SQL事务自动回滚

Posted 2021-04-08

我正在使用Storedproc，DML语句发生在Transaction中。在交易中，我们正在更新多个列，如下所示：

SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED

BEGIN TRAN

UPDATE TBLMarket SET [YR] = NULL WHERE ImportTrnId = @pi_ImportTrnId AND [YR] = ' ';
UPDATE TBLMarket SET [TYBEG] = NULL WHERE ImportTrnId = @pi_ImportTrnId AND [TYBEG] = ' ';
UPDATE TBLMarket SET [TYEND] = NULL WHERE ImportTrnId = @pi_ImportTrnId AND [TYEND] = ' ';
UPDATE TBLMarket SET [PSEQ] = NULL WHERE ImportTrnId = @pi_ImportTrnId AND [PSEQ] = ' ';
UPDATE TBLMarket SET [CTI] = NULL WHERE ImportTrnId = @pi_ImportTrnId AND [CTI] = ' ';
UPDATE TBLMarket SET [GTI] = NULL WHERE ImportTrnId = @pi_ImportTrnId AND [GTI] = ' ';
UPDATE TBLMarket SET [PTI] = NULL WHERE ImportTrnId = @pi_ImportTrnId AND [PTI] = ' ';
UPDATE TBLMarket SET [TIPR] = NULL WHERE ImportTrnId = @pi_ImportTrnId AND [TIPR] = ' ';
UPDATE TBLMarket SET [RAR] = NULL WHERE ImportTrnId = @pi_ImportTrnId AND [RAR] = ' ';
UPDATE TBLMarket SET [TMOD_E] = NULL WHERE ImportTrnId = @pi_ImportTrnId AND [TMOD_E] = ' ';
UPDATE TBLMarket SET [ATI] = NULL WHERE ImportTrnId = @pi_ImportTrnId AND [ATI] = ' ';
UPDATE TBLMarket SET [PERC] = NULL WHERE ImportTrnId = @pi_ImportTrnId AND [PERC] = ' ';
UPDATE TBLMarket SET [PPCT] = NULL WHERE ImportTrnId = @pi_ImportTrnId AND [PPCT] = ' ';
.
.
.
.
.
-----120 update statements
.
.

COMMIT TRAN

但是，当我并行运行多个事务时（我们尝试使用50个事务），我们遇到了这个错误。

“事务（进程ID 102）在锁资源上与另一个进程陷入僵局，并被选为死锁牺牲品。重新运行该事务。”

注意：每个事务都有不同的@pi_ImportTrnId，这意味着并行运行的事务永远不会尝试更新同一组行。

任何帮助/建议将不胜感激。谢谢！

答案

There are no indexes - 这就是问题所在。在ImportTrnId列上放置索引，以单语句方式重写查询，删除READ UNCOMMITTER，它将运行得很好。

UPDATE t SET
  [YR] = ISNULL(NULLIF(LTRIM(t.[YR]), ''), t.[YR]),
  [TYBEG] = ISNULL(NULLIF(LTRIM(t.[TYBEG]), ''), t.[TYBEG]),
  ...
FROM TBLMarket t
WHERE ImportTrnId = @pi_ImportTrnId