Oracle DB ratios explained

Here you will find two pdf (in french and english) with the explanation of the following ratios, and what to do to improve them, as well as your database performances:

• Buffer Cache Hit Ratio 
• Chained Row Ratio 
• Database CPU Time Ratio
• Database Wait Time Ratio
• Dictionary Cache Hit Ratio 
• Execute to Parse Ratio 
• Get Hit Ratio 
• Latch Hit Ratio 
• Library Cache Hit Ratio 
• Parse CPU to Elapsed Ratio 
• Pin Hit Ratio 
• Soft-Parse Ratio 
• Library cache reload Ratio
• Rollback Segment Wait to Get Ratio
• In (PGA) Memory Sort Ratio
• Buffer Nowait Ratio
• Redo Nowait Ratio

In english

In french

You can hit the gv$sysmetric view to most of those ratios.