This TIP comes from the site of Jonathan Lewis.
The original link is as follows:
http://www.jlcomp.demon.co.uk/faq/imp_slow.html
Why is IMP speed slow?
1. IMP made a lot of INSERT as ordinary ways
2. When IMP is created, an index is usually logging, which has a lot of undo and redo.
How to improve the speed of IMP
1. It is not recommended to use the commit parameters, because when IMP fails, it will lead to many subsequent troublesome things.
2. Increase the buffer parameter value to make a bigger Array
3. Set large initialization parameters sort_area_size to speed up the sort speed when creating an index
4. Increase the size of the recovery log to reduce the number of log switches, which is to reduce the number of checkpoints and reduce the number of write disks.
5. If you want to add data to the already existing table, then in some cases, such as a bitmap index in the table, it is best to remove the index, then import. Otherwise, a large number of waiting will be generated when the index is updated.
6. Use the indexfile and indexes parameters, then import the data and create an index.
