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Little script for finding tables for which dynamic sampling was used

Posted on October 7, 2014 by Sayan Malakshinov Posted in CBO, oracle, statistics 1,978 Page views 3 Comments

You can always download latest version here: http://github.com/xtender/xt_scripts/blob/master/dynamic_sampling_used_for.sql
Current source code:

col owner         for a30;
col tab_name      for a30;
col top_sql_id    for a13;
col temporary     for a9;
col last_analyzed for a30;
col partitioned   for a11;
col nested        for a6;
col IOT_TYPE      for a15;
with tabs as (
      select 
         to_char(regexp_substr(sql_fulltext,'FROM "([^"]+)"."([^"]+)"',1,1,null,1))  owner
        ,to_char(regexp_substr(sql_fulltext,'FROM "([^"]+)"."([^"]+)"',1,1,null,2))  tab_name
        ,count(*)                                                                    cnt
        ,sum(executions)                                                             execs
        ,round(sum(elapsed_time/1e6),3)                                              elapsed
        ,max(sql_id) keep(dense_rank first order by elapsed_time desc)               top_sql_id
      from v$sqlarea a
      where a.sql_text like 'SELECT /* OPT_DYN_SAMP */%'
      group by
         to_char(regexp_substr(sql_fulltext,'FROM "([^"]+)"."([^"]+)"',1,1,null,1))
        ,to_char(regexp_substr(sql_fulltext,'FROM "([^"]+)"."([^"]+)"',1,1,null,2))
)
select tabs.* 
      ,t.temporary
      ,t.last_analyzed
      ,t.partitioned
      ,t.nested
      ,t.IOT_TYPE
from tabs
    ,dba_tables t
where 
     tabs.owner    = t.owner(+)
 and tabs.tab_name = t.table_name(+)
order by elapsed desc
/
col owner         clear;
col tab_name      clear;
col top_sql_id    clear;
col temporary     clear;
col last_analyzed clear;
col partitioned   clear;
col nested        clear;
col IOT_TYPE      clear;

ps. Or if you want to find queries that used dynamic sampling, you can use query like that:

select s.*
from v$sql s
where 
  s.sql_id in (select p.sql_id 
               from v$sql_plan p
               where p.id=1
                 and p.other_xml like '%dynamic_sampling%'
              )
dynamic sampling dynamic_sampling
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