?
Solved

HOW IS TRANSACTION ISOLATION LEVEL SET  VS SESSION.tx_isolation?

Posted on 2014-02-25
11
Medium Priority
?
242 Views
Last Modified: 2014-11-03
This is a basic question or so I believe!

Where and how do you set a current transaction isolation setting
I checked @@session.tx_isoation an @@tx_isolation are the same

so what variable or sql command sequence  sets things such that it is either transaction specific to a specific transaction or the default for just begin end transactions???

there is supposed to be three different setting but I found only 2 so far: session and global
0
Comment
Question by:Robert Silver
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 5
  • 3
  • 2
11 Comments
 
LVL 22

Expert Comment

by:Steve Wales
ID: 39886313
(oops, ignore me, I gave you MSSQL advice, removing my comment, sorry about that)

However, in case you hadn't found it, since I've got a comment stuck here anyway, here's the link to the docs on isolation level for MySQL.

http://dev.mysql.com/doc/refman/5.0/en/set-transaction.html
0
 
LVL 2

Author Comment

by:Robert Silver
ID: 39887079
I know not much help I need specifics not given at your link
0
 
LVL 22

Expert Comment

by:Steve Wales
ID: 39887119
Sorry can't help you ... I don't know much about MySQL, mis-read it as MSSQL and replied based on that :-/
0
Windows Server 2016: All you need to know

Learn about Hyper-V features that increase functionality and usability of Microsoft Windows Server 2016. Also, throughout this eBook, you’ll find some basic PowerShell examples that will help you leverage the scripts in your environments!

 
LVL 2

Author Comment

by:Robert Silver
ID: 39931707
This question may not have an easy answer or even be so relevant.
I had heard  of this setting and wish to know how it is set that is all
0
 
LVL 2

Author Comment

by:Robert Silver
ID: 39931711
Perhaps the real answer here is the session becomes specific to a given Transaction given
it is within the same session but then why make the distinction?
Was that just a mistake that was made and there is no such setting at all?
That would be my current  thoughts on this?
With Multi-threading it just occurred to me that maybe I could set off one transaction or multiple transactions within the same session but I guess that is not possible given the response here

Anyone like to comment on that?
0
 
LVL 51

Expert Comment

by:Mark Wills
ID: 40365773
If I understand your question properly... You are correct, there are three.

The basic syntax is :
mysql> SET <extent> TRANSACTION ISOLATION LEVEL <level>;

You must specify the extent as being GLOBAL or SESSION and if neither keyword is mentioned, then it is for the next (unstarted) transaction only.

There are 4 levels (in sequence of increasing guaranteed integrity) :
READ UNCOMMITTED
READ COMMITTED
REPEATABLE READ
SERIALIZABLE

The  REPEATABLE READ level is the default...
0
 
LVL 51

Accepted Solution

by:
Mark Wills earned 2000 total points
ID: 40365823
Found an example for you at the transaction level and the results / outcomes between two sessions...

http://dba.fyicenter.com/faq/mysql/Change-Transaction-Isolation-Level.html
0
 
LVL 2

Author Comment

by:Robert Silver
ID: 40417809
I've requested that this question be deleted for the following reason:

No interest
0
 
LVL 51

Expert Comment

by:Mark Wills
ID: 40417810
Interesting to say "no interest"

There was an example given of how to set and test for current transaction, and previously, the three different methods used to set the isolation level... being Global or Session and if neither of those two keywords are mentioned, then it is Transaction.
0
 
LVL 2

Author Comment

by:Robert Silver
ID: 40419543
I've requested that this question be deleted for the following reason:

No decent answer or interest
0

Featured Post

Moving data to the cloud? Find out if you’re ready

Before moving to the cloud, it is important to carefully define your db needs, plan for the migration & understand prod. environment. This wp explains how to define what you need from a cloud provider, plan for the migration & what putting a cloud solution into practice entails.

Question has a verified solution.

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

Load balancing is the method of dividing the total amount of work performed by one computer between two or more computers. Its aim is to get more work done in the same amount of time, ensuring that all the users get served faster.
This post looks at MongoDB and MySQL, and covers high-level MongoDB strengths, weaknesses, features, and uses from the perspective of an SQL user.
In this video, Percona Solution Engineer Dimitri Vanoverbeke discusses why you want to use at least three nodes in a database cluster. To discuss how Percona Consulting can help with your design and architecture needs for your database and infras…
In this video, Percona Solution Engineer Rick Golba discuss how (and why) you implement high availability in a database environment. To discuss how Percona Consulting can help with your design and architecture needs for your database and infrastr…

764 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