Partitioning 101

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Partitioning 101
Connor McDonald
Developer Advocate

before we get started
6

Copyright © 2015, Oracle and/or its affiliates. All rights reserved. |7
Dump of memory from 0x07246400 to 0x07248400
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1064B6BF0 C10B02C1 0B06436F 6E6E6F72 C47E0605 [......Connor.~..]
table or index
block size
database version created in
relative block address

why ?
8
...now

version 8.0
9

today...
11

big data
12

What Makes it Big Data?
VOLUME VELOCITY VARIETY VALUE
SOCIAL
BLOG
SMART
METER
1011001010010
0100110101010
1011100101010
100100101

before "Big Data"

before the four V's

Big Data"My is getting too damn !"

the four V'sthe six P's

painful to backup
painful to manage
painful performance
probably partition

Part 1
partitioned tables

range partitioning

2009 2010 2011 2012
SALES

"all applications are (time)
windows on data"
http://thehelsinkideclaration.blogspot.com/

corollary:
everyone can benefit
from (time) range partitions

time the most common

SQL> create table DEMO
2 ( tstamp timestamp(6) not null,
3 empno number(10) not null,
4 ename varchar2(10) not null,
5 deptno varchar2(10) not null
6 )
7 PARTITION BY RANGE (TSTAMP)
8 (
9 PARTITION p01 VALUES LESS THAN
10 ( TIMESTAMP' 2010-01-01 00:00:00'),
12 ( TIMESTAMP' 2010-02-01 00:00:00'),
14 ( TIMESTAMP' 2010-03-01 00:00:00'),
...
...
26 ( TIMESTAMP' 2011-01-01 00:00:00')
27 );
Table created.

SQL> select partition_name pname,
2 partition_position pos,
3 high_value
4 from user_tab_partitions
5 where table_name = 'DEMO';
PNAME POS HIGH_VALUE
----- ---------- -------------------------------
P01 1 TIMESTAMP' 2010-01-01 00:00:00'
P02 2 TIMESTAMP' 2010-02-01 00:00:00'
P03 3 TIMESTAMP' 2010-03-01 00:00:00'
P04 4 TIMESTAMP' 2010-04-01 00:00:00'
P05 5 TIMESTAMP' 2010-05-01 00:00:00'
...

range partition boundaries
29

split by upper bound

PARTITION p01 VALUES LESS THAN
(TIMESTAMP' 2010-01-01 00:00:00'),
PARTITION p02 VALUES LESS THAN
(TIMESTAMP' 2010-02-01 00:00:00'),
January not February
P02 >= 2010-01-01
P02 < 2010-02-01

possible benefits

performance

partition pruning

SQL> set autotrace traceonly explain
SQL> select * from DEMO
2 where TSTAMP = to_date('11-JUN-2010');
---------------------------------------------------------------
| Id | Operation | Name | Rows | Pstart| Pstop |
---------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | | |
| 1 | PARTITION RANGE SINGLE| | 1 | 7 | 7 |
|* 2 | TABLE ACCESS FULL | DEMO | 1 | 7 | 7 |
---------------------------------------------------------------

3 high_value
----- ---------- -------------------------------
P01 1 TIMESTAMP' 2010-01-01 00:00:00'
P02 2 TIMESTAMP' 2010-02-01 00:00:00'
P03 3 TIMESTAMP' 2010-03-01 00:00:00'
P04 4 TIMESTAMP' 2010-04-01 00:00:00'
P05 5 TIMESTAMP' 2010-05-01 00:00:00'
P06 6 TIMESTAMP' 2010-06-01 00:00:00'
P07 7 TIMESTAMP' 2010-07-01 00:00:00'
P08 8 TIMESTAMP' 2010-08-01 00:00:00'
...

more later...

maintenance
add / drop
move
rebuild
backup / read-only
compress
cache control

availability
recovery
partition loss
a little dubious....

multi-column range

SQL> create table SALES_DATA
2 ( yyyy number(4) not null,
3 mm number(2) not null,
4 sales_id varchar2(10) not null,
5 amount number(10)
6 )
7 PARTITION BY RANGE (yyyy, mm)
8 (
9 PARTITION p01 VALUES LESS THAN (2010,02),
10 PARTITION p02 VALUES LESS THAN (2010,03),
11 PARTITION p03 VALUES LESS THAN (2010,04)
...
...
22 )
23 /
Table created.

tiebreaker ...

