THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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| PlantUML |
|---|
participant User participant Handler participant HdfsRegion participant OperationalData participant Filter User->Handler: Put KV activate Handler Handler->HdfsRegion: Add to buffer activate HdfsRegion HdfsRegion->Handler: HdfsRegion-->HDFS: Asynchronous deactivate HdfsRegion Handler->Filter: Test eviction logic activate Filter Filter->Handler: True/False deactivate Filter Handler->OperationalData: Put in cache activate OperationalData OperationalData->Handler: Return V* deactivate OperationalData Handler->User: Old V* deactivate Handler |
Get K
| PlantUML |
|---|
participant User
participant Handler
participant OperationalData
participant HdfsRegion
participant Filter
User->Handler: Get K
activate Handler
Handler->OperationalData: Get K
activate OperationalData
OperationalData->Handler:Return V
deactivate OperationalData
alt if V=null & Get from HDFS is enabled
Handler->HdfsRegion: Get K
activate HdfsRegion
HdfsRegion->HDFS:Read
activate HDFS
HDFS->HdfsRegion:
deactivate HDFS
HdfsRegion->Handler:
deactivate HdfsRegion
Handler->Filter: Test eviction logic
activate Filter
Filter->Handler: True/False
deactivate Filter
Handler->OperationalData: Put in cache
activate OperationalData
OperationalData->Handler:
deactivate OperationalData
end
Handler->User: V |
HDFS Store
HDFS stores provide a means of persisting data on HDFS. There can be multiple instance of HDFS stores in a cluster. A user will normally perform the following steps to enable HDFS persistence for a region:
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