## AWR - Buffer Hit Ratio в разрезе снапшотов

```oraclesql
with t as (
  SELECT s.BEGIN_INTERVAL_TIME start_dt,
         trunc((1-((physical_reads)/(db_block_gets+consistent_gets)))*100,2) buffer_hit_ratio ,
         physical_reads ph_r,
         lead(physical_reads) over (order by s.SNAP_ID) ph_r_next, 
         lead(physical_reads) over (order by s.SNAP_ID) - physical_reads ph_r_delta,
         db_block_gets gets, 
         lead(db_block_gets) over (order by s.SNAP_ID) gets_next,
         lead(db_block_gets) over (order by s.SNAP_ID) - db_block_gets gets_delta,
         consistent_gets c_gets, 
         lead(consistent_gets) over (order by s.SNAP_ID) c_gets_next, 
         lead(consistent_gets) over (order by s.SNAP_ID)- consistent_gets c_gets_delta
  FROM   dba_hist_buffer_pool_stat t
         join dba_hist_snapshot s on s.SNAP_ID = t.SNAP_ID
  where  trunc(BEGIN_INTERVAL_TIME) >= to_date('25.03.2024','dd.mm.yyyy')
  order by 1
)
SELECT t.start_dt,
       buffer_hit_ratio hit_g, 
       trunc((1-((ph_r_delta)/(gets_delta+c_gets_delta)))*100,2) hit_l 
FROM   t
         
```