ODBC CALL FAILED 63535

When you open the recordset, do you need to specify whether to use the Client side or Server side Cursor. I dunno, but maybe this might have something to do with it??

I think StillExecuting does not work well with other than microsoft databases.. check the documentation

This is how I initiate the query to the Oracle Server through ODBC:

Set dbs = CurrentDb()
Set odbcWorkspace = CreateWorkspace("ODBCWorkspace", "admin", "", dbUseODBC)
Workspaces.Append odbcWorkspace
Set OracleConnection = odbcWorkspace.OpenConnection("OracleDB", dbDriverNoPrompt, False, "ODBC;DSN=OracleDB;UID=BGW;PWD=THULE;")
Set qdfSearch = OracleConnection.CreateQueryDef("")          
qdfSearch.ODBCTimeout = 0
qdfSearch.SQL = SqlString
Set rstODBC = qdfSearch.OpenRecordset(dbOpenDynaset, dbRunAsync) <--- I open a Dynaset recordset type which is similar to an ODBC keyset cursor. If you do not specify the dbOpenDynaset the recordset is opened as a Forward-only type which corresponds to an ODBC forward-only cursor.

Also the above objects (queryDefs, Connections etc) are declared as Global in an Ms-Access module object so I can reference them anywhere in the code. Of course I take care not to reinitialise them once the query is executing in Oracle Server.

I did not find any relevant info on a StillExecuting problem apart from the fact that it had a problem with the True/False value which is fixed in VB.6 libraries.

I have updated the code to a more simple version with a modification which seems to have solved the problem (need to do more testing though):

Set OracleConnection = odbcWorkspace.OpenConnection("OracleDB", dbDriverNoPrompt, False, "ODBC;DSN=OracleDB;UID=BGW;PWD=THULE;")
OracleConnection.QueryTimeout = 0
Set rstODBC = OracleConnection.OpenRecordset(GlobalStringSql, dbOpenDynaset, dbRunAsync, dbReadOnly)
rstODBC.Connection.QueryTimeout = 0

Pay attention to the OpenRecordset command. I have added the dbReadOnly flag for the dbOpenDynaset recordset type. Since the error seemed to occur only for queries that had to search through vast ammount of data (searches for more that 10million records) I realised that the dbOpenDynaset recordset may by default make locks on the records matching the SQL criteria possibly returning an error due to these locks which to be honest I do not know if they remain active as long as the recordset is alive. Adding the dbReadOnly does not allow any locks to be placed possibly solving the problem. Can anyone comment/confirm on that?  

Nope still get the error 63535! When I get the error I can see that the session in Oracle is not gone. Howeverthe search does not make any more reads meaning that it has stopped. Are ther any hidden timeouts in Access for connection, recorset objects? Do I need to retreive the matched data regularly from Oracle? Does Oracle stops the query execution due to certain profile settings?

Just it case it help someone figure out a solution... The error does not seem to appear if the main query is brake up by the Oracle SQL Optimiser into smaller queries running in parallel which of course speeds up the search time! If this is done the results once the query ends are fetched normally back to MS-Access. I will always get the error if the query is not optimized (possibly due to heavy use of the Oracle DB).

Finally after a trace in the ODBC data source I found out that the actual Oracle error is ORA-0155 which of course refers to the rollback segments. After increasing the rollback segment from 300MB to 2GB the error appears rarely.