27.2. 累积统计收集器

27.2. 累积统计收集器
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27.2. 累积统计收集器 #

27.2.1. 统计收集配置
27.2.2. 内置统计视图概览
27.2.3. pg_stat_activity 视图
27.2.4. pg_stat_replication 视图
27.2.5. pg_stat_replication_slots 视图
27.2.6. pg_stat_wal_receiver 视图
27.2.7. pg_stat_recovery_prefetch 视图
27.2.8. pg_stat_subscription 视图
27.2.9. pg_stat_subscription_stats 视图
27.2.10. pg_stat_ssl 视图
27.2.11. pg_stat_gssapi 视图
27.2.12. pg_stat_archiver 视图
27.2.13. pg_stat_io 视图
27.2.14. pg_stat_bgwriter 视图
27.2.15. pg_stat_checkpointer 视图
27.2.16. pg_stat_wal 视图
27.2.17. pg_stat_database 视图
27.2.18. pg_stat_database_conflicts 视图
27.2.19. pg_stat_all_tables 视图
27.2.20. pg_stat_all_indexes 视图
27.2.21. pg_statio_all_tables 视图
27.2.22. pg_statio_all_indexes 视图
27.2.23. pg_statio_all_sequences 视图
27.2.24. pg_stat_user_functions 视图
27.2.25. pg_stat_slru 视图
27.2.26. 统计收集函数

PostgreSQL 内置了高性能的累积统计收集系统，能够记录对数据表的访问频次、磁盘 I/O 读写块数、WAL 生成量以及会话连接事件。

27.2.1. 统计收集配置 #

统计数据的采集开销极其低廉，默认全部自动开启（包括 track_activities、track_counts 与 track_io_timing）。

27.2.2. 内置统计视图概览 #

系统提供了两组核心内置视图：动态视图与累积统计视图。

Table 27.1. 动态统计视图

视图名称	说明
`pg_stat_activity`	每个活跃客户端会话的当前执行状态
`pg_stat_replication`	流复制连接的发送状态
`pg_stat_wal_receiver`	流复制接收端工作进程状态

Table 27.2. 累积统计视图

视图名称	说明
`pg_stat_database`	数据库级别的全局聚合度量
`pg_stat_all_tables`	表级别访问与元组增删改统计
`pg_stat_all_indexes`	索引使用频次与检索效率统计
`pg_statio_all_tables`	表级别磁盘读取与缓冲命中统计
`pg_stat_io`	全集群细粒度物理 I/O 统计
`pg_stat_wal`	WAL 写入与磁盘刷盘统计

27.2.3. `pg_stat_activity` 视图 #

显示每个后台连接进程的当前活动、正在执行的 SQL 语句文本、事务启动时间以及锁等待事件。

Table 27.3. pg_stat_activity 视图字段

字段名	说明
`pid`	后台进程 ID
`state`	当前连接状态（active, idle 等）
`query`	当前正在执行的 SQL

Table 27.4. 等待事件分类表

事件类型	说明
Lock	常规锁等待
IO	磁盘 I/O 读写等待

Table 27.5. Wait Events of Type Activity

`Activity` Wait Event	Description
`ArchiverMain`	Waiting in main loop of archiver process.
`AutovacuumMain`	Waiting in main loop of autovacuum launcher process.
`BgwriterHibernate`	Waiting in background writer process, hibernating.
`BgwriterMain`	Waiting in main loop of background writer process.
`CheckpointerMain`	Waiting in main loop of checkpointer process.
`CheckpointerShutdown`	Waiting for checkpointer process to be terminated.
`IoWorkerMain`	Waiting in main loop of IO Worker process.
`LogicalApplyMain`	Waiting in main loop of logical replication apply process.
`LogicalLauncherMain`	Waiting in main loop of logical replication launcher process.
`LogicalParallelApplyMain`	Waiting in main loop of logical replication parallel apply process.
`RecoveryWalStream`	Waiting in main loop of startup process for WAL to arrive, during streaming recovery.
`ReplicationSlotsyncMain`	Waiting in main loop of slot sync worker.
`ReplicationSlotsyncShutdown`	Waiting for slot sync worker to shut down.
`SysloggerMain`	Waiting in main loop of syslogger process.
`WalReceiverMain`	Waiting in main loop of WAL receiver process.
`WalSenderMain`	Waiting in main loop of WAL sender process.
`WalSummarizerWal`	Waiting in WAL summarizer for more WAL to be generated.
`WalWriterMain`	Waiting in main loop of WAL writer process.

