Activity/RecoveryWalStream

各版本描述

相邻版本里类型、名称与英文描述都相同的合并成一段，旧的在前。中文取自图谱或本站手册译文，没有译文的只给英文原文。

1. 10–12

   Activity/RecoveryWalStream

   在恢复期间，若所有来源（本地、归档或流）都没有可用的 WAL 数据，则在重新尝试获取 WAL 数据前等待。

   Waiting when WAL data is not available from any kind of sources (local, archive or stream) before trying again to retrieve WAL data, at recovery.

2. 13–20

   Activity/RecoveryWalStream

   流恢复期间，在启动进程主循环等待WAL到达。

   Waiting in main loop of startup process for WAL to arrive, during streaming recovery.

触发机制

WAIT_EVENT_RECOVERY_WAL_STREAM 位于 src/backend/access/transam/xlogrecovery.c:4038，是经 grep 核验的报告路径。公共身份/资源映射位于 src/backend/utils/activity/wait_event_names.txt:64。探针覆盖的操作是：流式恢复期间，在 startup 进程的主循环中等待 WAL 到达。RecoveryWalStream 后台路径在主循环暂时无事可做、进入 latch wait 前报告此事件；信号、计时器或新工作会唤醒进程并进入下一轮循环。

WAIT_EVENT_RECOVERY_WAL_STREAM at src/backend/access/transam/xlogrecovery.c:4038 is the grep-verified reporting path. The public identity/resource is mapped at src/backend/utils/activity/wait_event_names.txt:64. The instrumented operation is: Waiting in main loop of startup process for WAL to arrive, during streaming recovery. The RecoveryWalStream background path reports this event around its latch wait when its main loop has no immediate work. A signal, timeout, or new work clears the sleep and the process loops again.

诊断 SQL

直接在 psql 里跑；标注的是语句里用到的视图与列所要求的最低版本。

SELECT pid, backend_type, usename, datname, application_name,
       state, now() - query_start AS query_age,
       now() - xact_start AS xact_age,
       wait_event_type, wait_event,
       pg_blocking_pids(pid) AS blocking_pids,
       left(query, 160) AS query
FROM pg_stat_activity
WHERE wait_event_type = 'Activity'
  AND wait_event = 'RecoveryWalStream'
ORDER BY query_age DESC NULLS LAST;

SELECT wait_event, count(*) AS waiting_sessions,
       count(*) FILTER (WHERE state = 'active') AS active_waiters,
       max(now() - query_start) AS oldest_query
FROM pg_stat_activity
WHERE wait_event_type = 'Activity'
GROUP BY wait_event
ORDER BY waiting_sessions DESC, wait_event;

SELECT a.pid, l.locktype, l.mode, l.granted, l.fastpath,
       d.datname, n.nspname, c.relname,
       l.page, l.tuple, l.virtualxid, l.transactionid,
       l.classid, l.objid, l.objsubid
FROM pg_stat_activity AS a
LEFT JOIN pg_locks AS l ON l.pid = a.pid
LEFT JOIN pg_database AS d ON d.oid = l.database
LEFT JOIN pg_class AS c
  ON c.oid = l.relation
 AND l.database = (
       SELECT oid FROM pg_database WHERE datname = current_database()
     )
LEFT JOIN pg_namespace AS n ON n.oid = c.relnamespace
WHERE a.wait_event_type = 'Activity'
  AND a.wait_event = 'RecoveryWalStream'
ORDER BY a.pid, l.granted, l.locktype, l.mode;

处置步骤

1. 先与 backend_type 对照。
2. 检查该进程专属的积压与最后进展时间。
3. 修复缺失的工作信号或停滞的上游阶段，不要终止正常空闲的 worker。

相关参数与指标

wal_bufferssynchronous_commit waiting_sessionswait_event_sharewal_byteswal_write_time

源码证据

图谱在各版本源码树里核对到的位置，新的在前。「触发点」是真正上报等待事件的调用处，「目录定义」只说明这个名字在枚举里存在。

演化历史

相邻两个大版本之间的差异，新的在前。版本号链到该版的变动清单。

1. PostgreSQL 13 ← 12 描述更新

   描述措辞更新

   流恢复期间，在启动进程主循环等待WAL到达。

   描述前后对照

   Waiting when WAL data is not available from any kind of sources (local, archive or stream) before trying again to retrieve WAL data, at recovery. Waiting in main loop of startup process for WAL to arrive, during streaming recovery.

2. PostgreSQL 10 ← 9.6 新增此事件

   该版起出现

   在恢复期间，若所有来源（本地、归档或流）都没有可用的 WAL 数据，则在重新尝试获取 WAL 数据前等待。

同类事件