Solved

Query executes forever

Posted on 2013-01-25
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Last Modified: 2013-01-25
Hi all,

This gets stuck:

SELECT LATCHSTATUS FROM
      DBO.POSITION WHERE MJID = 3199 FETCH FIRST 1 ROWS ONLY      

If I change the number of rows, it returns instantly (there are no results).

Why? What am I doing wrong?

Any help is appreciated
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Question by:darrgyas
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7 Comments
 
LVL 143

Expert Comment

by:Guy Hengel [angelIII / a3]
ID: 38818326
would adding the following help your query:
OPTIMIZE FOR 1 ROW
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LVL 37

Accepted Solution

by:
momi_sabag earned 250 total points
ID: 38818372
FETCH FIRST 1 ROWS ONLY       implies OPTIMIZE FOR 1 ROW
this looks like some sort of a bug
i would try to run a reorg on the table and all the indexes and see if it solves it
0
 

Author Comment

by:darrgyas
ID: 38818476
adding OPTIMIZE FOR 1 ROW did not change anything.

Can't run reorg - there's no scheduled downtime for the table at all, it is being continuously written to.

Anything else I can try?
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LVL 143

Assisted Solution

by:Guy Hengel [angelIII / a3]
Guy Hengel [angelIII / a3] earned 250 total points
ID: 38818495
as momi_sabag indicated, this may be some bug you hit, at least that is what I saw on some forums searching for this error/problem.
if you don't see any difference in the explain plan, try FIRST 2 ROWS if that gives the same issue.
can you add a ORDER BY to the query?
what version are you using?
0
 

Author Comment

by:darrgyas
ID: 38818514
As I stated in the question, changing the # of rows gets rid of the problem, the statement executed in under a second.

 ORDER BY does not change anything.
0
 

Author Comment

by:darrgyas
ID: 38818520
I am using DB2 Express-C 9.74
0
 
LVL 37

Expert Comment

by:momi_sabag
ID: 38818733
then just change to fetch 2 rows
and in your code, only fetch one
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