Table 27.6. Wait Events of Type Bufferpin

`BufferPin` Wait Event	Description
`BufferPin`	Waiting to acquire an exclusive pin on a buffer.

Table 27.7. Wait Events of Type Client

`Client` Wait Event	Description
`ClientRead`	Waiting to read data from the client.
`ClientWrite`	Waiting to write data to the client.
`GssOpenServer`	Waiting to read data from the client while establishing a GSSAPI session.
`LibpqwalreceiverConnect`	Waiting in WAL receiver to establish connection to remote server.
`LibpqwalreceiverReceive`	Waiting in WAL receiver to receive data from remote server.
`SslOpenServer`	Waiting for SSL while attempting connection.
`WaitForStandbyConfirmation`	Waiting for WAL to be received and flushed by the physical standby.
`WalSenderWaitForWal`	Waiting for WAL to be flushed in WAL sender process.
`WalSenderWriteData`	Waiting for any activity when processing replies from WAL receiver in WAL sender process.

Table 27.8. Wait Events of Type Extension

`Extension` Wait Event	Description
`Extension`	Waiting in an extension.

Table 27.9. Wait Events of Type Io

`IO` Wait Event	Description
`AioIoCompletion`	Waiting for another process to complete IO.
`AioIoUringExecution`	Waiting for IO execution via io_uring.
`AioIoUringSubmit`	Waiting for IO submission via io_uring.
`BasebackupRead`	Waiting for base backup to read from a file.
`BasebackupSync`	Waiting for data written by a base backup to reach durable storage.
`BasebackupWrite`	Waiting for base backup to write to a file.
`BuffileRead`	Waiting for a read from a buffered file.
`BuffileTruncate`	Waiting for a buffered file to be truncated.
`BuffileWrite`	Waiting for a write to a buffered file.
`ControlFileRead`	Waiting for a read from the `pg_control` file.
`ControlFileSync`	Waiting for the `pg_control` file to reach durable storage.
`ControlFileSyncUpdate`	Waiting for an update to the `pg_control` file to reach durable storage.
`ControlFileWrite`	Waiting for a write to the `pg_control` file.
`ControlFileWriteUpdate`	Waiting for a write to update the `pg_control` file.
`CopyFileCopy`	Waiting for a file copy operation.
`CopyFileRead`	Waiting for a read during a file copy operation.
`CopyFileWrite`	Waiting for a write during a file copy operation.
`DataFileExtend`	Waiting for a relation data file to be extended.
`DataFileFlush`	Waiting for a relation data file to reach durable storage.
`DataFileImmediateSync`	Waiting for an immediate synchronization of a relation data file to durable storage.
`DataFilePrefetch`	Waiting for an asynchronous prefetch from a relation data file.
`DataFileRead`	Waiting for a read from a relation data file.
`DataFileSync`	Waiting for changes to a relation data file to reach durable storage.
`DataFileTruncate`	Waiting for a relation data file to be truncated.
`DataFileWrite`	Waiting for a write to a relation data file.
`DsmAllocate`	Waiting for a dynamic shared memory segment to be allocated.
`DsmFillZeroWrite`	Waiting to fill a dynamic shared memory backing file with zeroes.
`LockFileAddtodatadirRead`	Waiting for a read while adding a line to the data directory lock file.
`LockFileAddtodatadirSync`	Waiting for data to reach durable storage while adding a line to the data directory lock file.
`LockFileAddtodatadirWrite`	Waiting for a write while adding a line to the data directory lock file.
`LockFileCreateRead`	Waiting to read while creating the data directory lock file.
`LockFileCreateSync`	Waiting for data to reach durable storage while creating the data directory lock file.
`LockFileCreateWrite`	Waiting for a write while creating the data directory lock file.
`LockFileRecheckdatadirRead`	Waiting for a read during recheck of the data directory lock file.
`LogicalRewriteCheckpointSync`	Waiting for logical rewrite mappings to reach durable storage during a checkpoint.
