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From Sergi Vladykin <sergi.vlady...@gmail.com>
Subject Re: Off-Heap SQL Indexes
Date Sat, 05 Nov 2016 13:23:00 GMT
Your final statement seems correct to me, but I said exactly that, I don't
know where did you get that setOffHeapMaxMemory must be 0. May be you use
some weird email client which renders >> signs wrong?

Sergi

2016-11-04 22:25 GMT+03:00 Denis Magda <dmagda@gridgain.com>:

> Sergi,
>
> Thanks, now I found the exact conditions that switch the indexes from
> on-heap to off-heap.
>
> But looks like you did a misprint in your conclusion saying that
> setOffHeapMaxMemory should be 0.
> > Thus from the user standpoint we can say, that if either
> setOffHeapMaxMemory
> >> = 0 or setMemoryMode is set to any of off-heap modes, then indexes will
> go
> > off-heap.
>
> In fact, as you elaborated earlier, it has to be >= 0 which leads to the
> following final statement:
>
> SQL engine will store indexes in the off-heap region if
> setOffHeapMaxMemory parameter >= 0 or setMemoryMode is set to any supported
> off-heap mode. It worth to mention that setOffHeapMaxMemory is set to 0
> automatically if it’s value is less than -1 and one of off-heap memory
> modes is used.
>
> Are we on the same page now?
>
> —
> Denis
>
> > On Nov 4, 2016, at 1:51 AM, Sergi Vladykin <sergi.vladykin@gmail.com>
> wrote:
> >
> > Denis,
> >
> > I checked the code now as well. I actually was wrong, but your statement
> is
> > wrong either.
> >
> > If we are talking about indexes then the exact condition when index will
> be
> > off-heap is the following: either setOffHeapMaxMemory >= 0 or
> setMemoryMode
> > is OFFHEAP_TIERED.
> >
> > But if setMemoryMode is set to one of off-heap modes and
> setOffHeapMaxMemory is
> > -1, then setOffHeapMaxMemory is silently getting switched to 0.
> >
> > Thus from the user standpoint we can say, that if either
> setOffHeapMaxMemory
> >> = 0 or setMemoryMode is set to any of off-heap modes, then indexes will
> go
> > off-heap.
> >
> > Sergi
> >
> > 2016-11-04 6:30 GMT+03:00 Dmitriy Setrakyan <dsetrakyan@apache.org>:
> >
> >> Do we currently throw an exception if memory mode is set to off-heap by
> the
> >> max-offheap-memory is set to "-1"? Otherwise, it can get very confusing
> to
> >> users.
> >>
> >> On Thu, Nov 3, 2016 at 10:22 AM, Denis Magda <dmagda@gridgain.com>
> wrote:
> >>
> >>> Sergi,
> >>>
> >>> Referring to your response and the source code I should say that, in
> >> fact,
> >>> the documentation has to state the following:
> >>>
> >>> “To place both data and indexes in off heap memory CacheConfiguration.
> >> setMemoryMode
> >>> has to be set to one of off heap modes and CacheConfiguration.
> >> setOffHeapMaxMemory
> >>> has to be set to a value different from -1 (disabled). If at least one
> of
> >>> these conditions is not met then both data and indexes will be located
> in
> >>> on heap memory”
> >>>
> >>> Is this statement correct?
> >>>
> >>> —
> >>> Denis
> >>>
> >>>> On Nov 3, 2016, at 2:53 AM, Sergi Vladykin <sergi.vladykin@gmail.com>
> >>> wrote:
> >>>>
> >>>> Prachi,
> >>>>
> >>>> In [2] we refer to the same CacheConfiguration.setOffHeapMaxMemory
> >>>> property, so [1] is correct. If setOffHeapMaxMemory is disabled (set
> to
> >>>> -1), then indexes will never be stored offheap, regardless of
> >>> setMemoryMode
> >>>> setting.
> >>>>
> >>>> Probably we have to change [2] to make it clear, that it is about
> >>>> setOffHeapMaxMemory
> >>>> but not about setMemoryMode.
> >>>>
> >>>> Sergi
> >>>>
> >>>>
> >>>> 2016-11-03 2:25 GMT+03:00 Prachi Garg <pgarg@gridgain.com>:
> >>>>
> >>>>> Engineers,
> >>>>>
> >>>>> I was going through documentation for Off-Heap SQL Indexes
> >>>>> <https://apacheignite.readme.io/docs/sql-queries#off-heap-
> sql-indexes
> >>>
> >>> and
> >>>>> found two contradicting statements-
> >>>>>
> >>>>> According to [1] -  " `CacheConfiguration.setOffHeapMaxMemory` is
> the
> >>> only
> >>>>> property to enable or disable off-heap indexing. While
> >>>>> CacheConfiguration.setMemoryMode is used to configure off-heap
> memory
> >>>>> <https://apacheignite.readme.io/v1.7/docs/off-heap-memory>,
it does
> >> not
> >>>>> have any effect on indexing."
> >>>>>
> >>>>> According to [2] -  "Note that when off-heap memory is configured,
> >>> Ignite
> >>>>> will store query indexes off-heap as well."
> >>>>>
> >>>>>
> >>>>> Which one is true?
> >>>>>
> >>>>> [1] - https://apacheignite.readme.io/docs/sql-queries#off-heap-
> >>> sql-indexes
> >>>>>
> >>>>> [2] - http://apacheignite.gridgain.org/docs/off-heap-memory
> >>>>>
> >>>>>
> >>>>> Thanks,
> >>>>>
> >>>>> -Prachi
> >>>>>
> >>>
> >>>
> >>
>
>

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