[Bug] Cosmos DB Input Binding (Node.js) with enableCrossPartitionQuery=true Returns Empty Array Despite Matching Documents #766
Description
Body:
Hi team,
I'm in Ops, not a dev, but caught a potential issue in the Cosmos DB input binding for Azure Functions (Node.js) that might be worth a look.
💥 Problem
The binding returns an empty array ([]) when using enableCrossPartitionQuery: true, even though the data exists and matches the query. However, the exact same query works when run via:
The Azure Portal Data Explorer
The @azure/cosmos SDK directly from the same function
This suggests a silent failure at the binding level, not in the data or query itself.
⚙️ Repro
Azure Function App
Language: Node.js (v18)
Plan: Consumption
Function: GetPatient (HTTP Trigger)
Binding (function.json)
json
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Edit
{
"name": "patientDoc",
"type": "cosmosDB",
"direction": "in",
"databaseName": "HealthcareDB",
"containerName": "Patients",
"sqlQuery": "SELECT * FROM c WHERE c.patient_id = @patientID",
"partitionKey": null,
"enableCrossPartitionQuery": true,
"parameters": [
{
"name": "@patientID",
"value": "{patientId}"
}
]
}
Cosmos DB Details
DB: HealthcareDB
Container: Patients
Partition Key: /source
Verified Data: patient_id "P00100" exists (17 records across multiple partitions)
❌ Behavior
patientDoc from the binding is always []
SDK-based query with same settings returns all expected documents
✅ Workaround (SDK)
js
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Edit
const { CosmosClient } = require('@azure/cosmos');
const client = new CosmosClient(process.env.COSMOS_CONN);
const container = client.database('HealthcareDB').container('Patients');
const querySpec = {
query: 'SELECT * FROM c WHERE c.patient_id = @patientID',
parameters: [{ name: '@patientID', value: patientId }],
};
const { resources } = await container.items
.query(querySpec, { enableCrossPartitionQuery: true })
.fetchAll();
Returns expected results immediately.
📈 Impact
This affected a healthcare proof-of-concept (100+ patients, 20 records each), where relying on the binding would’ve silently dropped all patient data. Required moving to SDK-based logic for reliability.
🧠 My Take
Looks like the binding isn’t honoring enableCrossPartitionQuery: true in some edge cases. Happy to help further if logs or an isolated Function App are needed.
Thanks!
– Ruel