[infinispan-dev] cache loader/preload

[Sanne Grinovero]

On 14 August 2013 17:59, Mircea Markus <mmarkus at redhat.com> wrote:
>
> On 14 Aug 2013, at 15:26, Sanne Grinovero <sanne at infinispan.org> wrote:
>
>> On 14 August 2013 11:15, Mircea Markus <mmarkus at redhat.com> wrote:
>>> Currently the "preload" attribute is configured at *loaders* level and the first cache loader in the chain is used for preloading.
>>> A better place for preload might be the individual loader element: would indicate clearly which loader is used for preloading and also consistent with the fetchPeristentState which is again defined on a per loader basis.
>>>
>>> How does it sound?
>>
>> Very confusing actually :-)
>> Are you going to prevent me to enable "preload" on multiple Cache
>> Loaders elements?
>
> I'm not going to take anything from you, this is something you're not allowed to do ATM :-)

That's exactly my point. I'm not allowed to do it ATM, but if you
change the position of this attribute to *each* loader it will look
like I could enable/disable it differently on a per-instance.

>
>> And what if I'm actually storing entries in
>> different CacheStore instanced based on some discriminator, like the
>> value (key) type?
>>
>> To make a practical example, the Lucene Directory CacheLoader only
>> loads some specific types, and only from named indexes which match a
>> configured name. You could want multiple instances using different
>> configurations, so that for each index name stored in the same cache
>> you actually store them in different cachestores.
>>
>> Similar situation, with the JPA CacheStore you might want to use
>> multiple independent instances, one per mapped type. Not necessarily
>> needed (one could improve the CacheStore implementation as well) but
>> it gives lot of flexibility, like connecting to different RDBMs
>> instances or with different credentials/schemas, etc...
>
> Indeed user might want this in the future. Moving "preload" at "loader" level would only facilitate that.

Right. I'm making those examples to highlight the benefit of moving
the attribute to each cachestore, as you proposed, but this only makes
sense if you actually allow the option to be applied differently for
each instance.

>
>>
>> Cheers,
>> Sanne
>>
>>>
>>> Cheers,
>>> --
>>> Mircea Markus
>>> Infinispan lead (www.infinispan.org)
>>>
>>>
>>>
>>>
>>>
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>
> Cheers,
> --
> Mircea Markus
> Infinispan lead (www.infinispan.org)
>
>
>
>
>
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