Re: Concurrency question.

In article <32EA8AE1.2D75_at_Bryan.ftech.co.uk>, Bryan says...
>
>Hi,
>
>I am writting an app that will log into oracle upto 100 times
>concurrently using the same username/password/instance. If all of these
>instances were to attempt to write to the same table simultaneously will
>Oracle handle it.
>
>(The app is running on a multi-processor machine, so the concurrency is
>real.)
>
>I know that Oracle provides row level locking, but I wouldn't be
>accessing the same row concurrently. I am not shure anyway if this
>locking occurs between different users, rather than the same user
>multiple times.
>
>Any guidance would be appreciated greatly.
>
>Thanx.
>
>Bryan
>--
>Bryan Dollery BSc(Hons)
>ByteSmart Systems Ltd.

I'm not sure what your app will be doing but Oracle handles mulitple users updating the same table very well. Even though you have the same user sign-on they are all different sessions and will "play nice" with each other. Tip: when you create your table(s) if you are going to have many users updating rows that reside in the same block, set your INITRANS in your storage clause higher than the default of one. Oracle is supposed to dynamically manage the freelist in each block so that multiple users can be updating rows in the same data block. However, I have seen version 7.2.6 running in AIX 4.1.4 not do this even though there was plenty of free space in the datablock for Oracle to use. Hope that helps...

Carl Christianson
D.B.A. First Data Corp. Received on Sat Jan 25 1997 - 00:00:00 CST