> For the complete documentation index, see [llms.txt](https://doc.duaer.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://doc.duaer.com/integrations/builtin/cluster-nodes/sub-nodes/n8n-nodes-langchain.memorybufferwindow/common-issues.md).

# Common issues with Simple Memory in Duaer

Common Simple Memory issues in Duaer: no session ID, an empty Key, and whether memory nodes share history.
## Expressions resolve to the first item <a href="#processing-parameters" id="processing-parameters"></a>

Simple Memory is a sub-node. Most nodes resolve an expression once per input item; Duaer calls a sub-node with the first item only. Given five names, {{ $json.name }} is always the first name.

To use a different value per item, put the expression in the root node (such as the AI Agent prompt), or run Loop Over Items first so each run gets one item.

## Where the Session ID comes from <a href="#managing-the-session-id" id="managing-the-session-id"></a>

- Connected Chat Trigger Node: reads the sessionId field from the input. Chat Trigger outputs it for you.
- Define below: write it in Key, such as {{ $json.userId }}, so each user gets separate history.

Context Window Length sets how many recent turns to include. Default 5.

## No session ID found <a href="#no-session-id-found" id="no-session-id-found"></a>

Session ID is set to Connected Chat Trigger Node but the input has no sessionId. If the previous step is not a Chat Trigger, switch Session ID to Define below and fill in Key.

## Key parameter is empty <a href="#key-parameter-is-empty" id="key-parameter-is-empty"></a>

Session ID is set to Define below but Key is empty or its expression did not resolve. Enter a fixed value, or check the fields the expression references.

## Do separate Simple Memory nodes share history? <a href="#single-memory-instance" id="single-memory-instance"></a>

From Simple Memory 1.4, with Session ID set to Connected Chat Trigger Node, Duaer appends the memory node’s own name to the session ID. Two Simple Memory nodes with different names keep separate history, even for the same chat session.

To share one history between two AI nodes, connect the same Simple Memory node to both, or set both to Define below with the same Key.
## Questions

### Do two Simple Memory nodes share chat history in Duaer?

Not from version 1.4 with Connected Chat Trigger Node: Duaer stores each Simple Memory under its own node name. To share, connect the same node or use the same Key.