Partitioning existing tables

hello everyone,
I've to partition an existing table.
On searching net I found below example @ AskTom
It created a new table T2 and used DBMS_REDEFINITION package
I now have doubts regarding the same:
- What happens to existing table (here, T1)
- Does data also gets copied to T2
- Or why can't oracle provide us with something like 'alter table add List | range | hash partition ... ;
Thanks,
Rossy.Rocs

Hi,
- What happens to existing table (here, T1)
- Does data also gets copied to T2
- Or why can't oracle provide us with something like 'alter table add List | range | hash partition ... ;Refer to the link,
http://www.dba-oracle.com/oracle_news/2004_3_9_rittman.htm
and you can go for "EXCAHNGE PARTITION"
http://www.oracle-base.com/articles/8i/PartitionedTablesAndIndexes.php
- Pavan Kumar N
Oracle 9i/10g - OCP
http://oracleinternals.blogspot.com/

Similar Messages

Range Partitioning Existing table

Hi,
I have a table with numeric field. I want to range partition the existing table. I used the following query
alter table dept add partition by range(deptno) (
partition p1 values less than (20),
partition p1 values less than (40))
It gives me ORA-00902: invalid datatype.
What am I doing wrong? Is it possible to partition an existing table?
Regards,
Subbu S.

Hi,
You cannot partition an existing table with an ALTER TABLE command. There are couple of techinques with which you can partition an existing table, like:
1) Rename existing table, create a new partitoned table and move data.
2) Using DBMS_REDEFINITION package.
Have a look at the following links for details:
http://www.oracle-base.com/articles/misc/PartitioningAnExistingTable.php
http://www.dba-oracle.com/oracle_news/2004_3_9_rittman.htm
Regards
Asif Momen
http://momendba.blogspot.com

Partition Existing Table

Is it possibel add partitions an existing table that does not have any partions? If so what would the syntax look like. I have been racking my brain trying to do it. Probably long enough were I should have just created a new table with partitions and loaded the data too it. Now I am just curious

There is no ALTER TABLE....PARTITION BY HASH/RANGE/ETC syntax, you will have to create the table from scratch

I have partitioned my tables, do I need to rebuild the indexes of the table

Hello,
I have partition very huge tables, by using rage partition method. After that few queries taking more time than before. Does the old indexes needs to rebuild?
Thanks

929941 wrote:
Hello,
I have partition very huge tables, by using rage partition method. After that few queries taking more time than before. Does the old indexes needs to rebuild?
ThanksWhat do you think?
By the way, how did you partition existing tables? Did you use dbms_redefinition, or did you use CTAS, or some other method?
I love RAGE partitions. You should always always partition your rage.

Can we create partitions in an existing table?

Hi,
Can we create partitions in an existing table which has about a million rows? I am using oracle 9i database.
Can any one suggest me on this please.

07b3ea8e-c4c5-4559-9055-ed38853dc64e wrote:
Hi,
Can we create partitions in an existing table which has about a million rows? I am using oracle 9i database.
Can any one suggest me on this please.
can NOT be done.
research DBMS_REDEFINITION

Best way to change partition key on existing table

Hi,
Using Oracle 11.20.3 on AIX.
We have a table about 800 million rows and 120gb in size.
Want to try copies oif this table to evalaute different partitiong strategies.
What is the quickest way to do this?
Would have liked say datapump table 1 tro disk and datapumo import the data to new table but do the tables need to be of the same format.
Thanks

>
Using Oracle 11.20.3 on AIX.
We have a table about 800 million rows and 120gb in size.
Want to try copies oif this table to evalaute different partitiong strategies.
What is the quickest way to do this?
Would have liked say datapump table 1 tro disk and datapumo import the data to new table but do the tables need to be of the same format.
>
First your subject asks a different question that the text you posted: Best way to change partition key on existing table. The answer to that question is YOU CAN'T. All data has to be moved to change the partition key since each partition/subpartition is in its own segment. You either create a new table or use DBMS_REDEFINITION to redefine the table online.
Why do you want to export all data to a file first? That just adds to the time and cost of doing the op.
What problem are you trying to use partitioning to solve? Performance? Data maintenance? For performance the appropriate partitioning key and whether to use subpartitions depends on the types of queries and the query predicates you typically use as well as the columns that may be suitable for partition keys.
For maintenance a common method is to partition on a date by year/month/day so you can more easily load new daily/weekly/monthly data into its own partition or drop old data that no longer needs to be kept online.
You should use a small subset of the data when testing your partitionings strategies.
Can you do the partitioning offline in an outage window? If not then using the DBMS_REDEFINITION is your only option.
Without knowing what you are trying to accomplish only general advice can be given. You even mentioned that you might want to use a different set of columns than the curren table has.
A standard heap table uses ONE segment for its data (ignoring possible LOB segments). A partitioned/subpartitioned table uses ONE segment for each partition/subpartition. This means that ALL data must be moved to partition the table (unless you are only creating one partition).
This means that every partitioning scheme that uses a different partition key requires ALL data to be moved again for that test.
Provide some information about what problem you are trying to solve.
>
Is this quicker than datapump?
>
Yes - exporting the data simplying moves it all an additional time. Ok to export if you need a backup before you start.
>
Found artcle which talks about using merge option on datapump import to convert partitioned table to non-partitioned table.
>
How would that apply to you? That isn't what you said you wanted to do.

