MongoDB와 Elasticsearch는 왜 JPA보다 빠른 DB가 아닐까요?

GET /products?keyword=wireless&minPrice=10000&brand=aha

{
  "_id": "product-42",
  "name": "Wireless Keyboard",
  "brand": {
    "id": "brand-7",
    "name": "Aha Gear"
  },
  "options": [
    { "color": "black", "stock": 12 },
    { "color": "white", "stock": 4 }
  ],
  "reviewSummary": {
    "average": 4.7,
    "count": 128
  }
}

package com.example.catalog;

import java.util.List;
import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.mapping.Document;

@Document("product_catalog")
public class ProductCatalogDocument {

    @Id
    private String id;

    private String name;
    private BrandSnapshot brand;
    private List<ProductOptionSnapshot> options;
    private ReviewSummary reviewSummary;

    // constructors, getters
}

package com.example.catalog;

public record BrandSnapshot(
        String id,
        String name
) {
}

spring:
  mongodb:
    uri: "mongodb://localhost:27017/catalog"

package com.example.catalog;

import java.util.List;
import org.springframework.data.mongodb.repository.MongoRepository;

public interface ProductCatalogRepository
        extends MongoRepository<ProductCatalogDocument, String> {

    List<ProductCatalogDocument> findByBrandName(String brandName);
}

package com.example.catalog;

import java.util.List;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.data.mongodb.core.query.Criteria;
import org.springframework.data.mongodb.core.query.Query;
import org.springframework.stereotype.Repository;

@Repository
public class ProductCatalogQueryRepository {

    private final MongoTemplate mongoTemplate;

    public ProductCatalogQueryRepository(MongoTemplate mongoTemplate) {
        this.mongoTemplate = mongoTemplate;
    }

    public List<ProductCatalogDocument> findAvailableByBrand(String brandName) {
        Query query = Query.query(Criteria.where("brand.name").is(brandName)
                .and("options.stock").gt(0));

        return mongoTemplate.find(query, ProductCatalogDocument.class);
    }
}

GET /products/search?q=wireless keyboard

{
  "id": "product-42",
  "name": "Wireless Keyboard",
  "description": "Quiet mechanical keyboard for office desks",
  "brandName": "Aha Gear",
  "price": 49000,
  "tags": ["keyboard", "wireless", "office"]
}

package com.example.search;

import java.math.BigDecimal;
import java.util.List;
import org.springframework.data.annotation.Id;
import org.springframework.data.elasticsearch.annotations.Document;

@Document(indexName = "product-search")
public class ProductSearchDocument {

    @Id
    private String id;

    private String name;
    private String description;
    private String brandName;
    private BigDecimal price;
    private List<String> tags;

    // constructors, getters
}

package com.example.search;

import java.util.List;
import org.springframework.data.elasticsearch.repository.ElasticsearchRepository;

public interface ProductSearchRepository
        extends ElasticsearchRepository<ProductSearchDocument, String> {

    List<ProductSearchDocument> findByNameContaining(String keyword);
}

name = "Wireless Keyboard"

{
  "_id": "product-42",
  "name": "Wireless Keyboard",
  "shippingBadge": "오늘출발"
}

product/
├── Product.java                       # 업무 원본 Entity
├── ProductRepository.java             # JPA repository
├── ProductCommandService.java         # 생성, 수정, 재고 변경
├── catalog/
│   ├── ProductCatalogDocument.java    # MongoDB read model
│   └── ProductCatalogRepository.java
└── search/
    ├── ProductSearchDocument.java     # Elasticsearch search index model
    └── ProductSearchIndexer.java