aws dynamodb - 如何按日期查询排序键

Question

I want to query the table and get data which is after certain date.

Hash Key: id
Sort Key: timestamp

error

ValidationException: Query condition missed key schema element: id

index.js

var aws = require('aws-sdk');
const dynamodb = new aws.DynamoDB();

exports.handler = async (event, context, callback) => {
  const documentClient = new aws.DynamoDB.DocumentClient();

  const params = {
    TableName : 'dynamodb-log-testing',
    KeyConditionExpression: '#myTimestamp >= :myDate',
    ExpressionAttributeNames: {
      "#myTimestamp": "timestamp"
    },
    ExpressionAttributeValues: {   
        ':myDate': '2017-11-17'
    }
  };

    try{
        const data = await documentClient.query(params).promise();
        console.log(data)
    }catch(err){
      console.log(err)
    }

};

Answer 1

All queries on a DynamoDB table must include the partition key (aka HASH). You can use scan , but it's not recommended for most use cases. You can create a GSI where the partition on the index is a fixed value, and have the same timestamp value for the sort key. That will allow you to query the index in the way you are describing (except that you'll include the fixed value in the query as well). Your query would look like this:

var aws = require('aws-sdk');
const dynamodb = new aws.DynamoDB();

exports.handler = async (event, context, callback) => {
  const documentClient = new aws.DynamoDB.DocumentClient();

  const params = {
    TableName : 'dynamodb-log-testing',
    IndexName: 'myGSI1',
    KeyConditionExpression: 'gsi1pk = :fixedValue and #myTimestamp >= :myDate',
    ExpressionAttributeNames: {
      "#myTimestamp": "timestamp"
    },
    ExpressionAttributeValues: {   
        ':myDate': '2017-11-17',
        ':fixedValue': 'some fixed value'
    }
  };

    try{
        const data = await documentClient.query(params).promise();
        console.log(data)
    }catch(err){
      console.log(err)
    }

};

Keep in mind that this model has a strong potential for hot partitions on the GSI if your data is large. For that reason you may want to rethink the access pattern a bit. If you can do something like maybe include the date part of the timestamp in the partition and just include the time in the sort that would help. That does mean that you can't query across days in a single query.

Best Practices for Designing and Architecting with DynamoDB has a lot of good information on best practices for DynamoDB.