# A move that kept the answers

> A production move from self-managed Apache Solr to managed OpenSearch, checked by whether the top results still agreed.

## The problem

A platform change is easy to announce and hard to trust. The cluster can be healthy while the answers quietly drift.

## The approach

I have taken search through Solr version upgrades and through a move from self-managed Solr to AWS managed OpenSearch, with no downtime on that production cut. Relevancy parity was checked with Jaccard overlap on top results, and with like-for-like displacement where the product returns one record.

## Subjects

- [Apache Solr](https://oppority.com/topics/apache-solr.md)
- [OpenSearch](https://oppority.com/topics/opensearch.md)
- [Relevance](https://oppority.com/topics/relevance.md)
- [Enterprise search](https://oppority.com/topics/enterprise-search.md)

## The conclusion

Finish the migration when the results agree, not when the dashboard is green. The same habit applies to hybrid retrieval: measure the blend, do not assume the new signal is kinder.