ETL query running very slow

  • I have a large table about 8 millions of row and my simple select statement takes more then hour to fetch the data.

    SELECT col1, col2, col3, col4, col5

    FROM datatable AS tt

    ORDER BY tt.col1, tt.col2

    I am planning to add covering non clustered index on 2 column in order by clause. Max & min memeory is et to 28 GB & 16 GB. I may not be able to change this query whic is used to compare two table data.

    Where to look at and any tips to tune it.

    Cheers,

    Got an idea..share it !!

    DBA_Vishal

  • SELECT col1, col2, col3, col4, col5

    FROM datatable AS tt

    ORDER BY tt.col1, tt.col2

    Where/What is "datatable"...is it a SQL table on your server, a table in a linked server, a table you access via ODBC...?

    Is this your complete code?....you mention ETL (Extract,Transform,Load)...are you trying to load this data into another table?

    regards gah

    ________________________________________________________________
    you can lead a user to data....but you cannot make them think
    and remember....every day is a school day

  • What are the indexes on the table?

    Have you looked at the execution plan (even estimated) as I'd guess the sort is killing performance?

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