fix: serialize concurrent PG schema init with advisory lock
ci / test (push) Successful in 23m44s

Startup race: concurrent init_db (cloud-server + worker) ran
CREATE TABLE / CREATE INDEX IF NOT EXISTS against a DB where the
object did not exist yet; the check-then-create is not atomic, so
both sessions created it and one died with UniqueViolation on
pg_type_typname_nsp_index (tables) or pg_class_relname_nsp_index
(indexes). Hit on the 37ba687 and 7983567 deploys (7983567 added
idx_tasks_parent); systemd restart healed it every time.

Fix (advisory lock, not catch-duplicate_object): init_postgres_schema
takes pg_advisory_xact_lock (key 20261108, released at its commit),
and server.init_db takes the session-level lock for the whole PG
branch so the _ensure_* objects outside POSTGRES_SCHEMA
(task_continue_messages, user_gateway_keys, task_attempts,
task_audit_loop_state) are covered too. Same idiom as the existing
RATE_LIMIT_SWEEP_ADVISORY_KEY sweep lock; key is distinct.

Tests: two new real-PG regression tests (skipped without
CLOUD_TEST_PG_DSN), 4 processes racing on an empty schema, for
init_postgres_schema and for full init_db; both fail on the
unfixed code and pass with the fix.
This commit is contained in:
host committed 2026-11-08 05:49:52 +00:00
1 parent 7983567491
commit 8b2686548c
4 files changed
+222

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+55
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@@ -1165,6 +1165,49 @@ POSTGRES_SCHEMA = (
)
# 启动期 schema 初始化 advisory lock key(Postgres):
# 并发启动(cloud-server 与 worker 同时 init_db)时,CREATE TABLE /
# CREATE INDEX 的 IF NOT EXISTS 检查与建对象不是原子的——两个会话
# 都查到“不存在”后同时建,会撞 pg_type_typname_nsp_index(建表)
# 或 pg_class_relname_nsp_index(建索引)的 UniqueViolation,启动
# 即崩、靠 systemd 重启才自愈(37ba687 与 7983567 两次部署均撞上;
# 7983567 新增的 idx_tasks_parent 是当时的新对象)。
# 持锁串行化整个初始化:init_postgres_schema 内持事务级锁(随本
# 函数末尾的 commit 释放),server.init_db 另持会话级锁覆盖其后
# 的 _ensure_*(task_continue_messages / user_gateway_keys /
# task_attempts / task_audit_loop_state 不在 POSTGRES_SCHEMA 里,同样
# 会撞)。key 须全项目唯一:限流清理另有
# RATE_LIMIT_SWEEP_ADVISORY_KEY = 20261027(cloud/server.py),
# 两处绝不能撞 key。
SCHEMA_INIT_ADVISORY_KEY = 20261108
def acquire_schema_init_lock(conn):
"""取 schema 初始化会话级 advisory 锁(阻塞等,不 try)。
调用方须在初始化全部完成后调 release_schema_init_lock 释放;
连接关闭时也会自动释放。初始化必须做完不能跳过,所以这里用
阻塞取锁,不用 pg_try_advisory_lock。
"""
conn.execute(
"SELECT pg_advisory_lock(?)",
(SCHEMA_INIT_ADVISORY_KEY,))
def release_schema_init_lock(conn):
"""放 schema 初始化会话级 advisory 锁(best-effort)。
事务已 abort 时 SELECT 本身也会失败——吞掉,连接关闭时锁
同样释放,绝不能让放锁失败再挡住启动。
"""
try:
conn.execute(
"SELECT pg_advisory_unlock(?)",
(SCHEMA_INIT_ADVISORY_KEY,))
except Exception:
pass
def init_postgres_schema(conn):
"""在给定适配连接上建出全部 Postgres 表(幂等),并提交。
@@ -1178,6 +1221,15 @@ def init_postgres_schema(conn):
库是 no-op。server.init_db 的 Postgres 分支还会再跑一次
migrate_projects_table,两次补列互不冲突(第二次是 no-op)。
"""
# 事务级 advisory 锁:并发 init_postgres_schema 串行执行,
# 随本函数末尾的 commit 释放;独立调用方(如 migrations)
# 同样受保护。server.init_db 另持会话级锁覆盖 _ensure_*。
# 不取结果行:pg_advisory_xact_lock 返回 void,且假连接
# (test_p2_migrations / test_audit_batch1 的 FakeCursor)
# 没有 fetchone——execute 本身已阻塞到取锁成功。
conn.execute(
"SELECT pg_advisory_xact_lock(?)",
(SCHEMA_INIT_ADVISORY_KEY,))
for statement in POSTGRES_SCHEMA:
conn.execute(statement)
cols = {row[1] for row in conn.execute(
