Forum Replies Created

Viewing 15 posts - 6,916 through 6,930 (of 49,552 total)

  • RE: Detach System Databases

    Process Explorer (sysinternals) or their simpler tool "handle"

    It could have been something as simple as an antivirus grabbing the files. It could have been that the cluster service noticed the...

    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: Detach System Databases

    You checked what process was using the files?

    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 2014 Checklist for Performance

    Uwe Ricken (12/29/2014)


    So DML is ALWAYS single threaded and the threshold of 5 seems to be o.k.

    SELECT, INSERT, UPDATE, DELETE are definitely not always single threaded. They can all run...

    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: Detach System Databases

    You said the files wouldn't copy, why wouldn't they copy?

    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 get data side by side

    Err, what????

    That now doesn't match the query you posted (which returns only two columns) and is the result that you're asking for. If you already have that result, why are...

    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 get data side by side

    What are the values for a.evs_CodeUsed in the table?

    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: Using the OVER command together with WITH, and Excel with a parameter

    Table definitions (as CREATE TABLE) and some sample data (as INSERT statements) please, if you want a tested answer.

    Initial guess, your ROW_NUMBER needs a Partition By

    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 2014 Checklist for Performance

    Paul Brewer (12/29/2014)


    This might be a good way of comparing 'create table' differences between table variables/temporary tables:

    http://www.sqlskills.com/blogs/paul/determine-causes-particular-wait-type/

    It describes a way of defining an extending events session to capture the internal...

    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 2014 Checklist for Performance

    Paul Brewer (12/29/2014)


    I'm not 100% sure to be honest, no. From experience the latch contention associated with table variables 'seems' a lot less profound but I've never investigated or tested...

    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 2014 Checklist for Performance

    Paul Brewer (12/29/2014)


    2. Do not cause any latch contention in tempdb, there are work arounds (trace flags and multiple tempdb files) but it's still a pain.

    Are you sure about...

    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 2014 Checklist for Performance

    m.kancleris (12/29/2014)


    Anyway, "index scan" is rare thing 🙂 on proper databases

    Is it? 😉

    It's surprisingly easy to have SQL tip to a table/index scan when it's using a non-covering...

    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 2014 Checklist for Performance

    m.kancleris (12/29/2014)


    It does not return rows multiple times and does not miss any row

    Yes, it can.

    http://technet.microsoft.com/en-us/library/ms190805%28v=sql.105%29.aspx

    Missing one or more rows that were not the target of update

    When you are...

    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: Deadlocks, wiats, deadlocks

    Igor Micev (12/29/2014)


    Then, even though the isolation level is READ COMMITTED using row versions, there are sill deadlocks.

    Yes, and?

    I've read that read committed snapshot uses pessimistic writes, and snapshot uses...

    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 2014 Checklist for Performance

    m.kancleris (12/29/2014)


    "Don't use NOLOCK" - should have "(depends)" tag too.

    It depends on database design. Personally, I use it a lot to increase SELECT performance.

    NOLOCK is not a performance tuning...

    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: Deadlocks, wiats, deadlocks

    Depends. If you explicitly request an isolation level, you get whichever one you request. If you allow the default of read committed, then you get read committed using row versions.

    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 - 6,916 through 6,930 (of 49,552 total)