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https://issues.apache.org/jira/browse/IOTDB-653?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Wei Shao reassigned IOTDB-653:
------------------------------

    Assignee: Wei Shao

> Separate LAST cache from MTree
> ------------------------------
>
>                 Key: IOTDB-653
>                 URL: https://issues.apache.org/jira/browse/IOTDB-653
>             Project: Apache IoTDB
>          Issue Type: Improvement
>          Components: Core/Engine
>            Reporter: Tian Jiang
>            Assignee: Wei Shao
>            Priority: Major
>              Labels: LAST, cluster, metadata
>
> Currently, we have a cache in MTree to store the LAST value of timeseries, in 
> the distributed version, however, the metadata and data are stored 
> separately, and when the metadata is needed, it will be pulled from another 
> node and stored in a local cache, resulting in that such timeseries does not 
> exist in MTree and its LAST cache is accessed, a PathNotExistException will 
> be raised.
> So we temporarily disable the LAST cache of the remotely existing timeseries, 
> but we hope we can modify it so that we can still cache the last value of 
> those timeseries.
> Here is one possible solution: abstract a LastCacheManager to manage all last 
> caches instead of storing them in MTree, so even when the timeseries does not 
> exist locally, its last value can still be cached and visited.



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