<a href="http://g.adspeed.net/ad.php?do=clk&zid=15220&wd=468&ht=60&pair=as" target="_blank"><img style="border:0px;" src="http://g.adspeed.net/ad.php?do=img&zid=15220&wd=468&ht=60&pair=as" alt="i" width="468" height="60"/></a>
Log in
::
Register
::
Not logged in
Home
Tags
Articles
Editorials
Stairways
Forums
Scripts
Videos
Blogs
QotD
Books
Ask SSC
SQL Jobs
Training
Authors
About us
Contact us
Newsletters
Write for us
<a href="http://g.adspeed.net/ad.php?do=clk&zid=15491&wd=120&ht=300&pair=as" target="_top"><img style="border:0px;" src="http://g.adspeed.net/ad.php?do=img&zid=15491&wd=120&ht=300&pair=as" alt="i" width="120" height="300"/></a>
Recent Posts
Recent Posts
Popular Topics
Popular Topics
Home
Search
Members
Calendar
Who's On
Home
»
SQL Server 2008
»
T-SQL (SS2K8)
»
ORDER BY = Bubble Sort ? Quick Sort ?...
23 posts, Page 2 of 3
««
1
2
3
»»
ORDER BY = Bubble Sort ? Quick Sort ? Insertion Sort ?
Rate Topic
Display Mode
Topic Options
Author
Message
GilaMonster
GilaMonster
Posted Friday, March 08, 2013 2:54 AM
SSC-Dedicated
Group: General Forum Members
Last Login: Yesterday @ 3:18 PM
Points: 37,744,
Visits: 30,025
karthik M (3/8/2013)
whereever the optimizer sort the data, it sould use some algorothim to do this operation? Right?
My question is simple, is there any alogrithm used for ORDER BY clause or not by the optimizer?
As I said earlier, the optimiser won't use any algorithm. The optimiser optimises queries, it doesn't run them.
Sure there will be algorithms used for order by (and for every single other operation given the definition of 'algorithm'). Why does it matter which one SQL uses?
Gail Shaw
Microsoft Certified Master: SQL Server 2008, MVP
SQL In The Wild
: Discussions on DB performance with occasional diversions into recoverability
We walk in the dark places no others will enter
We stand on the bridge and no one may pass
Post #1428467
karthik M
karthik M
Posted Friday, March 08, 2013 4:09 AM
SSCrazy
Group: General Forum Members
Last Login: Tuesday, May 21, 2013 2:56 AM
Points: 2,008,
Visits: 2,469
Why does it matter which one SQL uses?
I am asking "Out of Curiosity" to know the algorithm used by the engine.
karthik
Post #1428502
karthik M
karthik M
Posted Friday, March 08, 2013 4:10 AM
SSCrazy
Group: General Forum Members
Last Login: Tuesday, May 21, 2013 2:56 AM
Points: 2,008,
Visits: 2,469
is this a secret maintened by microsoft ?
karthik
Post #1428503
Grant Fritchey
Grant Fritchey
Posted Friday, March 08, 2013 4:20 AM
SSChampion
Group: General Forum Members
Last Login: Yesterday @ 3:41 AM
Points: 13,383,
Visits: 25,189
karthik M (3/8/2013)
is this a secret maintened by microsoft ?
Short answer, yes.
Longer answer, Microsoft publishes some of the internals because it helps people understand how or why things are occurring within the system. Also, some people figure out some of the internals through trial & error, investigation, or even putting a debugger on the system. But all the internals are not published. There are lots and lots of proprietary information that Microsoft has inside the code that they just don't feel the need to share. The exact sorting process used by the query engine (not the optimizer) is not something I've seen documentation on, so I suspect it's protected.
----------------------------------------------------
"The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood..." Theodore Roosevelt
The Scary DBA
Author of:
SQL Server 2012 Query Performance Tuning
SQL Server 2008 Query Performance Tuning Distilled
and
SQL Server Execution Plans
Product Evangelist for
Red Gate Software
Post #1428506
HowardW
HowardW
Posted Friday, March 08, 2013 4:22 AM
Ten Centuries
Group: General Forum Members
Last Login: 2 days ago @ 10:22 AM
Points: 1,037,
Visits: 7,695
karthik M (3/8/2013)
is this a secret maintened by microsoft ?
In the sense that it's proprietary information that they've chosen not to share and SQL Server is a closed source product, yes.
