# [[metric:oldest_transaction_age]]

> 最老打开事务或可见性边界的年龄。
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最老打开事务或可见性边界的年龄。

## 被哪些等待事件引用 {#wait-events}

- [Activity/AutovacuumMain](/zh/activity/autovacuum-main/)
- [IO/LogicalSubxactRead](/zh/io/logical-subxact-read/)
- [IO/LogicalSubxactWrite](/zh/io/logical-subxact-write/)
- [IPC/XactGroupUpdate](/zh/ipc/xact-group-update/)
- [LWLock/Autovacuum](/zh/lwlock/autovacuum/)
- [LWLock/AutovacuumSchedule](/zh/lwlock/autovacuum-schedule/)
- [LWLock/BtreeVacuum](/zh/lwlock/btree-vacuum/)
- [LWLock/ParallelVacuumDSA](/zh/lwlock/parallel-vacuum-dsa/)
- [LWLock/PerXactPredicateList](/zh/lwlock/per-xact-predicate-list/)
- [LWLock/ProcArray](/zh/lwlock/proc-array/)
- [LWLock/SerializableXactHash](/zh/lwlock/serializable-xact-hash/)
- [LWLock/WrapLimitsVacuum](/zh/lwlock/wrap-limits-vacuum/)
- [LWLock/XactBuffer](/zh/lwlock/xact-buffer/)
- [LWLock/XactSLRU](/zh/lwlock/xact-slru/)
- [LWLock/XactTruncation](/zh/lwlock/xact-truncation/)
- [Timeout/VacuumDelay](/zh/timeout/vacuum-delay/)
- [Timeout/VacuumTruncate](/zh/timeout/vacuum-truncate/)