DynamoDb update fails with error "The update expression attempted to update the secondary index key to unsupported type"

Question

I'm running a simple update to add a UUID to an array. It fails with the error message "The update expression attempted to update the secondary index key to unsupported type". But the fields I'm updating are not keys in any secondary indexes.

Here's the update code:

const params = {
    "TableName": "churches",
    "Key": {
        "churchId": "0194fb2a-9a0f-4b6a-b347-7adffbaed8ff",
        "countryId": "UK"
    },
    "ReturnValues": "ALL_NEW",
    "UpdateExpression": "set #team = list_append(if_not_exists(#team, :empty_list), :user)",
    "ExpressionAttributeNames": {
        "#team": "team"
    },
    "ExpressionAttributeValues": {
        ":empty_list": [],
        ":user": [
            "b23fe6cf-83e9-417c-b987-e8e645a29bcd"
        ]
    }
}
db.update(params,(err,data) => {
  if(err) console.log('ERROR:',err);
  if(data) console.log('DATA:',data);
})

The Partition Key is churchId and countryId is the sort key.

And here's the output:

ERROR: { ValidationException: The update expression attempted to update the secondary index key to unsupported type
    at Request.extractError (/Users/richbee/Library/Mobile Documents/com~apple~CloudDocs/code/ec-api/dbcodetest/node_modules/aws-sdk/lib/protocol/json.js:51:27)
    at Request.callListeners (/Users/richbee/Library/Mobile Documents/com~apple~CloudDocs/code/ec-api/dbcodetest/node_modules/aws-sdk/lib/sequential_executor.js:106:20)
    at Request.emit (/Users/richbee/Library/Mobile Documents/com~apple~CloudDocs/code/ec-api/dbcodetest/node_modules/aws-sdk/lib/sequential_executor.js:78:10)
    at Request.emit (/Users/richbee/Library/Mobile Documents/com~apple~CloudDocs/code/ec-api/dbcodetest/node_modules/aws-sdk/lib/request.js:683:14)
    at Request.transition (/Users/richbee/Library/Mobile Documents/com~apple~CloudDocs/code/ec-api/dbcodetest/node_modules/aws-sdk/lib/request.js:22:10)
    at AcceptorStateMachine.runTo (/Users/richbee/Library/Mobile Documents/com~apple~CloudDocs/code/ec-api/dbcodetest/node_modules/aws-sdk/lib/state_machine.js:14:12)
    at /Users/richbee/Library/Mobile Documents/com~apple~CloudDocs/code/ec-api/dbcodetest/node_modules/aws-sdk/lib/state_machine.js:26:10
    at Request.<anonymous> (/Users/richbee/Library/Mobile Documents/com~apple~CloudDocs/code/ec-api/dbcodetest/node_modules/aws-sdk/lib/request.js:38:9)
    at Request.<anonymous> (/Users/richbee/Library/Mobile Documents/com~apple~CloudDocs/code/ec-api/dbcodetest/node_modules/aws-sdk/lib/request.js:685:12)
    at Request.callListeners (/Users/richbee/Library/Mobile Documents/com~apple~CloudDocs/code/ec-api/dbcodetest/node_modules/aws-sdk/lib/sequential_executor.js:116:18)
  message:
   'The update expression attempted to update the secondary index key to unsupported type',
  code: 'ValidationException',
  time: 2019-09-20T16:51:08.712Z,
  requestId: 'IF0CSPBPQLHBAHOBK299V9KGMVVV4KQNSO5AEMVJF66Q9ASUAAJG',
  statusCode: 400,
  retryable: false,
  retryDelay: 4.443976966236384 }

These are the secondary indexes configured on the table: screeen shot of secondary indexes

So far, I've asked myself the following questions:

Am I updating a field that a secondary index uses as a key? - No, the only field I'm updating is 'team', which is a list.
Am I setting any field values to anything that JS can interpret as anything but a string? - No, it's a UUID

What am I missing?!

richbee richbee · Accepted Answer · 2019-09-23T10:41:27

This isn't a problem with the posted code but with the underlying database.

One of my indexes was expecting a String for its key, but a number of existing entries in the database had a placeholder field set to null (I knew I was going to add that key in as soon as I had it, and DynamoDB doesn't like empty strings, so I set them to null).

It seems that this creates an index key violation, which causes all subsequent writes to that record to fail until it is resolved:

https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/GSI.OnlineOps.ViolationDetection.html

The fix is to either remove that key completely, or put an actual string in it rather than leaving it floating about as null.

DynamoDb update fails with error "The update expression attempted to update the secondary index key to unsupported type"

2 Answers