在Oracle數據庫性能調優(yōu)的過程中，當需要觀察緩存命中率(Measure the Buffer Cache Hit Ratio)時，我們可以使用下面的語句:

rem-------------------------------------------rem 測量緩存命中率rem -------------------------------------------- 獲取初始緩存命中率...SELECT ROUND((1-(phy.value / (cur.value + con.value)))*100,2) 'Cache Hit Ratio'FROM v$sysstat cur, v$sysstat con, v$sysstat phyWHERE cur.name = 'db block gets'AND con.name = 'consistent gets'AND phy.name = 'physical reads'/-- 我們人為來增加緩存命中率...DECLAREv_dummy dual.dummy%TYPE;BEGINFOR I IN 1..1000 LOOPSELECT dummy INTO v_dummy FROM dual;END LOOP;END;/-- 我們再來測量...SELECT ROUND((1-(phy.value / (cur.value + con.value)))*100,2) 'Cache Hit Ratio'FROM v$sysstat cur, v$sysstat con, v$sysstat phyWHERE cur.name = 'db block gets'AND con.name = 'consistent gets'AND phy.name = 'physical reads'/