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

> And how do you handle things when both applications
> have to update and read the same table?

The business requirement might be your POS terminal inserting transactions and updating stock levels into your database and a second reporting application aggregating your data to give a point in time state of your business - for instance, a call centre number in queue, or for POS, might be number of customers, current days take etc...

This will do the same default behaviour as Oracle..

You would set the database options (once) to allow this functionality....

SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN SELECT.... (note, this will not block even if other connections are updating the rows you want)

UPDATE .... COMMIT If another connection has updated the row the update will fail correctly (you don't want your update to be overwritten), but other writers won't block readers which is what you guys keep saying can only happen in SQL Server.

Or, if you to wait on update...

SET TRANSACTION ISOLATION LEVEL READ COMMITTED SELECT .... (will not block, you will get the last committed value)

UPDATE... (writer will block writer)

Anyway, I'm done here; you guys believe what you want; the reality is different!

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


"Noons" <wizofoz2k_at_yahoo.com.au> wrote in message 
news:1140346663.923760.33420_at_o13g2000cwo.googlegroups.com...


> Tony Rogerson wrote:

>>

>> How do you do this in Oracle then?

>>

>

> You don't.  Period.  Read the manuals,

> it's basic stuff.

>

>> You have two applications, one requires you to implement the ANSI 

>> standard:

>> snapshot isolation and the other the ANSI standard: read committed.

>

> Really?  One of them is a POS, for starters.

> And how do you handle things when both applications

> have to update and read the same table?

> Or is the world black and white only, with SS?

>

>

>> That's why they have engineered it to allow you to choose the isolation

>> level you want.

>

> You can chose until the cows come home, it

> still won't make it right.

>