Hello, Ignite.

Finally, I've implemented this ticket! :)

Jira - https://issues.apache.org/jira/browse/IGNITE-9113
PR - https://github.com/apache/ignite/pull/6388

Tests seems to be OK.
Anyone wants to take a look?

В Чт, 09/08/2018 в 16:41 +0300, Alexey Goncharuk пишет:
> Once the OS gave us the pointer, no exceptions can be raised in the user
> code. If the OS overcommitted the memory, then the process will be halted
> when OOME occurs, not much we can do here.
> 
> My point was that dynamic data region allocation can lead to another
> dynamic exception that should be properly handled during cache start. When
> the data region is allocated statically, this exception is handled on node
> start, which is much easier.
> 
> ср, 8 авг. 2018 г. в 18:18, Dmitriy Pavlov <[email protected]>:
> 
> > I used to think that OS allocates pages not immediately after call to
> > allocate(), but only during first touch of each page.
> > 
> > I'm not sure every OS provides guaranee that 'allocated' memory will never
> > cause OOME. Please correct me if I'm wrong.
> > 
> > ср, 8 авг. 2018 г. в 17:38, Dmitriy Setrakyan <[email protected]>:
> > 
> > > Alexey,
> > > 
> > > I am not sure I understand. If cache creation proceeds, but memory region
> > > was not allocated, how can the cache operate?
> > > 
> > > D.
> > > 
> > > On Wed, Aug 8, 2018 at 8:05 AM, Alexey Goncharuk <
> > > [email protected]
> > > > wrote:
> > > > I do not mind making this change, but note that the reason for non-lazy
> > > > region allocation is the need to gracefully handle OOME errors during
> > > 
> > > cache
> > > > start. When a region is pre-allocated, no OOME can happen.
> > > > 
> > > > If a region is allocated dynamically, then all errors that happened
> > > 
> > > during
> > > > the node start before should be properly handled (a client node must be
> > > > stopped, but cache creation should proceed).
> > > > 
> > > > пт, 27 июл. 2018 г. в 20:04, Valentin Kulichenko <
> > > > [email protected]>:
> > > > 
> > > > > Ticket created: https://issues.apache.org/jira/browse/IGNITE-9113
> > > > > 
> > > > > -Val
> > > > > 
> > > > > On Fri, Jul 27, 2018 at 5:59 AM Dmitry Pavlov <[email protected]
> > > > > wrote:
> > > > > 
> > > > > > Maxim, thank you.
> > > > > > 
> > > > > > If it seems it is technically possible, we can file ticket for this
> > > > > 
> > > > > change.
> > > > > > 
> > > > > > I find this proposal reasonable, change makes perfectly sense to
> > 
> > me.
> > > > > > 
> > > > > > We can wait Alex G. feedback on this change before starting actual
> > > > > > implementation. It can take for a while, because he is travelling
> > > 
> > > now.
> > > > > > 
> > > > > > пт, 27 июл. 2018 г. в 14:35, Maxim Muzafarov <[email protected]>:
> > > > > > 
> > > > > > > Guys,
> > > > > > > 
> > > > > > > I can miss some details, but at the first glance we have
> > 
> > everething
> > > > we
> > > > > > need
> > > > > > > to defer
> > > > > > > region memory allocation if it has no cache groups assignments.
> > 
> > And
> > > > it
> > > > > > > doesn't matter
> > > > > > > where it happens on client or server nodes.
> > > > > > > 
> > > > > > > Currently region memory allocation happens at exchange future
> > 
> > init
> > > > > > method.
> > > > > > > At the
> > > > > > > node startup method initCachesOnLocalJoin executes. This method
> > > > > > 
> > > > > > resposnible
> > > > > > > for
> > > > > > > memory allocation (through initiating cache managers) and it also
> > > > > 
> > > > > starts
> > > > > > > caches.
> > > > > > > So, at this point we have all existing caches descriptors and can
> > > > 
> > > > find
> > > > > > out
> > > > > > > which
> > > > > > > cache matches which region to defer some regions initialization
> > 
> > to
> > > > the
> > > > > > > moment when
> > > > > > > newly cache assings to this region (happend at
> > > 
> > > onCacheChangeRequest).
> > > > > > > 
> > > > > > > Please, сorrect me if I'm wrong and missing something.