Post #1428508
GilaMonster
GilaMonster
Posted Friday, March 08, 2013 4:48 AM
SSC-Dedicated
Group: General Forum Members
Last Login: Yesterday @ 3:18 PM
Points: 37,744,
Visits: 30,025
karthik M (3/8/2013)
Why does it matter which one SQL uses?
I am asking "Out of Curiosity" to know the algorithm used by the engine.
So download the public symbols, attach a debugger to SQL Server and walk through what runs when you order a query.
Gail Shaw
Microsoft Certified Master: SQL Server 2008, MVP
SQL In The Wild
: Discussions on DB performance with occasional diversions into recoverability
We walk in the dark places no others will enter
We stand on the bridge and no one may pass
Post #1428519
Jason-299789
Jason-299789
Posted Friday, March 08, 2013 5:13 AM
SSC Eights!
Group: General Forum Members
Last Login: Wednesday, May 22, 2013 1:30 AM
Points: 803,
Visits: 2,124
I would suspect that there's some sort of internal algorithm used to select the best sort algorithm for a given data set, based on the data type, data volumes etc
_________________________________________________________________________
SSC Guide to Posting and Best Practices
Post #1428529
Matt Miller (#4)
Matt Miller (#4)
Posted Friday, March 08, 2013 8:23 AM
SSCertifiable
Group: General Forum Members
Last Login: Yesterday @ 8:43 PM
Points: 6,998,
Visits: 13,952
Besides - all of those sorts methods you mentioned presume a flat list structure. The internals for how tables are structured are anything but flat.
In short - I suspect the actual answer is "none of the above".
----------------------------------------------------------------------------------
Your lack of planning does not constitute an emergency on my part...unless you're my manager...or a director and above...or a really loud-spoken end-user..All right - what was my emergency again?
Post #1428602
crmitchell
crmitchell
Posted Monday, March 11, 2013 4:26 AM
SSC Rookie
Group: General Forum Members
Last Login: Wednesday, May 22, 2013 8:32 AM
Points: 48,
Visits: 201
Matt Miller (#4) (3/8/2013)
Besides - all of those sorts methods you mentioned presume a flat list structure. The internals for how tables are structured are anything but flat.
In short - I suspect the actual answer is "none of the above".
I'd tend to agree with Matt on this - my suspicion is that it will use a heavily optimised hash table in most circumstances but the only people that can give you a definitive answer would be Microsoft.
You could try asking on MSDN.
Post #1429143
Eugene Elutin
Eugene Elutin
Posted Monday, March 11, 2013 5:05 AM
SSCrazy
Group: General Forum Members
Last Login: 2 days ago @ 10:39 AM
Points: 2,556,
Visits: 4,398
Curiosity is a great thing!
Without it, elephants wouldn't have trunks...
What does the Crocodile have for dinner?...
_____________________________________________
"The only true wisdom is in knowing you know nothing"
"O skol'ko nam otkrytiy chudnyh prevnosit microsofta duh!"
(So many miracle inventions provided by MS to us...)
How to post your question to get the best and quick help
Post #1429162
« Prev Topic
|
Next Topic »
23 posts, Page 2 of 3
««
1
2
3
»»
Permissions
You
cannot
post new topics.
You
cannot
post topic replies.
You
cannot
post new polls.
You
cannot
post replies to polls.
You
cannot
edit your own topics.
You
cannot
delete your own topics.
You
cannot
edit other topics.
You
cannot
delete other topics.
You
cannot
edit your own posts.
You
cannot
edit other posts.
You
cannot
delete your own posts.
You
cannot
delete other posts.
You
cannot
post events.
You
cannot
edit your own events.
You
cannot
edit other events.
You
cannot
delete your own events.
You
cannot
delete other events.
You
cannot
send private messages.
You
cannot
send emails.
You
may
read topics.
You
cannot
rate topics.
You
cannot
vote within polls.
You
cannot
upload attachments.
You
may
download attachments.
You
cannot
post HTML code.
You
cannot
edit HTML code.
You
cannot
post IFCode.
You
cannot
post JavaScript.
You
cannot
post EmotIcons.
You
cannot
post or upload images.
Copyright © 2002-2013 Simple Talk Publishing. All Rights Reserved.
Privacy Policy.
Terms of Use.
Report Abuse.
