Very slow insert and update into ci_session

[eluser]pickupman[/eluser]
Surprising enough, a VPS maybe slower than shared hosting. You had not mentioned if the inserts were fine on shared hosting, but now slow on VPS. A VPS has a dedicated and fixed amount of resources. A shared account is generally has access to a lot more server resources with the trade off that it is shared with other sites. If you get on a cluster that has lower traffic sites, you will have alot more resources running on a shared.

Aside from that, is the insert still taking that long running the query via phpMyAdmin or login via shell and run the query from the command line. At least that will eliminate CI being a factor in the situation.