From 952c10955b428dd916392ed3f066bda59bf1ce96 Mon Sep 17 00:00:00 2001
From: OG T <ogt@WOOOMacMiniM4.local>
Date: Wed, 15 Apr 2026 15:38:43 +0800
Subject: [PATCH] =?UTF-8?q?fix(db):=20=E5=A4=9A=20replica=20=E4=B8=A6?=
 =?UTF-8?q?=E8=A1=8C=E5=95=9F=E5=8B=95=E7=AB=B6=E7=88=AD=20=E2=80=94=20?=
 =?UTF-8?q?=E6=AF=8F=20table=20=E7=8D=A8=E7=AB=8B=20tx=20+=20DROP=20INDEX?=
 =?UTF-8?q?=20IF=20EXISTS?=
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根因：單一大 transaction 內兩個 pod 同時建同一個 table，
其中一個 CREATE INDEX 失敗 → 整個 transaction ROLLBACK
→ table 也消失 → 下次重啟同樣情況 → 無限 CrashLoop。

修法三層：
1. 每個 table 用獨立 transaction 建立（失敗不影響其他）
2. 建 table 前先 DROP INDEX IF EXISTS 清殘留孤兒 index
3. 捕捉 "already exists" 讓並行 pod 優雅跳過（不 crash）

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 apps/api/src/db/base.py | 40 ++++++++++++++++++++++++++--------------
 1 file changed, 26 insertions(+), 14 deletions(-)

diff --git a/apps/api/src/db/base.py b/apps/api/src/db/base.py
index ede5270f..0990bd93 100644
--- a/apps/api/src/db/base.py
+++ b/apps/api/src/db/base.py
@@ -143,21 +143,33 @@ async def init_db() -> None:
     Call this at application startup.
     """
     engine = get_engine()
+
+    # 2026-04-15 ogt: 多 replica 並行啟動競爭修復
+    # 問題：單一大 transaction 裡兩個 pod 同時建 table → 其中一個 CREATE INDEX 失敗
+    #       PostgreSQL 中 transaction 內任何錯誤導致整個 transaction ROLLBACK
+    #       → table + index 全消失 → 下次重啟同樣問題 → 無限 CrashLoop
+    # 修法：每個 table 獨立 transaction；先 DROP INDEX IF EXISTS 清殘留孤兒 index；
+    #       捕捉 "already exists" 讓並行 pod 優雅跳過
+    async with engine.connect() as probe_conn:
+        existing = set(await probe_conn.run_sync(
+            lambda c: __import__('sqlalchemy', fromlist=['inspect']).inspect(c).get_table_names()
+        ))
+
+    for table in Base.metadata.sorted_tables:
+        if table.name not in existing:
+            try:
+                async with engine.begin() as conn:
+                    # 先清殘留孤兒 index（前次 CrashLoop 留下的部分狀態）
+                    for index in table.indexes:
+                        await conn.execute(text(f'DROP INDEX IF EXISTS "{index.name}"'))
+                    await conn.run_sync(table.create)
+            except Exception as exc:
+                if "already exists" in str(exc).lower():
+                    pass  # 並行 pod 已建好，忽略
+                else:
+                    raise
+
     async with engine.begin() as conn:
-        # SQLAlchemy 2.0 問題：create_all(checkfirst=True) 跳過 CREATE TABLE，
-        # 但仍對 __table_args__ Index 物件發出獨立 CREATE INDEX → CrashLoopBackOff
-        # 修法：先 inspect 取得現有 tables，只對不存在的 table 呼叫 table.create()
-        # 這樣 index 只隨新 table 一起建立，永遠不會 duplicate
-        # 2026-04-15 Claude Sonnet 4.6（亞太）Phase 3 修復
-        def _create_missing_tables(sync_conn):
-            from sqlalchemy import inspect as sa_inspect
-            existing = set(sa_inspect(sync_conn).get_table_names())
-            for table in Base.metadata.sorted_tables:
-                if table.name not in existing:
-                    table.create(sync_conn)
-
-        await conn.run_sync(_create_missing_tables)
-
         # 2026-04-02 Claude Code: 確保 risklevel enum 包含 'high' 值
         # Phase 23 新增，避免舊 DB 缺少此值導致 InvalidTextRepresentation
         await conn.execute(