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 sql server rowlock question

Author  Topic 

Starting Member

3 Posts

Posted - 2005-09-23 : 19:41:58
I need to know how does sql server locks the rows of a select.

With a statement like this:

select max(numero_reg)
from cont_registro with (holdlock,rowlock)
where serial_dia = 15

//// do my stuff


Is sql server locking all the rows of the where clause
"where serial_dia = 15"


Is sql server locking ONLY one row that complies whit
"max(numero_reg)" and has "serial_dia = 15"

Please help

Santiago G.

Almighty SQL Goddess

38200 Posts

Posted - 2005-09-23 : 19:44:14
You should begin tran until after your SELECT statement. All data gathering should be outside of the transaction.

SQL Server starts at row-level locking and escalates as needed. You can read all about locking in SQL Server Books Online if you need detailed information about it.

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Starting Member

3 Posts

Posted - 2005-09-23 : 19:48:24
Could you be more specific (like an example), since I have read a lot of information about locking and i don't understand it very well.

What i need is to lock all rows from table cont_registro that have serial_dia = 15.

Santiago G.
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Master Smack Fu Yak Hacker

3575 Posts

Posted - 2005-09-23 : 20:20:32
SQL Server may not put a rowlock on those rows, it might use a page lock instead. It all depends.

You can change (or try to change) sql servers locking behavior by using locking hints. Check BOL for details, here is a start:

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