The solution I'm looking for (if it exists) is to directly partition by the actual partition and not by a calculated value.
Table Pseudo-Code:
create table table_1 as (part_col DATE, val_col VARCHAR2(1))
partition by range part_col (
PARTITION t_20160515 VALUES LESS THAN (TO_DATE('2016-05-15','YYYY-MM-DD'))
PARTITION t_20160516 VALUES LESS THAN (TO_DATE('2016-05-16','YYYY-MM-DD'))
...
);
Select Pseudo-Code:
select partition as P, count(*) as C from table_1
group by partition;
Desired Result
P | C
-----------|-----
2016-05-15 | 8
2016-05-16 | 99
Works but not what I'm looking for:
select trunc(part_col) P, count(*) C from table_1;
Run this to generate a set of selects for each partition
SELECT 'SELECT ' || chr(39) || partition_Name || chr(39) || ', count(*)
FROM ' ||table_name ||' partition (' || partition_name ||
') UNION ALL ' as test
FROM all_tab_partitions
WHERE table_Name = 'Table_1'
Results in something like:
SELECT 'P1', count(*) FROM Table_1 partition (P1) UNION ALL
SELECT 'P2', count(*) FROM Table_1 partition (P2) UNION ALL
SELECT 'P3', count(*) FROM Table_1 partition (P3) UNION ALL
SELECT 'P4', count(*) FROM Table_1 partition (P4) UNION ALL
SELECT 'P5', count(*) FROM Table_1 partition (P5) UNION ALL
Copy and paste results removing last union all and then run. Not so sure about performance... I hit a table with 5 partitions and it completed in about 2 sec total rows only around 5 mil.
The query can count the rows in each partition for a given partitioned table as below.
select table_name ,Partition_name,high_value ,
to_number(extractvalue(xmltype(dbms_xmlgen.getxml('select /*+ parallel(a,8) */
count(*) c from '||table_name||' partition ('||partition_name||') a ')),'/ROWSET/ROW/C')) as count
from user_tab_partitions where table_name='LINEORDER';
LINEORDER P1 TO_DATE(' 1900-01-01 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIAN') 0
LINEORDER SYS_P4365 TO_DATE(' 1996-01-01 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIAN') 108
LINEORDER SYS_P4366 TO_DATE(' 1994-01-01 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIAN') 142
LINEORDER SYS_P4367 TO_DATE(' 1995-01-01 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIAN') 186
LINEORDER SYS_P4368 TO_DATE(' 1997-01-01 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIAN') 175
LINEORDER SYS_P4369 TO_DATE(' 1998-01-01 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIAN') 213
LINEORDER SYS_P4370 TO_DATE(' 1993-01-01 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIAN') 128
LINEORDER SYS_P4371 TO_DATE(' 1999-01-01 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIAN') 47
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