Solved

What is page locking

Posted on 1998-12-14
4
159 Views
Last Modified: 2010-07-27
What is page locking in SQL and how large is a page?
Has a page a fix size e.g. 4KB or 8KB or a number of records?
0
Comment
Question by:flmexpert
  • 2
4 Comments
 
LVL 7

Accepted Solution

by:
spiridonov earned 0 total points
ID: 1092277
Page locking is like putting a flag on the page. The flag, depending on lock can mean: 'Don't allow any one to access this page' (in case of update lock) or for example, 'Allow to read, but don't allow to update' (in case of shared select lock). There are several lock types, that can be placed on a page,you can read about them in SQL Books Online. Page size in Sql Server is 2Kb.
0
 
LVL 2

Expert Comment

by:tschill120198
ID: 1092278
SQL 7.0 increases the page size to 8K.
0
 

Author Comment

by:flmexpert
ID: 1092279
SQL 7.0 uses record locking and why should it use also pages ?

Also there is a problem:
If i have a record with a size of 3 KB and
make "update ... where <this record>".
SQL 7 locks only this record and SQL 6.5 ?
Locks it this record with two 2 KB pages ?

0
 
LVL 2

Expert Comment

by:tschill120198
ID: 1092280
This is called "lock escalation", where SQL converts many fine-grain locks into fewer course-grain locks to reduce the overhead of managing the locks...  

Resources that it can lock (from smaller to larger granularity) are: RID -> Key -> Page -> Extent -> Table -> Database.

Look in BOL under "lock escalation".

As for the update query locking 2 pages, since the record is 3K (and therefore resides on 2 pages), it would make sense that both pages for the record be locked.  Or am I missing something?

0

Featured Post

What is SQL Server and how does it work?

The purpose of this paper is to provide you background on SQL Server. It’s your self-study guide for learning fundamentals. It includes both the history of SQL and its technical basics. Concepts and definitions will form the solid foundation of your future DBA expertise.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Nowadays, some of developer are too much worried about data. Who is using data, who is updating it etc. etc. Because, data is more costlier in term of money and information. So security of data is focusing concern in days. Lets' understand the Au…
When you hear the word proxy, you may become apprehensive. This article will help you to understand Proxy and when it is useful. Let's talk Proxy for SQL Server. (Not in terms of Internet access.) Typically, you'll run into this type of problem w…
Familiarize people with the process of retrieving data from SQL Server using an Access pass-thru query. Microsoft Access is a very powerful client/server development tool. One of the ways that you can retrieve data from a SQL Server is by using a pa…
Viewers will learn how to use the INSERT statement to insert data into their tables. It will also introduce the NULL statement, to show them what happens when no value is giving for any given column.

856 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question