Hash Join

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Hash Join

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serg-52 SSCrazy Eights Points: 9913 More actions · Answer 1

Hardly can imagine adding UNIQUE on a column just becase the column takes part in some join.

Dana Medley SSCertifiable Points: 6764 More actions · Answer 2

DugyC (2/20/2012)
Ah! the disappointment of thinking you've done really well and ticked all the right boxes to then be told you are wrong!... however, faith can then be restored by clicking on Join the discussion and finding that you were right after all.
Phew 😀

+ 1. And here I thought Monday was gonna start bad. 🙂

Everything is awesome!

mtassin SSC-Insane Points: 23099 More actions · Answer 3

now it seems to select all of them.

Except the linked article doesn't mention anything about uniqueness constraints.

--Mark Tassin
MCITP - SQL Server DBA
Proud member of the Anti-RBAR alliance.
For help with Performance click this link[/url]
For tips on how to post your problems[/url]

Rich Weissler Hall of Fame Points: 3286 More actions · Answer 4

Kameswari Aravindh (2/20/2012)
:crying:I want my Points back

<AOL Mode> ME TOO! </AOL Mode> 😉

(But really, the reading I did before answering made it all worth while! Thank you for the question.)

mtassin SSC-Insane Points: 23099 More actions · Answer 5

mtassin (2/20/2012)
now it seems to select all of them.
Except the linked article doesn't mention anything about uniqueness constraints.

Actually, no I just misread it.

Make sure that statistics exist on the columns that are being joined or grouped., If statistics exist on the columns, update them., Use a different type of join. For example, use a MERGE or LOOP join instead, if appropriate., Apply Unique key constraint on the column.

Except that this link. http://technet.microsoft.com/en-us/library/ms190736.aspx says this

Make sure that statistics exist on the columns that are being joined or grouped.
If statistics exist on the columns, update them.
Use a different type of join. For example, use a MERGE or LOOP join instead, if appropriate.
Increase available memory on the computer. Hash recursion or bailout occurs when there is not enough memory to process queries in place and they need to spill to disk.

Which I was proud that I had actually figured out the right answers for this (once I read what a hash bailout is).

--Mark Tassin
MCITP - SQL Server DBA
Proud member of the Anti-RBAR alliance.
For help with Performance click this link[/url]
For tips on how to post your problems[/url]

dawryn SSCertifiable Points: 5481 More actions · Answer 6

:ermm: Another question somebody should proofread before posting :sick:

Unique constraint seemed false to me at a glance :unsure: so I searched a bit and found the same article that is given as reference :hehe:

Result has been :pinch: a big surprise :doze:

EL Jerry SSCertifiable Points: 7063 More actions · Answer 7

Hi!!! After thorough reading and searching I found and selected the right answers based on the same referenced article, just to find out they were wrong?

Looks to me that the question is incorrectly configured, so can you guys who contribute make sure this does not happen?

Thanks in advance,

"El" Jerry.

"A watt of Ottawa" - Gerardo Galvan

To better understand your help request, please follow these best practices.[/url]

JanR SSCrazy Points: 2812 More actions · Answer 8

I want my point !!!

Can you prepare task correctly? 🙁

Ron McCullough SSC Guru Points: 63877 More actions · Answer 9

EL Jerry (2/20/2012)
Hi!!! After thorough reading and searching I found and selected the right answers based on the same referenced article, just to find out they were wrong?
Looks to me that the question is incorrectly configured, so can you guys who contribute make sure this does not happen?
Thanks in advance,
"El" Jerry.

I am reasonably sure the contributor thought his contribution and the answers selected as correct were correct.

I believe it is the responsibility of some one at REDGATE to execute the submitted QOD and approve or disapprove its being published. I have had that happen to a couple of my submittals. Now just who that person(s) is or are is not know to myself.

I do know that Steve Jones will review these comments and the correct/incorrect answers and will "make things right/award points" if he deems it appropriate.

If everything seems to be going well, you have obviously overlooked something.

Ron

Please help us, help you -before posting a question please read[/url]
Before posting a performance problem please read[/url]

Steve Jones - SSC Editor SSC Guru Points: 736524 More actions · Answer 10

Apologies. The wrong item checked. 1,2,3,5 are correct.

Points awarded back

Ken SSCoach Points: 17191 More actions · Answer 11

I was surprised to see 100% right (297 correct, 1 incorrect). So I figured there must have been an issue with the question and that points were awarded back. Glad to see that I picked the correct answers anyway after Steve edited the question and awarded points back.

Britt Cluff SSCertifiable Points: 5083 More actions · Answer 12

Thanks for the question.

http://brittcluff.blogspot.com/

EL Jerry SSCertifiable Points: 7063 More actions · Answer 13

Thank you, Steve, I understand this can happen every once in a while.

Regards,

"El" Jerry.

"A watt of Ottawa" - Gerardo Galvan

To better understand your help request, please follow these best practices.[/url]

Cliff Jones SSChampion Points: 10547 More actions · Answer 14

I have never seen the term Grace Hash Join before and I have been doing this for a long time. Is it named for Grace 'The Great' Hopper per chance?

sandippani SSC Eights! Points: 957 More actions · Answer 15

Thanks Steve for the correction.

Thanks,

Sandip

http://sqlcommitted.com