Number of open file handles keeps on increasing on Ignite node on adding a new cache

[aMark <fe...@gmail.com>]

Hi,

I am running ignite cluster on replicated mode having 2 nodes on different
machines. 
Whenever I create a cache and write to it through ignite client, number of
open file handles increases by close to 1000. 

But these open file handles does not decreases even if I stop writing and
disconnect my client from the cluster. This is creating a problem in
scenario if I create many caches (around 30+) then my unix box (configured
with max 32K file handles) runs out of file handles. 

Please suggest how can I overcome the problem of ever increasing number of
file handles.

PS: I am using Ignite 2.1 version. I am using "lsof | wc -l" command to
check open file handles on my unix box.

Thanks,



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Re: Number of open file handles keeps on increasing on Ignite node on adding a new cache

[aMark <fe...@gmail.com>]

Thanks for reply.

Yes I use persistent store. For each cache there are close to 1.2 million
entries and it creates close to 500 files(part*.bin) of 1 MB in Persistent
store directory but questions is why Ignite keeps file handles opens even
after there is no active reader/writer to that cache.  

Rather than keeping file handles opens, it can keep information about the
files and can open file handles only in case read/write happens to cache.
Keeping file handles open doesn't seem right.

Thanks,



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Re: Number of open file handles keeps on increasing on Ignite node on adding a new cache

[afedotov <al...@gmail.com>]

Hi,

Do you use Ignite Persistent Store?
If that's the case, then for each cache partition there is a corresponding
file created.

Kind regards,
Alex



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Re: Number of open file handles keeps on increasing on Ignite node on adding a new cache

[Denis Magda <dm...@apache.org>]

Hi,

Sorry for a late reply. 

Yes, this benefit is expected after you turn to the cache groups. Keep using them if the performance of Scan and SQL queries is at a desired level.

As per your question about the open file handles, there is an assumption that caches are updated frequently which would require to reopen the handles endlessly. This is why Ignite keeps them open all the times.

—
Denis

> On Dec 4, 2017, at 5:04 AM, aMark <fe...@gmail.com> wrote:
> 
> Hi Denis,
> 
> After putting all the caches in single cache group, I dont have issue of too
> many open file handles.
> 
> Ignite is putting all the caches in the single persistence folder and now
> bin files count is static even with 200 caches but each single bin file size
> is getting increased.
> 
> Though I haven't yet noticed any significant performance impact of this on
> read but I will continue to monitor it.
> 
> Thanks for you help.
> 
> 
> Thanks,
> 
> 
> 
> --
> Sent from: http://apache-ignite-users.70518.x6.nabble.com/

Re: Number of open file handles keeps on increasing on Ignite node on adding a new cache

[aMark <fe...@gmail.com>]

Hi Denis,

After putting all the caches in single cache group, I dont have issue of too
many open file handles.

Ignite is putting all the caches in the single persistence folder and now
bin files count is static even with 200 caches but each single bin file size
is getting increased.

Though I haven't yet noticed any significant performance impact of this on
read but I will continue to monitor it.

Thanks for you help.


Thanks,



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Re: Number of open file handles keeps on increasing on Ignite node on adding a new cache

[aMark <fe...@gmail.com>]

Thanks Denis.

In my case there is only one type of cache. If I put all the cache in single
group, will it help ?

Thanks,



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Re: Number of open file handles keeps on increasing on Ignite node on adding a new cache

[Denis Magda <dm...@apache.org>]

Hi,

You can leverage from Cache Groups if a total number of opened files is an issue for your environment:
https://apacheignite.readme.io/docs/cache-groups <https://apacheignite.readme.io/docs/cache-groups>

—
Denis

> On Nov 28, 2017, at 11:34 PM, aMark <fe...@gmail.com> wrote:
> 
> Hi,
> 
> I am running ignite cluster on replicated mode having 2 nodes on different
> machines. 
> Whenever I create a cache and write to it through ignite client, number of
> open file handles increases by close to 1000. 
> 
> But these open file handles does not decreases even if I stop writing and
> disconnect my client from the cluster. This is creating a problem in
> scenario if I create many caches (around 30+) then my unix box (configured
> with max 32K file handles) runs out of file handles. 
> 
> Please suggest how can I overcome the problem of ever increasing number of
> file handles.
> 
> PS: I am using Ignite 2.1 version. I am using "lsof | wc -l" command to
> check open file handles on my unix box.
> 
> Thanks,
> 
> 
> 
> --
> Sent from: http://apache-ignite-users.70518.x6.nabble.com/