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Re: Database or store to handle 30 Mb/sec and 40,000 inserts/sec

From: Tony Rogerson <>
Date: Tue, 21 Feb 2006 17:44:28 -0000
Message-ID: <dtfjh9$anm$1$>

> Having looked at M$'s implementation in my lab my impression is that

Please post your DDL and SQL so we can all take a look - thankyou.

In reality they have reengineered the way a lot of things work to use the Row Versioning code, online index creation/rebuild, triggers, transaction isolations.

Tony Rogerson
SQL Server MVP - free video tutorials

"DA Morgan" <> wrote in message
> Serge Rielau wrote:

>> Mark Townsend wrote:
>>> Serge Rielau wrote:
>>>> Galen Boyer wrote:
>>>>> On 19 Feb 2006, wrote:
>>>>>> When would you ever want to read uncommitted records?
>>>> Uncommitted read is just fine for anything statistical.
>>>> When mining a DSS or ODS system there is no need to get exact data.
>>>> Whether someone returned a pair of shoes or not is irrelevant for trend
>>>> analysis.
>>>> Does Oracle support query sampling? If so, there you go...
>>> So IBM never recommends UR for DB2 LUW except for situations where users
>>> can tolerate wrong results (i.e data sampling ?).
>> Just like Oracle never recommends bitmap indexes in OLTP..
>> So _barring_stupidity_ I'd guess that's correct.
>> I can't warrant for 160,000 IGS employees ;-)
>>> And presumably you would advise MS users to not use UR as well ?
>> Unless they can tolerate the implication. Just like I wouldn't recommend
>> an Oracle customers snapshot isolation if their transaction must be
>> serializable.
>>> What is the default isolation level for DB2 LUW ?
>> Cursor stability (aka read committed).
>> This is also by far the most popular isolation level on DB2.
>> > What is the default isolation level for SQL Server 2005 ?
>> I have no clue. But apparently I'm on my way to becoming a SS2005 expert
>> in no time in this group. ;-)
>>>> I find it highly amusing how posters justify isolation levels based on
>>>> locking behavior.
>>>> Isolation is semantics, locking is implementation.
>>>> There are quite viable solutions for READ COMMITTED isolation level
>>>> which have the exactly same concurrency behavior as Oracle's
>>>> implementation of Snapshot Isolation.
>>> I'm sorry - but who's implementation of RC is the same as Oracle's MVRC
>>> ?
>> And here goes another twist. == Concurrency behavior <> implementation.
>> Not even <> isolation level.
>> SQL Server 2005, unless i'm gravely mistaken suppors two new twists.
>> One of them is MVRC, the other is last committed without readers blocking
>> writers.
>> The point being made (at least as I understand it) is that SQL Server's
>> IMPLEMENTATION of MVRC does not scale and is slow for unspecified reasons
>> and that last committed is a bad isolation level BECAUSE of readers
>> blocking writers.
>> So.. is there any interest in bringing the debate back to a technical
>> discussion?
>> Obviously I am not trolling for M$. I'm really interested on what folks
>> perceive as the issue.
>> Cheers
>> Serge
> > Having looked at M$'s implementation in my lab my impression is that > they have bolted MVRC on using scratch tables and huge amounts of CPU > just to be able to claim they can now do what they used to claim was > an Oracle weakness. > > The average SQL Server developer/DBA doesn't have the skill set required > to understand and use it. > > My impression is that it is there for marketing purposes only. No doubt > they will have a checkbox on a page with three columns something like > this: > > SQL Server Oracle DB2 > Tables Yes Yes Yes > Indexes Yes Yes Yes > MVRC Yes Yes No > > Followed by some nonsense pretending they have equivalent functionality. > Microsoft has never been about quality software ... rather quality > marketing. > -- > Daniel A. Morgan > > > (replace x with u to respond)
Received on Tue Feb 21 2006 - 11:44:28 CST

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