RBAR is a dog - woof! need performance improvement

  • I was part of an Oracle to SQL Server (2008 R2) conversion - the Oracle stored procedures used cursors a lot

    I tried to convert to set based queries but this one stumped me - and it takes over 45 minutes to run as part of a large nightly process

    legal told me to take it down:(

  • Let's start with formatting this so we can read it.

    ALTER PROCEDURE SlowStoredProcedure @FirstCUSTNO CHAR(6) = '000000'

    ,@LastCUSTNO CHAR(6) = '099999'

    ,@LowItem VARCHAR(30) = '0'

    ,@HighItem VARCHAR(30) = 'ZZZZZ'

    AS

    BEGIN

    SET NOCOUNT ON

    DECLARE @RightNow DATETIME

    DECLARE @sum_shipqty INT

    DECLARE @not_covered_qty INT

    DECLARE @ATS_ITEM_NO VARCHAR(30)

    DECLARE @ATS_CUSTNO CHAR(6)

    DECLARE @ATS_QUANTITY INT

    DECLARE @Availats TABLE (

    ITEM_NO VARCHAR(30)

    ,CUSTNO CHAR(6)

    ,ATS_QTY INT

    ,ID INT IDENTITY(1, 1) PRIMARY KEY

    )

    DECLARE @ATS_Kount INT

    DECLARE @ATS_Row_Kount INT

    DECLARE @E_ROWID BIGINT

    DECLARE @E_REQUIRED_QTY INT

    DECLARE @E_SNR_STATUS VARCHAR(3)

    DECLARE @Temp_Table TABLE (

    REQUIRED_QTY INT

    ,SNR_STATUS VARCHAR(3)

    ,RowID BIGINT

    ,ID INT IDENTITY(1, 1) PRIMARY KEY

    )

    DECLARE @Kount INT

    DECLARE @Row_Kount INT

    BEGIN TRY

    INSERT INTO @Availats (

    CUSTNO

    ,ITEM_NO

    ,ATS_QTY

    )

    SELECT DISTINCT A.CUSTNO

    ,A.ITEM_NO

    ,OPN_QTY

    FROM AVAILATS A

    INNER JOIN ORDER_ITEMS_STAGE ESS ON A.ITEM_NO = ESS.ITEM_NO

    AND A.CUSTNO = ESS.CUSTNO

    WHERE A.CUSTNO BETWEEN @FirstCUSTNO

    AND @LastCUSTNO

    AND A.ITEM_NO BETWEEN @LowItem

    AND @HighItem

    SET @ATS_Row_Kount = @@ROWCOUNT

    SET @ATS_Kount = 1

    WHILE @ATS_Kount <= @ATS_Row_Kount

    BEGIN

    SELECT @ATS_ITEM_NO = ITEM_NO

    ,@ATS_CUSTNO = CUSTNO

    ,@ATS_QUANTITY = ATS_QTY

    FROM @Availats

    WHERE ID = @ATS_Kount

    SET @sum_shipqty = @ATS_QUANTITY

    INSERT INTO @Temp_Table (

    REQUIRED_QTY

    ,SNR_STATUS

    ,RowID

    )

    SELECT REQUIRED_QTY

    ,SNR_STATUS

    ,RowID

    FROM ORDER_ITEMS_STAGE

    WHERE ITEM_NO = @ATS_ITEM_NO

    AND CUSTNO = @ATS_CUSTNO

    AND SNR_STATUS = ''

    ORDER BY REQUIRED_DATE

    IF @@ROWCOUNT > 0

    BEGIN

    SELECT @Kount = MIN(ID)

    FROM @Temp_Table

    SELECT @Row_Kount = MAX(ID)

    FROM @Temp_Table

    END

    ELSE

    BEGIN

    SET @Kount = 999

    SET @Row_Kount = 0

    END

    WHILE @sum_shipqty > 0

    AND @Kount <= @Row_Kount

    BEGIN

    SELECT @E_REQUIRED_QTY = REQUIRED_QTY

    ,@E_SNR_STATUS = SNR_STATUS

    ,@E_ROWID = RowID

    FROM @Temp_Table

    WHERE ID = @Kount

    IF @sum_shipqty < @E_REQUIRED_QTY

    BEGIN

    UPDATE ORDER_ITEMS_STAGE

    SET REQUIRED_QTY = @sum_shipqty

    ,SNR_STATUS = 'ATS'

    WHERE ROWID = @E_ROWID

    SET @sum_shipqty = @E_REQUIRED_QTY - @sum_shipqty

    INSERT INTO ORDER_ITEMS_STAGE (list OF columns)

    SELECT list OF columns

    FROM ORDER_ITEMS_STAGE

    WHERE ROWID = @E_ROWID

    SET @sum_shipqty = 0

    END

    ELSE

    BEGIN

    UPDATE ORDER_ITEMS_STAGE

    SET SNR_STATUS = 'ATS'

