Re: Lost updates vs resumable connections/transactions - Mailing list pgsql-interfaces

From Greg Stark
Subject Re: Lost updates vs resumable connections/transactions
Date
Msg-id 87is73qrde.fsf@stark.xeocode.com
Whole thread Raw
In response to Re: Lost updates vs resumable connections/transactions  (Jan Wieck <JanWieck@Yahoo.com>)
Responses Re: Lost updates vs resumable connections/transactions  (Jens Lechtenboerger <lechten@wi.uni-muenster.de>)
List pgsql-interfaces
Jan Wieck <JanWieck@Yahoo.com> writes:

> Even applications that have statefull enduser terminals (like SAP R/3 for
> example) never allow an open transaction over user interaction. 

I'm not sure using SAP as your paragon of design excellence is a wise choice
here. From what I understand SAP implemented its own locking system because
the database it was based on didn't offer any locking at all.

But your basic point is sound. For a web site I would definitely avoid using
anything like database locks and even avoid doing anything with application
locks if possible.

If you really really want to expose the database session state I think he's on
the right track using SQLRelay. This would let him handle reconnecting a user
with her session even if she's connecting to a different Apache process.

I suspect the database wouldn't really be able to suspend a database
connection using any less memory than just keeping the entire backend process
with its session around anyways.

-- 
greg



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