Is it possible to implement a fast search on fields with unstructured data?

Yes, fast search on fields with unstructured data is possible, but it usually requires specialized technologies and approaches. For example, full-text search or indexing with engines like Elasticsearch can be used, which are capable of efficiently working with JSON, text, and other unstructured formats.

In the context of Go, unstructured data can be stored in JSON format and external search engines can be used for quick search. Built-in Go data structures do not provide fast search on unstructured fields without additional indexing.

An example of using Elasticsearch for searching JSON documents:

// Example of a query to Elasticsearch for searching within a JSON field
query := `{
  "query": {
    "match": {
      "user.name": "Ivan"
    }
  }
}`
// Then send this query to Elasticsearch via an HTTP client

Thus, for fast search on unstructured data, it is better to use external systems with indexing.