User talk:Chris Purcell

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[edit] Welcome!

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[edit] Snapshot isolation (bias?)

Is it necessary to list some of the RDMS that implement Snapshot isolation? It's a horribly incomplete list, for example MS Sql Server implements it. Having an incomplete list looks like a bias to me. --Blowdart 18:23, 3 April 2006 (UTC)

That's just incomplete knowledge on my part. Please do add more. Taking it out may create the false impression that SI is only a theoretical tool, and not of practical use.

I took the list from Multiversion concurrency control, removing MySQL as I don't know whether the InnoDB engine implements only SI or is truly serializable. Should SQL Server be added there, too? --Chris Purcell 18:29, 3 April 2006 (UTC)

Oh heavens yes, SQL Server has had snapshot isolution since at least 6.5 :) This does bring the argument around listing software like this, as missing software out may give a false impression (?) --Blowdart 18:31, 3 April 2006 (UTC)

No, I don't think that's right. SQL Server had something that it called snapshot isolation in 6.5, but it wasn't actual snapshot isolation! To my knowledge it didn't get real snapshots until it got MCC in 2005. I don't recall the particulars, but ISTR that if you deleted a record from another transaction it would disappear inside the "snapshot." --Craig Stuntz 19:37, 3 April 2006 (UTC)

Ah yes, I see the list in Multiversion concurrency control. I've added Microsoft Sql Server to it, and the Snapshot isolation page. MS Sql Server did only get MCC in 2005 though. --Blowdart 18:36, 3 April 2006 (UTC)

Technically, Axion should be on the list, too. However, I don't see a WP page for it. I think "such as" should be an indication to the enterprising reader that a list does not aim for completeness ;) --Chris Purcell 18:40, 3 April 2006 (UTC)

I object to being labelled as not enterprising :p --Blowdart 18:43, 3 April 2006 (UTC)

Heheh :) Thanks for the peer review. Pretty fast, too! I'd barely had time to reload the page before you commented... --Chris Purcell 18:44, 3 April 2006 (UTC)

[edit] Wikiproject Computer science

Hi Chris, and welcome to WikiProject Computer science! Glad to have someone else with an interest in concurrency onboard (although my own interests lie more in the area of process algebras than lock-free data structures). --Allan McInnes (talk) 16:36, 4 April 2006 (UTC)