# MQTT Store & Forward

**URL:** <https://forum.inductiveautomation.com/t/mqtt-store-forward/65275>\
**Category:** Ignition\
**Created:** [October 17, 2022, 12:20pm UTC](https://forum.inductiveautomation.com/t/mqtt-store-forward/65275 "2022-10-17T12:20:07Z")\
**Posts on this page:** 1\
**Showing post:** 11

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**Author:** ![hunterdg](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/hunterdg/32/67774_2.png) [@hunterdg](https://forum.inductiveautomation.com/u/hunterdg)\
**Post date:** [November 16, 2023, 1:49am UTC](https://forum.inductiveautomation.com/t/mqtt-store-forward/65275/11 "2023-11-16T01:49:26Z")

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I've successfully tested both **out-of-order/direct-to-historian** and **in-order/flush (replay)** S&F modes (on both MQTT Engine tags and reference tags) using 4.0.19 Transmission/Engine modules.

I'm now curious if the latter (replay) method will flush/replay the cached data all the way through Ignition's OPC UA server - and if an OPC client will successfully log those historical values (if it's writing to a CSV or DB, for example).

It seems it should work _in theory_, but testing thusfar has failed to validate that.

Any thoughts on the matter @wes0johnson?

for reference: [Historian and Sparkplug-B - #5 by wes0johnson](https://forum.inductiveautomation.com/t/historian-and-sparkplug-b/28709/5)

![Screenshot 2023-11-15 at 7.54.00 PM](https://us1.discourse-cdn.com/inductiveautomation/original/3X/f/1/f1a586611d1c1fe2fcaaeeab6609142cb6236866.png)

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