SQL Server wait types

This collection of content will describe SQL Server wait types that can be encountered more or less commonly, which includes the description, steps that should be taken and additional resources that could be used for more serious troubleshooting.

A  B  C  D  E  F  H  I  L  M  O  P  R  S  T  W  X

A

ASYNC_DISKPOOL_LOCK
ASYNC_IO_COMPLETION
ASYNC_NETWORK_IO
ASYNC_OP_COMPLETION

B

BACKUP
BACKUP_OPERATOR
BACKUPBUFFER
BACKUPIO
BACKUPTHREAD
BROKER_CONNECTION_RECEIVE_TASK
BROKER_DISPATCHER
BROKER_ENDPOINT_STATE_MUTEX
BROKER_EVENTHANDLER
BROKER_FORWARDER
BROKER_INIT
BROKER_MASTERSTART
BROKER_RECEIVE_WAITFOR
BROKER_REGISTERALLENDPOINTS
BROKER_SERVICE
BROKER_SHUTDOWN
BROKER_TASK_SHUTDOWN
BROKER_TASK_STOP
BROKER_TASK_SUBMIT
BROKER_TRANSMISSION_OBJECT
BROKER_TRANSMISSION_TABLE
BROKER_TRANSMISSION_WORK
BROKER_TRANSMITTER

C

CLR_AUTO_EVENT
CLR_MONITOR
CLR_RWLOCK_READER
CLR_RWLOCK_WRITER
CLR_TASK_START
CMEMTHREAD
COMMIT_ACT
COMMIT_TABLE
CXPACKET

D

DAC_INIT
DBMIRROR_DBM_EVENT
DBMIRROR_DBM_MUTEX
DBMIRROR_SEND
DBMIRROR_WORKER_QUEUE
DBMIRRORING_CMD
DBSEEDING_FLOWCONTROL
DBSEEDING_OPERATION
DEADLOCK_ENUM_MUTEX
DEADLOCK_TASK_SEARCH
DIRTY_PAGE_POLL
DISKIO_SUSPEND
DISPATCHER_PRIORITY_QUEUE_SEMAPHORE
DLL_LOADING_MUTEX
DTC
DTC_ABORT_REQUEST
DTC_RESOLVE
DTC_STATE
DTC_TMDOWN_REQUEST
DTC_WAITFOR_OUTCOME
DTCPNTSYNC

E

EXCHANGE
EXECSYNC

F

FCB_REPLICA_READ
FCB_REPLICA_WRITE

H

HADR_AG_MUTEX
HADR_AR_CRITICAL_SECTION_ENTRY
HADR_AR_MANAGER_MUTEX
HADR_AR_UNLOAD_COMPLETED
HADR_ARCONTROLLER_NOTIFICATIONS_SUBSCRIBER_LIST
HADR_BACKUP_BULK_LOCK
HADR_BACKUP_QUEUE
HADR_COMPRESSED_CACHE_SYNC
HADR_CONNECTIVITY_INFO
HADR_DATABASE_FLOW_CONTROL
HADR_DATABASE_VERSIONING_STATE
HADR_DATABASE_WAIT_FOR_RESTART
HADR_DATABASE_WAIT_FOR_TRANSITION_TO_VERSIONING
HADR_DB_COMMAND
HADR_DB_OP_COMPLETION_SYNC
HADR_DB_OP_START_SYNC
HADR_DBR_SUBSCRIBER
HADR_DBR_SUBSCRIBER_FILTER_LIST
HADR_DBSEEDING
HADR_DBSEEDING_LIST
HADR_DBSTATECHANGE_SYNC
HADR_FABRIC_CALLBACK
HADR_FILESTREAM_BLOCK_FLUSH
HADR_FILESTREAM_FILE_CLOSE
HADR_FILESTREAM_FILE_REQUEST
HADR_FILESTREAM_IOMGR
HADR_FILESTREAM_MANAGER
HADR_GROUP_COMMIT
HADR_LOGCAPTURE_SYNC
HADR_LOGCAPTURE_WAIT
HADR_LOGPROGRESS_SYNC
HADR_NOTIFICATION_DEQUEUE
HADR_NOTIFICATION_WORKER_EXCLUSIVE_ACCESS
HADR_NOTIFICATION_WORKER_STARTUP_SYNC
HADR_NOTIFICATION_WORKER_TERMINATION_SYNC
HADR_PARTNER_SYNC
HADR_READ_ALL_NETWORKS
HADR_RECOVERY_WAIT_FOR_CONNECTION
HADR_RECOVERY_WAIT_FOR_UNDO
HADR_REPLICAINFO_SYNC
HADR_SYNC_COMMIT
HADR_SYNCHRONIZING_THROTTLE
HADR_TDS_LISTENER_SYNC
HADR_TDS_LISTENER_SYNC_PROCESSING
HADR_TIMER_TASK
HADR_TRANSPORT_DBRLIST
HADR_TRANSPORT_FLOW_CONTROL
HADR_TRANSPORT_SESSION
HADR_WORK_POOL
HADR_WORK_QUEUE
HADR_XRF_STACK_ACCESS

