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From Dmitriy Govorukhin <dmitriy.govoruk...@gmail.com>
Subject Re: Memory usage per cache
Date Fri, 30 Mar 2018 09:04:17 GMT
Folks,

I created 2 Jira issue for new metrics. Also, I think they will be useful.
Let's discuss in comments.

- Add new metrics for data storage IGNITE-8078
<https://issues.apache.org/jira/browse/IGNITE-8078>
- Implement new JMX metrics for transactions IGNITE-8077
<https://issues.apache.org/jira/browse/IGNITE-8077>

On Thu, Mar 29, 2018 at 8:26 PM, Denis Magda <dmagda@apache.org> wrote:

> Alexey,
>
> If to rephrase it differently, if a cache/table belongs to a single cache
> group then its entries will never be mixed with the entries of another
> caches/tables in both data and index pages. Please confirm that my
> statement is correct. Also, does that counter accumulates size of
> BinaryObjects or the whole data/index pages?
>
> Finally, do you plan to rework CacheMetrics.getOffHeapAllocatedSize method
> for this purpose? (btw, to my knowledge the method is broken at the moment
> and returns 0).
>
> --
> Denis
>
>
> On Thu, Mar 29, 2018 at 1:20 AM, Alexey Goncharuk <
> alexey.goncharuk@gmail.com> wrote:
>
> > Denis,
> >
> > Currently there is an easy way to add per-cache-group metrics for data
> and
> > index pages. There is an internal counter, but it is not published as an
> > MBean metric, we will do this as a part of IEP-6.
> >
> > As for the per-cache metrics, this can be implemented, but it will take a
> > significantly greater effort and most likely will affect performance. As
> > Andrey noted, when two caches share the same cache group, multiple
> entries
> > may be written to the same page, this needs special handling. I suggest
> we
> > first start with per-cache-group metrics and then, if there is high
> demand,
> > start thinking about per-cache metrics.
> >
> > --AG
> >
> > 2018-03-27 15:18 GMT+03:00 Andrey Kuznetsov <stkuzma@gmail.com>:
> >
> > > I apologize for the previous message sent in hurry. It's imposible to
> > > measure the difference between 'precise' and 'estimated' page memory
> > usage
> > > per cache unless we fully implement approach 2. Current model allows to
> > > store objects from several caches in a single page.
> > >
> > > 2018-03-23 22:21 GMT+03:00 Andrey Kuznetsov <stkuzma@gmail.com>:
> > >
> > > > Denis,
> > > >
> > > > I'll need to conduct some experiments to estimate the difference. And
> > the
> > > > answer will depend on numerous parameters: object sizes, number of
> > > caches,
> > > > that share the same data region and so on.
> > > >
> > > > пт, 23 марта 2018, 21:53 Denis Magda <dmagda@apache.org>:
> > > >
> > > >> Andrey,
> > > >>
> > > >> How good will be the estimate if we go for 1. and utilize
> > > pagesFillFactor
> > > >> somehow? In other words, how big can be a difference between 100%
> > > precise
> > > >> calculation you the approach you're suggesting?
> > > >>
> > > >> --
> > > >> Denis
> > > >>
> > > >>
> > >
> > >
> > > --
> > > Best regards,
> > >   Andrey Kuznetsov.
> > >
> >
>

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