[ZODB-Dev] Checking transaction status?

[Jim Fulton]

ender wrote:
> 
> On Tuesday 10 July 2001 12:30, Greg Ward wrote:
> >>On 10 July 2001, Christian Robottom Reis said:
> >>> I think (know?) this can be done with threads, but my app is really
> >>> single-threaded right now, and I don't want to have to think about that
> >>> right now.
> >>
> >>My understanding is that you can do that with multiple Connections.
> >>I've never tried it, though, so I don't know how it works and I can't
> >>vouch for it.
> 
> My understanding is that won't work. you could get separate object spaces
> with multiple connections but of limited utility since they wouldn't have
> transaction isolation. the transaction semantics assign transactions based on
> thread not connection which get its accessor installed as a builtin. so all
> objects get registered in the same transaction and a single commit would
> commit all of them (albeit to different connections), but still not the
> semantics of what christian wants.

This is exactly right.  There are a couple of issues here:

  - The transaction implementation needs to be replaceable, 
    so that you can implement different transaction management
    policies. I'd like to see:

    o Transactions moved into a separate package (from ZODB)

    o Some attention given to making transactions more controllable.

  - There has to be a way for objects find the transaction manager 
    globally. This seems to mean that there can only be one 
    transaction per thread. Maybe there should be a version of 
    get_transaction that lets you pass an argument (e.g. a connection)
    that that could contain data for deciding what transaction to return.
    Hm. This deserves some more thought.

Jim

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