Overview

Product search requires three things: relevance (full-text), filtering (facets), and performance (shard sizing). This mapping addresses all three.

Index settings + mapping (PUT /products-000001)

{
  "settings": {
    "number_of_shards":   3,
    "number_of_replicas": 1,
    "analysis": {
      "filter": {
        "english_stemmer":  { "type": "stemmer", "language": "english" },
        "product_synonyms": {
          "type": "synonym_graph",
          "synonyms": [
            "tv, television, telly",
            "laptop, notebook, macbook => laptop"
          ]
        }
      },
      "analyzer": {
        "product_analyzer": {
          "type":      "custom",
          "tokenizer": "standard",
          "filter":    ["lowercase", "product_synonyms", "english_stemmer"]
        }
      }
    },
    "index.max_result_window": 50000
  },
  "mappings": {
    "dynamic": "strict",
    "properties": {
      "id":          { "type": "keyword" },
      "sku":         { "type": "keyword" },
      "name": {
        "type": "text",
        "analyzer": "product_analyzer",
        "fields": {
          "keyword": { "type": "keyword", "ignore_above": 256 },
          "suggest": { "type": "completion" }
        }
      },
      "description": { "type": "text", "analyzer": "product_analyzer" },
      "brand":       { "type": "keyword" },
      "category":    { "type": "keyword" },
      "tags":        { "type": "keyword" },
      "price":       { "type": "scaled_float", "scaling_factor": 100 },
      "sale_price":  { "type": "scaled_float", "scaling_factor": 100 },
      "in_stock":    { "type": "boolean" },
      "stock_qty":   { "type": "integer" },
      "rating_avg":  { "type": "half_float" },
      "rating_count":{ "type": "integer" },
      "images":      { "type": "keyword", "index": false },
      "attributes":  { "type": "flattened" },
      "created_at":  { "type": "date" },
      "updated_at":  { "type": "date" }
    }
  }
}

Example search query (BM25 + filters + boost)

{
  "query": {
    "bool": {
      "must": [
        {
          "multi_match": {
            "query":  "wireless headphones",
            "fields": ["name^3", "description", "tags^2"],
            "type":   "best_fields",
            "fuzziness": "AUTO"
          }
        }
      ],
      "filter": [
        { "term":  { "in_stock": true } },
        { "range": { "price": { "lte": 200 } } },
        { "terms": { "category": ["electronics", "audio"] } }
      ],
      "should": [
        { "range": { "rating_avg": { "gte": 4, "boost": 1.5 } } }
      ]
    }
  },
  "sort": [
    { "_score": "desc" },
    { "rating_count": "desc" }
  ],
  "aggs": {
    "brands":     { "terms": { "field": "brand", "size": 20 } },
    "price_range":{ "range": { "field": "price", "ranges": [
      { "to": 50 }, { "from": 50, "to": 200 }, { "from": 200 }
    ]}}
  }
}