Insert operation takes looooooooooong time

Question

One of our ETL procedures does an Insert operation on a table with the records selected from a couple of tables across DB link.
While the SELECT query takes about 6 seconds to retrieve nearly 42,00,000 records, the insert of those records to a table takes about 45 minutes.
Infact I've altered the table to NOLOGGING mode and the /*+ append */ comment(for Insert) is in place to reduce the redo logs.The destination table has no index and no constraints as well..
Is there any other way that I can adapt to reduce the time of insert operation?
Thanks,
Bhagat

Answer 1

>While the SELECT query takes about 6 seconds to retrieve nearly 42,00,000 records
Is this in TOAD? If so, TOAD actually returns rows in sections and may not be returning the full set. You would have to actually scroll to the bottom of the grid and wait for the data to finish loading. Caution, if you did not select the option to execute queries in threads in TOAD you will not have the cancel query ability.
>the insert of those records to a table takes about 45 minutes
Have you performed a CREATE TABLE AS using the query. This will give you a good benchmark for performance during a direct-path load. You can then look at the USER_SEGMENTS.BYTES column for that table after a load and, with your timings, check the data transfer rate with your network support.