Forum Replies Created

Viewing 15 posts - 11,536 through 11,550 (of 49,552 total)

  • RE: Index seek and Index scan ....order of columns

    No, that won't be a cause.

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • RE: Memory assigned to the OS

    There's no memory 'assigned' to the OS. 8GB is what SQL is leaving for the OS and any other app running on that server. That's rather a high figure for...

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • RE: Index seek and Index scan ....order of columns

    Primary purpose of an index is to reduce the number of rows in consideration for a query as early as possible. Which reduces row count, a filter or a join?

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • RE: How does Greater than operator works in Joins

    SELECT

    OfficerID,

    ShiftStart,

    ShiftEnd,

    CrimeTotal

    FROM

    Officer o

    CROSS APPLY (SELECT COUNT(*) AS CrimeTotal FROM Crime c WHERE CrimeDate BETWEEN o.ShiftStart AND o.ShiftEnd) c

    May well perform better, though would need testing. It's essentially the same as calling...

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • RE: SQL Server Enterprise Edition: Core-based Licensing (64-bit)

    The alternative to core-based licensing is CALs (and it's limited to a certain number of cores iirc), do you have CALs for all the clients that access sharepoint (each and...

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • RE: How does Greater than operator works in Joins

    busraker (9/26/2013)


    Good = take for instance:

    Say you have a table of salespeople with their hire dates (SalesPerson):

    <snip>

    How many orders did they have in the first 100 days? If you...

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • RE: How does Greater than operator works in Joins

    It works very badly most of the time because of some limitations of the optimiser. It'll usually result in multiple scans of one or both tables in the join.

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • RE: How to Hide/Encrypt/Password a Table

    Passwords should not be stored encrypted, they should be stored hashed. One-way cryptographic hash. There is no need to ever unencrypt a password. Hash whatever is entered and compare, don't...

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • RE: Query on identical objects different systems, A performs speedy with index seek, B performs poorly with clustered index scan

    You're really not making this easy...

    For anyone else who wants to have a look, plans are attached, edited to so that they're valid XML (had hidden illegal characters in them)...

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • RE: Query on identical objects different systems, A performs speedy with index seek, B performs poorly with clustered index scan

    Plans in XML format please. The text format is awfully hard to read and is missing about 99% of the information.

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • RE: Query on identical objects different systems, A performs speedy with index seek, B performs poorly with clustered index scan

    Probably stale stats. Update stats on the tables involved with full scan. But need execution plans from both to make anything more than a wild guess.

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • RE: Performance issues SQL 2012

    Rem70Rem (9/26/2013)


    I think this it the creation of the indexes that takes more time.

    Think? First thing you need to do is time the steps and see for absolute certain which...

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • RE: Performance issues SQL 2012

    Do the execution plans show any differences? What are the wait types?

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • RE: AlwaysOn performance on Replica databases

    http://www.sqldiablo.com/2012/08/01/alwayson-availability-groups-isolation-levels-selects-blocking-writers/

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • RE: Are the posted questions getting worse?

    Jeff Moden (9/26/2013)


    Jack Corbett (9/25/2013)


    GilaMonster (9/25/2013)


    Someone want to add a voice of reason to this?

    http://www.sqlservercentral.com/Forums/Topic1493948-391-1.aspx

    I'd try but that tempDB thread has worn me out.

    Is that the one where...

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass

Viewing 15 posts - 11,536 through 11,550 (of 49,552 total)