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Tricks how to deal with Microsoft SQL Server (MS-SQL).

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Featured Article

How can I simulate a deadlock for testing purposes?

Question:

How can I simulate a deadlock for testing purposes?

Answer:

Below is a quick recipe for a dead lock. Two transactions, one first updating table 1, then 2 and the other one doing it in reverse order.

Both transactions wait in the middle for 20 seconds to give you some time to execute them 'simulaneously'.

When you run the two in transactions in two windows 'at the same time', you'll only have to wait ~20 seconds, and one of the windows will experience a dead lock.

CREATE TABLE t1 (i int);
 CREATE TABLE t2 (i int);
 
 INSERT t1 SELECT 1;
 INSERT t2 SELECT 9;
 
 
 /* in one window enter: */
 BEGIN TRAN
 UPDATE t1 SET i = 11 WHERE i = 1
 WAITFOR DELAY '00:00:20'
 UPDATE t2 SET i = 99 WHERE i = 9
 COMMIT
 
 /* in a second window (another transaction) enter: */
 BEGIN TRAN
 UPDATE t2 SET i = 99 WHERE i = 9
 WAITFOR DELAY '00:00:20'
 UPDATE t1 SET i = 11 WHERE i = 1
 COMMIT

Most recent comments

2010-03-16 19:56:06:
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These scammer are realy stupid, they don't even change the content their send, what they did just copy and send

2010-03-16 19:28:04:
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hello ladys i sorry you got taken by this man I got taken to. he took my money and heart he promise he would come if i send mony. why do he do this?. i dont know. I wonder.? so he dont get more women ... read more

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[quote]Tatiana
tanya_angel
KishineMoldova[ /quote]

[r>[quote]Engli( Fluent)[/quote]

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Anna,
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2010-03-16 17:04:45:
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2010-03-16, 14:31:46
anonymous

{ I am curious. Does anyone no if a girl by the name of Evelyn James is a scammer. She says she is from Lagos Nigeria. }

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2010-03-16 16:50:58:
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on Dating scammer Nancy Milman from Accra, Ghana:

2010-03-16, 14:47:15 Page # 177
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Hello Your request for Help trying to find out if She is a scammer
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2010-03-16 15:23:47:
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2010-03-16 15:11:09:
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