Re: Q: Imports

In article <3s9dve$bei_at_bell.ukonline.co.uk>

           chris_at_perihelion.co.uk "Chris Selwyn" writes:

: Could someone please tell me why creating hash clusters is soooooo slow?
: I am trying to create a 150M cluster and so far it has taken ~3/4 hr
: on a Alpha OSf/1 Oracle 7.1.4 system (and it's still going :-( ).
:

Rows in hash clusters are put into a block whose address is dictated by applying a function to values in the row, so each row inserted into your table is effectively going to a random position somewhere in the 150M.

Unless you have a _very_ large SGA and file-system buffer, you are probably suffering from a very high rate of physical disk reads as Oracle is going to be flushing and re-reading blocks all the time.

For a rough estimate of total time required, I'd bet on something like one-twentieth of a second per row.

-- 
Jonathan Lewis