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From Ankit Singhal <ankitsingha...@gmail.com>
Subject Re: Weird High Read throuput of SYSTEM.STATS
Date Fri, 21 Apr 2017 05:32:14 GMT
During bulkload, compaction might be getting triggered which is generating
new stats ( and delete the stale one's with a scan) then the table
cache(containg stats) will also get refreshed (with another scan).
Depending upon the no. of time the compactions is triggered and no. of
times the stats needs to be cached again might be correlated with your
observation.

On Wed, Apr 19, 2017 at 4:10 AM, Sergey Soldatov <sergeysoldatov@gmail.com>
wrote:

> The bulk load itself should not cause any read activity on SYSTEM.STATS.
> But if you run something like select count(1) from table to check whether
> the bulk load was successful, it may cause read activity on SYSTEM.STATS
> table.
>
> Thanks,
> Sergey
>
> On Wed, Apr 12, 2017 at 10:38 PM, Mac Fang <mac.fangzhen.dev@gmail.com>
> wrote:
>
>> Josh,
>>
>> Thanks for the reply,
>> It is a CDH vendor version (4.7.0_1.3.0). Mutations are reasonable when
>> we do bulk load. Question is why we have the high read load of the
>> SYSTEM.STATS table.
>>
>>
>> On Thu, Apr 13, 2017 at 11:42 AM, Josh Elser <josh.elser@gmail.com>
>> wrote:
>>
>>> What version of Phoenix are you using? (an Apache release? some vendors'
>>> packaging?)
>>>
>>> Academically speaking, when you bulk load some data, the stats table
>>> should get updated (otherwise the stats are wrong until a compaction
>>> occurs), but I can't specifically point you at a line of code that is doing
>>> this (nor am I 100% positive it happens).
>>>
>>>
>>> On Wed, Apr 12, 2017 at 3:12 AM, Mac Fang <mac.fangzhen.dev@gmail.com>
>>> wrote:
>>>
>>>> Hi, Guys,
>>>>
>>>>
>>>> We are notices some weird high read throuput of the HBase,
>>>>
>>>> The HBase Read Rate
>>>>
>>>>
>>>> ​
>>>> And the SYSTEM.STATS Read Rate
>>>>
>>>>
>>>> ​
>>>> During that time frame, the system did not have a high QPS. However, it
>>>> did import some data (some millions) data via the "Phoenix Bulk Load".
>>>>
>>>> The question is what does phoenix do with the SYSTEM.STATS table when
>>>> we do "Bulk Load"?
>>>>
>>>> We did not find any clues while we looked into the code. Any hints ?
>>>>
>>>>
>>>> --
>>>> regards
>>>> macf
>>>>
>>>
>>>
>>
>>
>> --
>> regards
>> macf
>>
>
>

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