Re: Transaction Processing

In article <33225CC6.1068_at_popd.ix.netcom.com> venusub_at_popd.ix.netcom.com writes:
>I am pretty new to Oracle and I have a couple of questions on
>Transaction Processing.
>
>Does Oracle have a Transaction Queue that it maintains to keep track of
>transactions from many users?
>Can they be prioritized so that a higher priority transaction can
>preempt a lower priority one?
>
>I looked for answers to these in the Reference manual and the on-line
>Books. Couldn't fine any.
>
>Any pointers will be appreciated.
>
>- Venu

Check out the Concepts manual. It explains that it is really timestamp based in order to maintain read-consistency. Each transaction is given a sequence number when the transaction is committed. The queues are inside a black box. You must trust Oracle to get it right. What prioritization do you want to make, exactly? Normally, the changes to the database are made when the database writer gets around to it, which may be a while after the online redo log file is written (which is the real "commit"). Another user looking at the data makes Oracle look at the buffers to see if there are dirty ones that have to be accounted for. If you have the procedural option, you can improve performance with a discrete transaction procedure. It just depends on what you want to do.

-- 
Joel Garry               joelga_at_rossinc.com               Compuserve 70661,1534
These are my opinions, not necessarily those of Ross Systems, Inc.   <> <>
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