how to choose correct db isolation level for Financial Accounting app ?

[masummymesingh]

I am using EJB 3.2 and wirldfly 8

what level is appropriate for this our financial app ??????????

Isolation Level

Read Committed

Repeatable Read

Serializable

[martinschweigert]

Sorry for being rude, but do yourself and your customer(!) a favor and find some professional who codes your "financial app". I'm sure you can so much more learn from her/him.

[wdfink]

To be a bit more detailed

If you have no idea what the different isolation levels are I agree to martinschweigert.

The isolation depends on your requirements (performance/consistence) and you need to have that coordinated with your application.

[masummymesingh]

Hi  wolf-Dieter ,

This app requirements is :

1. banking accounting system

2. high concurrent user

3. need high level data consistency

4. also need regular performance

       I want to know that  for this situation what is the best practice of DB isolation level ???

==================================

level	Why Occur	problem	Use case	Performance /overhead		Java ee	db
Read Uncommitted	Rollback/failed	3	Search /Select	***
Read committed	Unrepeatable -Update multiple reads in same transaction	2	only committed records	**		***	***oracle default
Repeatable Read	Phantom - Insert	1	to read a row exclusively	*		Programmically /Solution is Optimistic Lock Read/Write Lock in EJB
Serializable		0	data consistency is an absolute requirement	Very slow /Deadlock			***

[wdfink]

The answer is in that table

As you need Performance, concurrency and consistency I would use RepeatableRead and Optimistic locking (OL).

OL is provided by JPA, you need to define a 'version' column which ensure that you can not upddate if a concurrent change was made.

You should read the JPA tutorial/docs

[masummymesingh]

Thanks wolf-Dieter for your  suggestion .

i want to use Read committed .

in this situation i shall face those three concurrency problem . I want to overcome those problem using following solution

                                       for isolation level -------------Read committed

problem 1 :  Lost Update Problem

----------------(old value)-------------JPA Optimistic locking (OL).

problem 2 :   Unrepeatable

---------------(Single Row)------------ JPA entity read /write lock

problem 3 :   Phantom

-----------(Multi Row)------------------ ????????????

  Can you tell me that what is appropriate solution for problem-3 : phantom ???

  is it possible any solution (problem 3 ) for when using Read committed ?

[wdfink]

Phantom read might be acceptable in most cases as you can prevent it in you logic with locks