Report cause db to hang

  • Have a report the developers run and each time this is run and another report is run it is blocked .The argument is they are read only?Why block other processes .

    Currently running a trace to collect locking and deadlock info but not sure this has answers to why reads are able to block other processes.

    Your input as usual is appreciated

     

  • Well, it happens to me too! Same thing, running traces. Moreover, if a report is run in the security context of read-only user for the user DB his TempDB rights are write at least so TempDB is able to grow and you have to watch it. I have reporting / data extraction locking once in a while with both .NET and MySQL front ends with read-only users.

     

    Regards,Yelena Varsha

  • Hi,

    Your developers may only have readonly rights but if they run a standard select you will get shared locks on the tables.

    Perhaps they should try and set the transaction isolation level to read-uncommitted.

    Regards..Graeme

  • Are you saying when some one has read only access they will have shared blocking locks on tables they query?

     

    Thanks

  • I am assuming you have set your developers to have the role of db_Datareader. All this means is that they cannot make any modifications to data or structure. When they select data, they are still bound by the locking rules of SQL Server.

    A shared lock is created when a select statement is run. This means other connections can select data but cannot modify it.

    I cannot comment on your reports as I have not seen them. If they are complicated you may be generating a lot of locks that are taking a while to be released.

    Have you actually seen the process being blocked ?

    Graeme

  • http://support.microsoft.com/default.aspx/kb/906344

     

    This to me might be the cause of the problem...

Viewing 6 posts - 1 through 5 (of 5 total)

You must be logged in to reply to this topic. Login to reply