Where would you use XACT_STATE

  • Hello

    Using the example provided by BOL for XACT_STATE
    With stripped out comments and print statements below

    I'm struggling to see how XACT_STATE() is used in TRY...CATCH
    As a result, I'm struggling to understand exactly why XACT_STATE is used

    BEGIN TRY
      BEGIN TRANSACTION;
     
      DELETE FROM Production.Product WHERE ProductID = 980;

      COMMIT TRANSACTION;
    END TRY
    BEGIN CATCH
      IF (XACT_STATE()) = -1
       ROLLBACK TRANSACTION;
     
      IF (XACT_STATE()) = 1
       COMMIT TRANSACTION; 
    END CATCH;
    GO

    Surely, if the transaction fails due to FK issues i.e. the transaction would be uncommitable, it would jump to the CATCH part
    If so, why is XACT_STATE even relevent
    Surely, in this instance, it will always be -1 so you will always ROLLBACK

    Appreciate, it could be 0 if the statement is non-critical e.g. SELECT ...
    In this case though, it's been specifically coded as a delete

    Suppose, I'm really trying to get a good example of exactly how/where/why XACT_STATE() is used

    Thanks

    - Damian

  • DamianC - Thursday, September 27, 2018 3:34 AM

    Hello

    Using the example provided by BOL for XACT_STATE
    With stripped out comments and print statements below

    I'm struggling to see how XACT_STATE() is used in TRY...CATCH
    As a result, I'm struggling to understand exactly why XACT_STATE is used

    BEGIN TRY
      BEGIN TRANSACTION;
     
      DELETE FROM Production.Product WHERE ProductID = 980;

      COMMIT TRANSACTION;
    END TRY
    BEGIN CATCH
      IF (XACT_STATE()) = -1
       ROLLBACK TRANSACTION;
     
      IF (XACT_STATE()) = 1
       COMMIT TRANSACTION; 
    END CATCH;
    GO

    Surely, if the transaction fails due to FK issues i.e. the transaction would be uncommitable, it would jump to the CATCH part
    If so, why is XACT_STATE even relevent
    Surely, in this instance, it will always be -1 so you will always ROLLBACK

    Appreciate, it could be 0 if the statement is non-critical e.g. SELECT ...
    In this case though, it's been specifically coded as a delete

    Suppose, I'm really trying to get a good example of exactly how/where/why XACT_STATE() is used

    Thanks

    Some of it depends on what you are using for xact_abort and if you are managing the rollback of a single statement or an entire transaction. There is a good explanation and example in the following article:
    On Transactions, errors and rollbacks

    Sue

  • You use XACT_STATE() to:
    (1) avoid attempting a ROLLBACK or COMMIT when a trans is not active
    (2) to know whether to do a ROLLBACK or COMMIT in certain cases (if it's -1, you can't COMMIT the trans, even if you want to).

    SQL DBA,SQL Server MVP(07, 08, 09) "It's a dog-eat-dog world, and I'm wearing Milk-Bone underwear." "Norm", on "Cheers". Also from "Cheers", from "Carla": "You need to know 3 things about Tortelli men: Tortelli men draw women like flies; Tortelli men treat women like flies; Tortelli men's brains are in their flies".

  • Thanks for the feedback
    Think I get this now

    Think some of the examples where a record is deleted then an audit of the deletion are better
    e.g. XACT_STATE example

    If, within a transaction, we want a deletion to occur even if the auditting fails

    SET XACT_ABORT ON first

    So, if the delete succeeds BUT the audit insert fails, it jumps to CATCH (as an error as occured)
    Here XACT_STATE() will equal 1 as we have a commitable active user transaction (the delete)
    So, this is committed and @@TRANCOUNT is reset to 0

    If both failed, XACT_STATE would be -1 as both are uncommitable
    So, this is rolled back and @@TRANCOUNT is reset to 0

    - Damian

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