# Apache Solr

> A search server on Apache Lucene: schema, request handlers, and the operation of a cluster. It is the engine I have spent the most years with.

Broader subject: [Search engines](https://oppority.com/topics/search-engines.md).

## Work

- [Public search at country scale](https://oppority.com/work/public-search.md): Search a citizen can use: a polling place, a beneficiary record, found in hundreds of millions of rows.
- [Concept search before vectors were the default](https://oppority.com/work/concept-search.md): A books-and-journals search that let people explore by concepts, built in 2018 from phrases and similarity, not from a vector database.
- [One catalog, many storefronts](https://oppority.com/work/retail-search.md): Product search, autosuggest, filters, and per-field similarity for an omnichannel retailer: web, marketplace, and stores.
- [A move that kept the answers](https://oppority.com/work/platform-move.md): A production move from self-managed Apache Solr to managed OpenSearch, checked by whether the top results still agreed.
- [The team's output](https://oppority.com/work/search-team.md): Leading a search engineering group while staying close enough to the system to tell a relevance question from an operations question.