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Introduction

Store and Forward allows data to be buffered locally at a client when connections are down to a cloud endpoint and deliver that data when the connection is restored. This feature is critical in most applications because if we lose connection to the cloud end point, we will lose data if it is not buffered locally. When Store and Forward is enabled and the edge node detects a disconnect to the cloud end point, messages will be stored locally in a history store. When the edge node can reconnect to the cloud end point, it will publish any stored messages. The rate at which these stored messages are flushed from the history store is configurable to prevent any delays in the delivery of live data.

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• Type
  • The type of History Store with options of In-Memory and Disk-Backed (available in 4.0.17)
  • Data stored in an In-Memory History Store will not be persisted across a module configuration change, module disable/enable, module restart or power loss. 
  • Data stored in a Disk-Backed History Store will persist across a module configuration change, module disable/enable, module restart or power loss.
• Message Capacity - deprecated in 4.0.19
  • The maximum number of messages to store before dropping the oldest historical messages
• History Max Size
  • The maximum number of megabytes history can use before dropping the data
  • In_Memory Store & Forward will use the Ignition Java Heap memory
  • Default is 500
• History Max Age
  
  • Maximum number of minutes to store history before dropping the data.
  • Default 44640 (31 days)
• Flush Period
  • The period to wait in milliseconds between publishes when flushing messages upon reestablishing communication.
  • The publishing of historic data messages is interleaved with the publishing of live data messages. 
  • Default 100

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