`LogicalRewriteMappingSync`	Waiting for mapping data to reach durable storage during a logical rewrite.
`LogicalRewriteMappingWrite`	Waiting for a write of mapping data during a logical rewrite.
`LogicalRewriteSync`	Waiting for logical rewrite mappings to reach durable storage.
`LogicalRewriteTruncate`	Waiting for truncate of mapping data during a logical rewrite.
`LogicalRewriteWrite`	Waiting for a write of logical rewrite mappings.
`RelationMapRead`	Waiting for a read of the relation map file.
`RelationMapReplace`	Waiting for durable replacement of a relation map file.
`RelationMapWrite`	Waiting for a write to the relation map file.
`ReorderBufferRead`	Waiting for a read during reorder buffer management.
`ReorderBufferWrite`	Waiting for a write during reorder buffer management.
`ReorderLogicalMappingRead`	Waiting for a read of a logical mapping during reorder buffer management.
`ReplicationSlotRead`	Waiting for a read from a replication slot control file.
`ReplicationSlotRestoreSync`	Waiting for a replication slot control file to reach durable storage while restoring it to memory.
`ReplicationSlotSync`	Waiting for a replication slot control file to reach durable storage.
`ReplicationSlotWrite`	Waiting for a write to a replication slot control file.
`SlruFlushSync`	Waiting for SLRU data to reach durable storage during a checkpoint or database shutdown.
`SlruRead`	Waiting for a read of an SLRU page.
`SlruSync`	Waiting for SLRU data to reach durable storage following a page write.
`SlruWrite`	Waiting for a write of an SLRU page.
`SnapbuildRead`	Waiting for a read of a serialized historical catalog snapshot.
`SnapbuildSync`	Waiting for a serialized historical catalog snapshot to reach durable storage.
`SnapbuildWrite`	Waiting for a write of a serialized historical catalog snapshot.
`TimelineHistoryFileSync`	Waiting for a timeline history file received via streaming replication to reach durable storage.
`TimelineHistoryFileWrite`	Waiting for a write of a timeline history file received via streaming replication.
`TimelineHistoryRead`	Waiting for a read of a timeline history file.
`TimelineHistorySync`	Waiting for a newly created timeline history file to reach durable storage.
`TimelineHistoryWrite`	Waiting for a write of a newly created timeline history file.
`TwophaseFileRead`	Waiting for a read of a two phase state file.
`TwophaseFileSync`	Waiting for a two phase state file to reach durable storage.
`TwophaseFileWrite`	Waiting for a write of a two phase state file.
`VersionFileSync`	Waiting for the version file to reach durable storage while creating a database.
`VersionFileWrite`	Waiting for the version file to be written while creating a database.
`WalsenderTimelineHistoryRead`	Waiting for a read from a timeline history file during a walsender timeline command.
`WalBootstrapSync`	Waiting for WAL to reach durable storage during bootstrapping.
`WalBootstrapWrite`	Waiting for a write of a WAL page during bootstrapping.
`WalCopyRead`	Waiting for a read when creating a new WAL segment by copying an existing one.
`WalCopySync`	Waiting for a new WAL segment created by copying an existing one to reach durable storage.
`WalCopyWrite`	Waiting for a write when creating a new WAL segment by copying an existing one.
`WalInitSync`	Waiting for a newly initialized WAL file to reach durable storage.
`WalInitWrite`	Waiting for a write while initializing a new WAL file.
`WalRead`	Waiting for a read from a WAL file.
`WalSummaryRead`	Waiting for a read from a WAL summary file.
`WalSummaryWrite`	Waiting for a write to a WAL summary file.
`WalSync`	Waiting for a WAL file to reach durable storage.
`WalSyncMethodAssign`	Waiting for data to reach durable storage while assigning a new WAL sync method.
`WalWrite`	Waiting for a write to a WAL file.

