
> > > > > > > > heartbeat
> > > > > > > > > > >
> > > > > > > > > > > (checking
> > > > > > > > > > > > > > > > > > > milestones)
> > > > > > > > > > > > > > > > > > > - Too many system resources used by a
> > > thread
> > > > > for the
> > > > > > > > > >
> > > > > > > > > > long
> > > > > > > > > > > period
> > > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > time
> > > > > > > > > > > > > > > > > > > (allocated memory, CPU)
> > > > > > > > > > > > > > > > > > > - Timing fields associated with each
> > > thread
> > > > > status
> > > > > > > > > > >
> > > > > > > > > > > exceeded a
> > > > > > > > > > > > > > > > maximum
> > > > > > > > > > > > > > > > > > time
> > > > > > > > > > > > > > > > > > > limit.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Third (not too many options here),
> > > > > > > > > > > > > > > > > > > - `log everything` should be the
> default
> > > > > behaviour
> > > > > > > >
> > > > > > > > in
> > > > > > > > > >
> > > > > > > > > > all
> > > > > > > > > > > these
> > > > > > > > > > > > > > > > cases,
> > > > > > > > > > > > > > > > > > > since it may be difficult to find the
> > cause
> > > > > after the
> > > > > > > > > > >
> > > > > > > > > > > restart.
> > > > > > > > > > > > > > > > > > > - Wait some interval of time and kill
> > the
> > > > > hanging
> > > > > > > >
> > > > > > > > node
> > > > > > > > > > >
> > > > > > > > > > > (cluster
> > > > > > > > > > > > > > > > should
> > > > > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > > > configured stable enough)
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Questions,
> > > > > > > > > > > > > > > > > > > - Not sure, but can workers miss their
> > > > > heartbeat
> > > > > > > > > > >
> > > > > > > > > > > deadlines if CPU
> > > > > > > > > > > > > > > > loads
> > > > > > > > > > > > > > > > > > up
> > > > > > > > > > > > > > > > > > > to 80%-90%? Bursts of momentary
> overloads
> > > can
> > > > > be
> > > > > > > > > > > > > > > > > > > expected behaviour as a normal part
> > of
> > > > > system
> > > > > > > > > > >
> > > > > > > > > > > operations.
> > > > > > > > > > > > > > > > > > > - Why do we decide that critical
> thread
> > > > should
> > > > > > > >
> > > > > > > > monitor
> > > > > > > > > > >
> > > > > > > > > > > each other?
> > > > > > > > > > > > > > > > For
> > > > > > > > > > > > > > > > > > > instance, if all the tasks were blocked
> > and
> > > > > unable to
> > > > > > > > > >
> > > > > > > > > > run,
> > > > > > > > > > > > > > > > > > > node reset would never occur. As
> for
> > > me,
> > > > a
> > > > > better
> > > > > > > > > > >
> > > > > > > > > > > solution is
> > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > use
> > > > > > > > > > > > > > > > > > a
> > > > > > > > > > > > > > > > > > > separate monitor thread or pool (maybe
> > both
> > > > > with
> > > > > > > >
> > > > > > > > software
> > > > > > > > > > > > > > > > > > > and hardware checks) that not only
> > > checks
> > > > > > > >
> > > > > > > > heartbeats
> > > > > > > > > > >
> > > > > > > > > > > but
> > > > > > > > > > > > > > > > monitors the
> > > > > > > > > > > > > > > > > > > other system as well.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > On Mon, 10 Sep 2018 at 00:07 David
> > Harvey <
> > > > > > > > > > >
> > > > > > > > > > > syssoftsol@gmail.com>
> > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > It would be safer to restart the
> entire
> > > > > cluster
> > > > > > > >
> > > > > > > > than to
> > > > > > > > > > >
> > > > > > > > > > > remove
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > last
> > > > > > > > > > > > > > > > > > > > node for a cache that should be
> > > redundant.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > On Sun, Sep 9, 2018, 4:00 PM Andrey
> > Gura
> > > <
> > > > > > > > > > >
> > > > > > > > > > > agura@apache.org>
> > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > Hi,
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > I agree with Yakov that we can
> > provide
> > > > some
> > > > > > > >
> > > > > > > > option
> > > > > > > > > > >
> > > > > > > > > > > that manage
> > > > > > > > > > > > > > > > worker
> > > > > > > > > > > > > > > > > > > > > liveness checker behavior in case
> of
> > > > > observing
> > > > > > > >
> > > > > > > > that
> > > > > > > > > > >
> > > > > > > > > > > some worker
> > > > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > > > > > > blocked too long.
