SQL Server Latch Classes Library

(Companion SQL Server Wait Types Library)

This site lists all latch classes in SQL Server 2005 through SQL Server 2019/Azure SQL Database and gives detailed information about where they occur inside SQL Server. I created this site to be a comprehensive resource for the SQL Server community as this information is not available anywhere else. I hope it helps you with troubleshooting and understanding SQL Server in more depth.

For an introduction to what latches are, why they’re needed, and the mechanics of how they work, see my post here.

Usage: you may link to/use this information any way you want, except you may not include this information in a commercial product/website, or republish information from this library in any form without *first* getting permission from me.

For info on how to help gathering data for this site, and to submit general feedback (or even just to let me know that you found it useful and/or tell me how you used it), please send me email.

Thanks!

Paul

People who have helped/are helping gather data for the latch classes library: Jonathan Kehayias, Erin Stellato, Tim Radney, Anthony Nocentino, Arun Sirpal

SQL Server Latch Classes

Latch classes covered: 188 with detailed information on 35 (updated 2/9/2022)

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


A

ACCESS_METHODS_ACCESSOR_CACHE
ACCESS_METHODS_BULK_ALLOC
ACCESS_METHODS_CACHE_ONLY_HOBT_ALLOC
ACCESS_METHODS_COLUMN_CACHE_SHARING
ACCESS_METHODS_DATASET_PARENT
ACCESS_METHODS_HOBT
ACCESS_METHODS_HOBT_COUNT
ACCESS_METHODS_HOBT_FACTORY
ACCESS_METHODS_HOBT_VIRTUAL_ROOT
ACCESS_METHODS_INDEX_BUILD_ALLOCATION
ACCESS_METHODS_IOAFF_KEY_RANGE_GENERATOR
ACCESS_METHODS_IOAFF_KEY_TARGET_PAGE_CNT
ACCESS_METHODS_IOAFF_QUEUE
ACCESS_METHODS_IOAFF_READAHEAD
ACCESS_METHODS_IOAFF_READAHEAD_QUEUE
ACCESS_METHODS_IOAFF_WAITING_WORKER_QUEUE
ACCESS_METHODS_KEY_RANGE_GENERATOR
ACCESS_METHODS_SCAN_RANGE_GENERATOR
ACCESS_METHODS_STRING_COMPARE
ALLOC_CACHE_MANAGER
ALLOC_CREATE_FREESPACE_CACHE
ALLOC_CREATE_RINGBUF
ALLOC_EXTENT_CACHE
ALLOC_FREESPACE_CACHE
ALLOC_IAM_PAGE_RANGE_CACHE
APPEND_ONLY_STORAGE_FIRST_ALLOC
APPEND_ONLY_STORAGE_INSERT_POINT
APPEND_ONLY_STORAGE_MANAGER
APPEND_ONLY_STORAGE_UNIT_MANAGER
ASYNC_TRANSPORT_MULTI_SESSION


B

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BACKUP_FILE_HANDLE
BACKUP_INSTANCE_ID
BACKUP_LOG_REDO
BACKUP_MANAGER
BACKUP_MANAGER_DIFFERENTIAL
BACKUP_OPERATION
BACKUP_RESULT_SET
BACKUP_TAPE_POOL
BLOB_ACCESS_LEASE_RENEWAL
BUFFER
BUFFER_POOL_GROW


C

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CHECK_PRINT_RECORD
CLR_DATAT_ACCESS
CLR_PROCEDURE_HASHTABLE
CLR_UDT_HASHTABLE
CLR_UDX_STORE
CLR_XVAR_PROXY_LIST
COLUMNSTORE_ATTRIB_CACHE
COLUMNSTORE_INDEX_BUILD
COLUMNSTORE_LOAD_DELETE_BUFFERS
COLUMNSTORE_LOAD_METADATA
COLUMNSTORE_OBJECT
COLUMNSTORE_ROWGROUP_COLLECTION
CSIBUILD_HASHDICT_BUCKET
CSIBUILD_HASHDICT_GLOBAL
CSIBUILD_STRINGSTORE_GLOBAL


D

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DATABASE_AUTONAME_MANAGER
DATABASE_CHECKPOINT
DATABASE_MIRRORING_CONNECTION
DATABASE_MIRRORING_MANAGER_COMMAND
DATABASE_MIRRORING_REDO
DATABASE_MIRRORING_SERVER
DATABASE_MIRRORING_STREAM
DBCC_CHECK_AGGREGATE
DBCC_CHECK_RESULTSET
DBCC_CHECK_TABLE_INIT
DBCC_CHECK_TRACE_LIST
DBCC_FILE_CHECK_OBJECT
DBCC_FS_FILE_CHECK_STATE
DBCC_HASH_DLL
DBCC_MULTIOBJECT_SCANNER
DBCC_OBJECT_METADATA
DBCC_PERF
DBCC_PFS_STATUS


