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From Prachi Garg <pg...@gridgain.com>
Subject Re: Off-Heap SQL Indexes
Date Mon, 21 Nov 2016 20:32:23 GMT
Fixed. Please review -
http://apacheignite.gridgain.org/v1.7/docs/sql-queries#off-heap-sql-indexes

-P

On Mon, Nov 7, 2016 at 9:36 AM, Denis Magda <dmagda@gridgain.com> wrote:

> Sergi,
>
> May be you use
> some weird email client which renders >> signs wrong?
>
>
> Right, my Apple’s Mail agent omitted ‘>’ character from your original
> statement applying some HTML formatting.
>
> *Prachi*, please update all the docs keeping in my that this sentence is
> technically correct
>
> 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.
>
>
> —
> Denis
>
> On Nov 5, 2016, at 6:23 AM, Sergi Vladykin <sergi.vladykin@gmail.com>
> wrote:
>
> 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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