    WHERE ROWID = @E_ROWID

    IF @sum_shipqty = @E_REQUIRED_QTY

    BEGIN

    SET @sum_shipqty = 0

    END

    ELSE -- @sum_shipqty > @E_REQUIRED_QTY

    BEGIN

    SET @sum_shipqty = @sum_shipqty - @E_REQUIRED_QTY

    END

    END

    SET @Kount = @Kount + 1

    END

    SET @ATS_Kount = @ATS_Kount + 1

    DELETE @Temp_Table

    END

    END TRY

    BEGIN CATCH

    DECLARE @ErrorMsg VARCHAR(MAX)

    ,@ErrorNumber INT

    ,@ErrorProc SYSNAME

    ,@ErrorLine INT

    SELECT @ErrorMsg = ERROR_MESSAGE()

    ,@ErrorNumber = ERROR_NUMBER()

    ,@ErrorProc = ERROR_PROCEDURE()

    ,@ErrorLine = ERROR_LINE();

    PRINT @ErrorMsg

    PRINT CAST(@ErrorNumber AS VARCHAR) + ' ' + CAST(@ErrorProc AS VARCHAR) + ' ' + CAST(@ErrorLine AS VARCHAR)

    PRINT @ATS_ITEM_NO + ' ' + @ATS_CUSTNO + ' ' + CAST(GetDate() AS VARCHAR)

    END CATCH

    END

    Without any idea what this is supposed to be doing or ddl or sample data we don't have a whole lot to work with here. Please take a few minutes and read the article found by following the first link in my signature.

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    Understanding and Using APPLY (Part 1) - http://www.sqlservercentral.com/articles/APPLY/69953/
    Understanding and Using APPLY (Part 2) - http://www.sqlservercentral.com/articles/APPLY/69954/

  • thank you for making the stored procedure more readable

    here's what the procedure does:

    it takes a file of Available to Ship

    with ItemNo CUSTNO and qty

    then matches to another table (I renamed it to disguise my client - I think I called it MasterOrder or something like that) on ItemNo and Custno

    then if it finds a match it marks the column SNR_STATUS with ATS

    for rows until the qty from the ATS table is all used up,

    reducing the running amount by REQUIRED_QTY

    if the REQUIRED_QTY on the last row is greater than the remaining ATS_QTY

    then it splits the Master Order table,

    writing out a record with remainder with a blank SNR_QTY

    instead of cursor(s) I pump my two tables into table variables with identity columns

    and iterate through using WHILE loops

  • Seggerman-675349 (3/12/2014)


    thank you for making the stored procedure more readable

    here's what the procedure does:

    it takes a file of Available to Ship

    with ItemNo CUSTNO and qty

    then matches to another table (I renamed it to disguise my client - I think I called it MasterOrder or something like that) on ItemNo and Custno

    then if it finds a match it marks the column SNR_STATUS with ATS

    for rows until the qty from the ATS table is all used up,

    reducing the running amount by REQUIRED_QTY

    if the REQUIRED_QTY on the last row is greater than the remaining ATS_QTY

    then it splits the Master Order table,

    writing out a record with remainder with a blank SNR_QTY

    instead of cursor(s) I pump my two tables into table variables with identity columns

    and iterate through using WHILE loops

    While loops are nothing but a cursor without any of the settings. 😉 Tough moving from Oracle where cursors are pretty fast to sql server where they are simply awful.

    There is no chance I have of helping with nothing to work with. I can't possibly write any code against tables that I don't have. This can absolutely be done in a set based manner but without ddl and some sample data it is nearly impossible.

    _______________________________________________________________

    Need help? Help us help you.

    Read the article at http://www.sqlservercentral.com/articles/Best+Practices/61537/ for best practices on asking questions.

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    Cross Tabs and Pivots, Part 1 – Converting Rows to Columns - http://www.sqlservercentral.com/articles/T-SQL/63681/
    Cross Tabs and Pivots, Part 2 - Dynamic Cross Tabs - http://www.sqlservercentral.com/articles/Crosstab/65048/
    Understanding and Using APPLY (Part 1) - http://www.sqlservercentral.com/articles/APPLY/69953/
    Understanding and Using APPLY (Part 2) - http://www.sqlservercentral.com/articles/APPLY/69954/

  • I'll second what Sean has said, but I wanted to add something.

    It is good that you have recognized that the problem is the loops and cursors. And that a set-based solution is what you'll need to speed it up.

    Now monitoring this thread so in case you can provide the DDL and sample data, maybe I too can help.


    My mantra: No loops! No CURSORs! No RBAR! Hoo-uh![/I]

    My thought question: Have you ever been told that your query runs too fast?

