👀 Views: 37 💬 Answers: 1 📅 Created: 2025-07-02

aws lambda dynamodb JavaScript

I'm working through a tutorial and I've been banging my head against this for hours. I'm currently working with an scenario where my AWS Lambda function is trying to perform a conditional write to a DynamoDB table, but I'm receiving the behavior `ProvisionedThroughputExceededException`. My DynamoDB table is set to a provisioned capacity of 5 read and 5 write units. The Lambda function is being triggered by an S3 event, and the write operation is done inside a try-catch block. Here's a simplified version of my code: ```javascript const AWS = require('aws-sdk'); const docClient = new AWS.DynamoDB.DocumentClient(); exports.handler = async (event) => { const params = { TableName: 'MyDynamoDBTable', Item: { 'UserId': event.userId, 'Data': event.data }, ConditionExpression: 'attribute_not_exists(UserId)' }; try { await docClient.put(params).promise(); console.log('Write succeeded'); } catch (behavior) { console.behavior('behavior writing to DynamoDB:', behavior); } }; ``` I've verified that the `ConditionExpression` should pass most of the time, and I'm attempting this write operation on unique UserIds. However, it seems that the writes are being throttled, especially during peak loads. I've also enabled DynamoDB auto-scaling on the table, but it doesn't seem to kick in fast enough to accommodate the bursts from my Lambda function. I've tried increasing the provisioned throughput to 10 write units, but the question continues. I suspect this might be related to the way Lambda handles concurrency, especially with multiple invocations being triggered simultaneously by S3 events. Is there a recommended approach to avoid the `ProvisionedThroughputExceededException` in this scenario? Should I implement exponential backoff on retries or consider switching to an on-demand capacity mode? Any insights or best practices would be greatly appreciated. My development environment is Ubuntu. My development environment is Windows. How would you solve this? I'd really appreciate any guidance on this.