How about skipWalOnRebalancing or disableWalOnRebalancing? I like the first
one better and both are shorter.

--Yakov

2018-04-09 19:55 GMT+03:00 Denis Magda <dma...@apache.org>:

> I would enable this option only after we confirm it's stable. Until it
> happens it should be treated as an experimental feature that is turned on
> manually with a parameter like Ilya is suggesting.
>
> Ilya, the name sounds good to me.
>
> --
> Denis
>
> On Mon, Apr 9, 2018 at 9:16 AM, Anton Vinogradov <a...@apache.org> wrote:
>
> > Ilya,
> >
> > WAL should be automatically disabled at initial rebalancing.
> > It can't be disabled at regilar rebalancing, since you never ready to
> lose
> > data you protected by WAL.
> > Is there any need to have special param in that case?
> >
> > 2018-04-09 16:41 GMT+03:00 Ilya Lantukh <ilant...@gridgain.com>:
> >
> > > Igniters,
> > >
> > > I am currently at the finish line of
> > > https://issues.apache.org/jira/browse/IGNITE-8017 ("Disable WAL during
> > > initial preloading") implementation. And I need that such behavior
> should
> > > be configurable. In my intermediate implementation I have parameter
> > called
> > > "disableWalDuringRebalancing" in IgniteConfiguration. Do you thing such
> > > name is meaningful and self-explanatory? Do we need to ensure that it
> has
> > > the same value on every node? Should I make it configurable per cache
> > > rather than globally?
> > >
> > > Please share your thoughts.
> > >
> > > On Mon, Apr 9, 2018 at 4:32 PM, Ilya Lantukh <ilant...@gridgain.com>
> > > wrote:
> > >
> > > > Denis,
> > > >
> > > > Those ticket are rather complex, and so I don't know when I'll be
> able
> > to
> > > > start working on them.
> > > >
> > > > On Fri, Mar 30, 2018 at 11:45 PM, Denis Magda <dma...@apache.org>
> > wrote:
> > > >
> > > >> Ilya,
> > > >>
> > > >> Just came across the IEP put together by you:
> > > >> https://cwiki.apache.org/confluence/display/IGNITE/IEP-16%
> > > >> 3A+Optimization+of+rebalancing
> > > >>
> > > >> Excellent explanation, thanks for aggregating everything there.
> > > >>
> > > >> Two tickets below don't have a fixed version assigned:
> > > >> https://issues.apache.org/jira/browse/IGNITE-8020
> > > >> https://issues.apache.org/jira/browse/IGNITE-7935
> > > >>
> > > >> Do you plan to work on them in 2.6 time frame, right?
> > > >>
> > > >> --
> > > >> Denis
> > > >>
> > > >> On Tue, Mar 27, 2018 at 9:29 AM, Denis Magda <dma...@apache.org>
> > wrote:
> > > >>
> > > >> > Ilya, granted you all the required permissions. Please let me know
> > if
> > > >> you
> > > >> > still have troubles with the wiki.
> > > >> >
> > > >> > --
> > > >> > Denis
> > > >> >
> > > >> > On Tue, Mar 27, 2018 at 8:56 AM, Ilya Lantukh <
> > ilant...@gridgain.com>
> > > >> > wrote:
> > > >> >
> > > >> >> Unfortunately, I don't have permission to create page for IEP on
> > > wiki.
> > > >> >> Denis, can you grant it? My username is ilantukh.
> > > >> >>
> > > >> >> On Mon, Mar 26, 2018 at 8:04 PM, Anton Vinogradov <a...@apache.org
> >
> > > >> wrote:
> > > >> >>
> > > >> >> > >> It is impossible to disable WAL only for certain partitions
> > > >> without
> > > >> >> > >> completely overhauling design of Ignite storage mechanism.
> > Right
> > > >> now
> > > >> >> we
> > > >> >> > can
> > > >> >> > >> afford only to change WAL mode per cache group.
> > > >> >> >
> > > >> >> > Cache group rebalancing is a one cache rebalancing, and then
> this
> > > >> cache
> > > >> >> > ("cache group") can be presented as a set of virtual caches.
> > > >> >> > So, there is no issues for initial rebalancing.
> > > >> >> > Lets disable WAL on initial rebalancing.