Table 27.10. Wait Events of Type Ipc

`IPC` Wait Event	Description
`AppendReady`	Waiting for subplan nodes of an `Append` plan node to be ready.
`ArchiveCleanupCommand`	Waiting for archive_cleanup_command to complete.
`ArchiveCommand`	Waiting for archive_command to complete.
`BackendTermination`	Waiting for the termination of another backend.
`BackupWaitWalArchive`	Waiting for WAL files required for a backup to be successfully archived.
`BgworkerShutdown`	Waiting for background worker to shut down.
`BgworkerStartup`	Waiting for background worker to start up.
`BtreePage`	Waiting for the page number needed to continue a parallel B-tree scan to become available.
`BufferIo`	Waiting for buffer I/O to complete.
`CheckpointDelayComplete`	Waiting for a backend that blocks a checkpoint from completing.
`CheckpointDelayStart`	Waiting for a backend that blocks a checkpoint from starting.
`CheckpointDone`	Waiting for a checkpoint to complete.
`CheckpointStart`	Waiting for a checkpoint to start.
`ExecuteGather`	Waiting for activity from a child process while executing a `Gather` plan node.
`HashBatchAllocate`	Waiting for an elected Parallel Hash participant to allocate a hash table.
`HashBatchElect`	Waiting to elect a Parallel Hash participant to allocate a hash table.
`HashBatchLoad`	Waiting for other Parallel Hash participants to finish loading a hash table.
`HashBuildAllocate`	Waiting for an elected Parallel Hash participant to allocate the initial hash table.
`HashBuildElect`	Waiting to elect a Parallel Hash participant to allocate the initial hash table.
`HashBuildHashInner`	Waiting for other Parallel Hash participants to finish hashing the inner relation.
`HashBuildHashOuter`	Waiting for other Parallel Hash participants to finish partitioning the outer relation.
`HashGrowBatchesDecide`	Waiting to elect a Parallel Hash participant to decide on future batch growth.
`HashGrowBatchesElect`	Waiting to elect a Parallel Hash participant to allocate more batches.
`HashGrowBatchesFinish`	Waiting for an elected Parallel Hash participant to decide on future batch growth.
`HashGrowBatchesReallocate`	Waiting for an elected Parallel Hash participant to allocate more batches.
`HashGrowBatchesRepartition`	Waiting for other Parallel Hash participants to finish repartitioning.
`HashGrowBucketsElect`	Waiting to elect a Parallel Hash participant to allocate more buckets.
`HashGrowBucketsReallocate`	Waiting for an elected Parallel Hash participant to finish allocating more buckets.
`HashGrowBucketsReinsert`	Waiting for other Parallel Hash participants to finish inserting tuples into new buckets.
`LogicalApplySendData`	Waiting for a logical replication leader apply process to send data to a parallel apply process.
`LogicalParallelApplyStateChange`	Waiting for a logical replication parallel apply process to change state.
`LogicalSyncData`	Waiting for a logical replication remote server to send data for initial table synchronization.
`LogicalSyncStateChange`	Waiting for a logical replication remote server to change state.
`MessageQueueInternal`	Waiting for another process to be attached to a shared message queue.
`MessageQueuePutMessage`	Waiting to write a protocol message to a shared message queue.
`MessageQueueReceive`	Waiting to receive bytes from a shared message queue.
`MessageQueueSend`	Waiting to send bytes to a shared message queue.
`MultixactCreation`	Waiting for a multixact creation to complete.
`ParallelBitmapScan`	Waiting for parallel bitmap scan to become initialized.
`ParallelCreateIndexScan`	Waiting for parallel `CREATE INDEX` workers to finish heap scan.
`ParallelFinish`	Waiting for parallel workers to finish computing.
`ProcarrayGroupUpdate`	Waiting for the group leader to clear the transaction ID at transaction end.
`ProcSignalBarrier`	Waiting for a barrier event to be processed by all backends.
`Promote`	Waiting for standby promotion.
`RecoveryConflictSnapshot`	Waiting for recovery conflict resolution for a vacuum cleanup.
`RecoveryConflictTablespace`	Waiting for recovery conflict resolution for dropping a tablespace.
`RecoveryEndCommand`	Waiting for recovery_end_command to complete.
`RecoveryPause`	Waiting for recovery to be resumed.
`ReplicationOriginDrop`	Waiting for a replication origin to become inactive so it can be dropped.
`ReplicationSlotDrop`	Waiting for a replication slot to become inactive so it can be dropped.
`RestoreCommand`	Waiting for restore_command to complete.
`SafeSnapshot`	Waiting to obtain a valid snapshot for a `READ ONLY DEFERRABLE` transaction.
`SyncRep`	Waiting for confirmation from a remote server during synchronous replication.
`WalReceiverExit`	Waiting for the WAL receiver to exit.
`WalReceiverUpstreamCatchup`	Waiting for upstream server WAL flush position to catch up to requested start point.
`WalReceiverWaitStart`	Waiting for startup process to send initial data for streaming replication.
`WalSummaryReady`	Waiting for a new WAL summary to be generated.
`XactGroupUpdate`	Waiting for the group leader to update transaction status at transaction end.

