Publisher Summary This chapter reveals that the ratios can be useful to indicate a possible problem or problems. A low or high ratio could indicate a possible problem. It could also conceal a possible problem. Additionally, a ratio can also indicate no problem at all. A ratio is best viewed as a possible symptom of a problem, rather than as a problem by itself. Ratios have received a lot of bad press recently. Ratios are not completely useless—they can provide clues as to where to look for a problem when attempting to solve a performance problem. The solution is perhaps to use both ratios and other tools to resolve performance issues. This ratio should not be used as an indicator of database performance health. In the past, Oracle software documentation touted the database buffer cache hit ratio as being one of the most important tuning metrics. It is the opinion of many that this statement is often a complete and absolute falsity.