# Database Discussions > MS SQL Server 7/MS SQL Server 2000 >  Waittype LCK_M_IS

## Jeff Turlington

Anyone know where I can get documentation on what the various wait types shown in SQL 7 Enterprise Manager mean? I&#39;m looking under current activity and see a waiting process with a wait type listed as LCK_M_IS and another with LCK_M_IX. I can&#39;t find a list of the valid wait types anywhere?

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## Tom Schraer

Jeff,

These are describing the locking modes that the transaction is in.

In BOL Search for &#34;Understanding Locking in SQL Server&#34;

About 1/2 way down in describes what IS and IX are.

LCK_M is stating that it is in a lock mode.

Intent shared (IS) Indicates the intention of a transaction to read some (but not all) resources lower down in the hierarchy by placing S locks on those individual resources. 
Intent exclusive (IX) Indicates the intention of a transaction to modify some (but not all) resources lower down in the hierarchy by placing X locks on those individual resources. IX is a superset of IS. 
Shared with intent exclusive (SIX) Indicates the intention of the transaction to read all of the resources lower down in the hierarchy and modify some (but not all) resources lower down in the hierarchy by placing IX locks on those individual resources. Concurrent IS locks at the top-level resource are allowed. For example, an SIX lock on a table places an SIX lock on the table (allowing concurrent IS locks), and IX locks on the pages being modified (and X locks on the modified rows). There can be only one SIX lock per resource at one time preventing updates to the resource made by other transactions, although other transactions can read resources lower down in the hierarchy by obtaining IS locks at the table level. 


Hope this helps

Tom


On 2/19/99 10:27:17 AM, Jeff Turlington wrote: 
> Anyone know where I can get documentation on what the various wait types 
> shown in SQL 7 Enterprise Manager mean? I&#39;m looking under current 
> activity and see a waiting process with a wait type listed as LCK_M_IS and 
> another with LCK_M_IX. I can&#39;t find a list of the valid wait types 
> anywhere?

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