    My advice:
    INDEXing a poor-performing query is like putting sugar on cat food. Yeah, it probably tastes better but are you sure you want to eat it?
    The path of least resistance can be a slippery slope. Take care that fixing your fixes of fixes doesn't snowball and end up costing you more than fixing the root cause would have in the first place.

    Need to UNPIVOT? Why not CROSS APPLY VALUES instead?[/url]
    Since random numbers are too important to be left to chance, let's generate some![/url]
    Learn to understand recursive CTEs by example.[/url]
    [url url=http://www.sqlservercentral.com/articles/St

  • At least try to get rid of inner loop

    WHILE @sum_shipqty > 0.

    1.Add running total column say RT to @Temp_Table.

    2.After inserting to @Temp_Table compute RT. @Temp_Table is under your total control, so you can easily meet all the conditions and use "Quirky Update", see Jeff Moden's article http://qa.sqlservercentral.com/articles/T-SQL/68467/

    3.UPDATE ORDER_ITEMS_STAGE

    SET ...

    ,REQUIRED_QTY = CASE WHEN tmp.RT < @sum_shipqty

    THEN REQUIRED_QTY ELSE tmp.RT - @sum_shipqty END

    ...

    JOIN @Temp_Table tmp

    ON ... AND (tmp.RT-tmp.REQUIRED_QTY < @sum_shipqty )

    4. INSERT ORDER_ITEMS_STAGE ...

    SELECT ...

    FROM ORDER_ITEMS_STAGE

    JOIN @Temp_Table tmp

    ON ... AND (tmp.RT-tmp.REQUIRED_QTY < @sum_shipqty )

    AND (tmp.RT > @sum_shipqty )

    Rgds,

    Serg

  • the real AVAILATS has 40K records - and the real ORDER_ITEMS_STAGE 3 million records

    CREATE TABLE AVAILATS

    (ITEM_NO VARCHAR(30) NULL,

    CUSTNO CHAR(6) NULL,

    OPN_QTY INT NULL)

    INSERT AVAILATS VALUES('PARTNO001','000050',6)

    INSERT AVAILATS VALUES('PARTNO002','000050',4)

    INSERT AVAILATS VALUES('PARTNO003','000050',2)

    INSERT AVAILATS VALUES('PARTNO004','002999',8)

    CREATE TABLE ORDER_ITEMS_STAGE

    (ITEM_NO VARCHAR(30) NULL,

    CUSTNO CHAR(6) NULL,

    REQUIRED_QTY INT,

    SNR_STATUS VARCHAR(3),

    RowID BIGINT IDENTITY(1,1))

    INSERT INTO ORDER_ITEMS_STAGE VALUES ('PARTNO001','000050',2,'')

    INSERT INTO ORDER_ITEMS_STAGE VALUES ('PARTNO001','000050',2,'')

    INSERT INTO ORDER_ITEMS_STAGE VALUES ('PARTNO001','000050',4,'')

    INSERT INTO ORDER_ITEMS_STAGE VALUES ('PARTNO002','000050',4,'')

    INSERT INTO ORDER_ITEMS_STAGE VALUES ('PARTNO004','002999',4,'')

  • Noted REQUIRED_DATE is missing which defines the order of servicing.

  • right you are

    CREATE TABLE AVAILATS

    (ITEM_NO VARCHAR(30) NULL,

    CUSTNO CHAR(6) NULL,

    OPN_QTY INT NULL)

    INSERT AVAILATS VALUES('PARTNO001','000050',6)

    INSERT AVAILATS VALUES('PARTNO002','000050',4)

    INSERT AVAILATS VALUES('PARTNO003','000050',2)

    INSERT AVAILATS VALUES('PARTNO004','002999',8)

    CREATE TABLE ORDER_ITEMS_STAGE

    (ITEM_NO VARCHAR(30) NULL,

    CUSTNO CHAR(6) NULL,

    REQUIRED_DATE DATE NULL,

    DPAS_RTNG CHAR(4) NULL,

    REQUIRED_QTY INT,

    SNR_STATUS VARCHAR(3),

    RowID BIGINT IDENTITY(1,1))

    INSERT INTO ORDER_ITEMS_STAGE

    VALUES ('PARTNO001','000050','04/01/2014','',2,'')

    INSERT INTO ORDER_ITEMS_STAGE

    VALUES ('PARTNO001','000050','05/01/2014','RBAR',2,'')

    INSERT INTO ORDER_ITEMS_STAGE

    VALUES ('PARTNO001','000050','05/01/2014','DTOA',4,'')

    INSERT INTO ORDER_ITEMS_STAGE

    VALUES ('PARTNO002','000050','04/01/2014','',4,'')

    INSERT INTO ORDER_ITEMS_STAGE

    VALUES ('PARTNO004','002999','04/01/2014','',4,'')

  • We are getting close to an understanding. We now have the two tables (AVAILATS and ORDER_ITEMS_STAGE).

