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PG.CENTER connects PostgreSQL documentation, reference, and ecosystem knowledge. Maintained by Pigsty.

REFERENCE / 302 EVENTS

What PostgreSQL is waiting for, with definitions and diagnostic context.

302 of 302 eventsFilled cells = documented or sourced presence. Select a cell to read that version.
Wait EventsVersion coverage
9.09.19.29.39.49.59.61011121314151617181920
ArchiverMainActivity

Waiting in main loop of archiver process.

10 – 20
AutovacuumMainActivity

Waiting in main loop of autovacuum launcher process.

10 – 20
BgwriterHibernateActivity

Waiting in background writer process, hibernating.

10 – 20
BgwriterMainActivity

Waiting in main loop of background writer process.

10 – 20
CheckpointerMainActivity

Waiting in main loop of checkpointer process.

10 – 20
CheckpointerShutdownActivity

Waiting for checkpointer process to be terminated.

18 – 20
IoWorkerMainActivity

Waiting in main loop of IO Worker process.

18 – 20
LogicalApplyMainActivity

Waiting in main loop of logical replication apply process.

10 – 20
LogicalLauncherMainActivity

Waiting in main loop of logical replication launcher process.

10 – 20
LogicalParallelApplyMainActivity

Waiting in main loop of logical replication parallel apply process.

16 – 20
PgStatMainActivity

Waiting in main loop of statistics collector process.

10 – 14 · No PG 18 snapshot
RecoveryWalAllActivity

Waiting for WAL from a stream at recovery.

10 – 12 · No PG 18 snapshot
RecoveryWalStreamActivity

Waiting in main loop of startup process for WAL to arrive, during streaming recovery.

10 – 20
ReplicationSlotsyncMainActivity

Waiting in main loop of slot sync worker.

17 – 20
ReplicationSlotsyncShutdownActivity

Waiting for slot sync worker to shut down.

17 – 20
SysloggerMainActivity

Waiting in main loop of syslogger process.

10 – 20
WalReceiverMainActivity

Waiting in main loop of WAL receiver process.

10 – 20
WalSenderMainActivity

Waiting in main loop of WAL sender process.

10 – 20
WalSummarizerWalActivity

Waiting in WAL summarizer for more WAL to be generated.

17 – 20
WalWriterMainActivity

Waiting in main loop of WAL writer process.

10 – 20
BufferCleanupBuffer

Waiting to acquire an exclusive pin on a buffer.

19 – 20 · No PG 18 snapshot
BufferExclusiveBuffer

Waiting to acquire an exclusive lock on a buffer.

19 – 20 · No PG 18 snapshot
BufferPinBuffer

Waiting to acquire an exclusive pin on a buffer.

9.6 – 18
BufferSharedBuffer

Waiting to acquire a shared lock on a buffer.

19 – 20 · No PG 18 snapshot
BufferShareExclusiveBuffer

Waiting to acquire a share exclusive lock on a buffer.

19 – 20 · No PG 18 snapshot
ClientReadClient

Waiting to read data from the client.

10 – 20
ClientWriteClient

Waiting to write data to the client.

10 – 20
GssOpenServerClient

Waiting to read data from the client while establishing a GSSAPI session.

12 – 20
LibpqwalreceiverConnectClient

Waiting in WAL receiver to establish connection to remote server.

10 – 20
LibpqwalreceiverReceiveClient

Waiting in WAL receiver to receive data from remote server.

10 – 20
SslOpenServerClient

Waiting for SSL while attempting connection.

10 – 20
WaitForStandbyConfirmationClient

Waiting for WAL to be received and flushed by the physical standby.

17 – 20
WalSenderWaitForWalClient

Waiting for WAL to be flushed in WAL sender process.

10 – 20
WalSenderWriteDataClient

Waiting for any activity when processing replies from WAL receiver in WAL sender process.

10 – 20
ExtensionExtension

Waiting in an extension.

10 – 20
AioIoCompletionIO

Waiting for another process to complete IO.

