ENTRYPOINT ["java", \
  "-XX:+UseG1GC", \
  "-XX:MaxRAMPercentage=75.0", \
  "-XX:InitialRAMPercentage=50.0", \
  "-XX:+UseStringDeduplication", \
  "-Xlog:gc*:file=/app/logs/gc.log:time,uptime,level,tags", \
  "-jar", "app.jar"]

// 実行成功

java -XX:+UseZGC \
     -XX:MaxRAMPercentage=75.0 \
     -XX:+ZGenerational \
     -Xlog:gc*:file=gc.log \
     -jar app.jar

// コマンド実行成功

spring:
  datasource:
    hikari:
      maximum-pool-size: 20
      minimum-idle: 20
      connection-timeout: 3000
      idle-timeout: 600000
      max-lifetime: 1800000
      leak-detection-threshold: 60000
      pool-name: OrderFlowHikariCP

設定が反映されました。

# リーク検出を有効化 (コネクション保持が60秒を超えると警告ログ)
spring:
  datasource:
    hikari:
      leak-detection-threshold: 60000

WARN  - Connection leak detection triggered for {conn-12345}
  Stack trace of the call site that acquired the connection:
    at com.orderflow.service.OrderService.getOrder(OrderService.java:45)
    ...

// 悪い例: N+1問題
// 100件の注文を取得する1SQL + 各注文のitemsを取得する100SQL = 合計101SQL!
List<Order> orders = orderRepository.findAll();
for (Order order : orders) {
    order.getItems().size();  // 各注文の遅延ロードをトリガー
}

// 実行成功

// 良い例: JOIN FETCHで単一クエリ
@Query("SELECT DISTINCT o FROM Order o JOIN FETCH o.items i JOIN FETCH i.product WHERE o.status = :status")
List<Order> findByStatusWithItems(@Param("status") String status);

// 実行成功

@Entity
@NamedEntityGraph(
    name = "Order.withItemsAndProduct",
    attributeNodes = {
        @NamedAttributeNode("items"),
        @NamedAttributeNode(value = "items", subgraph = "item-product")
    },
    subgraphs = {
        @NamedSubgraph(name = "item-product", attributeNodes = @NamedAttributeNode("product"))
    }
)
public class Order { /* ... */ }

// リポジトリでの使用
@EntityGraph(value = "Order.withItemsAndProduct", type = EntityGraphType.LOAD)
List<Order> findByStatus(String status);

// 実行成功

-- 注文ステータス照会用インデックス
CREATE INDEX idx_order_status ON orders(status);

-- 一般的なクエリパターン用複合インデックス
CREATE INDEX idx_order_status_created ON orders(status, created_at DESC);

-- 商品検索用インデックス
CREATE INDEX idx_product_name ON products(name);

-- 注文アイテムの商品検索用インデックス
CREATE INDEX idx_order_item_product ON order_items(product_id);

CREATE TABLE

-- MySQL スロークエリログ設定
SET GLOBAL slow_query_log = ON;
SET GLOBAL long_query_time = 1;  -- 1秒を超えるクエリをログに記録
SET GLOBAL log_queries_not_using_indexes = ON;

-- クエリ実行計画を分析
EXPLAIN SELECT o.*, i.*
FROM orders o
JOIN order_items i ON o.id = i.order_id
WHERE o.status = 'PENDING'
  AND o.created_at > '2024-01-01'
ORDER BY o.created_at DESC
LIMIT 20;

CREATE TABLE

# application-prod.yml (最適化版)
spring:
  datasource:
    hikari:
      maximum-pool-size: 20
      minimum-idle: 20
      connection-timeout: 3000
      leak-detection-threshold: 60000
  jpa:
    hibernate:
      ddl-auto: validate
    show-sql: false
    properties:
      hibernate:
        default_batch_fetch_size: 100
        jdbc:
          batch_size: 50
        order_inserts: true
        order_updates: true

# JVMパラメータ (Docker ENTRYPOINT)
java -XX:+UseG1GC \
     -XX:MaxRAMPercentage=75.0 \
     -XX:InitialRAMPercentage=50.0 \
     -XX:+UseStringDeduplication \
     -XX:MaxGCPauseMillis=100 \
     -Xlog:gc*:file=/app/logs/gc.log:time,uptime,level,tags \
     -jar app.jar

// EntityGraphとバッチフェッチで最適化されたOrderRepository
public interface OrderRepository extends JpaRepository<Order, Long> {

    @EntityGraph(value = "Order.withItemsAndProduct", type = EntityGraphType.LOAD)
    @Query("SELECT o FROM Order o WHERE o.status = :status ORDER BY o.createdAt DESC")
    Page<Order> findByStatusPaged(@Param("status") String status, Pageable pageable);

    @EntityGraph(value = "Order.withItemsAndProduct", type = EntityGraphType.LOAD)
    Optional<Order> findById(Long id);
}

// Hibernateバッチサイズ設定でコレクションのN+1を解消
// application.yml: hibernate.default_batch_fetch_size=100