Importing a huge Dump

Question

Hello all,
I am importing a dump of size 17 GB (Production server dump). Its running pretty slow. Can anyone tell me how much sizes I should give for rollback, redo etc. Request any way of improving import performance.
Regards,
Ravi Duvvuri

Answer 1

In addition to what's been said the following should help too.
1. Use the export parameter commit=n - this will cause a commit to happen after each object instead of after each buffer.
2. If possible increase greatly increase the init.ora parameter sort_area_size. For my databases I'll increase this from 128kb to 6mb.
3. Increase the init.ora parameter db_block_buffers. Try increasing this by 25-50% if possible.
2 and 3 above may be irrelevant if you're using 9i or greater and have memory dynamically allocated.
In my experience commit=n buffers=xxxxxx and setting the sort_area_size and db_block_buffers have had the most dramitic effects of increasing import performance. I've seen import times drop in half in certain instances.
If you have metalink access look for document 93763.1 - Tuning Considerations When Import Is Slow for more information.