18 – 20
AioIoUringExecutionIO

Waiting for IO execution via io_uring.

18 – 20
AioIoUringSubmitIO

Waiting for IO submission via io_uring.

18 – 20
BasebackupReadIO

Waiting for base backup to read from a file.

14 – 20
BasebackupSyncIO

Waiting for data written by a base backup to reach durable storage.

15 – 20
BasebackupWriteIO

Waiting for base backup to write to a file.

15 – 20
BuffileReadIO

Waiting for a read from a buffered file.

10 – 20
BuffileTruncateIO

Waiting for a buffered file to be truncated.

14 – 20
BuffileWriteIO

Waiting for a write to a buffered file.

10 – 20
ControlFileReadIO

Waiting for a read from the pg_control file.

10 – 20
ControlFileSyncIO

Waiting for the pg_control file to reach durable storage.

10 – 20
ControlFileSyncUpdateIO

Waiting for an update to the pg_control file to reach durable storage.

10 – 20
ControlFileWriteIO

Waiting for a write to the pg_control file.

10 – 20
ControlFileWriteUpdateIO

Waiting for a write to update the pg_control file.

10 – 20
CopyFileCopyIO

Waiting for a file copy operation.

18 – 20
CopyFileReadIO

Waiting for a read during a file copy operation.

10 – 20
CopyFileWriteIO

Waiting for a write during a file copy operation.

10 – 20
CopyFromReadIO

Waiting to read data from a pipe, a file or a program during COPY FROM.

19 – 20 · No PG 18 snapshot
CopyToWriteIO

Waiting to write data to a pipe, a file or a program during COPY TO.

19 – 20 · No PG 18 snapshot
DataFileExtendIO

Waiting for a relation data file to be extended.

10 – 20
DataFileFlushIO

Waiting for a relation data file to reach durable storage.

10 – 20
DataFileImmediateSyncIO

Waiting for an immediate synchronization of a relation data file to durable storage.

10 – 20
DataFilePrefetchIO

Waiting for an asynchronous prefetch from a relation data file.

10 – 20
DataFileReadIO

Waiting for a read from a relation data file.

10 – 20
DataFileSyncIO

Waiting for changes to a relation data file to reach durable storage.

10 – 20
DataFileTruncateIO

Waiting for a relation data file to be truncated.

10 – 20
DataFileWriteIO

Waiting for a write to a relation data file.

10 – 20
DsmAllocateIO

Waiting for a dynamic shared memory segment to be allocated.

16 – 20
DsmFillZeroWriteIO

Waiting to fill a dynamic shared memory backing file with zeroes.

10 – 20
LockFileAddtodatadirReadIO

Waiting for a read while adding a line to the data directory lock file.

10 – 20
LockFileAddtodatadirSyncIO

Waiting for data to reach durable storage while adding a line to the data directory lock file.

10 – 20
LockFileAddtodatadirWriteIO

Waiting for a write while adding a line to the data directory lock file.

10 – 20
LockFileCreateReadIO

Waiting to read while creating the data directory lock file.

10 – 20
LockFileCreateSyncIO

Waiting for data to reach durable storage while creating the data directory lock file.

10 – 20
LockFileCreateWriteIO

Waiting for a write while creating the data directory lock file.

10 – 20
LockFileRecheckdatadirReadIO

Waiting for a read during recheck of the data directory lock file.

10 – 20
LogicalChangesReadIO

Waiting for a read from a logical changes file.

14 – 14 · No PG 18 snapshot
LogicalChangesWriteIO

Waiting for a write to a logical changes file.

14 – 14 · No PG 18 snapshot
LogicalRewriteCheckpointSyncIO

Waiting for logical rewrite mappings to reach durable storage during a checkpoint.

10 – 20
LogicalRewriteMappingSyncIO

Waiting for mapping data to reach durable storage during a logical rewrite.

10 – 20
LogicalRewriteMappingWriteIO

Waiting for a write of mapping data during a logical rewrite.