Table 27.11. Wait Events of Type Lock

`Lock` Wait Event	Description
`advisory`	Waiting to acquire an advisory user lock.
`applytransaction`	Waiting to acquire a lock on a remote transaction being applied by a logical replication subscriber.
`extend`	Waiting to extend a relation.
`frozenid`	Waiting to update `pg_database`.`datfrozenxid` and `pg_database`.`datminmxid`.
`object`	Waiting to acquire a lock on a non-relation database object.
`page`	Waiting to acquire a lock on a page of a relation.
`relation`	Waiting to acquire a lock on a relation.
`spectoken`	Waiting to acquire a speculative insertion lock.
`transactionid`	Waiting for a transaction to finish.
`tuple`	Waiting to acquire a lock on a tuple.
`userlock`	Waiting to acquire a user lock.
`virtualxid`	Waiting to acquire a virtual transaction ID lock; see Section 67.1.

Table 27.12. Wait Events of Type Lwlock

`LWLock` Wait Event	Description
`AddinShmemInit`	Waiting to manage an extension's space allocation in shared memory.
`AioUringCompletion`	Waiting for another process to complete IO via io_uring.
`AioWorkerSubmissionQueue`	Waiting to access AIO worker submission queue.
`AutoFile`	Waiting to update the `postgresql.auto.conf` file.
`Autovacuum`	Waiting to read or update the current state of autovacuum workers.
`AutovacuumSchedule`	Waiting to ensure that a table selected for autovacuum still needs vacuuming.
`BackgroundWorker`	Waiting to read or update background worker state.
`BtreeVacuum`	Waiting to read or update vacuum-related information for a B-tree index.
`BufferContent`	Waiting to access a data page in memory.
`BufferMapping`	Waiting to associate a data block with a buffer in the buffer pool.
`CheckpointerComm`	Waiting to manage fsync requests.
`CommitTs`	Waiting to read or update the last value set for a transaction commit timestamp.
`CommitTsBuffer`	Waiting for I/O on a commit timestamp SLRU buffer.
`CommitTsSLRU`	Waiting to access the commit timestamp SLRU cache.
`ControlFile`	Waiting to read or update the `pg_control` file or create a new WAL file.
`DSMRegistry`	Waiting to read or update the dynamic shared memory registry.
`DSMRegistryDSA`	Waiting to access dynamic shared memory registry's dynamic shared memory allocator.
`DSMRegistryHash`	Waiting to access dynamic shared memory registry's shared hash table.
`DynamicSharedMemoryControl`	Waiting to read or update dynamic shared memory allocation information.
`InjectionPoint`	Waiting to read or update information related to injection points.
`LockFastPath`	Waiting to read or update a process' fast-path lock information.
`LockManager`	Waiting to read or update information about “heavyweight” locks.
`LogicalRepLauncherDSA`	Waiting to access logical replication launcher's dynamic shared memory allocator.
`LogicalRepLauncherHash`	Waiting to access logical replication launcher's shared hash table.
`LogicalRepWorker`	Waiting to read or update the state of logical replication workers.
`MultiXactGen`	Waiting to read or update shared multixact state.
`MultiXactMemberBuffer`	Waiting for I/O on a multixact member SLRU buffer.
`MultiXactMemberSLRU`	Waiting to access the multixact member SLRU cache.
`MultiXactOffsetBuffer`	Waiting for I/O on a multixact offset SLRU buffer.
`MultiXactOffsetSLRU`	Waiting to access the multixact offset SLRU cache.
`MultiXactTruncation`	Waiting to read or truncate multixact information.
`NotifyBuffer`	Waiting for I/O on a `NOTIFY` message SLRU buffer.
`NotifyQueue`	Waiting to read or update `NOTIFY` messages.
`NotifyQueueTail`	Waiting to update limit on `NOTIFY` message storage.
`NotifySLRU`	Waiting to access the `NOTIFY` message SLRU cache.
`OidGen`	Waiting to allocate a new OID.
`ParallelAppend`	Waiting to choose the next subplan during Parallel Append plan execution.
`ParallelBtreeScan`	Waiting to synchronize workers during Parallel B-tree scan plan execution.
