fix(search): ts_stat 改单参(text),避免 'a' mask 静默 0 行

zhparser 不标 A 权重(也不标 B/C/D),传 'a' mask 给 ts_stat(text, weights) 会过滤掉所有词
但不报错,静默 0 行。改成 ts_stat(text) 单参(等价 mask='abcd',聚合所有权重)。

修:
- 0010 迁移里 refresh_search_keywords() 改用单参 ts_stat
- 0010 迁移 downgrade 部分同步修
- 0009 迁移 refresh_search_keywords() 同步修
- services/search.py _fallback_keywords 改用 chinese_zh + 单参 ts_stat

backend/alembic/versions/0009_search_suggestions.py

@@ -218,10 +218,7 @@ def upgrade() -> None:
                     FROM generate_series(1, length(word)) AS n
                 )
             FROM ts_stat(
-                'simple',
+                $$SELECT to_tsvector('simple',
-                (
-                    SELECT to_tsvector(
-                        'simple',
                     coalesce(title_zh, '') || ' ' ||
                     coalesce(body_zh_text, '') || ' ' ||
                     coalesce(commentary, '') || ' ' ||
@@ -231,10 +228,9 @@ def upgrade() -> None:
                 WHERE title_zh IS NOT NULL
                    OR body_zh_text IS NOT NULL
                    OR commentary IS NOT NULL
-                       OR commentary_meituan IS NOT NULL
+                   OR commentary_meituan IS NOT NULL$$
-                )
+            ) AS s
-            )
+            WHERE length(s.word) >= 2;  -- 过滤单字噪音(中文标点/单字停用词)
-            WHERE length(word) >= 2;  -- 过滤单字噪音(中文标点/单字停用词)
 
         END;
         $$ LANGUAGE plpgsql;

backend/alembic/versions/0010_zhparser_chinese.py

@@ -80,7 +80,8 @@ def upgrade() -> None:
             TRUNCATE search_keywords;
 
             -- ts_stat(query text) 接受 SQL 字符串,内部执行并聚合词频
-            -- 'a' = 任意权重(A/B/C/D 四档,这里聚合所有)
+            -- 单参(等价 mask='abcd',聚合所有权重)
+            -- ⚠️ 不能传 'a' mask — zhparser 不标 A 权重,会 0 行
             INSERT INTO search_keywords (keyword, source, weight, prefix_keys)
             SELECT
                 word,
@@ -91,8 +92,7 @@ def upgrade() -> None:
                     FROM generate_series(1, length(word)) AS n
                 )
             FROM ts_stat(
-                $q$
+                $$SELECT to_tsvector('chinese_zh',
-                SELECT to_tsvector('chinese_zh',
                     coalesce(title_zh, '') || ' ' ||
                     coalesce(body_zh_text, '') || ' ' ||
                     coalesce(commentary, '') || ' ' ||
@@ -102,10 +102,9 @@ def upgrade() -> None:
                 WHERE title_zh IS NOT NULL
                    OR body_zh_text IS NOT NULL
                    OR commentary IS NOT NULL
-                   OR commentary_meituan IS NOT NULL
+                   OR commentary_meituan IS NOT NULL$$
-                $q$, 'a'
+            ) AS s
-            )
+            WHERE length(s.word) >= 2;
-            WHERE length(word) >= 2;
         END;
         $func$ LANGUAGE plpgsql;
         """
@@ -135,8 +134,7 @@ def downgrade() -> None:
                     FROM generate_series(1, length(word)) AS n
                 )
             FROM ts_stat(
-                $q$
+                $$SELECT to_tsvector('simple',
-                SELECT to_tsvector('simple',
                     coalesce(title_zh, '') || ' ' ||
                     coalesce(body_zh_text, '') || ' ' ||
                     coalesce(commentary, '') || ' ' ||
@@ -146,10 +144,9 @@ def downgrade() -> None:
                 WHERE title_zh IS NOT NULL
                    OR body_zh_text IS NOT NULL
                    OR commentary IS NOT NULL
-                   OR commentary_meituan IS NOT NULL
+                   OR commentary_meituan IS NOT NULL$$
-                $q$, 'a'
+            ) AS s
-            )
+            WHERE length(s.word) >= 2;
-            WHERE length(word) >= 2;
         END;
         $func$ LANGUAGE plpgsql;
         """

backend/app/services/search.py

@@ -130,8 +130,9 @@ class SearchService:
     async def _fallback_keywords(self, q: str, limit: int) -> list[dict]:
         """回退:ts_stat 实时聚合(慢但能用)。
 
-        - 从 articles.title_zh + body_zh_text 实时 to_tsvector
+        - 从 articles.title_zh + body_zh_text 实时 to_tsvector(chinese_zh)
-        - 适用:search_keywords 表空 + ts_stat 之前的全量聚合
+        - 适用:search_keywords 表空 + worker 没刷新过
+        - ts_stat(text) 单参 — 第二参 weights mask 不能传 'a'(zhparser 不标 A 权重会 0 行)
         """
         from sqlalchemy import text
 
@@ -139,16 +140,13 @@ class SearchService:
             """
             SELECT word, nentry::int AS weight
             FROM ts_stat(
-                'simple',
+                $$SELECT to_tsvector('chinese_zh',
-                (
-                    SELECT to_tsvector(
-                        'simple',
                     coalesce(title_zh, '') || ' ' || coalesce(body_zh_text, '')
                 )
                 FROM articles
                 WHERE title_zh IS NOT NULL OR body_zh_text IS NOT NULL
-                )
+                LIMIT 500$$
-            )
+            ) AS s
             WHERE word LIKE :prefix
             ORDER BY nentry DESC
             LIMIT :lim