Lyall, Is the environment on which the query runs fast still in place? If so, can you create a sql trace on this environment for the problem query? It would remove a lot of uncertainties about possible differences in array sizes and number of rows returned. regards, Freek D'Hooge Uptime Oracle Database Administrator email: freek.dhooge@xxxxxxxxx tel +32(0)3 451 23 82 http://www.uptime.be disclaimer: www.uptime.be/disclaimer From: Niall Litchfield [niall.litchfield@xxxxxxxxx] Sent: 31 March 2011 08:26 To: D'Hooge Freek; ORACLE-L Subject: Re: RE: TKPROF output Freek, I don't think the comms are slow per se. If my math is right the avg wait is 3ms . There are a lot of them though. Of course we don't know rowsize or what the original system looks like.-- //www.freelists.org/webpage/oracle-l