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

You still haven't answered Serge's question about backing up your claims,
here are just some of your quotes from this thread....

"inferior implementation"
"Writers block readers and readers block writers in SQLServer. There is no
getting around this fundamental issue and because of it SQL Server
will always be fundamentally a completely inferior product"
"Well, that isn't an application, so, sure, deadlocks can happen."
"My biggest issue with this is that SQLServer has just implemented this.
I have no idea how well it works, and I have no trust that it actually
is a solid implementation. "

This is what I've taken issue with, lets go back to your quotes and ask you
to back up your statements with technical fact.....

"inferior implementation"

What parts of the design are inferior and why? Point to some benchmarks, or
at the very least post the SQL you used to test; note: Daniel has not done
this when asked.

Don't post hear-say or your feeling (probably based on no knowledge).

"Writers block readers and readers block writers in SQLServer. There is no
getting around this fundamental issue and because of it SQL Server
will always be fundamentally a completely inferior product"

This is completely un-true which is why I took issue, I am not saying SQL
Server is better than Oracle or the other way round, SQL Server has an
implementation that is up-to-date with current thinking and technology and
is not based on what the current thinking was 20 years ago.

Please shown me where it states that SQL Server 2005 blocks readers and
there is no getting round this fundemental issue.

"Well, that isn't an application, so, sure, deadlocks can happen."

With the deadlocks, again, we danced around a bit there until you finely
admitted they can happen in Oracle, I guess Oracle should never been used
with anything that might send adhoc queries against the database, like, say
a reporting application, an application with a dynamic search front end
etc...

"My biggest issue with this is that SQLServer has just implemented this.
I have no idea how well it works, and I have no trust that it actually
is a solid implementation. "

The beta program was around 3 years long (alpha to final beta), also, there
where 100,000's of developers, dbas etc... who installed and used the beta,
actually its probably a lot more, the SQL 2005 Express had around 40,000
downloads in one month tail end of last year; also, there where a lot of
significant companies go live with 2005 at rtm, one such one is a major
retail bank here in the UK - Nationwide Building Society.

Please give me references that back up your 'big issue', aside from Daniel
who hasn't backed it up either by posting DDL and SQL he was using (if he
ever did).

----

As to isolations, SQL Server implements all transaction isolations required
by the ANSI standard, I keep asking - does Oracle? - nobody has answered
except some ranting dissing the ANSI SQL standard (why am I not suprised
there, you guys like to keep it complicated so you can't easily move to
another platform)!

Just because you have been sucked into the Oracle isolation religion, a
religion that was started around 20 or 30 years ago doesn't mean we should
follow; I've been developing for 19 years now, started out on the mainframe
with DB2 for about 5 years. There are plenty of reasons to use each
isolation level but you will always disagree because you follow doctorine
and probably don't have any real rdbms experience aside from Oracle! Whereas
I guess SQL Server and DB2 guys implement what the business requires rather
than what the Oracle engine wants.

An example of Read Uncommitted would be getting the cardinatlity of a column
in a million row table, you want a value between 0.00 and 1.00 as to
uniqueness where unique is 1, this would be used for say the optimiser in
working out a query plan. You are not after a definitive reply from your
dataset but just a roundabout idea of the cardinatlity.

Another example is, depending on how you implement the queue, the statistics
of a call centre - where the business requirement is just an indiciation of
how many callers are waiting, it doesn't need to be exact because its for
the board in the call centre as a motiviator to the call centre staff to
answer calls quicker.

I'm not holding my breath, because you follow doctorine you won't agree with
the above but thats your religion rather than sound technical based reasons
based around the business requirements.

--
Tony Rogerson
SQL Server MVP
http://sqlserverfaq.com - free video tutorials


"Galen Boyer" <galen_boyer@xxxxxxxxx> wrote in message
news:uirr91hl4.fsf@xxxxxxxxxx
On Mon, 20 Feb 2006, srielau@xxxxxxxxxx wrote:
On 19 Feb 2006, galen_boyer@xxxxxxxxx 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.

Okay,

This doesn't answer what was really my question, which is, when would
someone want to read uncommitted records _in a transactional
environment_. I guess the question should have been more exact, but I
thought the thread was quite explicitly already in that context.



Whether someone returned a pair of shoes or not is irrelevant for
trend analysis.
Does Oracle support query sampling? If so, there you go...

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.
Declaring them worse or inadequate merely by virtue of not being
the same is pretty intolerant.

I know a bit about Oracle's implementation of snapshot isolation.
apparanetly there are posters here who believe they can compare
it to what MS has delivered. None of them, so far, has justified
their claims on lack of scalability (beyond "it's new", it can't
be trusted).

True, and Tony can't justify any of his thoughts other than to say, MS
has caught up with Oracle. We are both working from expertise compiled
mostly from the particular arguments side. But, my arguments have never
been trying to state the inner-workings of SQLServer, because I would
never try to show myself as that level of an expert, but I do know that
SQLServer has always had the issue that writers block readers and
readers block writers, while Oracle has never had this problem. This is
a fundamental issue, which still is not clear that SQLServer has solved.
Why is this? Because one has to ask for this new isolation level that
Tony is touting as "having caught up with Oracle". If it did catch up
MS to ORacle, then how come it is not the default. When would anyone
want writers to block readers or readers to block writers (Another
fundamental question I submit to Tony which can be in any environment,
transactional or not,)

Care to cough up some hard facts? Given that SQL Server 2000 is 6
years old and any Oracle product that age has been called
"neolithic" by some posters in this group, it is much more
interesting to compare the here and now that the history of any
vendors perceived shortcoming.

So why is SQL Server 2005's implementation of Snapshot isolation bad?

It is the fact that SQL Server has to even have this as an optional
implementation is what shows it to be bad in the first place. This
should be the default and no other implementation should be allowed.

Here is a snippet from an opening paragraph.

SQL Server 2005 introduces a new "snapshot" isolation level that is
intended to enhance concurrency for online transaction processing
(OLTP)
applications. In prior versions of SQL Server, concurrency was based
solely on locking, which can cause blocking and deadlocking problems
for
some applications. Snapshot isolation depends on enhancements to row
versioning and is intended to improve performance by avoiding
reader-writer blocking scenarios.

Sounds almost like what Oracle does right out of the box and the correct
scenario of only showing the committed rows. Okay great! So they
caught up with Oracle? Having read the basics of implementation, it
almost seems like they tried to use tempdb in the same manner that
Oracle uses rollback segments, XSN is analogous to SCN. Well, how come
one has to set an isolation level to get this? Why isn't it the default
that everything else is built on?

Again, when would one ever want to see committed rows in a transactional
environment? If the answer is never, then this implementation should be
the default, but since it isn't there must be sometime when a user would
want to see uncommitted records during the middle of a transaction, or
maybe there is some other reason, having to do with performance, or
scalability, or usability, or ...

--
Galen Boyer


.

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