{"Entry":{"collection":"waitevent","key":"ipc/MultixactCreation","name":"MultixactCreation","aliases":["MultixactCreation"],"metadata":{"aliases":["MultixactCreation"],"changed_in":[],"changes":[{"from":"16","moved":null,"renamed":null,"reworded":null,"status":"added","to":"17"}],"content_hash":"44b8b0beacc514cd069868e449d2c59fe20b65252c0ef9da924b61e40266ba23","dossier":{"actions":{"en":["Identify the peer or phase named by the event.","Inspect that participant's wait, error, and progress state.","Repair the stalled participant or upstream dependency instead of treating the waiter as the root cause."],"zh":["确认事件所指的对端或阶段。","检查该参与者的等待、错误与进展状态。","修复停滞的参与者或上游依赖，不要把等待者当作根因。"]},"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 = 'IPC'\n  AND wait_event = 'MultixactCreation'\nORDER BY query_age DESC NULLS LAST;","title":"Sessions waiting on IPC/MultixactCreation","title_zh":"正在等待 IPC/MultixactCreation 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 = 'IPC'\nGROUP BY wait_event\nORDER BY waiting_sessions DESC, wait_event;","title":"Current IPC cohort","title_zh":"当前 IPC 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 = 'IPC'\n  AND a.wait_event = 'MultixactCreation'\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":{"active_ranges":["17.0-17.7","18.0-18.1"],"dormant_ranges":["17.8+","18.2+"],"evidence":[{"label":"PostgreSQL 17.8 release note","url":"https://www.postgresql.org/docs/17/release-17-8.html"},{"label":"PostgreSQL 18.2 release note","url":"https://www.postgresql.org/docs/18/release-18-2.html"}],"historical_triggers":[{"line":1484,"path":"src/backend/access/transam/multixact.c","tag":"REL_17_7"},{"line":1493,"path":"src/backend/access/transam/multixact.c","tag":"REL_18_1"}],"reason":"wait loop removed while the catalog identity was retained for compatibility","status":"dormant"},"gucs":["autovacuum_multixact_freeze_max_age","vacuum_multixact_freeze_table_age"],"incident_pattern":{"en":"","zh":""},"mechanism":{"en":"The catalog identity is present, but source audit found no live reporter in 17.8+, 18.2+. Known active ranges: 17.0-17.7, 18.0-18.1. The definition location below is retained as negative evidence; this exact release cannot emit the event from a core code path. Evidence: [PostgreSQL 17.8 release note](https://www.postgresql.org/docs/17/release-17-8.html), [PostgreSQL 18.2 release note](https://www.postgresql.org/docs/18/release-18-2.html).","zh":"目录中仍保留该身份，但源码审计确认在 17.8+, 18.2+ 已没有活动报告点。已知曾可触发范围：17.0-17.7, 18.0-18.1。下方定义位置作为负面证据保留；当前精确版本不会从核心代码路径发出此事件。 证据：[PostgreSQL 17.8 release note](https://www.postgresql.org/docs/17/release-17-8.html)、[PostgreSQL 18.2 release note](https://www.postgresql.org/docs/18/release-18-2.html)。"},"metrics":["waiting_sessions","wait_event_share","oldest_multixact_age"],"normal":{"en":"No live core occurrence is expected on the audited release.","zh":"在已审计的精确版本上，不应出现活动的核心触发。"},"official_descriptions":{"17":"Waiting for a multixact creation to complete","18":"Waiting for a multixact creation to complete"},"record_kind":"event","source_locations":[{"commit":"724edf9bde9d356724ad384a2e196edc3c9f80f7","excerpt":"MULTIXACT_CREATION\t\"Waiting for a multixact creation to complete.\"","grep_pattern":"MULTIXACT_CREATION","grep_verified":true,"kind":"catalog_definition","line":143,"major":18,"path":"src/backend/utils/activity/wait_event_names.txt","status":"catalog_only","symbol":"MULTIXACT_CREATION","tag":"REL_18_6","url":"https://github.com/postgres/postgres/blob/REL_18_6/src/backend/utils/activity/wait_event_names.txt#L143","version":"18.6"}],"source_status":"catalog_only","trouble":{"en":"If telemetry shows it, verify the exact patch version, extension origin, and whether the sample is stale or came from a different server.","zh":"若监控仍显示它，应核对精确小版本、扩展来源，并确认样本是否陈旧或来自另一台服务器。"}},"first_version":"17","has_dossier":true,"imported_at":"2026-09-27T17:57:32.777192+08:00","key":"ipc/multixactcreation","last_version":"20","name":"MultixactCreation","position":162,"present_in":["17","18","19","20"],"slug":"multixact-creation","source_rev":"english-manuals:4c98e40012b65d8050c78e2ab1d44a511a3b62b64ad4627f884536c753ec8c52","summary":"Waiting for a multixact creation to complete.","summary_zh":"","type":"IPC","type_slug":"ipc","type_variants":["IPC"]}},"Definition":{"Collection":"waitevent","Key":"ipc/MultixactCreation","SourceDatabase":"center","Version":"18","SourceTable":"waitevent","SourceKey":"ipc/multixactcreation","SourceRevision":"english-manuals:4c98e40012b65d8050c78e2ab1d44a511a3b62b64ad4627f884536c753ec8c52","Facts":{"description":"Waiting for a multixact creation to complete.","description_zh":"","doc":{"anchor":"WAIT-EVENT-IPC-TABLE","file":"monitoring-stats.html","lang":"en","sha256":"aa979eed08627fbf715a9d792094a162a73671db5af810f3ab2aad3e073d5722","slug":"18"},"lang":"en","name":"MultixactCreation","source":"english-manual","type":"IPC","zh_from":""},"ManualEvidence":{"doc":{"anchor":"WAIT-EVENT-IPC-TABLE","file":"monitoring-stats.html","lang":"en","sha256":"aa979eed08627fbf715a9d792094a162a73671db5af810f3ab2aad3e073d5722","slug":"18"}},"MeasuredEvidence":{}},"Text":{"Collection":"waitevent","Key":"ipc/MultixactCreation","SourceDatabase":"pgweb","Version":"18","Locale":"zh-Hans","Title":"MultixactCreation","Summary":"等待多事务创建完成。","BodyHTML":"\u003cp\u003e等待多事务创建完成。\u003c/p\u003e","SourceRevision":"2026-08-31@34d13c8","ContentHash":"31676db93c5dda2a35addf3b81f0ec2016b1cc81ae762f7b96702b396bcddc7a","Payload":{"description_zh":"等待多事务创建完成。","zh_from":"doc"}},"RequestedLocale":"zh-Hans","Fallback":false,"Versions":["17","18","19","20"],"Locales":["en","zh-Hans"],"Signatures":null,"Spellings":null,"SQLState":null,"Evidence":null}