@@ -1379,6 +1431,9 @@ __all__ = [
"PgCursor",
"PgRow",
"POSTGRES_SCHEMA",
"SCHEMA_INIT_ADVISORY_KEY",
"acquire_schema_init_lock",
"release_schema_init_lock",
"init_postgres_schema",
"create_database",
"database_from_env",
+12
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@@ -88,7 +88,9 @@ from cloud.timeouts import validate_server_timeout as _validate_timeout
from cloud.auth import audit_on_conn as _audit_on_conn
from cloud.db import connect as _db_connect
from cloud.db import create_database as _create_database
from cloud.db import acquire_schema_init_lock as _acquire_schema_init_lock
from cloud.db import init_postgres_schema as _init_postgres_schema
from cloud.db import release_schema_init_lock as _release_schema_init_lock
from cloud.db import PostgresIntegrityError as _PgIntegrityError
from cloud.db import PostgresOperationalError as _PgOperationalError
from cloud.goal_command import parse_goal_command as _parse_goal_command
@@ -1667,6 +1669,14 @@ def init_db(db_path):
conn = _connect(db_path)
try:
if _is_postgres_backend():
# 会话级 advisory 锁覆盖整个 PG 初始化:_init_postgres_schema
# 内还有事务级锁,但其后的 _ensure_* 建的对象不全在
# POSTGRES_SCHEMA 里(task_continue_messages /
# user_gateway_keys / task_attempts / task_audit_loop_state),
# 只锁前者仍会在后者上撞 UniqueViolation;锁在最终 commit
# 后才放。连接在外层 finally 里关闭,锁至迟随连接释放。
_acquire_schema_init_lock(conn)
try:
_init_postgres_schema(conn)
migrate_tasks_table(conn)
migrate_projects_table(conn)
@@ -1683,6 +1693,8 @@ def init_db(db_path):
_ensure_audit_loop(conn)
conn.commit()
return
finally:
_release_schema_init_lock(conn)
conn.execute(
"CREATE TABLE IF NOT EXISTS projects("
"id TEXT PRIMARY KEY, "
+75
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@@ -28,7 +28,9 @@ import sqlite3
import sys
import tempfile
import time
import traceback
import unittest
from multiprocessing import Barrier, Process, Queue
from pathlib import Path
from types import SimpleNamespace
from unittest import mock
@@ -209,6 +211,18 @@ class SqliteUpsertTestCase(unittest.TestCase):
conn.close()
def _concurrent_init_db_worker(barrier, queue, wid, env):
"""并发启动子进程:与其它进程同时跑 server.init_db。"""
try:
os.environ.update(env)
barrier.wait(timeout=60)
from cloud.server import init_db
init_db(":memory:")
queue.put((wid, "ok", ""))
except Exception:
queue.put((wid, "FAIL", traceback.format_exc()))
class PgInitFixTestCase(unittest.TestCase):
"""真实 PG 测试:无 DSN/驱动时全部 skip。"""
@@ -331,6 +345,67 @@ class PgInitFixTestCase(unittest.TestCase):
finally:
conn.close()
def test_concurrent_init_db_no_unique_violation(self):
"""并发启动回归:4 进程同时 init_db,须全部成功。
覆盖整条启动路径(init_postgres_schema + _ensure_*):
_ensure_* 建的 task_continue_messages / user_gateway_keys /
task_attempts / task_audit_loop_state 不在 POSTGRES_SCHEMA
里,只锁 schema 函数不够;init_db 持会话级 advisory 锁
覆盖全程。空库上跑,未修复时第 1 轮即 3/4 进程报
UniqueViolation(pg_type_typname_nsp_index)。
"""
env = _pg_env()
if env is None:
self.skipTest("未设置可达的 CLOUD_TEST_PG_DSN 或未装驱动,"
"跳过真实 PG 测试")
from cloud.db import PostgresDatabase
db = PostgresDatabase(
host=env["CLOUD_DB_HOST"], port=int(env["CLOUD_DB_PORT"]),
dbname=env["CLOUD_DB_NAME"], user=env["CLOUD_DB_USER"],
password=env["CLOUD_DB_PASSWORD"])
conn = db.connect()
try:
conn.execute("DROP SCHEMA public CASCADE")
conn.execute("CREATE SCHEMA public")
conn.commit()
finally:
conn.close()
nworkers = 4
barrier = Barrier(nworkers)
