Okay - got it. The simple answer is that you're missing a histogram (or the histogram that Oracle acquired id garbage. Most efficient trick - you've run the query about which values appear how often - create a frequency histogram for the 250 most popular (or less if appropriate), include the low and high values put in one extra value with the number of rows x 2 that you want the optimizer to consider for all other values then call set_table_stats. See my latest article for allthingsoracle - published about 24 hours ago, by coincidence. Regards Jonathan Lewis http://jonathanlewis.wordpress.com/all-postings Author: Oracle Core (Apress 2011) http://www.apress.com/9781430239543 ----- Original Message ----- From: "Mohamed Houri" <mohamed.houri@xxxxxxxxx> To: "Jonathan Lewis" <jonathan@xxxxxxxxxxxxxxxxxx> Cc: "ORACLE-L" <oracle-l@xxxxxxxxxxxxx> Sent: Wednesday, October 02, 2013 12:39 PM Subject: Re: Statistics Problem on partitioned table Jonathan, I am sorry I may have not been clear but there are in fact 721,699 and that is what I showed above *select per_ind, count(1) cnt from XXX_PER_YYY group by per_ind;* 721,699 rows … PER_IND CNT ---------- ---------- 14820567 2 14820568 2 14823592 2 14888565 2 14332136 2 13565375 2 13617240 2 … 13546549 92 13546573 92 13546630 92 13546881 92 13546890 92 13546911 92 … 13546914 92… …. And so on until I arrived at the end (721,699) 13831389 130 13831395 130 13831404 130 13831451 130 0 6119655 ----> this is my predicate It is when I count how many distinct CNT I have that I found 59 rows (2, 92, 130, .......6119655) . That’s what I meant by 59 rows Best regards 2013/10/2 Jonathan Lewis <jonathan@xxxxxxxxxxxxxxxxxx> > > Mohamed, > > > > There's still the puzzle that you now show 56 distinct values, but the > stats show 721,599 distinct keys. > > We need to work out how this discrepancy could have appeared (it would > explain your plan, of course). > > > > Regards > > Jonathan Lewis > > > > > > ________________________________ > From: Mohamed Houri [mohamed.houri@xxxxxxxxx] > Sent: 02 October 2013 09:58 > To: Jonathan Lewis > Cc: ORACLE-L > Subject: Re: Statistics Problem on partitioned table > > > Jonathan > > > How come there is only one distinct value of per_ind (first post), but > the number of distinct keys in the index on per_ind is over 700,000 ? > > Again nicely spotted. Here below is the correct figure > > select per_ind, count(1) cnt from XXX_PER_YYY group by per_ind; > > 721,699 rows … > > I managed to put the result in a test table so that I can check how much > count I have for each per_ind and so on > > select distinct cnt from mho_test order by cnt asc; > > 2 > > 4 > > 6 > > 8 > > 10 > > 12 > > 14 > > … > > 6119655 ---> this the count for per_ind = 0 (at the moment the query was > issued) > > 56 rows > > > The old figure (that have prompted your question) was against a view > XXX_PER_YYY_VW (which is select * from XXX_PER_YYY where per_ind = 0). > > > There 4 columns on the XXX_PER_YYY table and they are all not null; > > SQL> select count(1) > > from > > ( > > select table_name, partition_name, global_stats, last_analyzed, > num_rows > > from all_tab_partitions > > where table_name='XXX_PAR_YYY’ > > ) > > where num_rows = 0; > > > > COUNT(1) > > ---------- > > 758 > > > > 785 empty partitions over 1493 partitions. > > -- //www.freelists.org/webpage/oracle-l