... not multi dimension

hash partitioning

big stuff is a pain

For younger audience members:
The phone book is an ancient device used by
your ancestors to discover the contact
information for a friend, relative, or business

possible benefits

manageability

move
backup
etc

insertion
performance

less relevant nowadays
for tables

ASSM
automatic
segment
space
management

...but still important
see later

SQL> create table T
2 ( x number(10) )
3 partition by hash ( x )
4 partitions 8
5 /
Table created.

even spread of values

SQL> create table T
2 ( x number(10) )
4 partitions 8
5 /
Table created.
SQL> insert into T
2 select level
3 from dual connect by level <= 100000
4 /
100000 rows created.
1,2,3,4 .... 100000

SQL> select DBMS_ROWID.ROWID_OBJECT(rowid) ptn,
2 count(*)
3 from T
4 group by DBMS_ROWID.ROWID_OBJECT(rowid);
PTN COUNT(*)
---------- ----------
72166 12381
72167 12628
72161 12603
72162 12574
72163 12581
72168 12382
72164 12508
72165 12342

predicting hash target

remember these
63
SQL> select dbms_rowid.ROWID_OBJECT(rowid) ptn,
2 count(*)
3 from T
4 group by dbms_rowid.ROWID_OBJECT(rowid)
5 order by 2;
PTN COUNT(*)
---------- ----------
73535 12342
73536 12381
73538 12382
73534 12508
73532 12574
73533 12581
73531 12603
73537 12628
SQL> select ora_hash(x,7), count(*)
2 from t
3 group by ora_hash(x,7)
4 order by 2;
ORA_HASH(X,7) COUNT(*)
------------- ----------
4 12342
5 12381
7 12382
3 12508
1 12574
2 12581
0 12603
6 12628

the power of 2 rule

SQL> create table T
2 ( x number(10) )
4 partitions 4 | 8 | 16 | 32 ...
5 /
Table created.

why ?

SQL> create table T
2 ( x number(10) )
4 partitions 5
5 /
Table created.
SQL> insert into T
2 select level
4 /

2 count(*)
3 from T
PTN COUNT(*)
---------- ----------
72174 12342
72172 25209
72171 24955
72173 24890
72170 12603
huh ?

deliberately
for maintenance...

Task:
from 5 to 8 partitions

"classical" redistribution

~every row moves

SQL> select count(*)
2 from T
3 where ora_hash(x,4) != ora_hash(x,7);
COUNT(*)
----------
87564
out of 100,000 rows

smart redistribution

2 count(*)
3 from T
PTN COUNT(*)
---------- ----------
72174 12342
72172 25209
72171 24955
72173 24890
72170 12603
5 rows selected.
pick one

SQL> alter table T add partition;
Table altered.
2 count(*)
3 from T
4 group by dbms_rowid.ROWID_OBJECT(rowid);
PTN COUNT(*)
---------- ----------
73515 25209
73516 24890
73517 12342
73519 12381
73518 12574
73513 12603

Table altered.
2 count(*)
3 from T
PTN COUNT(*)
---------- ----------
73516 24890
73517 12342
73519 12381
73518 12574
73521 12628
73520 12581
73513 12603

Table altered.
2 count(*)
3 from T
PTN COUNT(*)
---------- ----------
73517 12342
73523 12382
73522 12508
73519 12381
73518 12574
73521 12628
73520 12581
73513 12603

only 1 partition effort

handling a small number of values

range fiddly....
SQL> create table ...
...
20 values less than ('CAS'),
21 values less than ('MTS'),
22 values less than ('NWFC'),
23 values less than ('TAXJ'),

SQL> select distinct mode
2 from TRANSPORT;
SPORT
------
CAR
MTR
NWFB
TAXI

hash ... poor distribution
SQL> select mode, ora_hash(mode,3) hash
2 from transport;
MODE HASH
------ ----
CAR 3
MTR 3
NWFB 2
TAX 2

list

SQL> create table TRANSPORT
2 ( trans_id varchar2(10) not null,
3 mode varchar2(10) not null,
4 ...
5 )
6 PARTITION BY LIST (mode)
7 (
8 PARTITION P_CAR VALUES ('CAR'),
9 PARTITION P_MTR VALUES ('MTR'),
10 PARTITION P_NWFB VALUES ('NWFB'),
11 PARTITION P_TAXI VALUES ('TAXI'),
12 PARTITION WHO_CARES VALUES ('WALK','RUN',...)
13 )
14 /
Table created.

