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From "ASF GitHub Bot (JIRA)" <>
Subject [jira] [Commented] (NIFI-988) PutDistributedMapCache processor
Date Thu, 24 Sep 2015 09:07:04 GMT


ASF GitHub Bot commented on NIFI-988:

Github user joemeszaros commented on the pull request:
    Yes, you are correct. 
    The PutDisributeMapCache processor relies on the existing DistributedMapCacheServer, which
internally use class. If you are
intrested in the implementation details, please take a look at this class. It stores cache
entries in a HashMap<ByteBuffer, MapCacheRecord>. 
    You can control the size of the cache with two factors:
    - The max cache size option in the cache server, which controls the maximum number of
cache entries that the cache can hold (default value is 10000)
    - The max cache entry size in the PutDistributedMapCache processor, controlling the maximum
amount of data to put into cache (default value is 1 MB)
    Hope it clears your question.

> PutDistributedMapCache processor
> --------------------------------
>                 Key: NIFI-988
>                 URL:
>             Project: Apache NiFi
>          Issue Type: New Feature
>          Components: Core Framework
>            Reporter: Joe Mészáros
>            Priority: Minor
>              Labels: cache, distributed, feature, new, put
> There is a standard controller service, called DistributedMapCacheServer, which provides
a distributed cache, and an associated DistributedMapCacheClientService to interact with the
cache. But there is not any standard processor, which puts data into the cache, and helps
the user to leverage the distributed cache capabilities.
> The purpose of PutDistributedMapCache is very similar to the egress processors: it gets
the content of a FlowFile and puts it to a distributed map cache, using a cache key computed
from FlowFile attributes. If the cache already contains the entry and the cache update strategy
is 'keep original' the entry is not replaced.

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