Re: Question on locking - Mailing list pgsql-novice

Nevermind about the, "how do I tell if it is locked question". I just re-read
Michael Fuhr's post on this subject. I knew it was a stupid question ;o)

Thanks...

On Friday 05 November 2004 08:33 am, Terry Lee Tucker saith:
> See inserts below:
>
> On Friday 05 November 2004 07:30 am, M. Bastin saith:
> > Hi Terry,
> >
> > I figure that if you have your table to track edited records and use
> > that in conjunction with Tom's approach you have a pretty good system
> > with only one major problem:
> >
> > What happens when a user acquires an editable record but doesn't
> > release it because he gets disconnected disgraciously while editing
> > (somebody tripped over the ethernet cable)?
> >
> > You're probably using your time stamp to help you get out of this
> > situation but you can use just these techniques to circumvent the
> > problem:
> >
> > - at connection a client must release all his locks in case he was
> > disconnected disgraciously just before and had left some locks active.
>
> Yes, this is handled.
>
> > - a client must release all his locks when disconnecting graciously.
>
> Yes, this is handled.
>
> > - a client that encounters a record that is already being edited
> > should check whether the user who's editing it is still really
> > connected.
>
> No, this has not been done.
>
> > - all user names of connected users have to be unique.
>
> Already accomplished.
>
> > If you don't mind transactions that last for the time a user edits a
> > record then you can go the way described in the pgSQL4RB manual as
> > mentioned a few posts before where you don't need any of the tables
> > and techniques outlined above.  Just do a query to verify the record
> > is unlocked and then acquire a lock on it with SELECT FOR UPDATE for
> > the duration of the editing process.
>
> This probably a stupid question, but how can I tell if a record is unlocked
> from a query? And finally, where is the document pgSQL4RB located?
>
> > That's all.  (If your
> > transaction lasts too long, like a couple of hours in my tests, you
> > will loose it though so you might need some code for this situation.)
> >
> > Marc
>
> Thank you for all your comments.
> __
>  Work: 1-336-372-6812
>  Cell: 1-336-363-4719
> email: terry@esc1.com

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 Work: 1-336-372-6812
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