Originally posted by nagarjuna
nah.. Server processes do coalesc when you use the 'alter tablespace tsname coalesce;' command.
Where did you hear that????? Server proces *can never* write to the database file. Never! It can only read from database file. It would be a shocking news to me if you could prove me wrong on that.

Why would be any different with ALTER TABLESPACE COALESCE command? How does it differ with any other CREATE, ALTER, etc commands? No matter what command is executed, server process can only *read* from datafiles. All modifications that must be performed by server processare are executed in the buffer cache, and it is DBWR that performs any datafile writes associated with that.

Realy, can you provide any explanation/URL regarding what is so special about ALTER TABLESPACE COALESCE in this context?