What is a Pinecone namespace and when should you use it?

A namespace is a logical partition within a Pinecone index, letting you isolate vectors by user, tenant, document set, or language without creating separate indexes. Queries are scoped to a single namespace, which improves performance because the search only considers vectors in that namespace. Use namespaces for multi-tenant applications, per-user personal data, or A/B testing different embedding models. Namespaces are free to create, and a single index can hold thousands of them with no pre-declaration required.