Top Oracle shared pool scripts

Top Oracle shared pool scripts Oracle Tips by Burleson Consulting

The Oracle shared pool has very few tuning knobs other than adjusting theshared_pool_size, setting cursor_sharing andtuning the SQL that reside within the library cache of the shared pool.
A shortage ofshared pool RAM may result in high library cache reloads, high row cachereloads, and shared pool latch contention. You may also see the error:"ORA-04031: Out of shared pool memory".
Also see Oracle shared poollatch internals.
Oracle shared poolscripts
Here are somecommon shared pool scripts for monitoring the shared pool.  For a completeset of shared pool scripts, see my book "Oracle
Tuning: TheDefinitive Reference", with 950 pages of tuning tips andscripts. 
select * 

from(

   select 

      name, bytes/(1024*1024) MB 

   from 

      v$sgastat 

   where 

      pool ='shared pool' 

   order by 

      bytes desc

   ) 

where rownum < 20;
We also needscripts to monitor for non-reentrant SQL (SQL without bind variables, which canbe corrected by setting cursor_sharing=force). This shared pool script willidentify SQL where "executions=1", indicating
nonreentrant SQL:
select 

   count(1) num_sql, 

   sum(decode(executions, 1, 1, 0)) one_use_sql, 

   sum(sharable_mem)/1024/1024     meg_used, 

   sum(decode(

      executions,   1, 

      sharable_mem, 0)

   )/1024/1024                     mb_per

from 

   v$sqlarea

where 

   sharable_mem > 0;
This shared poolscript will display shared pool data from STATSPACK:
set lines80; 

set pages 999; 

 

column mydate heading 'Yr.  Mo Dy  Hr.' format a16 

column c1 heading "execs"    format 9,999,999 

column c2 heading "Cache Misses|While Executing"   format 9,999,999 

column c3 heading "Library Cache|Miss Ratio"    format 999.99999 

 

break on mydate skip 2; 

 

select  

   to_char(snap_time,'yyyy-mm-dd HH24')  mydate, 

   sum(new.pins-old.pins)              c1, 

  sum(new.reloads-old.reloads)         c2, 

   sum(new.reloads-old.reloads)/ 

  sum(new.pins-old.pins)               library_cache_miss_ratio 

from  

   stats$librarycache old, 

   stats$librarycache new, 

   stats$snapshot     sn 
see code depot for full scripts 

where 

   new.snap_id = sn.snap_id 

and 

   old.snap_id = new.snap_id-1 

and 

   old.namespace = new.namespace 

group by 

   to_char(snap_time,'yyyy-mm-dd HH24') 

; 
This shared poolscript will use the automatic workload repository (AWR) for a time-series lookat the shared pool:
columnenqueue_deadlocks format 999,999,999

select

   to_char(sn.end_interval_time,'dd Mon HH24:mi:ss') mydate,

   a.value enqueue_deadlocks

from

   dba_hist_sysstat a,

   dba_hist_snapshot sn
see code depot for full scripts

where

   sn.snap_id = (select max(snap_id) from dba_hist_snapshot)

   and a.snap_id = sn.snap_id

   and a.stat_name = 'enqueue deadlocks'

;