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From Denis Magda <dma...@gridgain.com>
Subject Re: Off-Heap SQL Indexes
Date Mon, 07 Nov 2016 17:36:33 GMT
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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