Linked Server Query incorrectly returns 0 rows on SSMS

  • Hi all,

    Need help to figure ut why the remote query I execute on the server return 0 rows , but the same query returns over 900k rows in the target DB.

    the string is less 8000 characters long so I won't post it here.  but this is the sctructure basically:

    declare @sql varchar(MAX);

    declare @D varchar(15);

    declare @Per varchar(15);

    declare @NextPer varchar(15);

    declare @NextYPer varchar(15);

    set @D = N'01-JUN-2019'

    set @Per = N'2020004';

    set @NextYPer = N'2021004'

    set @NextPer = N'2020005'

    set @sql = N' SELECT  ...... '

    set @sql = N'select * from openquery ([LK1], "'+@SQL+'")';

    execute( @sql);

    print @sql;

    Note: the linked server works and is used on other openqueries with shorter strings successfully. I tried using EXECUTE (@SQL) AT  and I still get 0 rows.  When i exexute the print output directly on the Oracle DB , the query runs for about 15 min and gives results.

    Please help me, I'm desperate. I appreciate it.

    • This topic was modified 5 years, 6 months ago by  saphiros.
  • Just a guess here but if it takes 15 minutes to run on the actual target DB there is a good chance your linked server connection is hitting a time out threshold.  Depending on the driver many connections have a time out built in.  Check your ODBC connections on the server.  Also I wouldn't be doing a 'SELECT *' over the network like that.  You will likely experience some serious network waits depending on the size of the expected result set.  Try the same query with a specific record first and see what comes back.


    SELECT quote FROM brain WHERE original = 1
    0 rows returned

  • the query runs for about 15 min and gives results.

    And you expect 900k rows, that's gonna take a while, so you probably get a network timeout.

    You could also minimize the transferred data to count the number of rows, for test.

    select [NumberOfRows] = count(1) from ....

    Later replace * with a list of needed columns.

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