> > > > > > > > > > > > > > > > > > > > > At least it will some workaround
> for
> > > > > cases when
> > > > > > > >
> > > > > > > > node
> > > > > > > > > > >
> > > > > > > > > > > fails is
> > > > > > > > > > > > > > > > too
> > > > > > > > > > > > > > > > > > > > > annoying.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > Backups count threshold sounds good
> > > but I
> > > > > don't
> > > > > > > > > > >
> > > > > > > > > > > understand how
> > > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > > will
> > > > > > > > > > > > > > > > > > > > > help in case of cluster hanging.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > The simplest solution here is alert
> > in
> > > > > cases of
> > > > > > > > > > >
> > > > > > > > > > > blocking of
> > > > > > > > > > > > > > > some
> > > > > > > > > > > > > > > > > > > > > critical worker (we can improve
> > > > > WorkersRegistry
> > > > > > > >
> > > > > > > > for
> > > > > > > > > > >
> > > > > > > > > > > this
> > > > > > > > > > > > > > > purpose
> > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > > expose list of blocked workers) and
> > > > > optionally
> > > > > > > >
> > > > > > > > call
> > > > > > > > > > >
> > > > > > > > > > > system
> > > > > > > > > > > > > > > > configured
> > > > > > > > > > > > > > > > > > > > > failure processor. BTW, failure
> > > processor
> > > > > can be
> > > > > > > > > > >
> > > > > > > > > > > extended in
> > > > > > > > > > > > > > > > order to
> > > > > > > > > > > > > > > > > > > > > perform any checks (e.g. backup
> > count)
> > > > and
> > > > > decide
> > > > > > > > > > >
> > > > > > > > > > > whether it
> > > > > > > > > > > > > > > > should
> > > > > > > > > > > > > > > > > > > > > stop node or not.
> > > > > > > > > > > > > > > > > > > > > On Sat, Sep 8, 2018 at 3:42 PM
> Andrey
> > > > > Kuznetsov <
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > stkuzma@gmail.com>
> > > > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > David, Yakov, I understand your
> > > fears.
> > > > > But
> > > > > > > >
> > > > > > > > liveness
> > > > > > > > > > >
> > > > > > > > > > > checks
> > > > > > > > > > > > > > > deal
> > > > > > > > > > > > > > > > > > with
> > > > > > > > > > > > > > > > > > > > > > _critical_ conditions, i.e. when
> > > such a
> > > > > > > >
> > > > > > > > condition
> > > > > > > > > >
> > > > > > > > > > is
> > > > > > > > > > > met we
> > > > > > > > > > > > > > > > > > conclude
> > > > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > > > node as totally broken, and there
> > is
> > > no
> > > > > sense
> > > > > > > >
> > > > > > > > to
> > > > > > > > > > >
> > > > > > > > > > > keep it
> > > > > > > > > > > > > > > alive
> > > > > > > > > > > > > > > > > > > > regardless
> > > > > > > > > > > > > > > > > > > > > > the data it contains. If we want
> to
> > > > give
> > > > > it a
> > > > > > > > > > >
> > > > > > > > > > > chance, then
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > condition
> > > > > > > > > > > > > > > > > > > > > > (long fsync etc.) should not
> > > considered
> > > > > as
> > > > > > > >
> > > > > > > > critical
> > > > > > > > > > >
> > > > > > > > > > > at all.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > сб, 8 сент. 2018 г. в 15:18,
> Yakov
> > > > > Zhdanov <
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > yzhdanov@apache.org>:
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > > Agree with David. We need to
> have
> > > an
> > > > > > > >
> > > > > > > > opporunity
> > > > > > > > > > >
> > > > > > > > > > > set backups
> > > > > > > > > > > > > > > > count
> > > > > > > > > > > > > > > > > > > > > threshold
> > > > > > > > > > > > > > > > > > > > > > > (at runtime also!) that will
> not
> > > > allow
> > > > > any
> > > > > > > > > > >
> > > > > > > > > > > automatic stop
> > > > > > > > > > > > > > > if
> > > > > > > > > > > > > > > > > > there
> > > > > > > > > > > > > > > > > > > > > will be
> > > > > > > > > > > > > > > > > > > > > > > a data loss. Andrey, what do
> you
> > > > think?
> > > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > > --Yakov
> > > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > --
> > > > > > > > > > > > > > > > > > > > > > Best regards,
> > > > > > > > > > > > > > > > > > > > > > Andrey Kuznetsov.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > --
> > > > > > > > > > > > > > > > > > > --
> > > > > > > > > > > > > > > > > > > Maxim Muzafarov
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > --
> > > > > > > > > > > > > > > > > Best regards,
> > > > > > > > > > > > > > > > > Andrey Kuznetsov.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > --
> > > > > > > > > > > > > > Best regards,
> > > > > > > > > > > > > > Andrey Kuznetsov.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > --
> > > > > > > > > > > > > Best Regards, Vyacheslav D.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > --
> > > > > > > > > > > Best Regards, Vyacheslav D.
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > --
> > > > > > > > > > --
> > > > > > > > > > Maxim Muzafarov
> > > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > >
> > > >
> > >
> > --
> > --
> > Maxim Muzafarov
> >
>
>
> --
> Best regards,
> Andrey Kuznetsov.
>