> > > > > > > 
> > > > > > > 
> > > > > > > 
> > > > > > > On Wed, 25 Jul 2018 at 19:32 Dmitry Pavlov <
> > 
> > [email protected]>
> > > > > > wrote:
> > > > > > > 
> > > > > > > > Hi Maxim,
> > > > > > > > 
> > > > > > > > thank you for stepping in. How do you think, is it possible to
> > > > 
> > > > check
> > > > > > > cache
> > > > > > > > assignment to region at stage of memory allocation?
> > > > > > > > 
> > > > > > > > Sincerely,
> > > > > > > > Dmitriy Pavlov
> > > > > > > > 
> > > > > > > > ср, 25 июл. 2018 г. в 18:22, Maxim Muzafarov <
> > 
> > [email protected]
> > > > :
> > > > > > > > 
> > > > > > > > > Folks,
> > > > > > > > > 
> > > > > > > > > I've checked memory allocation. It looks like we are
> > 
> > allocating
> > > > > > memory
> > > > > > > > only
> > > > > > > > > on the first exchange future init on local join occurs on
> > 
> > node.
> > > > > Also,
> > > > > > > > seems
> > > > > > > > > like we are allocating only the first chunk of memory (not
> > 
> > the
> > > > > whole
> > > > > > > > bunch)
> > > > > > > > > and it calculates as:
> > > > > > > > > 
> > > > > > > > > Math.max((maxSize - startSize) / (SEG_CNT - 1), 256L * 1024 *
> > > > 
> > > > 1024)
> > > > > > > > > 
> > > > > > > > > But, I'm agree with Val. It's better to allocate memory only
> > > 
> > > when
> > > > > > when
> > > > > > > > > the first cache assigned to this region.
> > > > > > > > > 
> > > > > > > > > 
> > > > > > > > > 
> > > > > > > > > Also, It seems like we have some problem with user
> > 
> > notification
> > > > > about
> > > > > > > > > available
> > > > > > > > > physical resources. For client nodes method requiredOffheap()
> > > > > 
> > > > > returns
> > > > > > > > > always
> > > > > > > > > zero [1]. That's why WARN message shown here [2] would be not
> > > 
> > > not
> > > > > > quite
> > > > > > > > > right
> > > > > > > > > if we have a lot of client nodes in cluster.
> > > > > > > > > 
> > > > > > > > > 
> > > > > > > > > [1]
> > > > > > > > > 
> > > > > > > > > 
> > > > > 
> > > > > https://github.com/apache/ignite/blob/master/modules/
> > > > 
> > > > core/src/main/java/org/apache/ignite/internal/managers/discovery/
> > > > GridDiscoveryManager.java#L1501
> > > > > > > > > [2]
> > > > > > > > > 
> > > > > > > > > 
> > > > > 
> > > > > https://github.com/apache/ignite/blob/master/modules/
> > > > 
> > > > core/src/main/java/org/apache/ignite/internal/IgniteKernal.java#L1489
> > > > > > > > > 
> > > > > > > > > сб, 21 июл. 2018 г. в 14:15, Dmitriy Setrakyan <
> > > > > > 
> > > > > > [email protected]
> > > > > > > > :
> > > > > > > > > 
> > > > > > > > > > On Sat, Jul 21, 2018 at 5:22 AM, Valentin Kulichenko <
> > > > > > > > > > [email protected]> wrote:
> > > > > > > > > > 
> > > > > > > > > > > Actually, I would go even further: only allocate a data
> > > > 
> > > > region
> > > > > > on a
> > > > > > > > > node
> > > > > > > > > > > when the first cache assigned to this region is deployed
> > 
> > on
> > > > > that
> > > > > > > > node.
> > > > > > > > > > > Because issue is broader than client nodes and local
> > > 
> > > caches.
> > > > > One
> > > > > > > can
> > > > > > > > > have
> > > > > > > > > > > server nodes without any caches as well - running only
> > > > > 
> > > > > services,
> > > > > > > for
> > > > > > > > > > > example.
> > > > > > > > > > > 
> > > > > > > > > > 
> > > > > > > > > > It would be great if this was possible, but to my
> > 
> > knowledge,
> > > > > > regions
> > > > > > > > need
> > > > > > > > > > to be allocated on startup.
> > > > > > > > > > 
> > > > > > > > > > Alexey Goncharuk, do you have any suggestions on this?
> > > > > > > > > > 
> > > > > > > > > > D.
> > > > > > > > > > 
> > > > > > > > > 
> > > > > > > > > --
> > > > > > > > > --
> > > > > > > > > Maxim Muzafarov
> > > > > > > > > 
> > > > > > > 
> > > > > > > --
> > > > > > > --
> > > > > > > Maxim Muzafarov
> > > > > > > 

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