SQL> create table TRANSPORT
2 ( trans_id varchar2(10) not null,
3 mode varchar2(10) not null,
4 ...
5 )
6 PARTITION BY LIST (mode)
7 (
8 PARTITION P_CAR VALUES ('CAR'),
9 PARTITION P_MTR VALUES ('MTR'),
10 PARTITION P_NWFB VALUES ('NWFB'),
11 PARTITION P_TAXI VALUES ('TAXI'),
12 PARTITION WHO_CARES VALUES (DEFAULT)
13 )
14 /
Table created.

think carefully on DEFAULT
add versus split

sometimes one level is not enough

ranges unevenly distributed

deletion of older data
2009
2010
2011 2012

composite partitions
range + hash
range + list
anything + anything

SQL> create table COMP
6 )
8 SUBPARTITION BY LIST (deptno)
9 (
11 (TIMESTAMP' 2010-01-01 00:00:00')
12 (SUBPARTITION p01_d1 VALUES (1),
13 SUBPARTITION p01_d2 VALUES (2),
15 SUBPARTITION p01_d4 VALUES (4)),
17 (TIMESTAMP' 2010-02-01 00:00:00')
18 (SUBPARTITION p02_d1 VALUES (1),
21 SUBPARTITION p02_d4 VALUES (4)),
.....

31 (TIMESTAMP' 2010-11-01 00:00:00')
32 (SUBPARTITION p01_d1 VALUES (1,2),
33 SUBPARTITION p01_d2 VALUES (3,4),
35 (TIMESTAMP' 2010-12-01 00:00:00')
37 (TIMESTAMP' 2011-01-01 00:00:00')
.....
coalesce / merge

long DDL .....

subpartition templates

6 )
9 SUBPARTITION TEMPLATE
10 (SUBPARTITION d1 VALUES (1),
11 SUBPARTITION d2 VALUES (2),
13 SUBPARTITION d4 VALUES (4))
14 (
16 (TIMESTAMP' 2010-01-01 00:00:00'),
18 (TIMESTAMP' 2010-02-01 00:00:00'),
19 ....
implicit
subpar's

3 high_value
4 from USER_TAB_PARTITIONS
5 where table_name = 'COMP';
---------- ---------- --------------------------------
P01 1 TIMESTAMP' 2010-01-01 00:00:00'
P02 2 TIMESTAMP' 2010-02-01 00:00:00'
P03 3 TIMESTAMP' 2010-03-01 00:00:00'
P04 4 TIMESTAMP' 2010-04-01 00:00:00'
P05 5 TIMESTAMP' 2010-05-01 00:00:00'
...

SQL> select subpartition_name pname,
2 subpartition_position pos,
3 high_value
4 from USER_TAB_SUBPARTITIONS
5 where table_name = 'COMP'
6 order by 1,2;
---------- ---------- ----------------------
P01_D1 1 '1'
P01_D2 2 '2'
P01_D3 3 '3'
P01_D4 4 '4'
P02_D1 1 '1'
P02_D2 2 '2'
...
auto named for
subpar templates

partitions
logical or physical

interval partitioning

the problem with ranges....

... they are a (finite) range

SQL> create table SALES
2 ( cal_year date,
3 txn_id int,
...
...
24 )
25 partition by range ( cal_year )
26 (
27 partition p_low values less than ( date '2000-01-01' ),
28 partition p2000 values less than ( date '2001-01-01' ),
...
...
34 partition p2016 values less than ( date '2017-01-01' )
35 );
Table created.

