Hi, 
Looking in Cognos Business Intelligence 10.1 Software Environments document (https://www-304.ibm.com/support/docview.wss?uid=swg27019126 ) it looks like all columnar DB appears in the table with title ODBC.
1.)  does it mean that Cognos connects to it through ODBC only ?
2)   does it impact on performance of report execution?
3)   any examples and best practices for working with columnar DBs as a data source especially Vertica or Sybase IQ?
Thanks
			
			
			
				for the most part ODBC yes. Unless otherwise stated.