> > > >> >> >
> > > >> >> > 2018-03-26 16:46 GMT+03:00 Ilya Lantukh <ilant...@gridgain.com
> >:
> > > >> >> >
> > > >> >> > > Dmitry,
> > > >> >> > > It is impossible to disable WAL only for certain partitions
> > > without
> > > >> >> > > completely overhauling design of Ignite storage mechanism.
> > Right
> > > >> now
> > > >> >> we
> > > >> >> > can
> > > >> >> > > afford only to change WAL mode per cache group.
> > > >> >> > >
> > > >> >> > > The idea is to disable WAL when node doesn't have any
> partition
> > > in
> > > >> >> OWNING
> > > >> >> > > state, which means it doesn't have any consistent data and
> > won't
> > > be
> > > >> >> able
> > > >> >> > to
> > > >> >> > > restore from WAL anyway. I don't see any potential use for
> WAL
> > on
> > > >> such
> > > >> >> > > node, but we can keep a configurable parameter indicating can
> > we
> > > >> >> > > automatically disable WAL in such case or not.
> > > >> >> > >
> > > >> >> > > On Fri, Mar 23, 2018 at 10:40 PM, Dmitry Pavlov <
> > > >> >> dpavlov....@gmail.com>
> > > >> >> > > wrote:
> > > >> >> > >
> > > >> >> > > > Denis, as I understood, there is and idea to exclude only
> > > >> rebalanced
> > > >> >> > > > partition(s) data. All other data will go to the WAL.
> > > >> >> > > >
> > > >> >> > > > Ilya, please correct me if I'm wrong.
> > > >> >> > > >
> > > >> >> > > > пт, 23 мар. 2018 г. в 22:15, Denis Magda <
> dma...@apache.org
> > >:
> > > >> >> > > >
> > > >> >> > > > > Ilya,
> > > >> >> > > > >
> > > >> >> > > > > That's a decent boost (5-20%) even having WAL enabled.
> Not
> > > sure
> > > >> >> that
> > > >> >> > we
> > > >> >> > > > > should stake on the WAL "off" mode here because if the
> > whole
> > > >> >> cluster
> > > >> >> > > goes
> > > >> >> > > > > down, it's then the data consistency is questionable. As
> an
> > > >> >> > architect,
> > > >> >> > > I
> > > >> >> > > > > wouldn't disable WAL for the sake of rebalancing; it's
> too
> > > >> risky.
> > > >> >> > > > >
> > > >> >> > > > > If you agree, then let's create the IEP. This way it will
> > be
> > > >> >> easier
> > > >> >> > to
> > > >> >> > > > > track this endeavor. BTW, are you already ready to
> release
> > > any
> > > >> >> > > > > optimizations in 2.5 that is being discussed in a
> separate
> > > >> thread?
> > > >> >> > > > >
> > > >> >> > > > > --
> > > >> >> > > > > Denis
> > > >> >> > > > >
> > > >> >> > > > >
> > > >> >> > > > >
> > > >> >> > > > > On Fri, Mar 23, 2018 at 6:37 AM, Ilya Lantukh <
> > > >> >> ilant...@gridgain.com
> > > >> >> > >
> > > >> >> > > > > wrote:
> > > >> >> > > > >
> > > >> >> > > > > > Denis,
> > > >> >> > > > > >
> > > >> >> > > > > > > - Don't you want to aggregate the tickets under an
> IEP?
> > > >> >> > > > > > Yes, I think so.
> > > >> >> > > > > >
> > > >> >> > > > > > > - Does it mean we're going to update our B+Tree
> > > >> >> implementation?
> > > >> >> > Any
> > > >> >> > > > > ideas
> > > >> >> > > > > > how risky it is?
> > > >> >> > > > > > One of tickets that I created (
> > > >> >> > > > > > https://issues.apache.org/jira/browse/IGNITE-7935)
> > > involves
> > > >> >> B+Tree
> > > >> >> > > > > > modification, but I am not planning to do it in the
> > nearest
> > > >> >> future.
> > > >> >> > > It
> > > >> >> > > > > > shouldn't affect existing tree operations, only
> introduce
> > > new
> > > >> >> ones
> > > >> >> > > > > (putAll,
> > > >> >> > > > > > invokeAll, removeAll).
> > > >> >> > > > > >
> > > >> >> > > > > > > - Any chance you had a prototype that shows
> performance
> > > >> >> > > optimizations
> > > >> >> > > > > the
> > > >> >> > > > > > approach you are suggesting to take?
