# How to join two stream data sources and find matches
**URL:** https://discuss.elastic.co/t/how-to-join-two-stream-data-sources-and-find-matches/346097
**Category:** Logstash
**Created:** [October 31, 2023, 8:22am UTC](https://discuss.elastic.co/t/how-to-join-two-stream-data-sources-and-find-matches/346097 "2023-10-31T08:22:08Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@fim01](https://discuss.elastic.co/u/fim01)
#### Post date: [October 31, 2023, 8:22am UTC](https://discuss.elastic.co/t/how-to-join-two-stream-data-sources-and-find-matches/346097/1 "2023-10-31T08:22:08Z")
I'm asking for an idea or approach to solve the following business problem:
Two stream data sources (A and B) continuously ingesting events into two separate indices (A and B) in Elasticsearch. Each of them has a unique \_id.
My goal is to merge Index A with Index B based on the unique \_id field of the document and split the result into three buckets:
Bucket 1: All documents from Index A without a matching \_id from Index B
Bucket 2: All documents from Index B without a matching \_id from Index A
Bucket 3: All documents which has been matched but shall only stored as a single document.
Keep in mind, the data might be incomplete at a certain time but documents may match in a later stage due to continuous document ingestion.
May I implement the explained scenario with Logstash (how?) or do I need other components like kafka and/or message queueing? What is the most convenient approach? Any experiences?
Thanks for you help.
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [November 28, 2023, 8:22am UTC](https://discuss.elastic.co/t/how-to-join-two-stream-data-sources-and-find-matches/346097/2 "2023-11-28T08:22:51Z")
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