RE: persist only on delete

[Shawn Du <sh...@neulion.com.cn>]

Hi, 

 

I tested that the cache value was still in memory when calling store delete method. For I leave write empty, so it can’t get it from persist store.

 

public void write(Cache.Entry<? extends String, ? extends T> entry)
{
    //do nothing
}

 

 

Thanks

Shawn

 

发件人: Vladislav Pyatkov [mailto:vldpyatkov@gmail.com] 
发送时间: 2017年2月6日 16:04
收件人: user@ignite.apache.org
主题: Re: 答复: persist only on delete

 

Hi,

 

I think it will be work, because each time when "get"  from a cache Ignite try to get the value from persistence story, if it will not find in memory.

 

On Mon, Feb 6, 2017 at 10:39 AM, Shawn Du <shawn.du@neulion.com.cn <ma...@neulion.com.cn> > wrote:

Hi,

 

In delete method, we can only get cache key.  In order to get cache entry value, we need get Ignite instance and get the cache.

 

Assume we already get all of them. Can we get value in the cache by the key? Which is still valid in cache?

 

Thanks

Shawn

 

发件人: Shawn Du [mailto:shawn.du@neulion.com.cn <ma...@neulion.com.cn> ] 
发送时间: 2017年2月6日 15:12
收件人: user@ignite.apache.org <ma...@ignite.apache.org> 
主题: persist only on delete 

 

Hi,

 

I have a case which cache entry will be update frequently, and I only want to persist it when the cache is manually remove(cache will not change anymore) by me.

 

For this case, It is a good idea to implement persist logic in delete/deleteAll method while write/writeAll do nothing?

 

@Override
public void delete(Object o)
{
    //do nothing, we never have this operation.
}

 

 

Thanks

Shawn





 

-- 

Vladislav Pyatkov

Re: persist only on delete

[vkulichenko <va...@gmail.com>]

Shawn,

I don't know, sounds wrong. Do you have a unit test reproducing this?

-Val



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RE: persist only on delete

[vkulichenko <va...@gmail.com>]

Hi Shawn,

Your approach sounds a bit dangerous. Store is called within an entry lock,
which means that if you do a distributed get there, you will likely get
thread starvation. This should not happen on stable topology, but if another
node fails or joins, you can get stuck.

I think you should use interceptor instead:
https://ignite.apache.org/releases/mobile/org/apache/ignite/cache/CacheInterceptor.html

-Val



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