![[wl_io.png|64]]
Waiting on disk read/write operations — the most common performance bottleneck. All events represent the process blocked waiting for the kernel to complete an I/O call.
![[BaseBackupRead]]
![[BaseBackupSync]]
![[BaseBackupWrite]]
![[BufFileRead]]
![[BufFileTruncate]]
![[BufFileWrite]]
![[ControlFileRead]]
![[ControlFileSync]]
![[ControlFileSyncUpdate]]
![[ControlFileWrite]]
![[ControlFileWriteUpdate]]
![[CopyFileRead]]
![[CopyFileWrite]]
![[DSMAllocate]]
![[DSMFillZeroWrite]]
![[DataFileExtend]]
![[DataFileFlush]]
![[DataFileImmediateSync]]
![[DataFilePrefetch]]
![[DataFileRead]]
![[DataFileSync]]
![[DataFileTruncate]]
![[DataFileWrite]]
![[LockFileAddToDataDirRead]]
![[LockFileAddToDataDirSync]]
![[LockFileAddToDataDirWrite]]
![[LockFileCreateRead]]
![[LockFileCreateSync]]
![[LockFileCreateWrite]]
![[LockFileReCheckDataDirRead]]
![[LogicalRewriteCheckpointSync]]
![[LogicalRewriteMappingSync]]
![[LogicalRewriteMappingWrite]]
![[LogicalRewriteSync]]
![[LogicalRewriteTruncate]]
![[LogicalRewriteWrite]]
![[RelationMapRead]]
![[RelationMapReplace]]
![[RelationMapWrite]]
![[ReorderBufferRead]]
![[ReorderBufferWrite]]
![[ReorderLogicalMappingRead]]
![[ReplicationSlotRead]]
![[ReplicationSlotRestoreSync]]
![[ReplicationSlotSync]]
![[ReplicationSlotWrite]]
![[SLRUFlushSync]]
![[SLRURead]]
![[SLRUSync]]
![[SLRUWrite]]
![[SnapbuildRead]]
![[SnapbuildSync]]
![[SnapbuildWrite]]
![[TimelineHistoryFileSync]]
![[TimelineHistoryFileWrite]]
![[TimelineHistoryRead]]
![[TimelineHistorySync]]
![[TimelineHistoryWrite]]
![[TwophaseFileRead]]
![[TwophaseFileSync]]
![[TwophaseFileWrite]]
![[VersionFileSync]]
![[VersionFileWrite]]
![[WALBootstrapSync]]
![[WALBootstrapWrite]]
![[WALCopyRead]]
![[WALCopySync]]
![[WALCopyWrite]]
![[WALInitSync]]
![[WALInitWrite]]
![[WALRead]]
![[WALSenderTimelineHistoryRead]]
![[WALSync]]
![[WALSyncMethodAssign]]
![[WALWrite]]
### MultiXact
![[MultiXactMemberBuffer]]
![[MultiXactMemberSLRU]]
![[MultiXactOffsetBuffer]]
![[MultiXactOffsetSLRU]]
![[MultiXactTruncation]]
### Notify
![[NotifyBuffer]]
![[NotifyQueue]]
![[NotifyQueueTail]]
![[NotifySLRU]]