Re: [boost] [transaction] New Boost.Transaction library under discussion

Subject: Re: [boost] [transaction] New Boost.Transaction library under discussion
From: strasser_at_[hidden]
Date: 2010-01-27 12:33:50

Zitat von Vicente Botet Escriba <vicente.botet_at_[hidden]>:

>
>
>
> strasser wrote:
>>
>> Zitat von Bob Walters <bob.s.walters_at_[hidden]>:
>>
>> I´ve been thinking about introducing a RM category for that:
>>
>> typedef one_phase_tag category;
>> //only supports one-phase commit.
>>
>> or
>>
>> typedef persistent_tag category;
>> //supports two-phase, persistent
>>
>> or
>>
>> typedef transient_tag category;
>> //supports two-phase, non-persistent
>>
>> only when 2 or more persistent_tag RMs are used in a global
>> transaction the TM has to prepare both and write to its log to have a
>> unique commit point, otherwise the commit of the only persistent_tag
>> RM is the commit point.
>> (any ideas for a better name for "one_phase_tag"?)
>>
>>
>
> non_recoverable?
>

is there a reason why this can't be a Service of the resource manager?
I don't have a clear definition of a Service so far, and neither does  
the XA standard linked above.
services usually are domain-specific functions intended to be called  
by the user interface (e.g. a function to get an instance of a  
persistent object), not functions handling transactions itself, but is  
there a reason why the optional interface for distributed transactions  
can't use the usual service interface?
I can't think of one right now.

the concept would probably look something like this:

concept DistributedTransactionService{
   typedef unspecified services; //MPL sequence containing  
distributed_transaction_service_tag
   typedef unspecified transaction;
   typedef unspecified transaction_id; //must be POD

   static bool const persistent=unspecified;

   bool prepare_transaction(transaction &);

   transaction_id get_transaction_id(transaction const &);

   template<class InputIterator> //must yield transaction_id
   void recover(InputIterator b,InputIterator e);
};

see  
https://svn.boost.org/svn/boost/sandbox/persistent/libs/persistent/doc/html/boost/persistent/ResourceManager.html and https://svn.boost.org/svn/boost/sandbox/persistent/libs/persistent/doc/html/persistent/extending.html#persistent.extending.services for information about  
services.

the one_phase_tag RMs discussed above would be a RM that doesn't offer  
the DistributedTransactionService.