RE: Are hash sub-partitions balanced?
- From: "Bobak, Mark" <Mark.Bobak@xxxxxxxxxxxx>
- To: "oracledbaquestions@xxxxxxxxx" <oracledbaquestions@xxxxxxxxx>, ORACLE-L <oracle-l@xxxxxxxxxxxxx>
- Date: Thu, 2 May 2013 15:31:40 +0000
What is the nature of the column you're partitioning on? How many unique
values does that column have?
-Mark
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Dba DBA
Sent: Thursday, May 02, 2013 11:24 AM
To: ORACLE-L
Subject: Re: Are hash sub-partitions balanced?
Followup. So we loaded some skewed data and tihs is a rolliup from my
sub-partitions spread across several partitions and I this does not appear to
be very well balanced. Is this something I can expect? I am following the power
of 2 with 16 hash sub-partitions. I am also going to get more data loaded.
I just analyzed the table with granularity='ALL'
select subpartition_position,sum(num_rows)
from user_tab_subpartitions
where table_name = '<my table>'
group by subpartition_position
order by 1
/
SUBPARTITION_POSITION SUM(NUM_ROWS)
--------------------- --------------------
1 18,337
2 32,184
3 18,259
4 22,271
5 6,944
6 15,905
7 28,929
8 41,466
9 19,585
10 21,391
11 23,895
12 8,206
13 26,849
14 12,293
15 21,284
16 8,395
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