[PATCH 2 of 5 STABLE] transaction: separate calculating TXNID from creating transaction object

[FUJIWARA Katsunori]

At Tue, 19 May 2015 17:26:39 -0500,
Pierre-Yves David wrote:
> 
> On 05/19/2015 10:39 AM, FUJIWARA Katsunori wrote:
> > # HG changeset patch
> > # User FUJIWARA Katsunori <foozy at lares.dti.ne.jp>
> > # Date 1432049572 -32400
> > #      Wed May 20 00:32:52 2015 +0900
> > # Branch stable
> > # Node ID ae2915053ec6ee06c64482fba7ba668ce91305e1
> > # Parent  11f3cae961f815ee7f8acc4e0312ed724d4ef8fe
> > transaction: separate calculating TXNID from creating transaction object
> >
> > Before this patch, transaction ID (TXNID) is calculated from
> > `transaction` object itself, but this prevents TXNID from being passed
> > to `pretxnopen` hooks, which should be executed before starting
> > transaction processing (also any preparations for it, like writing
> > journal files out).
> >
> > As a preparation for passing TXNID to `pretxnopen` hooks, this patch
> > separates calculation of TXNID from creation of `transaction` object.
> >
> > To keep uniqueness of assigned TXNID (= prevent `idobj` from being
> > reused at another `txnid()` invocation) while corresponded
> > `transaction` object is alive, this patch also adds `_txnid` field to
> > `transaction` and makes it refer the tuple returned by `txnid()`.
> 
> I think this object() business is to awful. We have been using id(txn) 
> because it was super simple and "good enough". But this is becoming to 
> complicated.
> 
> We need a simple way to generate unique ID. I would point at "uuid" if 
> the branch was not still Python2.4 compatible. Can I leave you with the 
> task of finding a good enough uniq (enough) id generator on stable? 
> (marmoute give a side looks at random) and send a V3 of this series?

I thought that `id(obj)` style is used because we don't want to use
"random" library (maybe for performance reason), "uuid" (performance
and Python 2.4 compatibility reason) or so.

I'll send V3 series using "random".


> -- 
> Pierre-Yves David
> 

----------------------------------------------------------------------
[FUJIWARA Katsunori]                             foozy at lares.dti.ne.jp