Merge pull request 'perf(search): 浏览路径部分复合索引 (0012)' (#27) from devin/1782279211-search-indexes into main

migrations/0012_search_indexes.down.sql

@@ -0,0 +1,2 @@
+DROP INDEX IF EXISTS idx_product_active_category;
+DROP INDEX IF EXISTS idx_product_active_quality;

migrations/0012_search_indexes.up.sql

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+-- 检索优化(可扩展性路线图 阶段0):为最常见的"浏览"路径补部分/复合索引。
+-- 搜索查询恒带 WHERE status = 'active';无关键词时按 quality_score DESC, name 排序。
+-- 现有索引无法同时满足"过滤 active + 按 quality_score/name 排序",深翻页时需要对全部
+-- active 行排序。下面的部分复合索引让规划器直接走索引顺序扫描,省掉排序、加速深翻页与
+-- count(*)。索引只覆盖 active 行,体积更小。
+
+-- 默认浏览(无关键词、无品类):ORDER BY quality_score DESC, name
+CREATE INDEX IF NOT EXISTS idx_product_active_quality
+    ON product (quality_score DESC, name)
+    WHERE status = 'active';
+
+-- 品类内浏览:先按 category_id 收敛,再按 quality_score 排序
+CREATE INDEX IF NOT EXISTS idx_product_active_category
+    ON product (category_id, quality_score DESC)
+    WHERE status = 'active';