Re: Locking Question (nowait, UPDATE etc)

"Holger Baer" <holger.baer_at_science-computing.de> wrote in message news:3E847E99.7090906_at_science-computing.de...

> Either I'm missing a point here, or you've never heard of read
consistency.
> Why (b)? After the export is finished, you don't care if someone modifies
your
> records, so why care while you're exporting? Or has the exported-success
flag
> any meaning to other sessions that they won't modify them afterwards?

After data is exported, any modifications mark the record as not-exported (i.e. in need of being exported again). For that reason I can not have any interference while the record is being exported: For the purpose of maintaining an accurate export-state, the export must be atomic with respect to any other modifications.

This can not be a unique requirement. The only thing here that is maybe a bit different is that the operation that is required to be atomic can take several minutes, and that I don't cant have the front-end locked up for that period of time if it happened to want to save data for the rows being exported.

On the other hand, it can't be that esoteric after all, otherwise Oracle wouldn't have put in the NOWAIT option for SELECT FOR UPDATE or, with 9i, the WAIT xxx option for SELECT FOR UPDATE.

JEE Received on Mon Mar 31 2003 - 09:21:59 CST