{"Entry":{"collection":"waitevent","key":"lwlock/LockManager","name":"LockManager","aliases":["LockManager","lock_manager"],"metadata":{"aliases":["LockManager","lock_manager"],"changed_in":["10","13"],"changes":[{"from":"9.6","moved":{"from":"LWLockTranche","to":"LWLock"},"renamed":null,"reworded":null,"status":"changed","to":"10"},{"from":"12","moved":null,"renamed":{"from":"lock_manager","to":"LockManager"},"reworded":{"from":"Waiting to add or examine locks for backends, or waiting to join or exit a locking group (used by parallel query).","to":"Waiting to read or update information about “heavyweight” locks."},"status":"changed","to":"13"}],"content_hash":"bb5f667cde3d949720bb288ecd37be4759925e28191552bcd09b97521e3924b8","dossier":{"actions":{"en":["Count pg_locks rows per PID and inspect the blocking tree.","Identify statements touching many relations or partitions.","Shorten transactions and reduce lock fan-out; raise max_locks_per_transaction only for genuine capacity errors."],"zh":["按 PID 统计 pg_locks 行数并检查阻塞树。","定位一次触碰大量关系或分区的语句。","缩短事务并降低锁扇出；只有真实容量报错时才提高 max_locks_per_transaction。"]},"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 = 'LWLock'\n  AND wait_event = 'LockManager'\nORDER BY query_age DESC NULLS LAST;","title":"Sessions waiting on LWLock/LockManager","title_zh":"正在等待 LWLock/LockManager 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 = 'LWLock'\nGROUP BY wait_event\nORDER BY waiting_sessions DESC, wait_event;","title":"Current LWLock cohort","title_zh":"当前 LWLock 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 = 'LWLock'\n  AND a.wait_event = 'LockManager'\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"},"gucs":["max_locks_per_transaction","max_connections"],"incident_pattern":{"en":"A deployment runs DDL across thousands of partitions while application sessions acquire relation locks, creating internal lock-table contention before a clear blocker is visible.","zh":"发布过程对数千分区执行 DDL，同时业务会话获取关系锁；在明显阻塞者出现前，内部锁表已经发生竞争。"},"mechanism":{"en":"Heavyweight lock bookkeeping is stored in shared hash tables partitioned by LockHashPartitionLock. Acquiring, granting, releasing, or inspecting many heavyweight locks can contend on the partition even when no SQL-level lock conflict exists.","zh":"重量级锁的账本存放在由 LockHashPartitionLock 分区保护的共享哈希表中。获取、授予、释放或检查大量重量级锁时，即使不存在 SQL 层锁冲突，也可能在分区锁上竞争。"},"metrics":["waiting_sessions","wait_event_share","locks_per_backend","blocked_sessions"],"normal":{"en":"Small bursts accompany ordinary relation and transaction lock traffic.","zh":"普通关系锁与事务锁流量会带来小规模突发。"},"official_descriptions":{"13":"Waiting to read or update information about “heavyweight” locks.","14":"Waiting to read or update information about “heavyweight” locks.","15":"Waiting to read or update information about “heavyweight” locks.","16":"Waiting to read or update information about “heavyweight” locks.","17":"Waiting to read or update information about \"heavyweight\" locks","18":"Waiting to read or update information about \"heavyweight\" locks"},"record_kind":"event","source_locations":[{"commit":"724edf9bde9d356724ad384a2e196edc3c9f80f7","excerpt":"size = add_size(size, LockManagerShmemSize());","grep_pattern":"LockManager","grep_verified":true,"kind":"resource_path","line":117,"major":18,"path":"src/backend/storage/ipc/ipci.c","status":"dynamic_trigger","symbol":"LockManager","tag":"REL_18_6","url":"https://github.com/postgres/postgres/blob/REL_18_6/src/backend/storage/ipc/ipci.c#L117","version":"18.6"},{"commit":"724edf9bde9d356724ad384a2e196edc3c9f80f7","excerpt":"pgstat_report_wait_start(PG_WAIT_LWLOCK | lock-\u003etranche);","grep_pattern":"pgstat_report_wait_start","grep_verified":true,"kind":"generic_reporter","line":739,"major":18,"path":"src/backend/storage/lmgr/lwlock.c","status":"dynamic_trigger","symbol":"pgstat_report_wait_start","tag":"REL_18_6","url":"https://github.com/postgres/postgres/blob/REL_18_6/src/backend/storage/lmgr/lwlock.c#L739","version":"18.6"},{"commit":"724edf9bde9d356724ad384a2e196edc3c9f80f7","excerpt":"LockManager\t\"Waiting to read or update information about \u003cquote\u003eheavyweight\u003c/quote\u003e locks.\"","grep_pattern":"LockManager","grep_verified":true,"kind":"catalog_definition","line":378,"major":18,"path":"src/backend/utils/activity/wait_event_names.txt","status":"dynamic_trigger","symbol":"LockManager","tag":"REL_18_6","url":"https://github.com/postgres/postgres/blob/REL_18_6/src/backend/utils/activity/wait_event_names.txt#L378","version":"18.6"}],"source_status":"dynamic_trigger","trouble":{"en":"A sustained share often follows lock fan-out: very large transactions, many partitions, DDL churn, or thousands of waiting lock requests.","zh":"持续占比通常来自锁扇出：超大事务、大量分区、频繁 DDL，或成千上万的排队锁请求。"}},"first_version":"9.6","has_dossier":true,"imported_at":"2026-09-27T17:57:32.90934+08:00","key":"lwlock/lockmanager","last_version":"20","name":"LockManager","position":225,"present_in":["9.6","10","11","12","13","14","15","16","17","18","19","20"],"slug":"lock-manager","source_rev":"english-manuals:5627b7e37f4bcbb49607b8245e24f010896abb03f6757f0d9fdc84212cf5c792","summary":"Waiting to read or update information about “heavyweight” locks.","summary_zh":"","type":"LWLock","type_slug":"lwlock","type_variants":["LWLock","LWLockTranche"]}},"Definition":{"Collection":"waitevent","Key":"lwlock/LockManager","SourceDatabase":"center","Version":"18","SourceTable":"waitevent","SourceKey":"lwlock/lockmanager","SourceRevision":"english-manuals:5627b7e37f4bcbb49607b8245e24f010896abb03f6757f0d9fdc84212cf5c792","Facts":{"description":"Waiting to read or update information about “heavyweight” locks.","description_zh":"","doc":{"anchor":"WAIT-EVENT-LWLOCK-TABLE","file":"monitoring-stats.html","lang":"en","sha256":"aa979eed08627fbf715a9d792094a162a73671db5af810f3ab2aad3e073d5722","slug":"18"},"lang":"en","name":"LockManager","source":"english-manual","type":"LWLock","zh_from":""},"ManualEvidence":{"doc":{"anchor":"WAIT-EVENT-LWLOCK-TABLE","file":"monitoring-stats.html","lang":"en","sha256":"aa979eed08627fbf715a9d792094a162a73671db5af810f3ab2aad3e073d5722","slug":"18"}},"MeasuredEvidence":{}},"Text":{"Collection":"waitevent","Key":"lwlock/LockManager","SourceDatabase":"pgweb","Version":"18","Locale":"zh-Hans","Title":"LockManager","Summary":"等待读取或更新有关“重量级”锁的信息。","BodyHTML":"\u003cp\u003e等待读取或更新有关“重量级”锁的信息。\u003c/p\u003e","SourceRevision":"2026-08-31@34d13c8","ContentHash":"5ebe0ca6c942827a1719303f5a94141aa1046f3f732696af42b4b7d804bf1157","Payload":{"description_zh":"等待读取或更新有关“重量级”锁的信息。","zh_from":"doc"}},"RequestedLocale":"zh-Hans","Fallback":false,"Versions":["10","11","12","13","14","15","16","17","18","19","20","9.6"],"Locales":["en","zh-Hans"],"Signatures":null,"Spellings":null,"SQLState":null,"Evidence":null}