Do selects fill logical logs?

I am currently investigating an incident on a 5.03 ONLINE engine where a select statement with a correlated subquery seems to populate the logical logs. Reputable sources tell me that this is standard procedure on complicated queries. Can anyone confirm this? Where is it documented? Precisely under what conditions are logs used by queries. Why does it need to be this way? Customer is more than disgruntled since the log requirements of this infamous query far exceeds those of all other processes in the system!!! Any Ideas? Andrew Cilia Philip Toledo Limited Notabile Road Mriehel Malta Fax: +356 484316 Phone: +356 445566 Mobile: +356 994176 Ph