[dba-VB] vb.net - Updates

jwcolby jwcolby at colbyconsulting.com
Wed Apr 30 12:32:45 CDT 2008


It started returning results in about 12-13 seconds.  You are asking for 
96 thousand result rows you realize.  This database is 96 million rows, 
so every thousandth row is 96K rows.

It is still processing at 9 minutes.  I'll email the final execution 
time whenever the query finishes.

This is fascinating because I pull just the fields into an ADO.Net table 
for 100K rows in just a second or two.  Of course these are consecutive 
rows, it is not scanning the entire table.

John W. Colby
www.ColbyConsulting.com


Shamil Salakhetdinov wrote:
> Hi John,
> 
> May I ask you to run this query (e.g. in MS SQL Management Studio) against
> your huge db table?
> 
> --- cut here ---
> 
> SELECT RowNum, PKID from  ( select  
> 	Cast(ROW_NUMBER() over (ORDER BY [PKID]) as int) as RowNum, 
> 	PKID, OWNERNAME, FName, MName, LName, NamePrefix, 
>     NameSuffix, Gender from [Names]) s  
> 	where (s.RowNum % 1000) = 1 
> union all
> Select NULL as RowNum, Max(PKID) as PKID from [Names]
> 
> --- cut here ---
> 
> M.B. [Names] have to be substituted with the name of your table - what is it
> BTW?
> 
> This query returns PKID of every 1000th row sorted by PKID + MAX(PKID)....
> 
> I'm curious to know how much time approx. this query will take to execute...
> 
> Thank you.
> 
> --
> Shamil
> 
> P.S. BTW, here is a useful for your case article on multi-threading
> (practical solution) with good introduction -
> http://www.dotnetjunkies.com/Tutorial/D7E688B8-0BDD-4D44-9A0F-4CD26FB35F51.d
> cik 
> 
> Sorry, I can't react promptly on your messages in this discussion thread: a
> lot of custom work here, long weekends and our time zones difference but I
> do continue to work in this direction and if I get some useful  results I
> will post them here...
> 
> P.P.S. This book could be also useful:
> 
> C# Threading Handbook 
> by Tobin Titus et al.   
> 
> ISBN:1861008295 
> 
> APress, LLC C 2004 (288 pages) 
> 
> This book addresses the fundamental units of Windows and .NET
> programming-threads. Coverage includes how .NET applications are executed,
> the life cycle of a thread in .NET, how the .NET Framework uses threads, and
> more.
> 
> 
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> 
> 



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