Problem Description
I’m using an n8n workflow to fetch content from a PostgreSQL database (public.contents table) based on a dynamic section_id. The workflow uses a PostgreSQL node to execute a query:
SELECT content
FROM public.contents
WHERE section_id = $1;
The section_id parameter is dynamically set using the queryReplacement option within the n8n PostgreSQL node:
{{ $fromAI('section_id') }}
Issue:
The issue is that the query seems to cache the section_id value from the first execution. Subsequent runs of the workflow with different section_id values incorrectly return the content associated with the original section_id. No error messages are displayed. The issue appears to be related to how the dynamic parameter (section_id) is being handled by the PostgreSQL node.
Observed Behavior:
- First Execution: Correct content is fetched for the given section_id.
// Input:
{
"section_id": "657dad6b-42a6-4990-8091-8b5c7d11af24"
}
// Output:
{
"content": "Content for section_id 657dad6b-42a6-4990-8091-8b5c7d11af24"
}
- Second Execution: Incorrectly returns the same content as the first execution, even with a new section_id.
// Input:
{
"section_id": "9b24f8e5-d08e-4567-93b3-5cabc1234567"
}
// Output:
{
"content": "Content for section_id 657dad6b-42a6-4990-8091-8b5c7d11af24"
}
Workflow Configuration (JSON):
Environment:
-
n8n version: 1.70.3
-
Database: PostgreSQL
-
n8n EXECUTIONS_PROCESS setting: Railway Execution
-
Running n8n via: Railway
-
Operating system: Ubuntu (likely)
Screenshots:
