Import performance wierdness dicovered!?!

Hi all,

I've been fooling around with the import program to find out if we can do imports more efficiently than at present, and have found the following to be true:

When I import a single table of 3440 rows from an import file that is ~21MB big (approx. 60 other tables data in the import file) and time it using /bin/time (Unix command, sorry DOSers), i get:

81.3 real 38.2 user 11.3 sys

i.e. 1.3 minutes real time to import the table.

WHEN I export JUST the table of 3440 rows, and THEN import THAT file (now only 240 KBytes big), it took a mere 7.3 seconds of real time to import the table!!!!!

What's up with that, eh?? Can this be explained by anyone out there?

Does import have to search the entire file for extra extents? (I exported both files with compress=Y, so I wouldn't think this could be true.)  

I just don't get it!

--
David Pape                               | "The people who own the country    |
pape_at_plato.Chemietechnik.Uni-Dortmund.DE |  ought to govern it"               |
Dortmund, Germany                        |  - John Jay                        |
tel: 49 231 7552682                      |  (signer of the U.S. Constitution) |