[douglas]

I notice you mentioned in the Dom 3 forum that about 100000 PMs were taking longer than everything else put together. Considering there are over 5 times that many posts alone, plus the user list and various other data on top of that, I can't think of any reasonable explanation for it other than an index or constraint requiring excessive redundant checking.

My first guess would be that the PM content column has a unique constraint but no index, which would force a string comparison of each and every PM with each and every other PM. This isn't that big a deal in normal use when you only have to worry about one new PM at a time, but doing 100k at once takes forever. Removing the constraint in this case would drop the import time immensely. Creating an index for it instead would greatly reduce the number of comparisons required, but the index itself would take some extra resources to maintain. Assuming my guess is correct, I would first try creating an index for the column and see how much that helps. If it still takes too long, then remove the constraint entirely before importing and then see if it can be added back in a reasonable amount of time.

Edit: Then again, I don't know that much about how most databases handle indexes on strings specifically, so it's possible that it does have an index on PM content and that removing that index could help. I doubt this is the case, but it might be possible.