> > > >> >> > > > > > I have a prototype for simplest improvements (
> > > >> >> > > > https://issues.apache.org/
> > > >> >> > > > > > jira/browse/IGNITE-8019 & https://issues.apache.org/
> > > >> >> > > > > > jira/browse/IGNITE-8018)
> > > >> >> > > > > > - together they increase throughput by 5-20%, depending
> > on
> > > >> >> > > > configuration
> > > >> >> > > > > > and environment. Also, I've tested different WAL modes
> -
> > > >> >> switching
> > > >> >> > > from
> > > >> >> > > > > > LOG_ONLY to NONE gives over 100% boost - this is what I
> > > >> expect
> > > >> >> from
> > > >> >> > > > > > https://issues.apache.org/jira/browse/IGNITE-8017.
> > > >> >> > > > > >
> > > >> >> > > > > > On Thu, Mar 22, 2018 at 9:48 PM, Denis Magda <
> > > >> dma...@apache.org
> > > >> >> >
> > > >> >> > > > wrote:
> > > >> >> > > > > >
> > > >> >> > > > > > > Ilya,
> > > >> >> > > > > > >
> > > >> >> > > > > > > That's outstanding research and summary. Thanks for
> > > >> spending
> > > >> >> your
> > > >> >> > > > time
> > > >> >> > > > > on
> > > >> >> > > > > > > this.
> > > >> >> > > > > > >
> > > >> >> > > > > > > Not sure I have enough expertise to challenge your
> > > >> approach,
> > > >> >> but
> > > >> >> > it
> > > >> >> > > > > > sounds
> > > >> >> > > > > > > 100% reasonable to me. As side notes:
> > > >> >> > > > > > >
> > > >> >> > > > > > >    - Don't you want to aggregate the tickets under an
> > > IEP?
> > > >> >> > > > > > >    - Does it mean we're going to update our B+Tree
> > > >> >> > implementation?
> > > >> >> > > > Any
> > > >> >> > > > > > >    ideas how risky it is?
> > > >> >> > > > > > >    - Any chance you had a prototype that shows
> > > performance
> > > >> >> > > > > optimizations
> > > >> >> > > > > > of
> > > >> >> > > > > > >    the approach you are suggesting to take?
> > > >> >> > > > > > >
> > > >> >> > > > > > > --
> > > >> >> > > > > > > Denis
> > > >> >> > > > > > >
> > > >> >> > > > > > > On Thu, Mar 22, 2018 at 8:38 AM, Ilya Lantukh <
> > > >> >> > > ilant...@gridgain.com
> > > >> >> > > > >
> > > >> >> > > > > > > wrote:
> > > >> >> > > > > > >
> > > >> >> > > > > > > > Igniters,
> > > >> >> > > > > > > >
> > > >> >> > > > > > > > I've spent some time analyzing performance of
> > > rebalancing
> > > >> >> > > process.
> > > >> >> > > > > The
> > > >> >> > > > > > > > initial goal was to understand, what limits it's
> > > >> throughput,
> > > >> >> > > > because
> > > >> >> > > > > it
> > > >> >> > > > > > > is
> > > >> >> > > > > > > > significantly slower than network and storage
> device
> > > can
> > > >> >> > > > > theoretically
> > > >> >> > > > > > > > handle.
> > > >> >> > > > > > > >
> > > >> >> > > > > > > > Turns out, our current implementation has a number
> of
> > > >> issues
> > > >> >> > > caused
> > > >> >> > > > > by
> > > >> >> > > > > > a
> > > >> >> > > > > > > > single fundamental problem.
> > > >> >> > > > > > > >
> > > >> >> > > > > > > > During rebalance data is sent in batches called
> > > >> >> > > > > > > > GridDhtPartitionSupplyMessages. Batch size is
> > > >> configurable,
> > > >> >> > > > default
> > > >> >> > > > > > > value
> > > >> >> > > > > > > > is 512KB, which could mean thousands of key-value
> > > pairs.
