{"Entry":{"collection":"waitevent","key":"timeout/RegisterSyncRequest","name":"RegisterSyncRequest","aliases":["RegisterSyncRequest"],"metadata":{"aliases":["RegisterSyncRequest"],"changed_in":[],"changes":[{"from":"11","moved":null,"renamed":null,"reworded":null,"status":"added","to":"12"}],"content_hash":"9fd2c1404056f63508429e7480bbc0a8f9ab1e05badda8c6d7aace6b0478af8f","dossier":{"actions":{"en":["Identify the GUC or function that owns the timer.","Compare productive work with time spent delayed.","Adjust the policy only after checking the CPU, I/O, and durability pressure it was designed to control."],"zh":["确认拥有该计时器的 GUC 或函数。","比较有效工作量与延迟时间。","先检查它原本要控制的 CPU、I/O 与持久性压力，再调整策略。"]},"diagnostic_sql":[{"id":"sessions","min_version":"13","sql":"SELECT pid, backend_type, usename, datname, application_name,\n       state, now() - query_start AS query_age,\n       now() - xact_start AS xact_age,\n       wait_event_type, wait_event,\n       pg_blocking_pids(pid) AS blocking_pids,\n       left(query, 160) AS query\nFROM pg_stat_activity\nWHERE wait_event_type = 'Timeout'\n  AND wait_event = 'RegisterSyncRequest'\nORDER BY query_age DESC NULLS LAST;","title":"Sessions waiting on Timeout/RegisterSyncRequest","title_zh":"正在等待 Timeout/RegisterSyncRequest 的会话"},{"id":"cohort","min_version":"13","sql":"SELECT wait_event, count(*) AS waiting_sessions,\n       count(*) FILTER (WHERE state = 'active') AS active_waiters,\n       max(now() - query_start) AS oldest_query\nFROM pg_stat_activity\nWHERE wait_event_type = 'Timeout'\nGROUP BY wait_event\nORDER BY waiting_sessions DESC, wait_event;","title":"Current Timeout cohort","title_zh":"当前 Timeout 等待分布"},{"id":"lock_objects","min_version":"13","sql":"SELECT a.pid, l.locktype, l.mode, l.granted, l.fastpath,\n       d.datname, n.nspname, c.relname,\n       l.page, l.tuple, l.virtualxid, l.transactionid,\n       l.classid, l.objid, l.objsubid\nFROM pg_stat_activity AS a\nLEFT JOIN pg_locks AS l ON l.pid = a.pid\nLEFT JOIN pg_database AS d ON d.oid = l.database\nLEFT JOIN pg_class AS c\n  ON c.oid = l.relation\n AND l.database = (\n       SELECT oid FROM pg_database WHERE datname = current_database()\n     )\nLEFT JOIN pg_namespace AS n ON n.oid = c.relnamespace\nWHERE a.wait_event_type = 'Timeout'\n  AND a.wait_event = 'RegisterSyncRequest'\nORDER BY a.pid, l.granted, l.locktype, l.mode;","title":"Lock and relation context for these sessions","title_zh":"这些会话的锁与关系上下文"}],"emission":{"status":"active","verified_release":"18.6"},"incident_pattern":{"en":"","zh":""},"mechanism":{"en":"`WAIT_EVENT_REGISTER_SYNC_REQUEST` at `src/backend/storage/sync/sync.c:615` is the grep-verified reporting path. The public identity/resource is mapped at `src/backend/utils/activity/wait_event_names.txt:180`. The instrumented operation is: Waiting while sending synchronization requests to the checkpointer, because the request queue is full. The RegisterSyncRequest path deliberately waits on a timer, retry interval, throttle, or safety backoff. The latch timeout expires before work is reconsidered.","zh":"`WAIT_EVENT_REGISTER_SYNC_REQUEST` 位于 `src/backend/storage/sync/sync.c:615`，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:180`。探针覆盖的操作是：由于请求队列已满，在向 checkpointer 发送同步请求时等待。RegisterSyncRequest 路径有意等待计时器、重试间隔、节流或安全退避；latch 超时后才重新评估工作。"},"metrics":["waiting_sessions","wait_event_share"],"normal":{"en":"The wait is normal when the configured policy is intentional and useful work advances at the expected rate.","zh":"当配置策略是有意的，而且有效工作按预期速率推进时，这项等待正常。"