E

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EVENTING_CACHE


F

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FCB
FCB_REPLICA
FGCB_ADD_REMOVE
FGCB_ALLOC
FILE_MANAGER
FILEGROUP_MANAGER
FILESTREAM_ALLOCATION_MANAGER
FILESTREAM_CONTAINER_HEADER
FILESTREAM_DFS_ROOT
FILESTREAM_DOWNLEVEL_LOGGING
FILESTREAM_FCB
FILESTREAM_FILE_MANAGER
FILESTREAM_GHOST_FILES
FT Compidx mg
FULLTEXT_ADMIN
FULLTEXT_AMDIN_COMMAND_CACHE
FULLTEXT_CRAWL_CATALOG
FULLTEXT_CRAWL_DM_LIST
FULLTEXT_CRAWL_LOG
FULLTEXT_DOCUMENT_ID
FULLTEXT_DOCUMENT_ID_NOTIFY
FULLTEXT_DOCUMENT_ID_TRANSACTION
FULLTEXT_FILE_MANAGER
FULLTEXT_LANGUAGE_TABLE
FULLTEXT_LOGS


G

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GHOST_CLEANUP_SYNC_MANAGER


H

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HADR_BACKUP_LOCK_RESQUEUE_TABLE
HADR_BACKUP_TASK_TABLE
HADR_XDES_TABLE
HOBT_LOBPAGEINFO


I

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J

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K

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KTM_VIRTUAL_CLOCK


L

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LOG_MANAGER
LOGBLOCK_GENERATIONS


M

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METADATA_CLONE_ACCESS_TICKET
METADATA_SEQUENCE_GENERATOR
MSQL_TRANSACTION_MANAGER


N

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NESTING_TRANSACTION_FULL
NESTING_TRANSACTION_READONLY
NESTING_TRANSACTION_READONOY


O

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P

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PVS_ADD_RECORD


Q

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QUERY_OPTIMIZER_ID_MANAGER
QUERY_OPTIMIZER_VD_MANAGER
QUERY_OPTIMIZER_VIEW_REP
QUERY_STORE_ACCESS_CACHE


R

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RBIO_REQUEST
RECOVERY_BAD_PAGE_TABLE
RECOVERY_MANAGER


S

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SECURITY_ACCESS_CHECK_CACHE
SECURITY_ASYMMETRIC_KEY_INIT
SECURITY_CERTIFICATE_INIT
SECURITY_CRYPTO
SECURITY_EXECUTE_AS_ENCRYPTION_TOKEN_CREATE
SECURITY_EXECUTE_AS_ENCRYPTION_TOKEN_INIT
SECURITY_KEY_LIST
SECURITY_KEY_RING
SECURITY_OBJPERM_CACHE
SECURITY_OPERATION_RULE_TABLE
SECURITY_PRIMARY_LOOKUP
SECURITY_ROW_LEVEL_SECURITY_CACHE
SECURITY_USER_INSTANCE
SECURITY_XPCMDSHELL
SERVICE_BROKER_DISPATCHER
SERVICE_BROKER_FORWARDING_MGR
SERVICE_BROKER_MAP_MANAGER
SERVICE_BROKER_MIRROR_ROUTE
SERVICE_BROKER_READ_CACHE
SERVICE_BROKER_TRANSMISSION_INIT
SERVICE_BROKER_TRANSMISSION_STATE
SERVICE_BROKER_TRANSMISSION_TRANSACTION_DATA
SERVICE_BROKER_TRANSMISSION_UPDATE
SERVICE_BROKER_TRANSMISSION_WORK
SERVICE_BROKER_TRANSMISSION_WORKTABLE
SERVICE_BROKER_TRANSMITTER
SERVICE_BROKER_TRANSMITTER_ASB
SERVICE_BROKER_TRANSMITTER_EVENTS
SERVICE_BROKER_TRANSPORT
SERVICE_BROKER_TRANSPORT_MEMORY_NOTIF
SERVICE_BROKER_TRANSPORT_TIMER_EVENTS
SERVICE_BROKER_WAITFOR_MANAGER
SERVICE_BROKER_WAITFOR_TRANSACTION_DATA
SPACE_CACHES_MANAGER
SPACEMGR_ALLOCACHE_CREATE_RINGBUF
SPACEMGR_ALLOCEXTENT_CACHE
SPACEMGR_CREATE_FREESPACE_CACHE
SPACEMGR_CREATE_RINGBUF
SPACEMGR_FREESPACE_CACHE
SPACEMGR_IAM_PAGE_RANGE_CACHE
SYNC_DBTABLE


T

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TRACE
TRACE_AUDIT_ID
TRACE_CONTROLLER
TRACE_EVENT_QUEUE
TRACE_ID
TRANSACTION_DISTRIBUTED_MARK
TRANSACTION_OUTCOME
TRANSACTION_WORKSPACE_MANAGER


U

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UTILITY_DATABASE_DROP
UTILITY_DEBUG_FILESTREAM
UTILITY_DYNAMIC_MANAGER_VIEW
UTILITY_DYNAMIC_VECTOR
UTILITY_LOCK_INFORMATION
UTILITY_SPARSE_BITMAP


V

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VERSIONING_STATE
VERSIONING_STATE_CHANGE
VERSIONING_TRANSACTION
VERSIONING_TRANSACTION_CHAIN
VERSIONING_TRANSACTION_LIST


W

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WPR_BUCKET_ACCESS


X

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XFCB_CREDENTIAL
XFCB_CREDENTIAL_MANAGER
XFCB_LATCH_RENEWAL
XSTORE_CREDENTIAL
XSTORE_CREDENTIAL_MANAGER


Y

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Z

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