Databases
StackOverflow2013
Postsdbo
POmerge statement duplicate key bug
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POmerge statement duplicate key bug
    primarykey
    data
    text
    <p>I thought MERGE was an atomic insert/update operation, but running a test with multiple threads calling my sproc doing upsert I am running into duplicate key constraint violation, the sproc is not all that difficult</p> <pre><code>-- @someVal, @val1, @val2, @val3 are params passed to my sproc -- nothing fancy going on there (with the params) -- where MyVal is a unique non-clustered index MERGE dbo.MyTable T USING (@someVal [SomeVal]) S ON T.MyVal = S.SomeVal WHEN MATCHED THEN UPDATE SET A = @val1 ,B = @val2 ,C = @val3 WHEN NOT MATCHED THEN INSERT (MyVal, A, B, C) VALUES (@someVal, @val1, @val2, @val3) </code></pre> <p>Yet I get the following exception, the only way to get around this has been to either remove the unique index, or add a retry into the sproc.</p> <blockquote> <p>System.Data.SqlClient.SqlException (0x80131904): Cannot insert duplicate key row in object 'dbo.MyTable' with unique index 'UIX_MyUniqueConstraint'. The duplicate key value is (03414D0B-15D2-4AFA-BB7F-7359BB95668A).</p> </blockquote> <p>When testing without the unique index, I ran a dupe check which turned nothing, confirming the upsert did what it was supposed to and no dupes were actually inserted</p> <pre><code>SELECT MyVal, COUNT(1) FROM dbo.MyTable GROUP BY MyVal HAVING COUNT(1) &gt; 1 </code></pre> <p>Is this a known bug in SQL Server 2008 R2 and prior versions, or am I doing something wrong?</p> <p>I found this <a href="http://connect.microsoft.com/SQLServer/feedback/details/434632/cannot-insert-duplicate-key-row-in-object-xxx-with-unique-index-yyy" rel="nofollow">connect issue</a> which is very similar to my issue and it appears they fixed it in SQL Server 2012 but not in prior version</p>
    singulars
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PTQuestion
    1. USJason
    1. USJason
    plurals
    1. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POmerge statement duplicate key bug
      1. USHamlet Hakobyan
      1. VTFavorite
    1. COSounds to me that your UIX_MyUniqueConstraint index and the primary key are two different columns. Which one is the merge statement using in the join. The column(s) identified in the uniqueconstraint or the column defined by the primarykey. It appears you are joining on the PK but failing on the unique key.
      singulars
      1. POmerge statement duplicate key bug
      1. USRThomas
    2. COWhy don't you post the definition for the UIX_MyUniqueConstraint?
      singulars
      1. POmerge statement duplicate key bug
      1. USNotMe
    3. COAlso, you need to specify [@val1], [@val2], [@val3] in your source statement, not just the join value.
      singulars
      1. POmerge statement duplicate key bug
      1. USRThomas
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload