DIfferent perfromance of same query on two database

Question

We have our DEV database of 11.2.0.2 on Redhat 5.2, and our production database is a two node RAC of the same version on same ype of servers. Recently, we noticed that when run the same query on the two server, the DEV is 300 to 1000 times faster than on production, while the exec plan cost of DEV is one third of that of PRD. The query is SELECT PERSON_X_IDTY.PERSON_ID AS Facet_ID,1.0 AS Facet_Rank
FROM (IDTY INNER JOIN PERSON_X_IDTY ON ((IDTY.IDTY_ID = PERSON_X_IDTY.IDTY_ID)))
WHERE (((IDTY.IDTY_NAME_FIRST IS NOT NULL AND LOWER(IDTY.IDTY_NAME_FIRST) = LOWER('DAVID'))
AND (IDTY.IDTY_NAME_LAST IS NOT NULL AND LOWER(IDTY.IDTY_NAME_LAST) = LOWER('MILLER'))
AND (IDTY.IDTY_BIRTH_DATE IS NOT NULL
AND (IDTY.IDTY_BIRTH_DATE BETWEEN TO_DATE('1981-01-01 00:00:00','YYYY-MM-DD HH24:MI:SS')
AND TO_DATE('2000-12-31 23:59:59','YYYY-MM-DD HH24:MI:SS')))
AND (IDTY.IDTY_GENDER IS NOT NULL AND IDTY.IDTY_GENDER = 'M'))) AND ROWNUM<= 300 I know the query looks stupid, but that is generated and we are not to change it.
The exec plan show indexes are used for both table, but cost on PRD are heavier for index RANGE SCAN or BY INDEX ROWID. The index used for table IDTY is a functional index on IDTY.IDTY_NAME_LAST. I rebuild the indexes used but there is no improvement.
What parameters or configuration of database I need to check to find the reason for this case?
Thanks.

Answer 1

Thank you for all your replies. I did found some difference in init parameters and I restarted Oracle on PRD with a parameter file that is most copied from DEV and make the two as the same as possible. Not solve the problem. After noted that both tables involved are set to PARALLEL 4, I did SQL> alter table IDTY parallel 1;
SQL> alter table PERSON_X_IDTY patallel 1; The query plan got worse, but the query returned in a time comparable with DEV. THen I re-set parallelism back to 4 SQL> alter table IDTY parallel 4;
SQL> alter table PERSON_X_IDTY patallel 4; Query performance remained being good.
Now I have a work around, but hope can got an explaination? The parameters related to parallellism areNAME1                           VALUE_PRD                   VALUE_DEV                  
fast_start_parallel_rollback    LOW                         LOW                        
parallel_adaptive_multi_user    TRUE                        TRUE                       
parallel_automatic_tuning       FALSE                       FALSE                      
parallel_degree_limit           CPU                         CPU                        
parallel_degree_policy          MANUAL                      MANUAL                     
parallel_execution_message_size 16384                       16384                      
parallel_force_local            FALSE                       FALSE                      
parallel_io_cap_enabled         FALSE                       FALSE                      
parallel_max_servers            160                         160                        
parallel_min_percent            0                           0                          
parallel_min_servers            0                           0                          
parallel_min_time_threshold     AUTO                        AUTO                       
parallel_server                 TRUE                        FALSE                      
parallel_server_instances       2                           1                          
parallel_servers_target         64                          64                         
parallel_threads_per_cpu        2                           2                          
recovery_parallelism            0                           0