    Can you explain what should happen here. I think that what you want for Item_No PARTNO0001 is to update the SNR_STATUS to ATS for ROWIDs 1 and 2? I am not totally clear what happens with the remaining 2. Do we update ROWID3 and change the quantity to 2 and mark is at ATS as well as create a new row with a qty of 2 and status is empty?

    Also, do you do anything with the rows in AVAILATS? Do we update the OPN_QTY? If you could provide what these two tables should look like after this process runs and the business logic behind it we can help you figure this out.

    _______________________________________________________________

    Need help? Help us help you.

    Read the article at http://www.sqlservercentral.com/articles/Best+Practices/61537/ for best practices on asking questions.

    Need to split a string? Try Jeff Modens splitter http://www.sqlservercentral.com/articles/Tally+Table/72993/.

    Cross Tabs and Pivots, Part 1 – Converting Rows to Columns - http://www.sqlservercentral.com/articles/T-SQL/63681/
    Cross Tabs and Pivots, Part 2 - Dynamic Cross Tabs - http://www.sqlservercentral.com/articles/Crosstab/65048/
    Understanding and Using APPLY (Part 1) - http://www.sqlservercentral.com/articles/APPLY/69953/
    Understanding and Using APPLY (Part 2) - http://www.sqlservercentral.com/articles/APPLY/69954/

  • after the run

    ORDER_ITEMS_STAGE

    VALUES ('PARTNO001','000050','04/01/2014','',2,'ATS')

    ORDER_ITEMS_STAGE

    VALUES ('PARTNO001','000050','05/01/2014','RBAR',2,'ATS')

    ORDER_ITEMS_STAGE

    VALUES ('PARTNO001','000050','05/01/2014','DTOA',2,'ATS')

    ORDER_ITEMS_STAGE

    VALUES ('PARTNO001','000050','05/01/2014','DTOA',2,'') - inserted

    ORDER_ITEMS_STAGE

    VALUES ('PARTNO002','000050','04/01/2014','',4,'ATS')

    ORDER_ITEMS_STAGE

    VALUES ('PARTNO004','002999','04/01/2014','',4,'ATS')

    note no matching Order Item for PART003 - this is OK

  • I want to thank you guys (you are guys, right?) for all your help. I've got the running total working, now gotta get the rest of it working. I probably need to delete from @test_table rows above the first row where running total >= ship qty

  • Seggerman-675349 (3/13/2014)


    I want to thank you guys (you are guys, right?) for all your help. I've got the running total working, now gotta get the rest of it working. I probably need to delete from @test_table rows above the first row where running total >= ship qty

    Does your code have a cursor or a loop? If so, it isn't going to be any better.

    _______________________________________________________________

    Need help? Help us help you.

    Read the article at http://www.sqlservercentral.com/articles/Best+Practices/61537/ for best practices on asking questions.

    Need to split a string? Try Jeff Modens splitter http://www.sqlservercentral.com/articles/Tally+Table/72993/.

    Cross Tabs and Pivots, Part 1 – Converting Rows to Columns - http://www.sqlservercentral.com/articles/T-SQL/63681/
    Cross Tabs and Pivots, Part 2 - Dynamic Cross Tabs - http://www.sqlservercentral.com/articles/Crosstab/65048/
    Understanding and Using APPLY (Part 1) - http://www.sqlservercentral.com/articles/APPLY/69953/
    Understanding and Using APPLY (Part 2) - http://www.sqlservercentral.com/articles/APPLY/69954/

  • no, this stored procedure is running as part of a larger job run as part of a batch at night

  • Seggerman-675349 (3/13/2014)


    no, this stored procedure is running as part of a larger job run as part of a batch at night

    OK. So do you still need help? If so, what do you need?

    _______________________________________________________________

    Need help? Help us help you.

    Read the article at http://www.sqlservercentral.com/articles/Best+Practices/61537/ for best practices on asking questions.

    Need to split a string? Try Jeff Modens splitter http://www.sqlservercentral.com/articles/Tally+Table/72993/.

    Cross Tabs and Pivots, Part 1 – Converting Rows to Columns - http://www.sqlservercentral.com/articles/T-SQL/63681/
    Cross Tabs and Pivots, Part 2 - Dynamic Cross Tabs - http://www.sqlservercentral.com/articles/Crosstab/65048/
    Understanding and Using APPLY (Part 1) - http://www.sqlservercentral.com/articles/APPLY/69953/
    Understanding and Using APPLY (Part 2) - http://www.sqlservercentral.com/articles/APPLY/69954/

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