Click here to monitor SSC
SQLServerCentral is supported by Redgate
 
Log in  ::  Register  ::  Not logged in
 
 
 


higher cpu execution time


higher cpu execution time

Author
Message
IT researcher
 IT researcher
SSC Veteran
SSC Veteran (294 reputation)SSC Veteran (294 reputation)SSC Veteran (294 reputation)SSC Veteran (294 reputation)SSC Veteran (294 reputation)SSC Veteran (294 reputation)SSC Veteran (294 reputation)SSC Veteran (294 reputation)

Group: General Forum Members
Points: 294 Visits: 1798
I have a very simple query to select all columns from a table if a particular column does not a character...but its cpu time is very high



total_cpu_time: 2953125
total_execution_count: 7
number_of_statements:1



what could be the probable reason for this ...
GilaMonster
GilaMonster
SSC-Forever
SSC-Forever (47K reputation)SSC-Forever (47K reputation)SSC-Forever (47K reputation)SSC-Forever (47K reputation)SSC-Forever (47K reputation)SSC-Forever (47K reputation)SSC-Forever (47K reputation)SSC-Forever (47K reputation)

Group: General Forum Members
Points: 47198 Visits: 44367
No idea. Not enough information.

Please post query, table definition and index definitions,


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

We walk in the dark places no others will enter
We stand on the bridge and no one may pass


Sean Smith-776614
Sean Smith-776614
SSC-Addicted
SSC-Addicted (429 reputation)SSC-Addicted (429 reputation)SSC-Addicted (429 reputation)SSC-Addicted (429 reputation)SSC-Addicted (429 reputation)SSC-Addicted (429 reputation)SSC-Addicted (429 reputation)SSC-Addicted (429 reputation)

Group: General Forum Members
Points: 429 Visits: 942
Can you share the table definition, query, and number of unfiltered rows in the table?
Lowell
Lowell
SSChampion
SSChampion (14K reputation)SSChampion (14K reputation)SSChampion (14K reputation)SSChampion (14K reputation)SSChampion (14K reputation)SSChampion (14K reputation)SSChampion (14K reputation)SSChampion (14K reputation)

Group: General Forum Members
Points: 14944 Visits: 38940
well in general, "particular column does not a character" would mean a NOT LIKE '%X%' pr PATINDEX =0, right?, so that would requre a table scan of all rows, so i'm no suprised it has a big impact; every value has to be evaluated.
that would not be Sargable, so it cannot use an index.

Lowell

--
help us help you! If you post a question, make sure you include a CREATE TABLE... statement and INSERT INTO... statement into that table to give the volunteers here representative data. with your description of the problem, we can provide a tested, verifiable solution to your question! asking the question the right way gets you a tested answer the fastest way possible!

Erland Sommarskog
Erland Sommarskog
SSC Eights!
SSC Eights! (931 reputation)SSC Eights! (931 reputation)SSC Eights! (931 reputation)SSC Eights! (931 reputation)SSC Eights! (931 reputation)SSC Eights! (931 reputation)SSC Eights! (931 reputation)SSC Eights! (931 reputation)

Group: General Forum Members
Points: 931 Visits: 866
Lowell (8/6/2013)

well in general, "particular column does not a character" would mean a NOT LIKE '%X%' pr PATINDEX =0, right?, so that would requre a table scan of all rows, so i'm no suprised it has a big impact; every value has to be evaluated.


And furthermore, it requires a full scan of every column value, which is very expensive if the full rules of Unicode must be applied. Which they must, unless any of the below are true:
1) You have a binary collation.
2) The column is varchar and you have an SQL collation.

Erland Sommarskog, SQL Server MVP, www.sommarskog.se
Go


Permissions

You can't post new topics.
You can't post topic replies.
You can't post new polls.
You can't post replies to polls.
You can't edit your own topics.
You can't delete your own topics.
You can't edit other topics.
You can't delete other topics.
You can't edit your own posts.
You can't edit other posts.
You can't delete your own posts.
You can't delete other posts.
You can't post events.
You can't edit your own events.
You can't edit other events.
You can't delete your own events.
You can't delete other events.
You can't send private messages.
You can't send emails.
You can read topics.
You can't vote in polls.
You can't upload attachments.
You can download attachments.
You can't post HTML code.
You can't edit HTML code.
You can't post IFCode.
You can't post JavaScript.
You can post emoticons.
You can't post or upload images.

Select a forum

































































































































































SQLServerCentral


Search