10 – 20
LogicalRewriteSyncIO

Waiting for logical rewrite mappings to reach durable storage.

10 – 20
LogicalRewriteTruncateIO

Waiting for truncate of mapping data during a logical rewrite.

10 – 20
LogicalRewriteWriteIO

Waiting for a write of logical rewrite mappings.

10 – 20
LogicalSubxactReadIO

Waiting for a read from a logical subxact file.

14 – 14 · No PG 18 snapshot
LogicalSubxactWriteIO

Waiting for a write to a logical subxact file.

14 – 14 · No PG 18 snapshot
RelationMapReadIO

Waiting for a read of the relation map file.

10 – 20
RelationMapReplaceIO

Waiting for durable replacement of a relation map file.

16 – 20
RelationMapSyncIO

Waiting for the relation map file to reach durable storage.

10 – 15 · No PG 18 snapshot
RelationMapWriteIO

Waiting for a write to the relation map file.

10 – 20
ReorderBufferReadIO

Waiting for a read during reorder buffer management.

10 – 20
ReorderBufferWriteIO

Waiting for a write during reorder buffer management.

10 – 20
ReorderLogicalMappingReadIO

Waiting for a read of a logical mapping during reorder buffer management.

10 – 20
ReplicationSlotReadIO

Waiting for a read from a replication slot control file.

10 – 20
ReplicationSlotRestoreSyncIO

Waiting for a replication slot control file to reach durable storage while restoring it to memory.

10 – 20
ReplicationSlotSyncIO

Waiting for a replication slot control file to reach durable storage.

10 – 20
ReplicationSlotWriteIO

Waiting for a write to a replication slot control file.

10 – 20
SlruFlushSyncIO

Waiting for SLRU data to reach durable storage during a checkpoint or database shutdown.

10 – 20
SlruReadIO

Waiting for a read of an SLRU page.

10 – 20
SlruSyncIO

Waiting for SLRU data to reach durable storage following a page write.

10 – 20
SlruWriteIO

Waiting for a write of an SLRU page.

10 – 20
SnapbuildReadIO

Waiting for a read of a serialized historical catalog snapshot.

10 – 20
SnapbuildSyncIO

Waiting for a serialized historical catalog snapshot to reach durable storage.

10 – 20
SnapbuildWriteIO

Waiting for a write of a serialized historical catalog snapshot.

10 – 20
TimelineHistoryFileSyncIO

Waiting for a timeline history file received via streaming replication to reach durable storage.

10 – 20
TimelineHistoryFileWriteIO

Waiting for a write of a timeline history file received via streaming replication.

10 – 20
TimelineHistoryReadIO

Waiting for a read of a timeline history file.

10 – 20
TimelineHistorySyncIO

Waiting for a newly created timeline history file to reach durable storage.

10 – 20
TimelineHistoryWriteIO

Waiting for a write of a newly created timeline history file.

10 – 20
TwophaseFileReadIO

Waiting for a read of a two phase state file.

10 – 20
TwophaseFileSyncIO

Waiting for a two phase state file to reach durable storage.

10 – 20
TwophaseFileWriteIO

Waiting for a write of a two phase state file.

10 – 20
VersionFileSyncIO

Waiting for the version file to reach durable storage while creating a database.

15 – 20
VersionFileWriteIO

Waiting for the version file to be written while creating a database.

15 – 20
WalBootstrapSyncIO

Waiting for WAL to reach durable storage during bootstrapping.

10 – 20
WalBootstrapWriteIO

Waiting for a write of a WAL page during bootstrapping.

10 – 20
WalCopyReadIO

Waiting for a read when creating a new WAL segment by copying an existing one.

10 – 20
WalCopySyncIO

Waiting for a new WAL segment created by copying an existing one to reach durable storage.

10 – 20
WalCopyWriteIO

Waiting for a write when creating a new WAL segment by copying an existing one.

10 – 20
WalInitSyncIO

Waiting for a newly initialized WAL file to reach durable storage.

