Bulk-insert multiple documents into MongoDB with KNIME

KNIME Analytics Platform
1

Hello KNIME community,

I’m trying to bulk-insert rows from a KNIME data table into a MongoDB collection. Right now I’m converting each row to JSON and using the MongoDB Writer node to insert one document at a time—but that ends up taking forever on large tables.

What I’ve tried so far

  1. Convert each row to JSON
  • Used Columns To JSON to generate one JSON string per row.
  • Fed each into the MongoDB Update node.
  • Result: Works, but painfully slow.
  1. deleteMany example
    To delete multiple documents in one go I used a filter like:
{
  "_id": {
    "$in": [
      { "$oid": "6815fd39614ee74f14617b8a" },
      { "$oid": "6815fd39614ee74f14617b7b" }
    ]
  }
}

That correctly deletes all matched IDs.

What I’m looking for

  • insertMany (bulk insert) in a single call, not row-by-row.
  • The correct JSON structure (or wrapper) that KNIME’s MongoDB nodes expect for insertMany.

Example of desired payload

Here’s the JSON array I’d love to send in one shot:

[
  { "bnm": "A", "verd": "P", "exDate": "2025-02-27T17:31:54"},
  { "bnm": "B", "verd": "P", "exDate": "2025-02-27T17:31:54" },
  { "bnm": "A", "verd": "F", "exDate": "2025-02-27T17:31:54" }
]

I’ve also tried wrapping it like:

{ 
  "documents": [
    { "bnm": "A", "verd": "P", "exDate": "2025-02-27T17:31:54"},
    { "bnm": "B", "verd": "F",   "exDate": "2025-02-27T17:31:54"}
  ]
}

…but neither approach seems to work in the Update node.

Questions:

  1. What’s the correct JSON format to perform an insertMany in KNIME’s MongoDB nodes?
  2. Are there any KNIME best practices or example workflows for bulk-inserting large numbers of documents at once?

Thanks in advance for any guidance or example workflows you can share!

2

convert rows into json, group them into a set / list, convert that into a json again