I'm creating a database which will utilize composite partitioning. I will partition one table using range partitioning (by date)
and then further subpartition it by hash (by client id). So far so good, no problem, but I also need to have those partitions
stored in separate data files each dbf holding data for a single month. I'm reading on composite partitions and what I found
is that primary range partitioning will be only a logical one and data will be stored in subpartitions instead which seems to
make my goal impossible. Am I right and should look for a different solution?
Thanks in advance.
My databases are Oracle 11g and Oracle 12
On existing table you can move partitions or subpartitions to a different tablespace, i.e. different datafile, examples:
ALTER TABLE scuba_gear MOVE SUBPARTITION bcd_types TABLESPACE tbs23;
ALTER TABLE parts MOVE PARTITION depot2 TABLESPACE ts094;
see Moving Subpartitions and Moving Table Partitions
For new tables typically you would be create them like this:
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)
INTERVAL (NUMTOYMINTERVAL(1,'MONTH'))
STORE IN (ts_1, ts_2, ts_3, ts_4, ts_5, ts_6 ,ts_7 ,ts_8, ts_9, ts_10, ts_11, ts_12)
SUBPARTITION BY HASH (cust_id) SUBPARTITIONS 4
( PARTITION before_2000 VALUES LESS THAN (TO_DATE('01-JAN-2000','dd-MON-yyyy')));
Oracle then will put the monthly partitions by "round-robin" method to these 12 tablespaces. STORE IN clause is also possible for subpartitions, see Creating a composite range-hash partitioned table
Related
The code below would create a new partition if I would insert a date that does not exist in my table. Is it possible to do the same thing in a list partitioned table, where the partition is based on a VARCHAR2 column?
ALTER TABLE MY_TABLE MODIFY
PARTITION BY RANGE(DATE) INTERVAL(NUMTODSINTERVAL(1,'day'))
( partition MY_PARTITION values less than (to_date('2019-06-01', 'yyyy-mm-dd')));
Yes, it is possible starting from the Oracle 12.2.
See the details here.
I have a scenario in which want to partition an existing Oracle table using interval partitioning. I don't know what is the best approach in the database to do the same.
Table size is around 11 GB. Partitioning needs to be done on Date column with the interval of 1 month.
Recreate the table:
Rename your current table to something like <your-table-name>_OLD
Create a new partitioned table with your original table name.
Insert your table data from the old table to the new table.
Drop the old table.
Precondition: you have the required space available in your database.
And don't forget to recreate all needed constraints etc.
Or use Oracle's online table redefinition mechanism: https://docs.oracle.com/en/database/oracle/oracle-database/12.2/vldbg/evolve-nopartition-table.html#GUID-6054142E-207A-4DF0-A62A-4C1A94DD36C4
If you want only partition the new data and let the old table as one partition you may usi this ismple approach withou reorganisation and required twice space.
0) This is your sample data , ID id the partition column defined up to 10.000
create table my_tab
(id number,
vc1 varchar2(100));
insert into my_tab(id,vc1)
select rownum id, 'xxx'||rownum vc1 from dual connect by level <= 10000;
commit;
1) create empty interval partitione dtable with one partition covering all your data - here ID less then 10.001
create table my_part_tab
(id number,
vc1 varchar2(100))
PARTITION BY RANGE (id)
INTERVAL (1000)
(PARTITION p1 VALUES LESS THAN (10001));
2) Define identical indexes on the partition table as on the original table
3) Exchange your table with the initial partition.
alter table my_part_tab exchange partition P1
with table my_tab
including indexes;
Now your original table is empty and all data are in the partition P1of the partitioned table.
New data (higher keys) would be stored based on the interval partition policy.
I have existing table which has 10 years of data (I have taken dump).
I would like to Range partition the existing table on one date key column within the table.
Most of the examples I see are with CREATE TABLE..PARTITION BY RANGE... to add new partitions. But my table is existing table.
I assume I need some ALTER statement.
ALTER TABLE TABLE_NAME
PARTITION BY RANGE(CREATED_DATE)
PARTITION JAN16 VALUES LESS THAN (01-02-2016),
PARTITION FEB16 VALUES LESS THAN (01-03-2016) AND GREATER THAN(31-01-2016),//OR?
PARTITION MAR16 VALUES BETWEEN (01-03-2016) AND (31-03-2016), //OR?
Two questions..
Do I need Alter statement to add partitioning mechanism or need to work with create statement?
What is the proper syntax for keeping each partition having only ONE MONTH data.
If you are using Oracle 12c Release 2 you could use single ALTER to convert non-partitioned table to partitioned one (this is one way trip):
CREATE TABLE my_tab ( a NUMBER(38,0), b NUMBER(38,0));
ALTER TABLE MY_TAB MODIFY PARTITION BY RANGE (a) INTERVAL (1000) (
PARTITION p1 VALUES LESS THAN (1000)) ONLINE;
You could convert indexes too, adding:
update indexes (index_name [local/global]);
db<>fiddle demo
Beacuse your table non-partitioned you have two options:
Export data, drop table, create new patitioned table, import data.
Use split then exchange partition method. https://oracle-base.com/articles/misc/partitioning-an-existing-table-using-exchange-partition
Also, if you want new partition per month read about SET INTERVAL. For example:
CREATE TABLE tst
(col_date DATE)
PARTITION BY RANGE (col_date) INTERVAL (NUMTOYMINTERVAL(1, 'MONTH'))
(PARTITION col_date_min VALUES LESS THAN (TO_DATE('2010-01-01', 'YYYY-MM-DD')));
I'm working with an Oracle 11g DB that has an input of 3-5m rows a day. In the future I would like to use partitioning based on the column Timestamp. My goal is to create a new partition for every day, automatically.