10 – 20
WalInitWriteIO

Waiting for a write while initializing a new WAL file.

10 – 20
WalReadIO

Waiting for a read from a WAL file.

10 – 20
WalsenderTimelineHistoryReadIO

Waiting for a read from a timeline history file during a walsender timeline command.

10 – 20
WalSummaryReadIO

Waiting for a read from a WAL summary file.

17 – 20
WalSummaryWriteIO

Waiting for a write to a WAL summary file.

17 – 20
WalSyncIO

Waiting for a WAL file to reach durable storage.

12 – 20
WalSyncMethodAssignIO

Waiting for data to reach durable storage while assigning a new WAL sync method.

10 – 20
WalWriteIO

Waiting for a write to a WAL file.

10 – 20
AppendReadyIPC

Waiting for subplan nodes of an Append plan node to be ready.

14 – 20
ArchiveCleanupCommandIPC

Waiting for archive_cleanup_command to complete.

15 – 20
ArchiveCommandIPC

Waiting for archive_command to complete.

15 – 20
BackendTerminationIPC

Waiting for the termination of another backend.

14 – 20
BackupWaitWalArchiveIPC

Waiting for WAL files required for a backup to be successfully archived.

13 – 20
BgworkerShutdownIPC

Waiting for background worker to shut down.

10 – 20
BgworkerStartupIPC

Waiting for background worker to start up.

10 – 20
BtreePageIPC

Waiting for the page number needed to continue a parallel B-tree scan to become available.

10 – 20
BufferIoIPC

Waiting for buffer I/O to complete.

9.6 – 20
CheckpointDelayCompleteIPC

Waiting for a backend that blocks a checkpoint from completing.

17 – 20
CheckpointDelayStartIPC

Waiting for a backend that blocks a checkpoint from starting.

17 – 20
CheckpointDoneIPC

Waiting for a checkpoint to complete.

12 – 20
CheckpointStartIPC

Waiting for a checkpoint to start.

12 – 20
ChecksumEnableStartconditionIPC

Waiting for data checksums enabling to start.

19 – 20 · No PG 18 snapshot
ChecksumEnableTemptableWaitIPC

Waiting for temporary tables to be dropped for data checksums to be enabled.

19 – 20 · No PG 18 snapshot
ExecuteGatherIPC

Waiting for activity from a child process while executing a Gather plan node.

10 – 20
HashBatchAllocateIPC

Waiting for an elected Parallel Hash participant to allocate a hash table.

11 – 20
HashBatchElectIPC

Waiting to elect a Parallel Hash participant to allocate a hash table.

11 – 20
HashBatchLoadIPC

Waiting for other Parallel Hash participants to finish loading a hash table.

11 – 20
HashBuildAllocateIPC

Waiting for an elected Parallel Hash participant to allocate the initial hash table.

11 – 20
HashBuildElectIPC

Waiting to elect a Parallel Hash participant to allocate the initial hash table.

11 – 20
HashBuildHashInnerIPC

Waiting for other Parallel Hash participants to finish hashing the inner relation.

11 – 20
HashBuildHashOuterIPC

Waiting for other Parallel Hash participants to finish partitioning the outer relation.

11 – 20
HashGrowBatchesDecideIPC

Waiting to elect a Parallel Hash participant to decide on future batch growth.

11 – 20
HashGrowBatchesElectIPC

Waiting to elect a Parallel Hash participant to allocate more batches.

11 – 20
HashGrowBatchesFinishIPC

Waiting for an elected Parallel Hash participant to decide on future batch growth.

11 – 20
HashGrowBatchesReallocateIPC

Waiting for an elected Parallel Hash participant to allocate more batches.

11 – 20
HashGrowBatchesRepartitionIPC

Waiting for other Parallel Hash participants to finish repartitioning.

11 – 20
HashGrowBucketsElectIPC

Waiting to elect a Parallel Hash participant to allocate more buckets.