Creating Partitions in Existing tables with Data

Hello everyone,
I want to know what the best way of creating partitions, in tables having data, is .. ???
thanks
Rossy Rocs

There are two ways :
1a Create a new Partitioned Table
1b Copy data from the existing table to the new table
1c Create Indexes
1d Rename old table
1e Rename new table
OR
2 Use DBMS_REDEFINITION
See
http://www.oracle-base.com/articles/misc/PartitioningAnExistingTable.php
Hemant K Chitale

Suggestions for table partition for existing tables.

I have a table as below. This table contains huge data. This table has so many child tables .I am planning to do a 'Reference Partitioning' for the same.
create table PROMOTION_DTL
PROMO_ID              NUMBER(10) not null,
EVENT                 VARCHAR2(6),
PROMO_START_DATE      TIMESTAMP(6),
PROMO_END_DATE        TIMESTAMP(6),
PROMO_COST_START_DATE TIMESTAMP(6),
EVENT_CUT_OFF_DATE    TIMESTAMP(6),
REMARKS               VARCHAR2(75),
CREATE_BY             VARCHAR2(50),
CREATE_DATE           TIMESTAMP(6),
UPDATE_BY             VARCHAR2(50),
UPDATE_DATE           TIMESTAMP(6)
alter table PROMOTION_DTL
add constraint PROMOTION_DTL_PK primary key (PROMO_ID);
alter table PROMOTION_DTL
add constraint PROMO_EVENT_FK foreign key (EVENT)
references SP_PROMO_EVENT_MST (EVENT);
-- Create/Recreate indexes
create index PROMOTION_IDX1 on PROMOTION_DTL (PROMO_ID, EVENT)
create unique index PROMOTION_PK on PROMOTION_DTL (PROMO_ID)
-- Grant/Revoke object privileges
grant select, insert, update, delete on PROMOTION_DTL to SCHEMA_RW_ROLE;I would like to partition this table .Most of the queries contains the following conditions.
promo_end_date >=   SYSDATE
and
(event = :input_event OR
(:input_Start_Date <= promo_end_date
AND promo_start_date <= :input_End_Date))Any time the promotion can be closed by updating the PROMO_END_DATE.
Interval partioning on PROMO_END_DATE is not possible as PROMO_END_DATE is a nullable and updatable field.
I am now to table partition.
Any suggestions are welcome...

DO NOT POST THE SAME QUESTION IN MULTIPLE FORUMS PLEASE!
Suggestions for table partition of existing tables

Logical type Partition of an existing table

Dear All,
My database is 10gR2 and Linux is the operating system.
One of my table in production database is huge and contains lot of data. Table is growing on daily basis. There are many queries that users execute on this table and the criteria of selection is normally entry date of the record, its a field Entrty_Date with date datatype.
I want logical partition on this table in such a way, that the table name remains the same, and data is partitioned logically.
Like if the Entry_Date is starting from 2005, a partition is made on the criteria:
2005-2006
2006-2007
2011When user query for records having entry date > 2011... the query is made only this chunk of the table, making the query fast.
I hope I am able to make you understand my problem. If its possible in Oracle please let me know the name of the method and I will RND on this one. And I have to do it on existing table that contains lot of data.
Thanks,
Imran

For example:
CREATE TABLE sales
( prod_id NUMBER(6)
, cust_id NUMBER
, time_id DATE
, channel_id CHAR(1)
, promo_id NUMBER(6)
, quantity_sold NUMBER(3)
, amount_sold NUMBER(10,2)
PARTITION BY RANGE (time_id)
( PARTITION sales_q1_2006 VALUES LESS THAN (TO_DATE('01-APR-2006','dd-MON-yyyy')) TABLESPACE tsa
, PARTITION sales_q2_2006 VALUES LESS THAN (TO_DATE('01-JUL-2006','dd-MON-yyyy')) TABLESPACE tsb
, PARTITION sales_q3_2006 VALUES LESS THAN (TO_DATE('01-OCT-2006','dd-MON-yyyy')) TABLESPACE tsc
, PARTITION sales_q4_2006 VALUES LESS THAN (TO_DATE('01-JAN-2007','dd-MON-yyyy')) TABLESPACE tsd
);

How to create a partition on existing table?

