MS Access pass-through query - very slow when use ODBC connection string, fast when datasource selected manualy - where is the issue

Question

I connect from ms access (frontend) to MS SQL server (database) using ODBC and file datasource. I've created MS Access pass-trough query collecting data from SQL Server (directly calls MS SQL Server function returning table). When I run this query in MS SQL Management console, it runs about 1s. When I run it from MS Access, using ODBC connection string, the same query runs about 5 minutes (!!). But when I clear connection string from query properties, it runs between 1 and 2 seconds (so acceptable). Other queries and linked tables using the same connection string works correctly (so the string is rather OK) Why the hell this one makes problem? Any idea hat to check?

Answer 1

I use windows authentication (trust) only. "clear" means to remove all except "ODBC;" phrase. When I leave this notice in query properties, the Access asks for DSN, I select one, and then I got the results after 2 sek. But When I put full connection string

ODBC;Description=My Database;DRIVER=SQL Server;SERVER=MYSERVER;APP=2007 Microsoft Office system;DATABASE=MYDB_Prod;LANGUAGE=polski;Trusted_Connection=Yes

The query I call is:

SELECT * FROM dbo.fn_MyFunction()

Function fn_MyFunction() is table valued one, returns two rows and about 50 columns ( suspected large number of column might be the issue, because other queries have less one), and it is used in access report (that's why I use pass through query - the same happens when I test with MS SQL server view linked to MS Access tablle via odbc)

The same connection string works well with other queries

It seems I found solution (or workaround rather?) I've made the tests using VPN over internet link. When I move to office - it works well and return almost immediatelly with the string I wrote above.

It is strange for me that link type have such impact: other queries works well on both (LAN an VPN over internet), but this one - only on LAN ( works over internet too but with unacceptable performance). I could understand if all works slow.. by why this one? Any idea?

Answer 2

I know this is an old post but... I've been googling to no avail so I wanted to put this out there...

I have a drill down SP that returns.... 200 rows max The MS Access app uses ALL pass through queries to Azure. All work great except for this one. In SSMS it comes back almost instantly. ODBC string is the same on ALL Queries so the connection is fine.

After setting the max rows property to 1000, the form came back almost instantly. Cleared the property and it went back to slow...

This property definitely made the difference for me. Setting it to a number that is well beyond the upper limit really got this working as it should be.

hth, ..bob