11 – 20
HashGrowBucketsReallocateIPC

Waiting for an elected Parallel Hash participant to finish allocating more buckets.

11 – 20
HashGrowBucketsReinsertIPC

Waiting for other Parallel Hash participants to finish inserting tuples into new buckets.

11 – 20
LogicalApplySendDataIPC

Waiting for a logical replication leader apply process to send data to a parallel apply process.

16 – 20
LogicalParallelApplyStateChangeIPC

Waiting for a logical replication parallel apply process to change state.

16 – 20
LogicalSyncDataIPC

Waiting for a logical replication remote server to send data for initial table synchronization.

10 – 20
LogicalSyncStateChangeIPC

Waiting for a logical replication remote server to change state.

10 – 20
MessageQueueInternalIPC

Waiting for another process to be attached to a shared message queue.

10 – 20
MessageQueuePutMessageIPC

Waiting to write a protocol message to a shared message queue.

10 – 20
MessageQueueReceiveIPC

Waiting to receive bytes from a shared message queue.

10 – 20
MessageQueueSendIPC

Waiting to send bytes to a shared message queue.

10 – 20
MultixactCreationIPC

Waiting for a multixact creation to complete.

17 – 20
ParallelBitmapScanIPC

Waiting for parallel bitmap scan to become initialized.

10 – 20
ParallelCreateIndexScanIPC

Waiting for parallel CREATE INDEX workers to finish heap scan.

11 – 20
ParallelFinishIPC

Waiting for parallel workers to finish computing.

10 – 20
ProcarrayGroupUpdateIPC

Waiting for the group leader to clear the transaction ID at transaction end.

10 – 20
ProcSignalBarrierIPC

Waiting for a barrier event to be processed by all backends.

13 – 20
PromoteIPC

Waiting for standby promotion.

12 – 20
RecoveryConflictSnapshotIPC

Waiting for recovery conflict resolution for a vacuum cleanup.

13 – 20
RecoveryConflictTablespaceIPC

Waiting for recovery conflict resolution for dropping a tablespace.

13 – 20
RecoveryEndCommandIPC

Waiting for recovery_end_command to complete.

15 – 20
RecoveryPauseIPC

Waiting for recovery to be resumed.

13 – 20
RepackWorkerExportIPC

Waiting for decoding worker to export a new output file.

19 – 20 · No PG 18 snapshot
ReplicationOriginDropIPC

Waiting for a replication origin to become inactive so it can be dropped.

10 – 20
ReplicationSlotDropIPC

Waiting for a replication slot to become inactive so it can be dropped.

10 – 20
RestoreCommandIPC

Waiting for restore_command to complete.

15 – 20
SafeSnapshotIPC

Waiting to obtain a valid snapshot for a READ ONLY DEFERRABLE transaction.

10 – 20
SyncRepIPC

Waiting for confirmation from a remote server during synchronous replication.

10 – 20
WaitForWalFlushIPC

Waiting for WAL flush to reach a target LSN on a primary or standby.

19 – 20 · No PG 18 snapshot
WaitForWalReplayIPC

Waiting for WAL replay to reach a target LSN on a standby.

19 – 20 · No PG 18 snapshot
WaitForWalWriteIPC

Waiting for WAL write to reach a target LSN on a standby.

19 – 20 · No PG 18 snapshot
WalReceiverExitIPC

Waiting for the WAL receiver to exit.

14 – 20
WalReceiverUpstreamCatchupIPC

Waiting for upstream server WAL flush position to catch up to requested start point.

17 – 20
WalReceiverWaitStartIPC

Waiting for startup process to send initial data for streaming replication.

10 – 20
WalSummaryReadyIPC

Waiting for a new WAL summary to be generated.

17 – 20
XactGroupUpdateIPC

Waiting for the group leader to update transaction status at transaction end.

11 – 20
AddinShmemInitLWLock

Waiting to manage an extension's space allocation in shared memory.

9.6 – 20
AioUringCompletionLWLock

Waiting for another process to complete IO via io_uring.

