Check all active processes, the latest SQL, and the SQL hit ratio

This script is very useful for Oracle DBAs in the process of tuning and identifying slow SQL. It will provide information about the currently active sessions, the latest SQL, as well as the hit ratio. When the server becomes slow, use this SQL to find out all ACTIVE connections with hit ratio and SQL. It has been tested on Oracle 8.1.x platforms (8.1.5, 8.1.6, and 8.1.7).

set linesize 2000
column HitRatio format 99999.99
column username format a12
column osuser format a20
column sql_text format a1000
select a.status, a.sid, a.serial#, a.username, a.terminal, 
       a.osuser, c.Consistent_Gets, c.Block_Gets, c.Physical_Reads,
       (100*(c.Consistent_Gets+c.Block_Gets-c.Physical_Reads)/
       (c.Consistent_Gets+c.Block_Gets)) HitRatio, c.Physical_Reads, b.sql_text
from v$session a, v$sqlarea b, V$SESS_IO c
where a.sql_hash_value = b.hash_value 
  and a.SID = c.SID
  and (c.Consistent_Gets+c.Block_Gets)>0
  and a.Username is not null
  and a.status = 'ACTIVE'
 Order By a.status asc, c.Consistent_Gets desc , c.Physical_Reads desc;

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