June 6, 2014 at 8:43 am
Koen Verbeeck (6/6/2014)
I think I have finally met the "exception on the rule" for SELECT *.Select on an Oracle view with all the of the columns in the SELECT clause: 36 minutes (for 250,000 rows. Unfortunately I have no control over the view definition). SELECT * on same view: 2 minutes 50 seconds.
I am not kidding.
I talked with the Oracle DBA and he confirmed there are 2 different execution plans. The fast one is with nested loops, the second one with hashing.
He thinks that the SELECT * is faster because Oracle doesn't have to touch every table mentioned in the view to see if one of the selected columns is in there. When all the columns are explicitly mentioned, he has to check every table. Somehow this results in a vastly different execution plan.
I have seen the same behavior in very wide denormalized tables in SQL Server. I wrote a blog post about it.
Jason...AKA CirqueDeSQLeil
_______________________________________________
I have given a name to my pain...MCM SQL Server, MVP
SQL RNNR
Posting Performance Based Questions - Gail Shaw[/url]
Learn Extended Events
June 6, 2014 at 3:05 pm
Impromptu announcement-of-not-too-much-note time, I suppose!
Decided to switch my posting name from one of my usual online aliases to my own name. Read Brad McGehee's book on becoming an exceptional DBA, and online branding was a pretty healthy focus.
I figured it couldn't hurt, and I registered for the site under my pseudonym since I figured I wouldn't get too involved with it. Well, that changed a decent bit :-).
So, err, I guess this is part where I should make the remark that I'm Andrew, and I'm a SQLHolic :-P.
Well, back to the regularly scheduled activity of The Thread 😀
- 😀
June 6, 2014 at 3:32 pm
Andrew Kernodle (6/6/2014)
So, err, I guess this is part where I should make the remark that I'm Andrew, and I'm a SQLHolic :-P.
HI ANDREW!!! 😛
--Jeff Moden
Change is inevitable... Change for the better is not.
June 6, 2014 at 3:57 pm
Hi Andrew!
Could you remind me your previous username? My ADHD won't let me remember. 😀
June 6, 2014 at 4:08 pm
Oh great, now I look at my previous post and I notice I didn't even mention that part :-P. I'm the poster previously known as hisakimatama! Clearly my faulty memory is a result of me ingesting too much SQLhol in the last hour 🙂
- 😀
June 8, 2014 at 7:07 am
Okay, I really need to step away from this person:
Welsh Corgi (6/8/2014)
Lynn Pettis (6/7/2014)
Welsh Corgi (6/7/2014)
That is sweet. I have the sizes stored in KB's. What statement could I used to convert from KB to GB?Thanks a bunch!
Divide twice by 1024.0.
Syntax please? :unsure:
< RANT >
Really, you need someone to actually spell this out for you?
Joined: 2/18/2005 10:38:00 AM (4,213 visits since) and still can't do simple queries??
You have been working with SQL Server for over 9 years, this should be second nature by now.
< /RANT >
June 8, 2014 at 2:36 pm
Lynn Pettis (6/8/2014)
Okay, I really need to step away from this person:Welsh Corgi (6/8/2014)
Lynn Pettis (6/7/2014)
Welsh Corgi (6/7/2014)
That is sweet. I have the sizes stored in KB's. What statement could I used to convert from KB to GB?Thanks a bunch!
Divide twice by 1024.0.
Syntax please? :unsure:
< RANT >
Really, you need someone to actually spell this out for you?
Joined: 2/18/2005 10:38:00 AM (4,213 visits since) and still can't do simple queries??
You have been working with SQL Server for over 9 years, this should be second nature by now.
< /RANT >
Wut? This seems inbelievable.
Need an answer? No, you need a question
My blog at https://sqlkover.com.
MCSE Business Intelligence - Microsoft Data Platform MVP
June 9, 2014 at 2:21 am
Koen Verbeeck (6/8/2014)
Wut? This seems inbelievable.
Not the first time I've seen that kind of thing from that person.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
June 9, 2014 at 5:31 am
I saw that exact post over the weekend and had to look at it twice to make sure I wasn't missing something. I too was in disbelief.
June 9, 2014 at 5:48 am
Koen Verbeeck (6/8/2014)
Lynn Pettis (6/8/2014)
Okay, I really need to step away from this person:Welsh Corgi (6/8/2014)
Lynn Pettis (6/7/2014)
Welsh Corgi (6/7/2014)
That is sweet. I have the sizes stored in KB's. What statement could I used to convert from KB to GB?Thanks a bunch!
Divide twice by 1024.0.
Syntax please? :unsure:
< RANT >
Really, you need someone to actually spell this out for you?
Joined: 2/18/2005 10:38:00 AM (4,213 visits since) and still can't do simple queries??
You have been working with SQL Server for over 9 years, this should be second nature by now.
< /RANT >
Wut? This seems inbelievable.
Which one - Lynn staying away, or the asking for clarification? 😛
Both are a bit surprising, although not exactly shocking.
Sometimes a quick glance and quick reply leads to some interesting online exchanges.
June 9, 2014 at 8:50 am
Corgi's trolling, just ignore. Not a new developer, he/she will figure it out.
Curious, is the TITD actually a TITD now?
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How best to post your question[/url]
How to post performance problems[/url]
Tally Table:What it is and how it replaces a loop[/url]
"stewsterl 80804 (10/16/2009)I guess when you stop and try to understand the solution provided you not only learn, but save yourself some headaches when you need to make any slight changes."
June 9, 2014 at 9:47 am
jcrawf02 (6/9/2014)
Corgi's trolling, just ignore. Not a new developer, he/she will figure it out.Curious, is the TITD actually a TITD now?
Not really. Could be if I slept in transient quarters. Glad I don't.
June 10, 2014 at 9:09 pm
Lynn Pettis (6/9/2014)
jcrawf02 (6/9/2014)
Corgi's trolling, just ignore. Not a new developer, he/she will figure it out.Curious, is the TITD actually a TITD now?
Not really. Could be if I slept in transient quarters. Glad I don't.
I envision the TITD to be something like this:
http://somedayillbethere.com/wp-content/uploads/2013/01/desert-camp.jpg
Wayne
Microsoft Certified Master: SQL Server 2008
Author - SQL Server T-SQL Recipes
June 13, 2014 at 6:23 am
Awful quiet in here over the last couple days...
Should we turn out the lights on this thread?
:hehe:
June 13, 2014 at 6:28 am
jasona.work (6/13/2014)
Awful quiet in here over the last couple days...Should we turn out the lights on this thread?
:hehe:
Why not? I could use some sleep 🙂
Need an answer? No, you need a question
My blog at https://sqlkover.com.
MCSE Business Intelligence - Microsoft Data Platform MVP
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