Isolation levels & Transaction levels?


The isolation level measures concurrent transaction’s capacity to view data that have been updated, but not yet committed, by another transaction if other transactions were allowed to read data that are as yet uncommitted, those transactions could end up with inconsistent data were the transaction to roll back, or end up waiting unnecessarily were the transaction to commit successfully.
A higher isolation level means less concurrence and a greater likelihood of performance bottleneck, but also a decreased chance of reading inconsistent data. A good rule of thumb is to use the highest isolation level that yields an acceptable performance level. The following are common isolation levels, arranged from lowest to highest.
1) ReadUncommitted: Data that have been updated but not yet committed by a transaction my be read by other transactions
2) Readcommitted: Only data that have been committed by a transaction can be read by other transactions.
3) Repeatable Read: Only data that have been commited by a trasaction can be read by other transactions, and multiple reads will yield the same result as log as the data have been committed.
4) Serializable: This highest possible iosolation level, ensures a transaction’s execlusive read-write access to data, it includes the conditions of ReadCommitted and Repeatable Read and stiplulates that all transactions run serially to achieve maximum data integrity. This yields the slowest performance and least concurrency. The term serializable in this context is absolutely unrelated to the database.

Advertisements
About

I born in Good cultural place called India. My family is traditional family. We fallow all Indian traditions.

Tagged with:
Posted in JAVA

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Enter your email address to subscribe to this blog and receive notifications of new posts by email.

Join 678 other followers

Calendar
April 2010
M T W T F S S
« Jul   May »
 1234
567891011
12131415161718
19202122232425
2627282930  
Mallikarjun Gunda

This is Mallikarjun Gunda, I am working as a software professional. Blogging is my Passion. This blog contains the posts on Java related technologies and programming languages. I am happy to share my knowledge through the blogs.

Blog Stats
  • 280,989 hits
IndiBlogger
malliktalksjava.wordpress.c...
70/100