Home/ Questions/Q 3611626
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-18T21:53:55+00:00

I have the following SP: CREATE PROCEDURE [dbo].[sp_LockReader] AS BEGIN SET NOCOUNT ON; begin

  • 0

I have the following SP: 

CREATE PROCEDURE [dbo].[sp_LockReader]  
AS  
BEGIN  
SET NOCOUNT ON;  
begin try   
set transaction isolation level serializable  
begin tran  
select * from teste  
commit tran  
end try  
begin catch  
rollback tran  
set transaction isolation level READ COMMITTED  
end catch  
set transaction isolation level READ COMMITTED  
END

The table “test” has many values, so “select * from teste” takes several seconds. I run the sp_LockReader at same time in two diferent query windows and the second one starts showing test table contents without the first one terminates.

  • Shouldn’t serializeble level forces the second query to wait?
  • How do i get the described behaviour?

Thanks

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    SERIALIZABLE at the most basic means “hold locks for longer”. When you SELECT, the held lock is a shared lock which allows other readers.

    If you want to block readers, use WITH (TABLOCKX) hint to take an exclusive lock where you don’t need SERIALIZABLE. Or XLOCK with SERIALIZABLE

    In other words:

    • SERIALIZABLE = Isolation Level = lock duration, concurrency
    • XLOCK = mode= sharing/exclusivity

    • TABLOCK = Granularity = what is locked

    • TABLOCKX = combined

    See this question/answer for more info

    • 0