queue = Queue()
procs = [Process(target=_concurrent_init_db_worker,
args=(barrier, queue, i, env))
for i in range(nworkers)]
try:
for proc in procs:
proc.start()
for proc in procs:
proc.join(timeout=180)
finally:
for proc in procs:
if proc.is_alive():
proc.terminate()
results = [queue.get() for _ in range(nworkers)]
failures = [r for r in results if r[1] == "FAIL"]
self.assertEqual([], failures,
"并发 init_db 有进程失败:%s" % (failures,))
# 初始化完整:schema 表与 _ensure_* 表都在。
conn = db.connect()
try:
rows = db.read_all(
conn,
"SELECT table_name FROM information_schema.tables"
" WHERE table_schema = 'public'",
())
names = {r["table_name"] for r in rows}
for table in ("users", "projects", "tasks",
"task_continue_messages", "user_gateway_keys",
"task_attempts", "task_audit_loop_state"):
self.assertIn(table, names)
finally:
conn.close()
if __name__ == "__main__":
unittest.main()
+80
View File
@@ -17,7 +17,9 @@
import os
import socket
import sys
import traceback
import unittest
from multiprocessing import Barrier, Process, Queue
from pathlib import Path
from unittest import mock
from urllib.parse import unquote, urlparse
@@ -386,3 +388,81 @@ class RealPostgresSchemaTestCase(unittest.TestCase):
except Exception:
pass
conn.close()
def _concurrent_schema_worker(barrier, queue, wid, params):
"""并发初始化子进程:与其它进程同时跑 init_postgres_schema。"""
try:
host, port, dbname, user, password = params
barrier.wait(timeout=60)
db = PostgresDatabase(host=host, port=port, dbname=dbname,
user=user, password=password)
conn = db.connect()
try:
init_postgres_schema(conn)
finally:
conn.close()
queue.put((wid, "ok", ""))
except Exception:
queue.put((wid, "FAIL", traceback.format_exc()))
class RealPostgresConcurrentInitTestCase(unittest.TestCase):
"""真实 PG 并发初始化:无 DSN 或不可达时 skip。
回归:启动竞态(37ba687 与 7983567 两次部署均撞上)——
cloud-server 与 worker 并发 init 时,CREATE TABLE / CREATE
INDEX 的 IF NOT EXISTS 检查与建对象不是原子的,并发建同名
对象会撞 pg_type_typname_nsp_index(建表)或
pg_class_relname_nsp_index(建索引)的 UniqueViolation。
修法是 schema 初始化持 advisory 锁串行化;本用例在空库上
4 进程同时初始化,必须全部成功、表齐全、无一例异常外泄。
"""
def test_concurrent_init_postgres_schema_no_unique_violation(self):
params = _real_pg_params()
if params is None:
self.skipTest("未设置可达的 CLOUD_TEST_PG_DSN,跳过真实 PG 测试")
if not _has_real_driver():
self.skipTest("未装 psycopg 驱动,跳过真实 PG 测试")
host, port, dbname, user, password = params
db = PostgresDatabase(host=host, port=port, dbname=dbname,
user=user, password=password)
conn = db.connect()
try:
conn.execute("DROP SCHEMA public CASCADE")
conn.execute("CREATE SCHEMA public")
conn.commit()
finally:
conn.close()
nworkers = 4
barrier = Barrier(nworkers)
queue = Queue()
procs = [Process(target=_concurrent_schema_worker,
args=(barrier, queue, i, params))
for i in range(nworkers)]
try:
for proc in procs:
proc.start()
for proc in procs:
proc.join(timeout=120)
finally:
for proc in procs:
if proc.is_alive():
proc.terminate()
results = [queue.get() for _ in range(nworkers)]
failures = [r for r in results if r[1] == "FAIL"]
self.assertEqual([], failures,
"并发初始化有进程失败:%s" % (failures,))
conn = db.connect()
try:
rows = db.read_all(
conn,
"SELECT table_name FROM information_schema.tables"
" WHERE table_schema = 'public'",
())
names = {r["table_name"] for r in rows}
for table in SchemaStatementTestCase.EXPECTED_TABLES:
self.assertIn(table, names)
finally:
conn.close()