I

IO_COMPLETION

L

LATCH_DT
LATCH_EX
LATCH_KP
LATCH_NL
LATCH_SH
LATCH_UP
LAZYWRITER_SLEEP
LCK_M_BU
LCK_M_BU_ABORT_BLOCKERS
LCK_M_BU_LOW_PRIORITY
LCK_M_IS
LCK_M_IS_ABORT_BLOCKERS
LCK_M_IS_LOW_PRIORITY
LCK_M_IU
LCK_M_IU_ABORT_BLOCKERS
LCK_M_IU_LOW_PRIORITY
LCK_M_IX
LCK_M_IX_ABORT_BLOCKERS
LCK_M_IX_LOW_PRIORITY
LCK_M_RIn_NL
LCK_M_RIn_NL_ABORT_BLOCKERS
LCK_M_RIn_NL_LOW_PRIORITY
LCK_M_RIn_S
LCK_M_RIn_S_ABORT_BLOCKERS
LCK_M_RIn_S_LOW_PRIORITY
LCK_M_RIn_U
LCK_M_RIn_U_ABORT_BLOCKERS
LCK_M_RIn_U_LOW_PRIORITY
LCK_M_RIn_X
LCK_M_RIn_X_ABORT_BLOCKERS
LCK_M_RIn_X_LOW_PRIORITY
LCK_M_RS_S
LCK_M_RS_S_ABORT_BLOCKERS
LCK_M_RS_S_LOW_PRIORITY
LCK_M_RS_U
LCK_M_RS_U_ABORT_BLOCKERS
LCK_M_RS_U_LOW_PRIORITY
LCK_M_RX_S
LCK_M_RX_S_ABORT_BLOCKERS
LCK_M_RX_S_LOW_PRIORITY
LCK_M_RX_U
LCK_M_RX_U_ABORT_BLOCKERS
LCK_M_RX_U_LOW_PRIORITY
LCK_M_RX_X
LCK_M_RX_X_ABORT_BLOCKERS
LCK_M_RX_X_LOW_PRIORITY
LCK_M_S
LCK_M_S_ABORT_BLOCKERS
LCK_M_S_LOW_PRIORITY
LCK_M_SCH_M
LCK_M_SCH_M_ABORT_BLOCKERS
LCK_M_SCH_M_LOW_PRIORITY
LCK_M_SCH_S
LCK_M_SCH_S_ABORT_BLOCKERS
LCK_M_SCH_S_LOW_PRIORITY
LCK_M_SIU
LCK_M_SIU_ABORT_BLOCKERS
LCK_M_SIU_LOW_PRIORITY
LCK_M_SIX
LCK_M_SIX_ABORT_BLOCKERS
LCK_M_SIX_LOW_PRIORITY
LCK_M_U
LCK_M_U_ABORT_BLOCKERS
LCK_M_U_LOW_PRIORITY
LCK_M_UIX
LCK_M_UIX_ABORT_BLOCKERS
LCK_M_UIX_LOW_PRIORITY
LCK_M_X
LCK_M_X_ABORT_BLOCKERS
LCK_M_X_LOW_PRIORITY
LOGBUFFER
LOGMGR
LOGMGR_FLUSH
LOGMGR_QUEUE
LOGMGR_RESERVE_APPEND

M

MSQL_DQ
MSSEARCH
MSSQL_XP

O

OLEDB

P

PAGEIOLATCH_DT
PAGEIOLATCH_EX
PAGEIOLATCH_KP
PAGEIOLATCH_NL
PAGEIOLATCH_SH
PAGEIOLATCH_UP
PAGELATCH_DT
PAGELATCH_EX
PAGELATCH_KP
PAGELATCH_NL
PAGELATCH_SH
PAGELATCH_UP
PREEMPTIVE_OS_AUTHENTICATIONOPS
PREEMPTIVE_OS_BACKUPREAD
PREEMPTIVE_OS_CLUSTEROPS
PREEMPTIVE_OS_DEVICEOPS
PREEMPTIVE_OS_DTCOPS
PREEMPTIVE_OS_ENCRYPTMESSAGE
PREEMPTIVE_OS_FILEOPS
PREEMPTIVE_OS_FLUSHFILEBUFFERS
PREEMPTIVE_OS_GENERICOPS
PREEMPTIVE_OS_GETDISKFREESPACE
PREEMPTIVE_OS_GETPROCADDRESS
PREEMPTIVE_OS_LIBRARYOPS
PREEMPTIVE_OS_LOOKUPACCOUNTSID
PREEMPTIVE_OS_PIPEOPS
PREEMPTIVE_OS_QUERYREGISTRY
PREEMPTIVE_OS_SECURITYOPS
PREEMPTIVE_OS_SERVICEOPS
PREEMPTIVE_OS_SQLCLROPS
PREEMPTIVE_OS_WRITEFILEGATHER

R

REPLICA_WRITES
REQUEST_FOR_DEADLOCK_SEARCH
RESOURCE_QUEUE
RESOURCE_SEMAPHORE
RESOURCE_SEMAPHORE_MUTEX
RESOURCE_SEMAPHORE_QUERY_COMPILE

S

SLEEP_TASK
SOS_SCHEDULER_YIELD
SP_SERVER_DIAGNOSTICS_SLEEP
SQLTRACE_BUFFER_FLUSH
SQLTRACE_FILE_BUFFER
SQLTRACE_FILE_READ_IO_COMPLETION
SQLTRACE_FILE_WRITE_IO_COMPLETION
SQLTRACE_INCREMENTAL_FLUSH_SLEEP
SQLTRACE_PENDING_BUFFER_WRITERS
SQLTRACE_SHUTDOWN

T

TEMPOBJ
THREADPOOL
TRACEWRITE

W

WAITFOR
WRITE_COMPLETION
WRITELOG

X

XACT_OWN_TRANSACTION
XACTLOCKINFO
XE_LIVE_TARGET_TVF

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