Copying across databases

Is INSERT INTO .. SELECT FROM inherently slow across databases? Does it keep having to re-make database connections or something? I am getting startlingly slower performance attempting to copy a big table across databases using this method compared to other methods. My client has either tried or considered: - dbexport / dbimport - until he hit the 2Gig limit on unload. - Art's dbcopy utility - until we discovered he has the wrong kind of C compiler. (It needs ANSI, he has the crippleware one) Of course there are all sorts of reasons why a table copy might go slowly but what I want to understand before deciding whether to try a different method (ipload, onload, get him to buy the right C compiler to use Art's utility ... ) is why dbexport+dbimport were considerably quicker than INSERT INTO .. SELECT FROM. Can anyone shed any light on what might be going on and either confirm or refute the 'repeated connect' theory, as well as nominating their preferred way of doing the job? An in-place method would be nice rather than one that dumps and re-imports. It's 7.31 on HPUX 11. Many thanks -- Genuine reply address. Andy Kent Bristol, UK