[Mulgara-dev] Fixing transactions.

Andrae Muys andrae at netymon.com
Sat Sep 30 13:47:56 UTC 2006

Well on Monday I plan to start addressing http://mulgara.org/jira/ 
browse/MGR-19.  This is a critical bug that has been unaddressed for  
too long.

The summary of the bug is:
Fix transaction support in Mulgara to support concurrent reads and  
read-only transactions. - Currently ACID failure

This requires refactoring (and some rewriting of) transaction support  
in the Session layer of Mulgara to support three-level transaction  

User - We require a seperate transaction object representing a users  
transaction. Currently represented by a javax.transaction.Transaction  
object on DatabaseSession. This needs encapsulating.
Query - We don't currently have any concept of a transaction at the  
per-query level. Without this concurrent reads can't be supported.
Method - Currently supported via methods on DatabaseSession. These  
need to be lifted into a seperate manager object which can manage  
their interaction with query and user transactional contexts.

My biggest concern is that there be sufficient review of my work to  
ensure that we maintain ACID.  Consequently it would be great if I  
could have volunteers to review the code, if you are willing to help  
with this please let me know.  It would also be great if anyone  
reviewing the code understood the existing transactional infrastructure.

Key to this would be understanding the transactional code in

DatabaseSession and DatabaseOperationContext.


Andrae Muys
andrae at netymon.com
Principal Mulgara Consultant
Netymon Pty Ltd

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