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Message Posted: Mon, 14 Mar 2005 @ 22:11:30 GMT


     
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Subj:   Re: TPump Update
 
From:   Prescott, Kyle R

Bill,

Have you explained the update statement with the input data type? What is your UPI data type? I have seen locking issues where the locking is at the table level unless the input data is the same data type as UPI/NUPI column.

The utility VARTEXT input data format may be contributing to the locking. The explain output should show a write lock on the table vs. row- level.

--If the TransactionControlNumber is numeric (decimal/integer/etc.) and the input data is character

     explain
     using (TCN  VARCHAR(17)
           )
     UPDATE xxxx.claimheader
            Set FinalVersionInd = 'N'
      Where TransactionControlNumber = :TCN;

     --should see similar explain output for all-amp full table lock
       1) First, we lock xxxx.claimheader for write.

-- Vs. the TransactionControlNumber is numeric (decimal/integer/etc.) and the input data is also numeric

     explain
     using (TCN  decimal(15,0)
           )
     UPDATE xxxx.claimheader
            Set FinalVersionInd = 'N'
      Where TransactionControlNumber = :TCN;

     --should see similar explain output for row-level lock
       1) First, we do a single-AMP RETRIEVE step from xxxx.claimheader
          by way of the unique primary index "xxxx.claimheader.TransactionControlNumber = :TCN"
       2) Next, We do a single-AMP MERGE into xxxx.claimheader from
          Spool 2 (Last Use).
       3) We do a single-AMP UPDATE from xxxx.claimheader by way of the
          unique primary index "xxxx.claimheader.TransactionControlNumber = :TCN" with no residual conditions.

Kyle Prescott
UnumProvident, Data Strategies 3-S



     
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