18 – 20
AioWorkerControlLWLock

Waiting to update AIO worker information.

19 – 20 · No PG 18 snapshot
AioWorkerSubmissionQueueLWLock

Waiting to access AIO worker submission queue.

18 – 20
AutoFileLWLock

Waiting to update the postgresql.auto.conf file.

9.6 – 20
AutovacuumLWLock

Waiting to read or update the current state of autovacuum workers.

9.6 – 20
AutovacuumScheduleLWLock

Waiting to ensure that a table selected for autovacuum still needs vacuuming.

9.6 – 20
BackendRandomLockLWLock

Waiting to generate a random number.

10 – 11 · No PG 18 snapshot
BackgroundWorkerLWLock

Waiting to read or update background worker state.

9.6 – 20
BtreeVacuumLWLock

Waiting to read or update vacuum-related information for a B-tree index.

9.6 – 20
BufferContentLWLock

Waiting to access a data page in memory.

9.6 – 18
BufferMappingLWLock

Waiting to associate a data block with a buffer in the buffer pool.

9.6 – 20
CheckpointLWLock

Waiting to begin a checkpoint.

9.6 – 13 · No PG 18 snapshot
CheckpointerCommLWLock

Waiting to manage fsync requests.

9.6 – 20
CommitTsLWLock

Waiting to read or update the last value set for a transaction commit timestamp.

9.6 – 20
CommitTsBufferLWLock

Waiting for I/O on a commit timestamp SLRU buffer.

9.6 – 20
CommitTsSLRULWLock

Waiting to access the commit timestamp SLRU cache.

9.6 – 20
ControlFileLWLock

Waiting to read or update the pg_control file or create a new WAL file.

9.6 – 20
DataChecksumsWorkerLWLock

Waiting for data checksums worker.

19 – 20 · No PG 18 snapshot
DSMRegistryLWLock

Waiting to read or update the dynamic shared memory registry.

17 – 20
DSMRegistryDSALWLock

Waiting to access dynamic shared memory registry's dynamic shared memory allocator.

17 – 20
DSMRegistryHashLWLock

Waiting to access dynamic shared memory registry's shared hash table.

17 – 20
DynamicSharedMemoryControlLWLock

Waiting to read or update dynamic shared memory allocation information.

9.6 – 20
InjectionPointLWLock

Waiting to read or update information related to injection points.

17 – 20
LockFastPathLWLock

Waiting to read or update a process' fast-path lock information.

9.6 – 20
LockManagerLWLock

Waiting to read or update information about “heavyweight” locks.

9.6 – 20
LogicalDecodingControlLWLock

Waiting to read or update logical decoding status information.

19 – 20 · No PG 18 snapshot
LogicalRepLauncherDSALWLock

Waiting to access logical replication launcher's dynamic shared memory allocator.

16 – 20
LogicalRepLauncherHashLWLock

Waiting to access logical replication launcher's shared hash table.

16 – 20
LogicalRepWorkerLWLock

Waiting to read or update the state of logical replication workers.

10 – 20
MultiXactGenLWLock

Waiting to read or update shared multixact state.

9.6 – 20
MultiXactMemberBufferLWLock

Waiting for I/O on a multixact member SLRU buffer.

9.6 – 20
MultiXactMemberSLRULWLock

Waiting to access the multixact member SLRU cache.

9.6 – 20
MultiXactOffsetBufferLWLock

Waiting for I/O on a multixact offset SLRU buffer.

9.6 – 20
MultiXactOffsetSLRULWLock

Waiting to access the multixact offset SLRU cache.

9.6 – 20
MultiXactTruncationLWLock

Waiting to read or truncate multixact information.

9.6 – 20
NotifyBufferLWLock

Waiting for I/O on a NOTIFY message SLRU buffer.

9.6 – 20
NotifyChannelHashLWLock

Waiting to access the NOTIFY channel hash table.

19 – 20 · No PG 18 snapshot
NotifyQueueLWLock

Waiting to read or update NOTIFY messages.

9.6 – 20
NotifyQueueTailLWLock

Waiting to update limit on NOTIFY message storage.

9.6 – 20
NotifySLRULWLock

Waiting to access the NOTIFY message SLRU cache.

9.6 – 20
OidGenLWLock

Waiting to allocate a new OID.

9.6 – 20
OldSnapshotTimeMapLWLock

Waiting to read or update old snapshot control information.

9.6 – 16 · No PG 18 snapshot
ParallelAppendLWLock

Waiting to choose the next subplan during Parallel Append plan execution.

11 – 20
ParallelBtreeScanLWLock

Waiting to synchronize workers during Parallel B-tree scan plan execution.

18 – 20
ParallelHashJoinLWLock

Waiting to synchronize workers during Parallel Hash Join plan execution.

11 – 20
ParallelQueryDSALWLock

Waiting for parallel query dynamic shared memory allocation.

10 – 20
ParallelVacuumDSALWLock

Waiting for parallel vacuum dynamic shared memory allocation.

17 – 20
PerSessionDSALWLock

Waiting for parallel query dynamic shared memory allocation.

13 – 20
PerSessionRecordTypeLWLock

Waiting to access a parallel query's information about composite types.

13 – 20
PerSessionRecordTypmodLWLock

Waiting to access a parallel query's information about type modifiers that identify anonymous record types.

13 – 20
PerXactPredicateListLWLock

Waiting to access the list of predicate locks held by the current serializable transaction during a parallel query.

12 – 20
PgStatsDataLWLock

Waiting for shared memory stats data access.

15 – 20
PgStatsDSALWLock

Waiting for stats dynamic shared memory allocator access.

15 – 20
PgStatsHashLWLock

Waiting for stats shared memory hash table access.

15 – 20
PredicateLockManagerLWLock

Waiting to access predicate lock information used by serializable transactions.

9.6 – 20
ProcArrayLWLock

Waiting to access the shared per-process data structures (typically, to get a snapshot or report a session's transaction ID).

9.6 – 20
RelationMappingLWLock

Waiting to read or update a pg_filenode.map file (used to track the filenode assignments of certain system catalogs).

9.6 – 20
RelCacheInitLWLock

Waiting to read or update a pg_internal.init relation cache initialization file.

9.6 – 20
ReplicationOriginLWLock

Waiting to create, drop or use a replication origin.

9.6 – 20
ReplicationOriginStateLWLock

Waiting to read or update the progress of one replication origin.

9.6 – 20
ReplicationSlotAllocationLWLock

Waiting to allocate or free a replication slot.

9.6 – 20
ReplicationSlotControlLWLock

Waiting to read or update replication slot state.

9.6 – 20
ReplicationSlotIOLWLock

Waiting for I/O on a replication slot.

9.6 – 20
SerialBufferLWLock

Waiting for I/O on a serializable transaction conflict SLRU buffer.

9.6 – 20
SerialControlLWLock

Waiting to read or update shared pg_serial state.

17 – 20
SerializableFinishedListLWLock

Waiting to access the list of finished serializable transactions.

9.6 – 20
SerializablePredicateListLWLock

Waiting to access the list of predicate locks held by serializable transactions.

9.6 – 20
SerializableXactHashLWLock

Waiting to read or update information about serializable transactions.

9.6 – 20
SerialSLRULWLock

Waiting to access the serializable transaction conflict SLRU cache.

9.6 – 20
SharedTidBitmapLWLock

Waiting to access a shared TID bitmap during a parallel bitmap index scan.

10 – 20
SharedTupleStoreLWLock

Waiting to access a shared tuple store during parallel query.

13 – 20
ShmemIndexLWLock

Waiting to find or allocate space in shared memory.

9.6 – 20
SInvalReadLWLock

Waiting to retrieve messages from the shared catalog invalidation queue.

9.6 – 20
SInvalWriteLWLock

Waiting to add a message to the shared catalog invalidation queue.

