How to Find partition name by value ?

Question

hey,
I have a big loading process into a certain fact table. the table is partitioned first by interval on a date column and then sub partitioned by hash. this is a big fact table so there are alot of bitmap indexes on it.
i want to disable all indexes on a specific partition given a certain value of the partition key.
is there any nice good looking way of finding the partition name by value ?
i would realy like to avoid running a loop on the high_value long column in all_tab_partitions
the etl process is running on the entire partition - after finding the partition name i would disable all sub partitions
if i could only do something like...
select $partition_name from some_table for (to_date('01/03/2012','dd/mm/yyyy'));i'm using oracle 11.2.0.2

Answer 1

haki_benita wrote:
now if we want to find the corresponding partition for a given value we need to check for the partition it's high value is greater then thy value and the previous one is lower then.Not necessarily. You can use the CBO to tell you what partition(s) will be used for a SQL statement. E.g.
// partition range table using dates and yearly partitions
SQL> create table testtab(
  2          id      number,
  3          day     date,
  4          flag    varchar2(1)
  5  )
  6  partition by range(day)
  7  (
  8          partition year_1900 values less than (TO_DATE('2000/01/01','yyyy/mm/dd')),
  9          partition year_2000 values less than (TO_DATE('2001/01/01','yyyy/mm/dd')),
10          partition year_2001 values less than (TO_DATE('2002/01/01','yyyy/mm/dd')),
11          partition year_2002 values less than (TO_DATE('2003/01/01','yyyy/mm/dd')),
12          partition year_2003 values less than (TO_DATE('2004/01/01','yyyy/mm/dd')),
13          partition year_2004 values less than (TO_DATE('2005/01/01','yyyy/mm/dd')),
14          partition year_2005 values less than (TO_DATE('2006/01/01','yyyy/mm/dd')),
15          partition year_2006 values less than (TO_DATE('2007/01/01','yyyy/mm/dd')),
16          partition year_2007 values less than (TO_DATE('2008/01/01','yyyy/mm/dd')),
17          partition year_2008 values less than (TO_DATE('2009/01/01','yyyy/mm/dd')),
18          partition year_2009 values less than (TO_DATE('2010/01/01','yyyy/mm/dd')),
19          partition year_2010 values less than (TO_DATE('2011/01/01','yyyy/mm/dd')),
20          partition year_2011 values less than (TO_DATE('2012/01/01','yyyy/mm/dd')),
21          partition year_2012 values less than (TO_DATE('2013/01/01','yyyy/mm/dd'))
22  );
Table created.
// the following can be automated using PL/SQL - e.g. passing the date parameter to
// a PL/SQL function and the function using the following approach to determine the
// target partition
SQL> explain plan
  2          set statement_id = 'partition.testtab.1' for
  3  select * from testtab where day = to_date( '2002/10/09','yyyy/mm/dd' );
Explained.
SQL> col PARTITIONS format a40
SQL> select
  2          column_value    as PARTITIONS
  3  from       TABLE(
  4                  XmlSequence( extract(
  5                          DBMS_XPLAN.Build_Plan_Xml( 'PLAN_TABLE', 'partition.testtab.1' ),
  6                          '/plan/operation/partition'
  7                  )
  8                )
  9          );
PARTITIONS
<partition start="4" stop="4"/>
<partition start="4" stop="4"/>
SQL> select partition_name from user_tab_partitions where table_name = 'TESTTAB' and partition_position = 4;
PARTITION_NAME
YEAR_2002
SQL>