[Engine-devel] Default TransactionScope at engine

[Livnat Peer]

On 08/02/12 17:21, Michael Kublin wrote:
> Hi All,
> 
> Today most of the flows of runAction at engine look like at the following way:
> 
> 1. Perform some selects
> 2. Perform call to host (xml rpc) or call to some number of other actions in synchronous way 
> 3. If a call success than perform update to DB.
> 

There are also the following flows to consider -

* An action that is internal to the engine and does not involve a round
trip to the host, like all MLA related flows, quota etc.

* An action that is not internal but commits before the round trip to
the host like adding entities to db or changing entities status.

In addition we need to figure how this idea works when moving to JPA.


> It is means that we actually need open transaction only at the step 3, it is mean that by default
> we are keeping transaction much more longer than it should be, the call to host can take a while.
> 
> So, the possible plan of action is
> 1. Change a default scope of transaction from TransactionScopeOption.Required to TransactionScopeOption.Suppress
> 2. Remove annotation NonTransactiveCommandAttribute
> 3. The actions which are need to run in transaction - appropriate transaction scope should be passed via parameters 
> 
> It is a lot of dirty and not to interesting work, but I think it will provide a great benefit:
> 1. Reduced a time of open transaction 
> 2. Better db connection utilization
> 3. I think that number of open transaction will also reduce 
> 4. As a result performance will improve
> 
> By the way, many of new actions which are written today by default marked as NonTransactiveCommandAttribute, if we will continue
> in such way almost every class will be marked with NonTransactiveCommandAttribute
> 
> Regards Michael
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