Hey
Could some one please tell me on how to create a partition on existing table?

Could some one please tell me on how to create a partition on existing table?
You can't - that isn't possible. Unless a table is already partitioned you can NOT create another partition on it.
You must either redefine the table as a partitioned table (using the DBMS_REDEFINITION package) or create a new partitioned table and move the data to its new partitions.
The choice will depend on how much data the existing table has and whether you can do it offline.

How to add create partition to an existing table?

hi,
please tell me how to add partition to an existing table.
i have tried
alter table mvr add partition sno
but getting error : ORA-14501: object is not partitioned
thanks.

Just Googling for ora-14501 resulted in the following
Adding a partition results in ORA-14501: object is not partitioned
It is really sad you can not do this on your own, and always need someone to do this for you.
Sybrand Bakker
Senior Oracle DBA

Can we addnew partition and sub partition in the existing table in one shor

can we addnew partition and sub partition in the existing table in one short

nav wrote:
can we addnew partition and sub partition in the existing table in one shortYes,
You can and below is the example for Range-List partition
ALTER TABLE <table_name>
   ADD PARTITION <partition_name> VALUES LESS THAN (<value>
      STORAGE (INITIAL 20K NEXT 20K) TABLESPACE <TS name> NOLOGGING
          SUBPARTITION Clause
          SUBPARTITION Clause
          SUBPARTITION Clause
          SUBPARTITION Clause
           );

What's the best practice to partition an existing table?

We are using Oracle 11g EE 11.2.0.3.0. We want to partition an existing table. I found some information from this link [http://www.oracle-base.com/articles/misc/partitioning-an-existing-table.php], but I am not sure whether that's the best way. Could anyone share the best practice of partitioning an existing table?
Thanks.
Jun

>
We want to partition a few related tables. A couple of tables have about 30 million rows, and a couple of other tables have about 10 million rows. The data for those tables is for ~2000 accounts, each of them is identified by a column named "account_id". We want to partition the tables by using the "account_id" as the partition key to gain better performance for queries, so we would probably use hash partition. Please advise.
>
1. What evidence do you have that your performance will be any better if you partition those tables?
2. What evidence do you have that there is anything wrong with the performance of your current queries?
3. Have you reviewed the actual execution plans for your most important queries to see if there is even any room for improvement?
If your query uses account_id as a predicate but only pulls a few records from a 'master' table for that key value your performance may actually be worse if you partition that table. That is because using an index range scan Oracle can easily find the ROWIDs of the rows that need to be selected and then easily retrieve them regardless of their physical location.
If you have queries that do NOT use account_id but currently use indexes the performance of those queries may also be worse if you partition that table. Those indexes will be GLOBAL.
There are two major implications when you use hash partitioning:
1. Any query that does NOT include the partitioning key (account_id for your case) will, of necessity, have to use a full table scan if an appropriate index is not available.
2. You will get NO management benefits such as being able to add/remove partitions that include old data.
Before you decide to partition a table you should conduct tests and examine the execution plans for your important queries.

Oracle partitioning - change in existing tables

I recently started working with legacy code and noticed that some huge tables (5 years worth of data, don't have more details on me right now but can post later if needed) are partitioned based on time sequence number column while majority of queries are done based on time (different column). Queries performance is degrading over time and I'd like to try to modify partitioning and run some tests to see if there is a performance improvement.
My only concern is this is a lot of data and they are all live, so I have to come up with some sort of solution on how to switch partitioning with the least impact on applications running 24 x 7.
Can someone suggest a viable solution? Something you have done in the same situation and it worked?
If there is a certain technique on how to do it, please give me search keywords and I will google the rest.
Thanks,
S.

You can't change the partitioning of an existing table.
You can, however, use the DBMS_REDEFINITION package to do an online redefinition. Behind the scenes, what you're really doing is
- Creating a new table with the new partitioning scheme
- Copying the data from the old table to the new table
- Dropping the old table
- Renaming the new table to the name used by the old table
Now, if the large table is only being queried, not updated (or at least you have a window where it is read-only), it's probably easier to just do these steps manually rather than using DBMS_REDEFINITION where you at least have finer grained control over the steps. You'll still need a moment where the table is inaccessible to do the actual rename.
Justin

Partitioning an Existing Table with data

Hi All,
I am few tables with data, I need to Partition the table without affecting existing table values is it possible?.
if yes then Please suggest me some ideas to archive that..
Thanks & Regards
Sami

Hi All,
I Need to partition for existing table with 1 million records
1. First partition should be created for 6 months
2.Second partition should created for 1 year.
3.So as of now we have 6 months Data in production + another 6 months data in First partition + another 1 year data in Second partition.
4.More than 2 year’s data’s should be moved other partition or archived.
kindly provide your valuabe suggestion.
Thanks & Regards
Sami

Partitioning existing tables

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