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GeneralRe: CentOS6.9 (MySql v5.7.22) use mysql C API mysql_real_query cause the memory always growing Pin
normga23-May-19 9:27
membernormga23-May-19 9:27 
GeneralRe: CentOS6.9 (MySql v5.7.22) use mysql C API mysql_real_query cause the memory always growing Pin
jschell2-Jun-19 8:25
memberjschell2-Jun-19 8:25 
QuestionBest way to batchprocess a large update Pin
Jörgen Andersson23-May-19 2:09
protectorJörgen Andersson23-May-19 2:09 
AnswerRe: Best way to batchprocess a large update Pin
Richard Deeming23-May-19 7:38
mveRichard Deeming23-May-19 7:38 
GeneralRe: Best way to batchprocess a large update Pin
Jörgen Andersson23-May-19 7:52
protectorJörgen Andersson23-May-19 7:52 
GeneralRe: Best way to batchprocess a large update Pin
Jörgen Andersson23-May-19 22:08
protectorJörgen Andersson23-May-19 22:08 
GeneralRe: Best way to batchprocess a large update Pin
Richard Deeming24-May-19 0:44
mveRichard Deeming24-May-19 0:44 
GeneralRe: Best way to batchprocess a large update Pin
Jörgen Andersson24-May-19 1:45
protectorJörgen Andersson24-May-19 1:45 
Richard Deeming wrote:
When you use the TOP clause with the UPDATE statement, there's no guarantee that the rows to update will be picked in any particular order. Using the MAX(id) option, you could end up missing rows.

I know, and you can't add an order by to an UPDATE or INSERT.
But you can put the SELECT with TOP and ORDER BY in a CTE.
Richard Deeming wrote:
I notice you've replaced the temporary table with a table variable. Was there a reason for that?

No particular reason. I like to keep the scope as local as possible, so it's mostly a habit.
Richard Deeming wrote:
IIRC, execution plans for table variables tend to assume they contain a very low number of rows, which might explain the poor performance.

Table variables don't have statistics, which obviously could affect the plan, but since all ID's are unique I don't think it would make a big difference in this case

But I will test it.

<edit>Oh, and table variables can't go parallell, which obviously can affect performance a lot in this case.</edit>
Wrong is evil and must be defeated. - Jeff Ello

GeneralRe: Best way to batchprocess a large update Pin
Jörgen Andersson26-May-19 23:17
protectorJörgen Andersson26-May-19 23:17 
AnswerRe: Best way to batchprocess a large update Pin
Eddy Vluggen24-May-19 0:04
mveEddy Vluggen24-May-19 0:04 
GeneralRe: Best way to batchprocess a large update Pin
Jörgen Andersson24-May-19 1:24
protectorJörgen Andersson24-May-19 1:24 
AnswerRe: Best way to batchprocess a large update Pin
#realJSOP29-May-19 0:43
mve#realJSOP29-May-19 0:43 
GeneralRe: Best way to batchprocess a large update Pin
Richard Deeming29-May-19 0:52
mveRichard Deeming29-May-19 0:52 
GeneralRe: Best way to batchprocess a large update Pin
#realJSOP29-May-19 1:06
mve#realJSOP29-May-19 1:06 
GeneralRe: Best way to batchprocess a large update Pin
Richard Deeming29-May-19 1:12
mveRichard Deeming29-May-19 1:12 
GeneralRe: Best way to batchprocess a large update Pin
#realJSOP29-May-19 1:20
mve#realJSOP29-May-19 1:20 
GeneralRe: Best way to batchprocess a large update Pin
Jörgen Andersson29-May-19 2:59
protectorJörgen Andersson29-May-19 2:59 
GeneralRe: Best way to batchprocess a large update Pin
#realJSOP29-May-19 5:13
mve#realJSOP29-May-19 5:13 
AnswerRe: Best way to batchprocess a large update Pin
#realJSOP29-May-19 1:14
mve#realJSOP29-May-19 1:14 
GeneralRe: Best way to batchprocess a large update Pin
Jörgen Andersson29-May-19 3:01
protectorJörgen Andersson29-May-19 3:01 
QuestionMongoDB Int Primary Key Pin
Kevin Marois17-May-19 8:41
professionalKevin Marois17-May-19 8:41 
AnswerRe: MongoDB Int Primary Key Pin
jschell18-May-19 7:09
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GeneralRe: MongoDB Int Primary Key Pin
Kevin Marois20-May-19 6:21
professionalKevin Marois20-May-19 6:21 
GeneralRe: MongoDB Int Primary Key Pin
jschell23-May-19 5:33
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QuestionMySQL Pin
Member 1437004615-May-19 3:07
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