`ParallelHashJoin`	Waiting to synchronize workers during Parallel Hash Join plan execution.
`ParallelQueryDSA`	Waiting for parallel query dynamic shared memory allocation.
`ParallelVacuumDSA`	Waiting for parallel vacuum dynamic shared memory allocation.
`PerSessionDSA`	Waiting for parallel query dynamic shared memory allocation.
`PerSessionRecordType`	Waiting to access a parallel query's information about composite types.
`PerSessionRecordTypmod`	Waiting to access a parallel query's information about type modifiers that identify anonymous record types.
`PerXactPredicateList`	Waiting to access the list of predicate locks held by the current serializable transaction during a parallel query.
`PgStatsData`	Waiting for shared memory stats data access.
`PgStatsDSA`	Waiting for stats dynamic shared memory allocator access.
`PgStatsHash`	Waiting for stats shared memory hash table access.
`PredicateLockManager`	Waiting to access predicate lock information used by serializable transactions.
`ProcArray`	Waiting to access the shared per-process data structures (typically, to get a snapshot or report a session's transaction ID).
`RelationMapping`	Waiting to read or update a `pg_filenode.map` file (used to track the filenode assignments of certain system catalogs).
`RelCacheInit`	Waiting to read or update a `pg_internal.init` relation cache initialization file.
`ReplicationOrigin`	Waiting to create, drop or use a replication origin.
`ReplicationOriginState`	Waiting to read or update the progress of one replication origin.
`ReplicationSlotAllocation`	Waiting to allocate or free a replication slot.
`ReplicationSlotControl`	Waiting to read or update replication slot state.
`ReplicationSlotIO`	Waiting for I/O on a replication slot.
`SerialBuffer`	Waiting for I/O on a serializable transaction conflict SLRU buffer.
`SerialControl`	Waiting to read or update shared `pg_serial` state.
`SerializableFinishedList`	Waiting to access the list of finished serializable transactions.
`SerializablePredicateList`	Waiting to access the list of predicate locks held by serializable transactions.
`SerializableXactHash`	Waiting to read or update information about serializable transactions.
`SerialSLRU`	Waiting to access the serializable transaction conflict SLRU cache.
`SharedTidBitmap`	Waiting to access a shared TID bitmap during a parallel bitmap index scan.
`SharedTupleStore`	Waiting to access a shared tuple store during parallel query.
`ShmemIndex`	Waiting to find or allocate space in shared memory.
`SInvalRead`	Waiting to retrieve messages from the shared catalog invalidation queue.
`SInvalWrite`	Waiting to add a message to the shared catalog invalidation queue.
`SubtransBuffer`	Waiting for I/O on a sub-transaction SLRU buffer.
`SubtransSLRU`	Waiting to access the sub-transaction SLRU cache.
`SyncRep`	Waiting to read or update information about the state of synchronous replication.
`SyncScan`	Waiting to select the starting location of a synchronized table scan.
`TablespaceCreate`	Waiting to create or drop a tablespace.
`TwoPhaseState`	Waiting to read or update the state of prepared transactions.
`WaitEventCustom`	Waiting to read or update custom wait events information.
`WALBufMapping`	Waiting to replace a page in WAL buffers.
`WALInsert`	Waiting to insert WAL data into a memory buffer.
`WALSummarizer`	Waiting to read or update WAL summarization state.
`WALWrite`	Waiting for WAL buffers to be written to disk.
`WrapLimitsVacuum`	Waiting to update limits on transaction id and multixact consumption.
`XactBuffer`	Waiting for I/O on a transaction status SLRU buffer.
`XactSLRU`	Waiting to access the transaction status SLRU cache.
`XactTruncation`	Waiting to execute `pg_xact_status` or update the oldest transaction ID available to it.
`XidGen`	Waiting to allocate a new transaction ID.

