Re: Remote Select opening transaction

  • From: "Marc Demlenne" <marc.demlenne@xxxxxxxxx>
  • To: mark.powell@xxxxxxx
  • Date: Thu, 5 Apr 2007 02:34:09 +0200

Ok. Seems to be a not well-known feature anyway, and by-the-way very
dangerous.

Thanks for all those replies !

On 4/3/07, Powell, Mark D <mark.powell@xxxxxxx> wrote:

 For a demo on this topic you can see the following:



Why does it seem that a select over a db link requires a commit after
execution?

* http://www.jlcomp.demon.co.uk/faq/dblink_commit.html*


-- Mark D Powell --
Phone (313) 592-5148


 ------------------------------
*From:* oracle-l-bounce@xxxxxxxxxxxxx [mailto:
oracle-l-bounce@xxxxxxxxxxxxx] *On Behalf Of *Marc Demlenne
*Sent:* Tuesday, April 03, 2007 8:43 AM
*To:* Kerber, Andrew W.
*Cc:* oracle-l@xxxxxxxxxxxxx
*Subject:* Re: Remote Select opening transaction

Hi,

It is ! You can try the following :
- Do a select * from remoteDB.remoteTable@remoteHost (but remoteDB is
enought, can be same host)
- Don't commit, rollback or quit. Be carefull not to exit in timeout
- And monitor the RBS. you'll notice that your sqlplus process is locking
one of the RBS, and the number of extent will start growing up and up until
you'll recah the ORA-01562 error.
I use :
select rn.name, r.curext, t.start_uext, r.extents, t.xidusn, s.sid,
s.process, t.start_time
from V$rollstat r,  v$rollname rn, V$transaction t, v$session S
WHERE t.addr = s.taddr (+) and t.XIDUSN=r.USN AND r.usn(+) = rn.usn

Exiting your sqlplus (or commit or rollback) will unblock the situation,
freeing your RBS. In my case, we use the "OPTIMAL" parameter and see the
number of extents immediately reducing to it's optimal value ...

Best Regards,

On 4/3/07, Kerber, Andrew W. <Andrew.Kerber@xxxxxxx> wrote:
>
>  Hi.  I am pretty sure your information is incorrect.  I have never seen
> a select across a db link open a transaction.
>
>
>
> -----Original Message-----
> *From:* oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]
> *On Behalf Of *Marc Demlenne
> *Sent:* Tuesday, April 03, 2007 7:08 AM
> *To:* oracle-l@xxxxxxxxxxxxx
> *Subject:* Remote Select opening transaction
>
>
>
> Hello,
>
> In Oracle 8, when performing a select query on another database threw DB
> link, Oracle opens a transaction that could only be closed by commit or
> rollback. That could be harmful when developers are not aware of this and
> don't close transaction. (leading to ORA-01562.)
>
> What is the reason of this behaviour ? Is there some docs / faq
> explaining this ?
> Is this feature also common to later versions of Oracle ?
>
> Thanks a lot for any piece of information given,
>
> --
> Marc
>
>
> ------------------------------------------------------------------------------
> NOTICE: This electronic mail message and any attached files are
> confidential. The information is exclusively for the use of the individual
> or entity intended as the recipient. If you are not the intended recipient,
> any use, copying, printing, reviewing, retention, disclosure, distribution
> or forwarding of the message or any attached file is not authorized and is
> strictly prohibited. If you have received this electronic mail message in
> error, please advise the sender by reply electronic mail immediately and
> permanently delete the original transmission, any attachments and any copies
> of this message from your computer system. Thank you.
>
>
> ==============================================================================
>



--
Marc Demlenne




--
Marc Demlenne

Other related posts: