Ok, reading the javax spec - it would appear that CacheLoader load() only
gets invoked (automatically by the cache engine such as Ignite) only if the
data is not available in cache.
"
* If the cache is configured to use read-through, and get would return null
* because the entry is missing from the cache, the Cache's {@link
CacheLoader}
* is called in an attempt to load the entry.
"
Thanks!
On Mon, Jun 29, 2015 at 3:32 PM, Ognen Duzlevski <[email protected]>
wrote:
> Dmitriy,
>
> Thanks. Just so I understand: I am looking at the CacheStore example and
> the whole discussion on:
> http://apacheignite.readme.io/v1.1/docs/persistent-store
>
> In that example the load() method takes a key which is then used
> automatically to query the underlying SQL persistent store and the results
> are served back to client.
>
> How about this scenario? I get the key in the load method and I first
> check to see if my data is in cache. If it is, I serve the result from
> cache, otherwise I go to persistent storage.
>
> Is this handled automatically by Ignite in the background and that's why
> the load() method in the example pays no attention to the possibility of
> the key/value already existing in memory? Or is that something I have to
> explicitly check for in the load() implementation?
>
> Thanks!
>
> On Mon, Jun 29, 2015 at 2:53 PM, Dmitriy Setrakyan <[email protected]>
> wrote:
>
>>
>> On Mon, Jun 29, 2015 at 12:38 PM, Ognen Duzlevski <
>> [email protected]> wrote:
>>
>>> How about SQL queries on ignite? Do they end up being translated into
>>> series of gets() and hence make use of the read-through CacheStore
>>> implementation?
>>>
>>
>> The answer is No. Queries are executed only on the in-memory data. To
>> support what you are suggesting, we would have to execute a query on the
>> database, get all the keys back, and then execute a bunch of cache.get(..)
>> calls for each returned key. Overall, this would be very slow and that's
>> why was not done for Ignite.
>>
>> Having said that, we can enhance our Hibernate integration to support
>> this use case. I will file a ticket.
>>
>> D.
>>
>>
>