},"official_descriptions":{"13":"Waiting while sending synchronization requests to the checkpointer, because the request queue is full.","14":"Waiting while sending synchronization requests to the checkpointer, because the request queue is full.","15":"Waiting while sending synchronization requests to the checkpointer, because the request queue is full.","16":"Waiting while sending synchronization requests to the checkpointer, because the request queue is full.","17":"Waiting while sending synchronization requests to the checkpointer, because the request queue is full","18":"Waiting while sending synchronization requests to the checkpointer, because the request queue is full"},"record_kind":"event","source_locations":[{"commit":"724edf9bde9d356724ad384a2e196edc3c9f80f7","excerpt":"WAIT_EVENT_REGISTER_SYNC_REQUEST);","grep_pattern":"WAIT_EVENT_REGISTER_SYNC_REQUEST","grep_verified":true,"kind":"trigger","line":615,"major":18,"path":"src/backend/storage/sync/sync.c","status":"live_trigger","symbol":"WAIT_EVENT_REGISTER_SYNC_REQUEST","tag":"REL_18_6","url":"https://github.com/postgres/postgres/blob/REL_18_6/src/backend/storage/sync/sync.c#L615","version":"18.6"},{"commit":"724edf9bde9d356724ad384a2e196edc3c9f80f7","excerpt":"REGISTER_SYNC_REQUEST\t\"Waiting while sending synchronization requests to the checkpointer, because the request queue is full.\"","grep_pattern":"REGISTER_SYNC_REQUEST","grep_verified":true,"kind":"catalog_definition","line":180,"major":18,"path":"src/backend/utils/activity/wait_event_names.txt","status":"live_trigger","symbol":"REGISTER_SYNC_REQUEST","tag":"REL_18_6","url":"https://github.com/postgres/postgres/blob/REL_18_6/src/backend/utils/activity/wait_event_names.txt#L180","version":"18.6"}],"source_status":"live_trigger","trouble":{"en":"Investigate when the policy causes missed maintenance, recovery, backup, or latency objectives, or when a spin delay persists.","zh":"策略导致维护、恢复、备份或延迟目标无法达成，或者 spin delay 持续时，应当调查。"}},"first_version":"12","has_dossier":true,"imported_at":"2026-09-27T17:57:33.108977+08:00","key":"timeout/registersyncrequest","last_version":"20","name":"RegisterSyncRequest","position":298,"present_in":["12","13","14","15","16","17","18","19","20"],"slug":"register-sync-request","source_rev":"english-manuals:5a5b8821725367f98c5d373b72dba2eaa5057d7d26b4f02e82bf30692b4e533b","summary":"Waiting while sending synchronization requests to the checkpointer, because the request queue is full.","summary_zh":"","type":"Timeout","type_slug":"timeout","type_variants":["Timeout"]}},"Definition":{"Collection":"waitevent","Key":"timeout/RegisterSyncRequest","SourceDatabase":"center","Version":"18","SourceTable":"waitevent","SourceKey":"timeout/registersyncrequest","SourceRevision":"english-manuals:5a5b8821725367f98c5d373b72dba2eaa5057d7d26b4f02e82bf30692b4e533b","Facts":{"description":"Waiting while sending synchronization requests to the checkpointer, because the request queue is full.","description_zh":"","doc":{"anchor":"WAIT-EVENT-TIMEOUT-TABLE","file":"monitoring-stats.html","lang":"en","sha256":"aa979eed08627fbf715a9d792094a162a73671db5af810f3ab2aad3e073d5722","slug":"18"},"lang":"en","name":"RegisterSyncRequest","source":"english-manual","type":"Timeout","zh_from":""},"ManualEvidence":{"doc":{"anchor":"WAIT-EVENT-TIMEOUT-TABLE","file":"monitoring-stats.html","lang":"en","sha256":"aa979eed08627fbf715a9d792094a162a73671db5af810f3ab2aad3e073d5722","slug":"18"}},"MeasuredEvidence":{}},"Text":{"Collection":"waitevent","Key":"timeout/RegisterSyncRequest","SourceDatabase":"pgweb","Version":"18","Locale":"zh-Hans","Title":"RegisterSyncRequest","Summary":"向检查点进程发送同步请求时，因请求队列已满而等待。","BodyHTML":"\u003cp\u003e向检查点进程发送同步请求时，因请求队列已满而等待。\u003c/p\u003e","SourceRevision":"2026-08-31@34d13c8","ContentHash":"1289d8262473947bcfb4d6e875302211b44da7fa82e07c1e39cce05d1f86c8dc","Payload":{"description_zh":"向检查点进程发送同步请求时，因请求队列已满而等待。","zh_from":"doc"}},"RequestedLocale":"zh-Hans","Fallback":false,"Versions":["12","13","14","15","16","17","18","19","20"],"Locales":["en","zh-Hans"],"Signatures":null,"Spellings":null,"SQLState":null,"Evidence":null}