From 7ae2c8d73d033f6209b8d9d4f5ea240ee529f62d Mon Sep 17 00:00:00 2001
From: Anca Lita <27920906+ancalita@users.noreply.github.com>
Date: Sat, 28 Jan 2023 11:15:07 +0000
Subject: [PATCH] Document fall back tracker store mechanism (#11976)

* document fall back tracker store mechanism

* add changelog, fix typo ci flag

* address feedback
---
 changelog/11976.doc.md       |  1 +
 docs/docs/tracker-stores.mdx | 17 +++++++++++++++++
 2 files changed, 18 insertions(+)
 create mode 100644 changelog/11976.doc.md

diff --git a/changelog/11976.doc.md b/changelog/11976.doc.md
new file mode 100644
index 000000000000..c8f88bbac57e
--- /dev/null
+++ b/changelog/11976.doc.md
@@ -0,0 +1 @@
+Add section in tracker store docs to document the fallback tracker store mechanism.
diff --git a/docs/docs/tracker-stores.mdx b/docs/docs/tracker-stores.mdx
index 085c58f33e38..f3ac71f4a2d1 100644
--- a/docs/docs/tracker-stores.mdx
+++ b/docs/docs/tracker-stores.mdx
@@ -394,3 +394,20 @@ extending the Rasa image to include the module, or mounting the module as volume
    a_parameter: a value
    another_parameter: another value
  ```
+
+## Fallback Tracker Store
+
+In case the primary tracker store configured in `endpoints.yml` becomes unavailable, the rasa agent will issue an
+error message and fall back on the `InMemoryTrackerStore` implementation. A new dialogue session will be started for
+each turn, which will be saved separately in the `InMemoryTrackerStore` fallback.
+
+As soon as the primary tracker store comes back up, it will replace the fallback tracker store and save the
+conversation from this point going forward. However, note that any previous states saved in the `InMemoryTrackerStore`
+fallback will be lost.
+
+:::warning Using the same redis instance as lock-store and tracker store
+
+You must not use the same Redis instance as both lock store and tracker store.
+If the Redis instance becomes unavailable, the conversation will hang because there is no fall back mechanism
+implemented for the lock store (as it is for the tracker store interfaces).
+:::