Скачать или смотреть How to Aggregate Elasticsearch Data by @ timestamp for Recent Values

Learn how to effectively use Elasticsearch queries to filter and aggregate data based on `@ timestamp`, ensuring you retrieve the most recent document values for your analysis.
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This video is based on the question https://stackoverflow.com/q/63215326/ asked by the user 'JeyJ' ( https://stackoverflow.com/u/4340793/ ) and on the answer https://stackoverflow.com/a/63218066/ provided by the user 'Joe - Check out my books' ( https://stackoverflow.com/u/8160318/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Introduction

When working with Elasticsearch, one common requirement is to analyze documents stored in an index that may have varying structures. A common scenario involves retrieving the latest values for specific shared keys, such as store data, owners, and product counts. This post explores how to achieve this by using Elasticsearch's powerful query capabilities to filter by @ timestamp and aggregate results effectively.

The Problem

In our case, we have multiple documents indexed with shared keys that include a store name, owner, products, and a @ timestamp. For example, your documents may look like this:

[[See Video to Reveal this Text or Code Snippet]]

The challenge is to retrieve the most recent document for each store, specifically the last values of owner and products based on the @ timestamp. Thus, we need a way to sort and filter documents within our aggregation query correctly.

The Solution

To address this issue, we'll break the solution down into two main tasks:

Filter Documents by Date Range

Aggregate and Sort Results by @ timestamp using top_hits

1. Filter Documents by Date Range

To filter the documents for the last two days, you need to add a range query for the @ timestamp field. Here’s how to do this in your Elasticsearch query:

[[See Video to Reveal this Text or Code Snippet]]

This query ensures that only documents created in the last two days will be considered in your aggregation.

2. Aggregate and Sort Results Using top_hits

Now that we have our date filtering in place, the next step involves structuring your aggregation to ensure that the most recent values are retrieved for each store. We will use top_hits aggregation to sort the results by @ timestamp. Below is the complete query setup:

[[See Video to Reveal this Text or Code Snippet]]

Explanation of the Query

The size is set to 0 so that we don't retrieve the actual search hits, just the aggregation results.

The terms aggregation under store_aggr groups the documents by the field Store.

For each store, we have nested aggregations for owner and products, respectively.

The top_hits aggregation retrieves the most recent values sorted by @ timestamp in descending order, ensuring the latest values appear at the top.

Conclusion

By applying these techniques, you can effectively filter and aggregate Elasticsearch data by @ timestamp. This approach ensures that you always get the most recent values you need for your analysis. With a well-structured aggregation query, handling documents with varying structures becomes much more manageable.

Feel free to implement this query in your Elasticsearch application, and watch as it simplifies your data retrieval process!