Re: Changing isolation level?

From: mcstock <_at_>
Date: Wed, 3 Dec 2003 22:06:33 -0500
Message-ID: <VN6dndJo6Lp8OVOiRVn-ig@comcast.com>

"Hemant Shah" <shah_at_typhoon.xnet.com> wrote in message news:bqlt5h$j25$3_at_flood.xnet.com...
| While stranded on information super highway mcstock wrote:
| :)
| :)"Daniel Morgan" <damorgan_at_x.washington.edu> wrote in message
| :)news:1070486233.549645_at_yasure...
| :)| D Alpern wrote:
| :)|
| :)| > SELECT... FOR UPDATE {WAIT | NOWAIT} springs to mind...
| :)| >
| :)| > David
| :)|
| :)| Why would that spring to mind?
| :)|
| :)| It doesn't block a read which is the point of the OP's request.
| :)|
| :)| --
| :)| Daniel Morgan
| :)| http://www.outreach.washington.edu/ext/certificates/oad/oad_crs.asp
| :)| http://www.outreach.washington.edu/ext/certificates/aoa/aoa_crs.asp
| :)| damorgan_at_x.washington.edu
| :)| (replace 'x' with a 'u' to reply)
| :)|
| :)
| :)actually, it does... it voluntarily blocks the read that it itself
| :)(grammar?) is attempting to do
| :)
| :)so, on a case by case basis (instead of a session or instance isolation
| :)level setting), the reader gets blocked by the writer
| :)
| :)unfortunately, the reader that uses this syntax now blocks writers, but
if
| :)serialization is what's required to meet the business requirement, this
| :)would seem to do it
| :)--
| :)Mark C. Stock
| :)mcstock -> enquery(dot)com
| :)www.enquery.com training & consulting
| :)

| This will not work.

| I have to read the next row to find out what it is and then delete it.
| If another process has already deleted the row, I should be getting the
old
| value. Oracle will not block readers.

|

not clear what you're trying to say. what is the next row that you have to read, and why? why do you have to read the 'next row' and delete it?

the point is, oracle does not normally block readers, the discussion is a perceived need to not read the old value of a deleted non-committed row

please clarify why SELECT FOR UPDATE will not work in preventing the read of a row that is already in a pending transaction.

Received on Wed Dec 03 2003 - 21:06:33 CST