Hi Paul,

Currently No. This is just a caching layer on the event table intended for
single node CEP instances. Hazelcast version might be useful as well, we
left that alone for this rollout.

--Srinath



On Fri, Mar 14, 2014 at 6:51 PM, Paul Fremantle <[email protected]> wrote:

> Do we use Hazelcast to implement the cache?
>
> Paul
>
>
> On 14 March 2014 11:32, Rajeev Sampath <[email protected]> wrote:
>
>> Following is a summary of how the current implementation of caching works:
>>
>>  - Existing events are loaded to the cache in lazy manner when they are
>> looked-up.
>> - When adding/removing events both cache and table is updated accordingly.
>> - When reading, cache is searched first and then the DB table. For events
>> that do not exist in the cache, they get added to the cache at this moment
>> and evictions happen if necessary.
>> - The events in the cache are evicted based on 3 algorithms. They are
>> Least Recently Used, Least Frequently Used and FIFO. User can choose what
>> to use in their query. (This is configurable per-table basis). Events get
>> evicted when the cache reaches the upper limit.
>> - Currently upper limits are constant (this implementation can be changed
>> easily to have a configurable value if needed - it's possible to allow the
>> user to define upper limits in the query)
>> - Currently caches do not support the distributed mode. This is not
>> implemented since there are pending changes to our distributed processing
>> implementation.
>> - Also in a future release we need to change the implementation of how
>> Join operations are done in Siddhi. With the current implementation, caches
>> can't be used effectively for Joins.
>>
>> The documentation can be found at [1]
>>
>> [1] https://docs.wso2.org/display/CEP310/Event+Table+Definitions
>>
>>
>> On Fri, Mar 14, 2014 at 7:25 AM, Srinath Perera <[email protected]> wrote:
>>
>>> How it works? when does it evict things? can we set limits.
>>>
>>> Please respond to this with details about the design
>>>
>>> --
>>> ============================
>>> Srinath Perera, Ph.D.
>>>    http://people.apache.org/~hemapani/
>>>    http://srinathsview.blogspot.com/
>>>
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>>>
>>
>>
>> --
>> Rajeev Sampath
>> Senior Software Engineer
>> WSO2, Inc.; http://www.wso2.com.
>>
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>>
>
>
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> Paul Fremantle
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-- 
============================
Srinath Perera, Ph.D.
  Director, Research, WSO2 Inc.
  Visiting Faculty, University of Moratuwa
  Member, Apache Software Foundation
  Research Scientist, Lanka Software Foundation
  Blog: http://srinathsview.blogspot.com/
  Photos: http://www.flickr.com/photos/hemapani/
   Phone: 0772360902
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