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From Юрий <jury.gerzhedow...@gmail.com>
Subject Re: SQL views for IO statistics
Date Wed, 16 Jan 2019 15:29:26 GMT
Denis,

Physical reads is load page from storage to memory.
Logical reads is read page which already in memory.

We gather IO statistics on CACHE_GROUP level due to Ignite use one page to
keep all caches related to one cache group.  Unfortunately gathering on
table level will be expensive due to the reason. That's way name of view
contains words cache and groups.

ср, 16 янв. 2019 г. в 17:52, Denis Magda <dmagda@apache.org>:

> Yury,
>
> How do we differentiate between logical and physical reads?
>
> Also, it looks counter-intuitive when "CACHE" is used in the name of the
> views for SQL table related statistics. It's still hard to explain the user
> the relations between caches and tables. Hopefully, this will be fixed in
> 3.0 with renaming but as for the statistics can we use anything neutral for
> the view names?
>
> -
> Denis
>
>
> On Tue, Jan 15, 2019 at 5:57 AM Юрий <jury.gerzhedowich@gmail.com> wrote:
>
> > Hi Igniters!
> >
> > As part of IEP-27
> > <
> >
> https://cwiki.apache.org/confluence/display/IGNITE/IEP-27%3A+Page+IO+statistics
> > >
> > we
> > already gathering IO statistics and expose it through JMX.
> >
> > User  who use only SQL should have access to the statistics also. So
> let's
> > discuss about how such SQL view should looks.
> >
> > My proposal it is two SQL views:
> > 1) STATIO_CACHE_GRP
> >
> > cache_grp_name         - Name of cache group
> > physical_read               - Number of physical read of pages
> > logical_read                  - Number of logical read of pages
> >
> >
> >      The view can be filtered by name, like SELECT * from
> > IGNITE.STATIO_CACHE_GRP where cache_grp_name='cache1'
> > 2) STATIO_IDX
> >
> > cache_grp_name         - Name of cache group
> >
> > idx_name                     - Name of index
> > physical_read               - Common number of physical reads of pages
> for
> > the index
> > logical_read                  - Common number of logical reads of pages
> for
> > the index
> >
> > leaf_logical_read          - Number of logical reads of index leaf pages
> >
> > leaf_physical_read       - Number of physical reads of index leaf pages
> >
> > inner_logical_read        - Number of logical reads of index inner pages
> >
> > inner_physical_read     - Number of physical reads of index leaf pages
> >
> >
> >      The view can be filtered by cache group name or by index name, like
> > SELECT * from IGNITE.STATIO_IDX where idx_name='cache1_name_idx'
> >
> > We also have time of start gathering statistics, but I'm not sure that it
> > should be exposed here.
> >
> >
> > WDYT about proposed format for the SQL views?
> >
> >
> >
> >
> >
> >
> > --
> > Живи с улыбкой! :D
> >
>


-- 
Живи с улыбкой! :D

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