The Oracle latch free wait event occurs when a session needs a latch, tries to get the latch, but fails because someone else has it.
Possible causes of ‘Latch Free’ wait.
– If its due to Shared pool or Library cache latching, then the problem is due to excessive hard-parsing. (Most likely because of lack of bind variables)
– Another possible cause may be due to ‘cache buffer chains latching’.
Reference : https://support.oracle.com/epmos/faces/DocumentDisplay?_afrLoop=454764592204737&id=34576.1&_afrWindowMode=0&_adf.ctrl-state=xsq7uenau_62