SQL View/Table question

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  • WertmanTheMad

    SQL View/Table question

    MVP's and the like

    I am looking for suggestions , confirmation

    Let me start by saying bar none, performance is paramount with the
    queries to be retured off this view/table query.

    To that end I am completley donormailzing the data into a view (or a
    table) with all possible legal combinations ( I have seen this reffered
    to as Croation Method ?) Its ends up at 3 total rows per account on
    average.

    THis query is to be executed only from the web, so once again the
    performance is paramount.

    Ok here is what I have so far I have a set of related tables 5 or so
    that are for the most part 1 to 1 but in the case of one particular
    table its an average raqtion of 20 to 1.

    Broken all out with 150k customer rows it ends up at 500k total rows in
    the view

    About 7 cols are dynamic aggregates (Sum(tran_AMT)) , min(tran_amt) ,
    etc

    I had it in a view and with 1/5 million rows (In the view) it performed
    adequatley, I will most likeley get to somewhere around 10 million
    total rows (In the view)

    I looked into indexing it but thats not going to happen because I am
    doing several subquery's , outer joins etc.

    The View with a Select * returns in 40 Seconds

    Now i ran into an issue with recursing this query into several seperate
    subqueries and hit the 256 table limit, after only about 15 recursions.

    Now the data only gets updated once , perhaps twice a day, in a batch
    transaction.

    So I Put all the data from the view into a table, and indexed that, I
    can return all rows in 12 seconds and any refining conditions I throw
    at it, like Date > 12/1/2003 (then it executes in under 6 second_ only
    slices the query time down big time (A very good thing)

    Since its only updates 2x a day I drop and recreate the table in my DTS
    , and I have triggers on the other tables for Online updates (usually
    no more that 100 a day) but to ensure the table is ALWAYS current it
    gets recreated on import of additional rows.

    Is there a name to this maddness ? My co-workers aree leary of it but
    they come from a dbase background, denomailzing it into a table and
    then indexing the table I couldnt be happeier with ther performance.

    Are there any lurking gremlins in this design ?

    I cannot see any pitfalls with doing this , or are there some ?,
    basically I am denomailizing for read-only query performance.

    They are concerned about the denorilization for performance, even
    though its only on a read only table (was and could be a view I just
    cant index this particualr view)

    So I guess Im looking for a , "Sounds OK" or "Sounds Great" from the
    SQL Gods ....

    Chris

  • Erland Sommarskog

    #2
    Re: SQL View/Table question

    WertmanTheMad (cwertman@webch amps.com) writes:[color=blue]
    > Since its only updates 2x a day I drop and recreate the table in my DTS
    > , and I have triggers on the other tables for Online updates (usually
    > no more that 100 a day) but to ensure the table is ALWAYS current it
    > gets recreated on import of additional rows.
    >
    > Is there a name to this maddness ? My co-workers aree leary of it but
    > they come from a dbase background, denomailzing it into a table and
    > then indexing the table I couldnt be happeier with ther performance.
    >
    > Are there any lurking gremlins in this design ?
    >
    > I cannot see any pitfalls with doing this , or are there some ?,
    > basically I am denomailizing for read-only query performance.
    >
    > They are concerned about the denorilization for performance, even
    > though its only on a read only table (was and could be a view I just
    > cant index this particualr view)[/color]

    There is too little information in your post, to give any absolute blessing
    to this. But with the outline you give - source data updated twice,
    aggregating the data into a read-only table could very well be the winner.

    The alternative would be to look into the underlying query, and see if
    indexes etc can be improved. Without knowledge about the table and the
    queries, I cannot say whether this is workable or not.


    --
    Erland Sommarskog, SQL Server MVP, esquel@sommarsk og.se

    Books Online for SQL Server SP3 at
    Get the flexibility you need to use integrated solutions, apps, and innovations in technology with your data, wherever it lives—in the cloud, on-premises, or at the edge.

    Comment

    • WertmanTheMad

      #3
      Re: SQL View/Table question

      > The alternative would be to look into the underlying query, and see
      if[color=blue]
      > indexes etc can be improved. Without knowledge about the table and[/color]
      the[color=blue]
      > queries, I cannot say whether this is workable or not.[/color]

      Yeah, unfortunatley there are about 10 subqueries in the view and 5 or
      so outer joins, Indicies on the View are a No-Go hence I ended up here.

      Erland Sommarskog wrote:[color=blue]
      > WertmanTheMad (cwertman@webch amps.com) writes:[color=green]
      > > Since its only updates 2x a day I drop and recreate the table in my[/color][/color]
      DTS[color=blue][color=green]
      > > , and I have triggers on the other tables for Online updates[/color][/color]
      (usually[color=blue][color=green]
      > > no more that 100 a day) but to ensure the table is ALWAYS current[/color][/color]
      it[color=blue][color=green]
      > > gets recreated on import of additional rows.
      > >
      > > Is there a name to this maddness ? My co-workers aree leary of it[/color][/color]
      but[color=blue][color=green]
      > > they come from a dbase background, denomailzing it into a table and
      > > then indexing the table I couldnt be happeier with ther[/color][/color]
      performance.[color=blue][color=green]
      > >
      > > Are there any lurking gremlins in this design ?
      > >
      > > I cannot see any pitfalls with doing this , or are there some ?,
      > > basically I am denomailizing for read-only query performance.
      > >
      > > They are concerned about the denorilization for performance, even
      > > though its only on a read only table (was and could be a view I[/color][/color]
      just[color=blue][color=green]
      > > cant index this particualr view)[/color]
      >
      > There is too little information in your post, to give any absolute[/color]
      blessing[color=blue]
      > to this. But with the outline you give - source data updated twice,
      > aggregating the data into a read-only table could very well be the[/color]
      winner.[color=blue]
      >
      > The alternative would be to look into the underlying query, and see[/color]
      if[color=blue]
      > indexes etc can be improved. Without knowledge about the table and[/color]
      the[color=blue]
      > queries, I cannot say whether this is workable or not.
      >
      >
      > --
      > Erland Sommarskog, SQL Server MVP, esquel@sommarsk og.se
      >
      > Books Online for SQL Server SP3 at
      > http://www.microsoft.com/sql/techinf...2000/books.asp[/color]

      Comment

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