Table 27.13. Wait Events of Type Timeout

`Timeout` Wait Event	Description
`BaseBackupThrottle`	Waiting during base backup when throttling activity.
`CheckpointWriteDelay`	Waiting between writes while performing a checkpoint.
`PgSleep`	Waiting due to a call to `pg_sleep` or a sibling function.
`RecoveryApplyDelay`	Waiting to apply WAL during recovery because of a delay setting.
`RecoveryRetrieveRetryInterval`	Waiting during recovery when WAL data is not available from any source (`pg_wal`, archive or stream).
`RegisterSyncRequest`	Waiting while sending synchronization requests to the checkpointer, because the request queue is full.
`SpinDelay`	Waiting while acquiring a contended spinlock.
`VacuumDelay`	Waiting in a cost-based vacuum delay point.
`VacuumTruncate`	Waiting to acquire an exclusive lock to truncate off any empty pages at the end of a table vacuumed.
`WalSummarizerError`	Waiting after a WAL summarizer error.

27.2.4. `pg_stat_replication` 视图 #

显示主节点上正在向备节点流式发送 WAL 的 walsender 进程状态。

Table 27.14. pg_stat_replication 字段

字段	说明
`client_addr`	备库 IP 地址
`replay_lsn`	备库最新回放位点

27.2.5. `pg_stat_replication_slots` 视图 #

提供关于逻辑与物理复制槽的数据处理度量统计。

Table 27.15. pg_stat_replication_slots 字段

字段	说明
`slot_name`	复制槽名称
`spill_bytes`	解码溢出到磁盘的字节数

27.2.6. `pg_stat_wal_receiver` 视图 #

在备库上显示正在接收 WAL 流的 walreceiver 工作进程实时状态。

Table 27.16. pg_stat_wal_receiver 字段

字段	说明
`status`	接收器运行状态

27.2.7. `pg_stat_recovery_prefetch` 视图 #

显示备库或故障恢复期间预读磁盘块的命中统计。

Table 27.17. pg_stat_recovery_prefetch 字段

字段	说明
`prefetch`	预读页面计数

27.2.8. `pg_stat_subscription` 视图 #

显示订阅端上逻辑复制各个订阅工作进程的实时连接状态。

Table 27.18. pg_stat_subscription 字段

字段	说明
`subname`	订阅名称

27.2.9. `pg_stat_subscription_stats` 视图 #

提供逻辑复制订阅的累积失败与冲突度量统计。

Table 27.19. pg_stat_subscription_stats 字段

字段	说明
`confl_count`	写入冲突计数

27.2.10. `pg_stat_ssl` 视图 #

显示当前每个客户端会话的 SSL/TLS 连接加密详情（加密算法、协议版本等）。

Table 27.20. pg_stat_ssl 字段

字段	说明
`ssl`	是否启用 SSL

27.2.11. `pg_stat_gssapi` 视图 #

显示当前客户端连接的 GSSAPI 身份认证与加密状态。

Table 27.21. pg_stat_gssapi 字段

字段	说明
`gss_authenticated`	是否通过 GSSAPI 认证

