lock escalation : how "expensive" ?

stefan.albert

Hi folks,
we have a little discussion about lock escalation...

What is better for performance: To have an escalation "early" (smaller
locklist) or aviod the escalation with a big lock list?

We don't care about concurrency - because the changes have to be done,
other SQL waiting for this is OK.

Anyhow - I think: A lock table in exclusive mode would be the the most
performant way. Correct?

Any hints or other points of view?

thx
Stefan

Jun 21 '07 #1

Subscribe Reply

2195

Serge Rielau

stefan.albert wrote:

Anyhow - I think: A lock table in exclusive mode would be the the most
performant way. Correct?

Yes. It's a pretty brutal approach though....
--
Serge Rielau
DB2 Solutions Development
IBM Toronto Lab

Jun 21 '07 #2

stefan.albert

On 21 Jun., 13:11, Serge Rielau <srie...@ca.ibm .comwrote:

stefan.albert wrote:
Anyhow - I think: A lock table in exclusive mode would be the the most
performant way. Correct?

Yes. It's a pretty brutal approach though....
--
Serge Rielau
DB2 Solutions Development
IBM Toronto Lab

Hi Serge,

can you give me a hint: What is better for performance: Early
escalation or late one (or none at all)?

thx
Stefan

Jun 21 '07 #3

Serge Rielau

stefan.albert wrote:

On 21 Jun., 13:11, Serge Rielau <srie...@ca.ibm .comwrote:
>stefan.alber t wrote:
>>Anyhow - I think: A lock table in exclusive mode would be the the most
performant way. Correct?
Yes. It's a pretty brutal approach though....
can you give me a hint: What is better for performance: Early
escalation or late one (or none at all)?

Uhm.. I thought I was explicit enough. Anyway.
Lock escalation means a lot of effort is being wasted. I.e. teh
collecting of all the individual row locks. If you know you will update
the whole table (or you are de-facto alone on the system) you save all
that work by locking the table upfront.
Avoidance of lock-escalation is important to keep concurrency. Something
you say you don't care about.
So I would say:
1. LOCK table
2. Escalate
3. Avoid escalation
(exactly the opposite of what you would normally want)

For read queries in a read only database (perhaps a mart) i recommed
simply running UR.

Cheers
Serge
--
Serge Rielau
DB2 Solutions Development
IBM Toronto Lab

Jun 21 '07 #4

Similar topics

7640

what's "share-nothing archtecture"?

by: Hardy | last post by:

I'm pretty new in this field. when reading some 70x material, I met with this term but cannot catch its accurate meaning. who can help me? thanks in advance:)~

DB2 Database

3270

Access 2.0 supported Application.SetOption "Show ToolTips", False What can I run with Access 97 to achieve the same objective?

by: MLH | last post by:

Does Access 97 have something like this?

Microsoft Access / VBA

7358

"RuntimeError: dictionary changed size during iteration" ; Good atomiccopy operations?

by: robert | last post by:

In very rare cases a program crashes (hard to reproduce) : * several threads work on an object tree with dict's etc. in it. Items are added, deleted, iteration over .keys() ... ). The threads are "good" in such terms, that this core data structure is changed only by atomic operations, so that the data structure is always consistent regarding...

Python

3411

Why "class exceptions" are not deprecated?

by: Gregory Petrosyan | last post by:

1) From 2.4.2 documentation: There are two new valid (semantic) forms for the raise statement: raise Class, instance raise instance 2) In python: >>> raise NameError Traceback (most recent call last): File "<stdin>", line 1, in ? NameError

Python

2027

Why pointer to "one past" is allowed but pointer to "one before" is not ?

by: spibou | last post by:

Why is a pointer allowed to point to one position past the end of an array but not to one position before the beginning of an array ? Is there any reason why the former is more useful than the later ? Spiros Bousbouras

C / C++

3901

The illusion of "portability"

by: jacob navia | last post by:

In this group there is a bunch of people that call themselves 'regulars' that insist in something called "portability". Portability for them means the least common denominator. Write your code so that it will compile in all old and broken compilers, preferably in such a fashion that it can be moved with no effort from the embedded system...

C / C++

2563

Dynamically choosing what to "new"

by: Pat | last post by:

Hi, I've run into a strange problem, but one that seems like it might be fairly common. I have a single base class, from which several other classes are derived. To keep the example simple, the base class is "Animal" and the derived classes are "Cat," "Dog," and "Horse." The base class has a pure virtual method:

C / C++

350

11556

Do you use a garbage collector?

by: Lloyd Bonafide | last post by:

I followed a link to James Kanze's web site in another thread and was surprised to read this comment by a link to a GC: "I can't imagine writing C++ without it" How many of you c.l.c++'ers use one, and in what percentage of your projects is one used? I have never used one in personal or professional C++ programming. Am I a holdover to...

C / C++

3799

Why people use "new" & "delete" too much?!!

by: Medvedev | last post by:

i see serveral source codes , and i found they almost only use "new" and "delete" keywords to make they object. Why should i do that , and as i know the object is going to be destroy by itself at the end of the app for example: class test { public: int x;

C / C++

7693

What is ONU?

by: marktang | last post by:

ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main...

General

7605

Changing the language in Windows 10

by: Hystou | last post by:

Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it. First, let's disable language...

Windows Server

7917

Problem With Comparison Operator <=> in G++

by: Oralloy | last post by:

Hello folks, I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>". The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed. This is as boiled down as I can make it. ...

C / C++

8118

Maximizing Business Potential: The Nexus of Website Design and Digital Marketing

by: jinu1996 | last post by:

In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that...

Online Marketing

7962

Discussion: How does Zigbee compare with other wireless protocols in smart home applications?

by: tracyyun | last post by:

Dear forum friends, With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each protocol has its own unique characteristics and advantages, but as a user who is planning to build a smart home system, I am a bit confused by the...

General

5217

Couldn’t get equations in html when convert word .docx file to html file in C#.

by: conductexam | last post by:

I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert...

C# / C Sharp

3651

Trying to create a lan-to-lan vpn between two differents networks

by: TSSRALBI | last post by:

Hello I'm a network technician in training and I need your help. I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs. The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols. I succeeded, with both firewalls in...

Networking - Hardware / Configuration

2105

transfer the data from one system to another through ip address

by: 6302768590 | last post by:

Hai team i want code for transfer the data from one system to another through IP address by using C# our system has to for every 5mins then we have to update the data what the data is updated we have to send another system

C# / C Sharp

933

Comprehensive Guide to Website Development in Toronto: Expert Insights from BSMN Consultancy

by: bsmnconsultancy | last post by:

In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating...

General