Re: Access 7.0 -> Informix 7.1-2

Nils Myklebust <Nils.Myklebust@idg.no> wrote in article <32fafd05.9241017@gate.idg.no>... > <snip> > Testing a selection on an index returning about 31.000 rows from a > table of about 1.000.000 rows, dbaccess used about 33 seconds to > select them all and write them to a file. With MS Access I saw the > last row of the query after about 16 seconds. (MS Access have then > read all the 31.000 rows from the database and stored them locally on > my PC.) > > The interesting part here is that I get the same or better performance > using MS Access via ODBC as I see using dbaccess on the server on > similar operations. > > I repeat again that these are *very* informal tests Actually, if your table has a unique index, then MS-ACCESS has fetched all of the columns of the (first) unique index locally, and then fetched the rest of the columns for just the rows that you actually see on the last "page" of results. If the index is relatively small (say a single serial column?) and the rows relatively large, this could easily explain the difference. Try the same test on a table with no unique index defined. This will cause MS-ACCESS to treat the table as a 'snapshot' and return all columns. I think you'll find MS-ACCESS much slower (mainly due to the network bandwidth) in this case. -- Irwin Goldstein Objective Software Systems, Inc. http://www.objectsoft.com