HI,

Regarding coleascing space, it is right that SMON wakes up every 5 minutes, to coalesce the free space provided the tablespace's pctfree setting is not zero.This is done regardless of whether the new continogous space is needed or not.

But in a situation where Oracle tries to allocate an extent and is not able to find an extent of such size, it will still automatically coalesce the space, regardless of the pctfree setting for the tablespace.

This was mentioned in one of white papers on 'Stop Defragmenting and Start Living' by Oracle Corp.I found this white paper quite interesting and is availabe on Oracle site.