I just found ways to create a given range of days i.e. 1-20 but not for a unlimited time (01.01.2014 to mm.dd.yyyy).
For daily ranges you can do it like this:
create table ...
...
interval(numtodsinterval(1, 'DAY'))
(
partition log_data_p1 values less than (to_date('22-04-2015', 'DD-MM-YYYY')),
partition log_data_p2 values less than (to_date('23-04-2015', 'DD-MM-YYYY'))
);
Important to use numtodsinterval instead of numtoyminterval
Oracle 11g does offer automatic partition creation, you just need to create table with proper syntax like this one:
create table
pos_data (
start_date DATE,
store_id NUMBER,
inventory_id NUMBER(6),
qty_sold NUMBER(3)
)
PARTITION BY RANGE (start_date)
INTERVAL(NUMTOYMINTERVAL(1, 'MONTH'))
(
PARTITION pos_data_p2 VALUES LESS THAN (TO_DATE('1-7-2007', 'DD-MM-YYYY')),
PARTITION pos_data_p3 VALUES LESS THAN (TO_DATE('1-8-2007', 'DD-MM-YYYY'))
);
Here, two partitions have been defined and an interval of one month has been specified. If date goes beyond the max date specified in partition then oracle automatically creates new partition.
Similarly you can specify partition for day range and oracle will take care of rest.
Apart from the obvious, can anyone explain the what is different between multicolumn partitioning and using a subpartition? And which one is better for a OLTP scenario? For details, see Managing Partitioned Tables and Indexes in the Oracle Database Administrator's Guide.
A (dumb) example of a table partitioned on multiple columns is:
CREATE TABLE demo1
(
year NUMBER,
month NUMBER,
day NUMBER,
instance NUMBER, /* assuming this can only be 1 or 2 */
other1 VARCHAR2(50),
other2 VARCHAR2(50),
other3 VARCHAR2(50)
)
PARTITION BY RANGE (year,instance)
(
PARTITION data_2009_inst1 VALUES less than (2009,2) TABLESPACE data_2009,
PARTITION data_2009_inst2 VALUES less than (2009,3) TABLESPACE data_2009,
PARTITION data_2010_inst1 VALUES less than (2010,2) TABLESPACE data_2010,
PARTITION data_2010_inst2 VALUES less than (2010,3) TABLESPACE data_2010,
PARTITION data_2011_inst1 VALUES less than (2011,2) TABLESPACE data_2011,
PARTITION data_2011_inst2 VALUES less than (2011,3) TABLESPACE data_2011
);
Similarly, example of a subpartitioned table is:
CREATE TABLE demo2
(
year NUMBER,
month NUMBER,
day NUMBER,
instance NUMBER, /* assuming this can only be 1 or 2 */
other1 VARCHAR2(50),
other2 VARCHAR2(50),
other3 VARCHAR2(50)
)
PARTITION BY RANGE (year)
SUBPARTITION BY LIST (instance) /* Cannot subpartition by range in 10gR2 */
SUBPARTITION template
(
SUBPARTITION i1 VALUES (1),
SUBPARTITION i2 VALUES (2),
SUBPARTITION ix VALUES (DEFAULT)
)
(
PARTITION data_2009 VALUES less than (2010) TABLESPACE data_2009,
PARTITION data_2010 VALUES less than (2011) TABLESPACE data_2010,
PARTITION data_2011 VALUES less than (2012) TABLESPACE data_2011
);
Now what is the difference between these tables? Are they not "logically" the same? I know its far easier to add partitions to demo2 as you need to split partitions on demo1 to get more partitions as time passes by. Which on is better in an OLTP scenario?
On a side note, the reason I am partitioning on the INSTANCE number has to do with Oracle RAC. I am trying to create an "instance affinity" to stop "hot block" from slowing down the database as these need be sent across the interconnect between the RAC nodes. (We have empirically proved that this does make a difference in our testing).
There probably isn't any difference in your case, but in general sub-partitioning allows you to partition in 2 different ways, such as range-hash, range-list. Your sub-partition example is range-list, but equivalent to the single-level range partitioning. However, you could not use a single-level if your sub-partitioning was like this example from the doc you linked:
ALTER TABLE quarterly_regional_sales
ADD PARTITION q1_2000 VALUES LESS THAN (TO_DATE('1-APR-2000','DD-MON-YYYY'))
STORAGE (INITIAL 20K NEXT 20K) TABLESPACE ts3 NOLOGGING
(
SUBPARTITION q1_2000_northwest VALUES ('OR', 'WA'),
SUBPARTITION q1_2000_southwest VALUES ('AZ', 'UT', 'NM'),
SUBPARTITION q1_2000_northeast VALUES ('NY', 'VM', 'NJ'),
SUBPARTITION q1_2000_southeast VALUES ('FL', 'GA'),
SUBPARTITION q1_2000_northcentral VALUES ('SD', 'WI'),
SUBPARTITION q1_2000_southcentral VALUES ('OK', 'TX')
);
One advantage of sub-partitions is that they allow individual fine-grained management of the sub-partitions. For example in a data archive table lets say there are different retention requirements based not only on the date, but another value as well.
Using your example perhaps you are required to keep data with value instance = 1 for 7 years, but data with instance = 2 can be discarded after 4 years. Sub-partitioning would allows you to drop the sub-partitions containing data with instance = 2 independently of the other values.