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Filter

Hi,

Since I have so many rows in DB, I try to use filter, say, ID>10, I thought it would be faster, but it is not, any ideas? thx
masterbaker
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  • masterbaker
    hi,

    Any ideas? thx
    masterbaker
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  • richardjm
    One thought is that the clustered index on the table isn't related to the ID column so a table scan has to be performed. Have a look at the execution plan for a select columns from table where ID > 0 to see which indexes are being used and how.

    That's for starters anyway.

    HTH

    :)
    richardjm
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  • masterbaker
    This is the structure I have:
    TableA:
    AID (Clustered PK)
    some fields


    TableB:
    BID (Clustered PK)
    AID
    some fields

    Inside the filter, I use AID >= 100 for both tables, it is slow because AID in TableB is not Clustered PK? thx
    masterbaker
    0
  • richardjm
    I would have thought that will be the issue in TableB certainly. The server has to scan all the rows to determine if or not a the row has an AID > a certain value. Whereas for TableA it can just get a chunk of the table and use that immediately.
    richardjm
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