27.2.12. `pg_stat_archiver` 视图 #

显示 WAL 归档进程的成功与失败计数及最近归档时间。

Table 27.22. pg_stat_archiver 字段

字段	说明
`archived_count`	成功归档段数

27.2.13. `pg_stat_io` 视图 #

提供整个集群按照后台进程类型、上下文目标与 I/O 操作类型划分的细粒度读写读写统计。

Table 27.23. pg_stat_io 字段

字段	说明
`backend_type`	后台进程类别
`reads`	物理读页面数

27.2.14. `pg_stat_bgwriter` 视图 #

显示后台写进程（bgwriter）的物理页面刷盘清理统计。

Table 27.24. pg_stat_bgwriter 字段

字段	说明
`buffers_clean`	清理写出的缓冲区页数

27.2.15. `pg_stat_checkpointer` 视图 #

显示检查点工作进程的执行频次、触发原因及刷盘耗时。

Table 27.25. pg_stat_checkpointer 字段

字段	说明
`num_timed`	定时检查点次数

27.2.16. `pg_stat_wal` 视图 #

显示预写式日志（WAL）的生成总量、写入与 fsync 刷盘开销。

Table 27.26. pg_stat_wal 字段

字段	说明
`wal_records`	生成的 WAL 记录数

27.2.17. `pg_stat_database` 视图 #

显示数据库级别的整体聚合度量（事务提交数、回滚数、死锁数、冲突数等）。

Table 27.27. pg_stat_database 字段

字段	说明
`xact_commit`	提交事务总数

27.2.18. `pg_stat_database_conflicts` 视图 #

显示热备节点上由不同原因导致的查询取消冲突统计。

Table 27.28. pg_stat_database_conflicts 字段

字段	说明
`confl_lock`	锁冲突取消计数

27.2.19. `pg_stat_all_tables` 视图 #

显示各数据表的顺序扫描次数、行读取数、存活与死元组数以及上次自动清理时间。

Table 27.29. pg_stat_all_tables 字段

字段	说明
`n_dead_tup`	死元组估计数量

27.2.20. `pg_stat_all_indexes` 视图 #

显示各索引的扫描次数、抓取元组数及效率。

Table 27.30. pg_stat_all_indexes 字段

字段	说明
`idx_scan`	索引扫描次数

27.2.21. `pg_statio_all_tables` 视图 #

显示表数据块的真实物理磁盘读取数与共享内存缓冲区命中数。

Table 27.31. pg_statio_all_tables 字段

字段	说明
`heap_blks_hit`	内存命中块数

27.2.22. `pg_statio_all_indexes` 视图 #

显示索引数据块的磁盘读取与内存命中统计。

Table 27.32. pg_statio_all_indexes 字段

字段	说明
`idx_blks_hit`	索引内存命中块数

27.2.23. `pg_statio_all_sequences` 视图 #

显示序列对象的 I/O 读写与缓存命中统计。

Table 27.33. pg_statio_all_sequences 字段

字段	说明
`blks_hit`	序列内存命中块数

27.2.24. `pg_stat_user_functions` 视图 #

显示用户自定义函数的执行次数、单次调用总耗时与自身耗时。

Table 27.34. pg_stat_user_functions 字段

字段	说明
`calls`	调用总次数

27.2.25. `pg_stat_slru` 视图 #

显示简单近期最少使用（SLRU）缓存的读写、命中与落盘统计。

Table 27.35. pg_stat_slru 字段

字段	说明
`blks_hit`	SLRU 命中块数

27.2.26. 统计收集函数 #

用于查询与重置统计收集器数据的内置函数。

Table 27.36. 常用统计查询函数

函数	说明
`pg_stat_reset()`	重置集群所有累积统计

Table 27.37. 后台统计提取函数

函数	说明
`pg_stat_get_backend_io()`	获取指定后台进程的 I/O 统计
`pg_stat_get_backend_wal()`	获取指定后台进程的 WAL 统计