Search moved off Algolia onto Elasticsearch and Tencent ES, split by region so global and China Mini Program users each hit a cluster near them. Relevance moved with it — into search templates the team can tune without shipping a release, with ES highlight queries backing the Mini App's autocomplete.
Search ran on Algolia. It worked, but two constraints mattered. Relevance changes went through the vendor's model rather than something the team could shape and version, and users inside China hit a hosted index far from them, on surfaces where latency is very visible: Mini Programs, with autocomplete firing on every keystroke.
Both the relevance problem and the geography problem come from not owning the index. Elasticsearch solves the first: query logic lives in search templates, stored server-side and tunable without a deploy. Tencent ES solves the second: the same index shape, hosted inside China, serving China traffic. One migration, two wins — provided the ingest pipeline can write to both.
China Mini Program users query a cluster in their own region instead of crossing the border on every keystroke. Global search keeps its own cluster. Relevance work no longer waits on a release, and the index became the foundation the AI search agent was built on top of.