Re: Wait for lock?

Comments embedded

Regards,

Sybrand Bakker, Oracle DBA

"dan wright" <dw420_at_nospammepleezeairmail.net> wrote in message news:A3D4FED550018CB5.B318B10D7607976E.F30CC76EE892BEF0_at_lp.airnews.net...
> Interesting that I got a much greater response from the Informix
> newsfroup about using Oracle after heavy use of Informix than I did from
> the Oracle newsfroup.
>

It is usually assumed here, people are capable of reading manuals.
>
> Anyway - apparently Oracle has no equivalent to Informix's ability to
> specify a timeout period when waiting for a lock.
>
> Is this correct? You can either tell Oracle to wait forever, or to not
> wait at all.
>

This is true

> So, if I expect the possibility of contention on a database table, but
> setting isolation to dirty read is not an option, I can't tell Oracle to
> keep trying for a few seconds?
>
> So, what in Informix would be a simple "SET LOCK MODE TO WAIT 5" would
> be implemented by trapping lock exceptions and retrying several times
> before giving up. What a pain....
>

In a well-designed Oracle application a lock is really transient. Contention on table-level wouldn't normally occur, as you are using row level locking implicitly. You shouldn't use table level locking explicitly of course.

Obviously, I don't discuss here people locking a record and going to fetch coffee, flush the toilet, or taking other 'breaks'. Those persons you need to whip more frequently :)

> And another thing - just what is the ANSI standard for an outer join? I
> thought both Informix and Oracle were ANSI-compliant, but the syntax for
> outer joins doesn't seem similar at all (At least in Informix it's
> simple and obvious).....
> (Incidentally Sybase has a really screwed up syntax for outer joins as
> well)
>
> Thanks for any input
>

The ANSI-standard has several compliance levels. I'm sure all of those products conform to the Ansi-standard, albeit to a different compliance level.

The screwed up Sybase syntax occurs in the Sqlserver world as well, as Microsoft initially was unable to develop their *own* database product and simply *bought* it from Sybase. Received on Sat Sep 16 2000 - 00:38:20 CDT