9.6 – 20
SubtransBufferLWLock

Waiting for I/O on a sub-transaction SLRU buffer.

9.6 – 20
SubtransSLRULWLock

Waiting to access the sub-transaction SLRU cache.

9.6 – 20
SyncRepLWLock

Waiting to read or update information about the state of synchronous replication.

9.6 – 20
SyncScanLWLock

Waiting to select the starting location of a synchronized table scan.

9.6 – 20
TablespaceCreateLWLock

Waiting to create or drop a tablespace.

9.6 – 20
TwoPhaseStateLWLock

Waiting to read or update the state of prepared transactions.

9.6 – 20
WaitEventCustomLWLock

Waiting to read or update custom wait events information.

17 – 20
WaitLSNLWLock

Waiting to read or update shared Wait-for-LSN state.

19 – 20 · No PG 18 snapshot
WALBufMappingLWLock

Waiting to replace a page in WAL buffers.

9.6 – 20
WALInsertLWLock

Waiting to insert WAL data into a memory buffer.

9.6 – 20
WALSummarizerLWLock

Waiting to read or update WAL summarization state.

17 – 20
WALWriteLWLock

Waiting for WAL buffers to be written to disk.

9.6 – 20
WrapLimitsVacuumLWLock

Waiting to update limits on transaction id and multixact consumption.

9.6 – 20
XactBufferLWLock

Waiting for I/O on a transaction status SLRU buffer.

9.6 – 20
XactSLRULWLock

Waiting to access the transaction status SLRU cache.

9.6 – 20
XactTruncationLWLock

Waiting to execute pg_xact_status or update the oldest transaction ID available to it.

10 – 20
XidGenLWLock

Waiting to allocate a new transaction ID.

9.6 – 20
advisoryLock

Waiting to acquire an advisory user lock.

9.6 – 20
applytransactionLock

Waiting to acquire a lock on a remote transaction being applied by a logical replication subscriber.

16 – 20
extendLock

Waiting to extend a relation.

9.6 – 20
frozenidLock

Waiting to update pg_database.datfrozenxid and pg_database.datminmxid.

9.6 – 20
objectLock

Waiting to acquire a lock on a non-relation database object.

9.6 – 20
pageLock

Waiting to acquire a lock on a page of a relation.

9.6 – 20
relationLock

Waiting to acquire a lock on a relation.

9.6 – 20
spectokenLock

Waiting to acquire a speculative insertion lock.

9.6 – 20
transactionidLock

Waiting for a transaction to finish.

9.6 – 20
tupleLock

Waiting to acquire a lock on a tuple.

9.6 – 20
userlockLock

Waiting to acquire a user lock.

9.6 – 20
virtualxidLock

Waiting to acquire a virtual transaction ID lock; see Section 67.1.

9.6 – 20
BaseBackupThrottleTimeout

Waiting during base backup when throttling activity.

10 – 20
CheckpointWriteDelayTimeout

Waiting between writes while performing a checkpoint.

14 – 20
CommitDelayTimeout

Waiting for commit delay before WAL flush.

19 – 20 · No PG 18 snapshot
PgSleepTimeout

Waiting due to a call to pg_sleep or a sibling function.

10 – 20
RecoveryApplyDelayTimeout

Waiting to apply WAL during recovery because of a delay setting.

10 – 20
RecoveryRetrieveRetryIntervalTimeout

Waiting during recovery when WAL data is not available from any source (pg_wal, archive or stream).

13 – 20
RegisterSyncRequestTimeout

Waiting while sending synchronization requests to the checkpointer, because the request queue is full.

12 – 20
SpinDelayTimeout

Waiting while acquiring a contended spinlock.

16 – 20
VacuumDelayTimeout

Waiting in a cost-based vacuum delay point.

13 – 20
VacuumTruncateTimeout

Waiting to acquire an exclusive lock to truncate off any empty pages at the end of a table vacuumed.

15 – 20
WalSummarizerErrorTimeout

Waiting after a WAL summarizer error.

17 – 20