SQL Server Lock Wait Types

There are many different types of lock within SQL Server.

AppDynamics for Databases will monitor time spent in any type of lock, so if you see excessive wait times on any of these lock types for a particular stored procedure or statement, then you need to investigate the blocking session.

The following table gives a short description of lock wait types.

Wait Type	Description
LCK_M_SCH_S	Schema stability
LCK_M_SCH_M	Schema modification
LCK_M_S	Share
LCK_M_U	Update
LCK_M_X	Exclusive
LCK_M_IS	Intent-Share
LCK_M_IU	Intent-Update
LCK_M_IX	Intent-Exclusive
LCK_M_SIU	Shared intent to update
LCK_M_SIX	Share-Intent-Exclusive
LCK_M_UIX	Update-Intent-Exclusive
LCK_M_BU	Bulk Update
LCK_M_RS_S	Range-share-share
LCK_M_RS_U	Range-share-Update
LCK_M_RI_NL	Range-Insert-NULL
LCK_M_RI_S	Range-Insert-Shared
LCK_M_RI_U	Range-Insert-Update
LCK_M_RI_X	Range-Insert-Exclusive
LCK_M_RX_S	Range-exclusive-Shared
LCK_M_RX_U	Range-exclusive-update
LCK_M_RX_X	Range-exclusive-exclusive