> > > >> >> > However,
> > > >> >> > > > we
> > > >> >> > > > > > > don't
> > > >> >> > > > > > > > take any advantage over this fact and process each
> > > entry
> > > >> >> > > > > independently:
> > > >> >> > > > > > > > - checkpointReadLock is acquired multiple times for
> > > every
> > > >> >> > entry,
> > > >> >> > > > > > leading
> > > >> >> > > > > > > to
> > > >> >> > > > > > > > unnecessary contention - this is clearly a bug;
> > > >> >> > > > > > > > - for each entry we write (and fsync, if
> > configuration
> > > >> >> assumes
> > > >> >> > > it)
> > > >> >> > > > a
> > > >> >> > > > > > > > separate WAL record - so, if batch contains N
> > entries,
> > > we
> > > >> >> might
> > > >> >> > > end
> > > >> >> > > > > up
> > > >> >> > > > > > > > doing N fsyncs;
> > > >> >> > > > > > > > - adding every entry into CacheDataStore also
> happens
> > > >> >> > completely
> > > >> >> > > > > > > > independently. It means, we will traverse and
> modify
> > > each
> > > >> >> index
> > > >> >> > > > tree
> > > >> >> > > > > N
> > > >> >> > > > > > > > times, we will allocate space in FreeList N times
> and
> > > we
> > > >> >> will
> > > >> >> > > have
> > > >> >> > > > to
> > > >> >> > > > > > > > additionally store in WAL O(N*log(N)) page delta
> > > records.
> > > >> >> > > > > > > >
> > > >> >> > > > > > > > I've created a few tickets in JIRA with very
> > different
> > > >> >> levels
> > > >> >> > of
> > > >> >> > > > > scale
> > > >> >> > > > > > > and
> > > >> >> > > > > > > > complexity.
> > > >> >> > > > > > > >
> > > >> >> > > > > > > > Ways to reduce impact of independent processing:
> > > >> >> > > > > > > > - https://issues.apache.org/
> jira/browse/IGNITE-8019
> > -
> > > >> >> > > > aforementioned
> > > >> >> > > > > > > bug,
> > > >> >> > > > > > > > causing contention on checkpointReadLock;
> > > >> >> > > > > > > > - https://issues.apache.org/
> jira/browse/IGNITE-8018
> > -
> > > >> >> > > inefficiency
> > > >> >> > > > > in
> > > >> >> > > > > > > > GridCacheMapEntry implementation;
> > > >> >> > > > > > > > - https://issues.apache.org/
> jira/browse/IGNITE-8017
> > -
> > > >> >> > > > automatically
> > > >> >> > > > > > > > disable
> > > >> >> > > > > > > > WAL during preloading.
> > > >> >> > > > > > > >
> > > >> >> > > > > > > > Ways to solve problem on more global level:
> > > >> >> > > > > > > > - https://issues.apache.org/
> jira/browse/IGNITE-7935
> > -
> > > a
> > > >> >> ticket
> > > >> >> > > to
> > > >> >> > > > > > > > introduce
> > > >> >> > > > > > > > batch modification;
> > > >> >> > > > > > > > - https://issues.apache.org/
> jira/browse/IGNITE-8020
> > -
> > > >> >> complete
> > > >> >> > > > > > redesign
> > > >> >> > > > > > > of
> > > >> >> > > > > > > > rebalancing process for persistent caches, based on
> > > file
> > > >> >> > > transfer.
> > > >> >> > > > > > > >
> > > >> >> > > > > > > > Everyone is welcome to criticize above ideas,
> suggest
> > > new
> > > >> >> ones
> > > >> >> > or
> > > >> >> > > > > > > > participate in implementation.
> > > >> >> > > > > > > >
> > > >> >> > > > > > > > --
> > > >> >> > > > > > > > Best regards,
> > > >> >> > > > > > > > Ilya
> > > >> >> > > > > > > >
> > > >> >> > > > > > >
> > > >> >> > > > > >
> > > >> >> > > > > >
> > > >> >> > > > > >
> > > >> >> > > > > > --
> > > >> >> > > > > > Best regards,
> > > >> >> > > > > > Ilya
> > > >> >> > > > > >
> > > >> >> > > > >
> > > >> >> > > >
> > > >> >> > >
> > > >> >> > >
> > > >> >> > >
> > > >> >> > > --
> > > >> >> > > Best regards,
> > > >> >> > > Ilya
> > > >> >> > >
> > > >> >> >
> > > >> >>
> > > >> >>
> > > >> >>
> > > >> >> --
> > > >> >> Best regards,
> > > >> >> Ilya
> > > >> >>
> > > >> >
> > > >> >
> > > >>
> > > >
> > > >
> > > >
> > > > --
> > > > Best regards,
> > > > Ilya
> > > >
> > >
> > >
> > >
> > > --
> > > Best regards,
> > > Ilya
> > >
> >
>

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