| Partitioning question [message #64582] |
Thu, 10 February 2005 07:54  |
Troy
Messages: 10
Registered: October 2000
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Junior Member |
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I've got a group of large tables that are range partitioned by a value, we'll call it Market. When the database was created, the group that defined the table made a mistake in defining the high value for each partition, and now the data is badly distributed amongst the partitions, like so:
PARTITION_NAME HIGH_VALUE NUM_ROWS
P1 '108' 9333270
P2 '165' 49359450
P3 '166' 3269760
...
P10 '430' 22351795
P11 '450' 6580400
P12 '550' 19690075
P13 '560' 194850
P14 '604' 21942905
...
Now what I want to do is this: In partitions such as P13 I want to increase the high value by 1 so that all the records with '560' that currently reside in P14 actually go to P13 where they belong. My question is what is the best way to do this, and if the partition ranges are changed will Oracle migrate the rows without being told? What is the I/O like on this operation? Any better ways to do it that I'm not thinking of?
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| Re: Partitioning question [message #64584 is a reply to message #64582] |
Thu, 10 February 2005 12:48  |
Sanjay Bajracharya
Messages: 279
Registered: October 2001
Location: Florida
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Senior Member |
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I would suggest you read on "splitting" a partition. There is nothing like "increasing the high value" as far as I know.
example: say splitting p14 and making a P13B with HIGH of say 580, and the original P14
this will make
P11 '450' 6580400
P12 '550' 19690075
P13 '560' 194850
P13B '580' *** NEW
P14 '604' 21942905
This will split P14 into P13B and P14 and the 21 mill rows will be split.
I use partition for our data, but we planned from the beginning (careful planning). We go by regions, so data is mis-balanced, but then we did expect that...like south-east has more data than west.
Before I go, I had to ask...will you be able to recreate the whole MARKET table ?? I assume you have tons of data, something like 75 mill....just a guess. Will be a whole weekend project or something like that, and mainly will you be able to have the system down to do this ??
Good luck.
--
Sanjay
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