But this default mssql behaviour is the performance 'gotcha' where readers
block writers and writers block readers isn't it?
Mike.
-----Original Message-----
Sent: 31 October 2002 09:12
To: Multiple recipients of list ORACLE-L
'Dirty reads' in SQL Server means that you can view records that have not
been committed. This is implemented by setting the TRANSACTION ISOLATION
LEVEL to READ UNCOMMITTED.
This is not default behaviour in SQL Server, the default TIL is READ
COMMITTED (for very good reason). I can think of very few situations where
you would want to see uncommitted records.
Dirty blocks in SQL Server/Oracle are the same thing ie. a block/page in
cache that has been changed but not flushed to disk.
Ade
-----Original Message-----
Sent: 30 October 2002 18:43
To: Multiple recipients of list ORACLE-L
It sounds like he is saying that, once an "insert, update or delete"
statement has been issued (without a following commit), then the records
acted upon are now considered "dirty" - i.e. needing writing to disk.
this is, of course, NOT what Oracle considers a dirty block.
I agree with you, Jared!
Tom Mercadante
Oracle Certified Professional
-----Original Message-----
Sent: Wednesday, October 30, 2002 1:21 PM
To: Multiple recipients of list ORACLE-L
At least one of us has the incorrect understanding of 'dirty' reads,
or I am taking you too literally, or something.
What are you really saying?
Oracle does not allow dirty reads.
All queries are consistent to a point in time, the beginning
of a transaction, whether implicit (select) or explicit ( start
transaction ).
SQL Server and Sybase do not guarantee this.
The 'dirty' reads you are speaking of sound more to me
like sloppy programming.
Is that what you're referring to?
Jared
"Yechiel Adar" <[EMAIL PROTECTED]>
Sent by: [EMAIL PROTECTED]
10/30/2002 08:54 AM
Please respond to ORACLE-L
To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]>
cc:
Subject: Re: RE: oracle or mssql
I would like to point out that what you call "dirty reads" are mostly
the correct reads. Oracle method IS the dirty read.
I am sure that your users does at least 1000 commits to every rollback.
So when oracle gives you the data it already knows that this data is
wrong. If you do the query again a minute later you will get new results
that were available when you did the original query but were committed
later. So you get a 1000/1 chance to get incorrect data.
The "dirty read" method, on the other hand, gives you the current values,
believing that they will be committed in a moment. So you get 1/1000
chance
to get wrong data.
Which odds will you bet on?
Yechiel Adar
Mehish
----- Original Message -----
To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]>
Sent: Tuesday, October 29, 2002 2:18 PM
List,
I'm always keen to refresh on database comparisons so thanks for
everyone's pointers.
I'm surprised Oracle doesn't make more of an issue about their locking and
concurrency methods (i.e. redo/rollback/undo).
MSSQL seems to deal with it in two ways:
Default: readers and writers prevent writers from accessing data until
they
are finished with it!
Other method: no control, you just get dirty reads!
Anyone got anything to add to this? Or am I wrong?
- Mike.
-----Original Message-----
Sent: 24 October 2002 17:29
To: Multiple recipients of list ORACLE-L
As I said, use mssql ONLY if your boss is willing to be strapped into a
MicroSlop only platform. If he's even remotely thinking of using a
different OS
then you can't use mssql.
Dick Goulet
____________________Reply Separator____________________
Author: [EMAIL PROTECTED]
Date: 10/23/2002 11:48 PM
goodmorning
everybody who responded to my basic question : thanks
summary
professional : use oracle enterprise edition
semi professional : use oracle standard edition / mssql enterprise edition
in all other cases mssql standard edition
> -----Oorspronkelijk bericht-----
> Van: Mohammad Rafiq [SMTP:[EMAIL PROTECTED]]
> Verzonden: woensdag 23 oktober 2002 20:51
> Aan: Multiple recipients of list ORACLE-L
> Onderwerp: RE: oracle or mssql
>
--
Please see the official ORACLE-L FAQ: http://www.orafaq.com
--
Author: Jenner Mike
INET: [EMAIL PROTECTED]
Fat City Network Services -- 858-538-5051 http://www.fatcity.com
San Diego, California -- Mailing list and web hosting services
---------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from). You may
also send the HELP command for other information (like subscribing).