SQL> insert into SALES
2 values ( trunc(sysdate), .... );
insert into SALES
*
ERROR at line 1:
ORA-14400: inserted partition key does not map to any partition

insurance policy

SQL> insert into DEMO
2 values ( to_date('01-JAN-2014'), .... );
1 row created.
26 (TIMESTAMP' 2011-01-01 00:00:00')
26 PARTITION pmax VALUES LESS THAN
27 (MAXVALUE)
28 );
magic value

why MAXVALUE might hurt
part 1

split not add

SQL> alter table DEMO split partition PMAX
2 at ( TIMESTAMP' 2012-02-01 00:00:00')
3 into ( partition p14, partition pmax )
4 /
Table altered.

index hassles
see later...

a better solution

interval partitioning

6 )
8 INTERVAL( NUMTOYMINTERVAL(1,'MONTH'))
9 (
10 PARTITION P00 VALUES LESS THAN
11 (TIMESTAMP' 2010-01-01 00:00:00')
11 );
Table created.

partitions created as required

SQL> select PARTITION_NAME, HIGH_VALUE
PARTITION_NAME HIGH_VALUE
------------------------- --------------------------------
P00 TIMESTAMP' 2010-01-01 00:00:00'
SQL> insert into DEMO
2 values ( to_date('12-DEC-2011'),....);
SQL> select PARTITION_NAME, HIGH_VALUE
PARTITION_NAME HIGH_VALUE
------------------------- --------------------------------
P00 TIMESTAMP' 2010-01-01 00:00:00'
SYS_P362 TIMESTAMP' 2012-01-01 00:00:00'

gaps allowed

range partition boundaries
119
Length Length Length

partition name control lost

SQL> alter table DEMO partition ??? move;

can rename …

can use FOR syntax

SQL> alter table DEMO partition
2 FOR ( TIMESTAMP' 2012-02-01 05:30:00')
3 move
4 /
Table altered.
not the upper bound

existing range tables ?

convert range to interval

SQL> alter table MY_RANGE_TABLE
2 SET INTERVAL ( NUMTOYMINTERVAL(1,'MONTH') );
Table altered.

SQL> insert into MY_RANGE_TABLE
2 values ( to_date('01-JAN-2017'),....);
1 row created.

3 high_value
5 where table_name = 'MY_RANGE_TABLE';
------------ ---------- --------------------------------
P01 1 TIMESTAMP' 2010-01-01 00:00:00'
P02 2 TIMESTAMP' 2010-02-01 00:00:00'
P03 3 TIMESTAMP' 2010-03-01 00:00:00'
...
P11 11 TIMESTAMP' 2010-11-01 00:00:00'
P12 12 TIMESTAMP' 2010-12-01 00:00:00'
P13 13 TIMESTAMP' 2011-01-01 00:00:00'
SYS_P1091 14 TIMESTAMP' 2017-02-01 00:00:00'

but be careful ...

high range value is a marker

Length Length Length

3 high_value, interval
PNAME POS HIGH_VALUE INTERVAL
------------ ---------- ------------------------------- --------
P01 1 TIMESTAMP' 2010-01-01 00:00:00' NO
P02 2 TIMESTAMP' 2010-02-01 00:00:00' NO
P03 3 TIMESTAMP' 2010-03-01 00:00:00' NO
P04 4 TIMESTAMP' 2010-04-01 00:00:00' NO
...
P13 13 TIMESTAMP' 2011-01-01 00:00:00' NO
SYS_P1112 14 TIMESTAMP' 2016-02-01 00:00:00' YES
SYS_P1111 15 TIMESTAMP' 2017-02-01 00:00:00' YES

SQL> alter table DEMO drop partition P01;
Table altered.
Table altered.
alter table DEMO drop partition P13
*
ERROR at line 1:
ORA-14758: Last partition in the range section
cannot be dropped

fixed in 12.2+

before 12.2 .... "re-range"

SQL> alter table DEMO
2 set interval (NUMTOYMINTERVAL(1,'MONTH'));
Table altered.

why MAXVALUE might hurt
part 2

6 )
8 (
10 (TIMESTAMP' 2010-01-01 00:00:00'),
...
25 partition PMAX values less than (MAXVALUE)
26 )
27 /
Table created.

SQL> alter table DEMO
2 set interval ( NUMTOYMINTERVAL(1,'MONTH') );
*
ERROR at line 1:
ORA-14759: SET INTERVAL is not legal on this table.

12.2, "interval" for lists

automatic lists

SQL> create table PEOPLE
2 (
3 id int,
4 forename varchar2(30),
5 surname varchar2(30),
6 gender varchar2(1)
7 )
8 partition by list (gender) automatic
9 (
10 partition male values ('M'),
11 partition female values ('F')
12 );
Table created. must still be >=1

SQL> insert into PEOPLE
2 values ( 1,'Connor','McDonald','U');
1 row created.
SQL> select partition_name
3 where table_name = 'PEOPLE';
PARTITION_NAME
-------------------------------------------------
FEMALE
MALE
SYS_P661

partitioned tables ...
the bigger picture

2009 2010 2011 2012
SALES
SALES_ITEMS
SQL> desc SALES_ITEMS
Name Null? Type
-------------------- -------- -----------
SALE_ID NOT NULL NUMBER(12)
ITEM_ID NOT NULL NUMBER(12)
...
SQL> desc SALES
Name Null? Type
-------------------- -------- --------------
SALE_DATE NOT NULL DATE
...

reference partitions

SQL> create table PARENT
2 ( dte date not null,
3 pk number(10) not null,
4 pad char(10)
5 )
6 PARTITION BY RANGE (dte)
7 (
8 PARTITION p1 VALUES LESS THAN ( to_date('01-JAN-2010')),
9 PARTITION p2 VALUES LESS THAN ( to_date('01-FEB-2010')),
...
15 PARTITION p8 VALUES LESS THAN ( to_date('01-AUG-2010')),
16 PARTITION p9 VALUES LESS THAN ( to_date('01-SEP-2010'))
17 );
Table created.
SQL> alter table PARENT add primary key ( pk );
Table altered.

SQL> create table CHILD
2 ( p number(10) not null,
3 c number(10) not null,
4 constraint CHILD_FK foreign key ( p )
5 references PARENT (pk)
6 on delete cascade
7 )
8 PARTITION BY REFERENCE (CHILD_FK)
9 /
Table created.

SQL> insert into PARENT
2 select sysdate+rownum, rownum, rownum
4 /
100 rows created.
SQL> insert into CHILD
2 select rownum, rownum
4 /
100 rows created.

SQL> exec dbms_stats.gather_table_stats(user,'CHILD');
SQL> select partition_name, num_rows
2 from USER_TAB_PARTITIONS
3 where table_name = 'CHILD';
PARTITION_NAME NUM_ROWS
------------------------------ ----------
P1 0
P2 0
P3 0
P4 0
P5 9
P6 31
P7 30
P8 30
P9 0

Part 2
indexes on partitioned tables

2009 2010 2011 2012
SALES
SQL> create index SALES_IX on SALES ( CUSTOMER );

2009 2010 2011 2012

global index

big....really big
extended rowid

ILM issues

2009 2010 2011 2012
SQL> alter table SALES drop partition SALES_2009

Table altered.
SQL> select status
2 from user_indexes
STATUS
--------
UNUSABLE
SQL> select * from DEMO where empno = 123;
------------------------------------------------------------
------------------------------------------------------------
| 1 | PARTITION RANGE ALL| | 50 | 1 | 13 |
------------------------------------------------------------

SQL> select value
2 from v$parameter
3 where name = 'skip_unusable_indexes';
VALUE
------------------------------
TRUE

keep the index valid

2009 2010 2011 2012
SQL> alter table SALES drop partition SALES_2009
2 update indexes;

 large delete
redo
undo

much better in 12c+
asynch cleanup

2009 2010 2011 2012

an alternative

local index

2009 2010 2011 2012
SQL> create index SALES_IX ON SALES ( CUSTOMER )
2 LOCAL;

smaller chunks

2009 2010 2011 2012
SQL> alter table SALES drop partition SALES_2009;

SQL> create index DEMO_IX on DEMO ( empno ) LOCAL;
Index created.
SQL> select partition_name, status
2 from user_ind_partitions
PARTITION_NAME STATUS
------------------------------ -------
P01 USABLE
P02 USABLE
P03 USABLE
P04 USABLE
...

Table altered.
SQL> select partition_name, status
2 from user_ind_partitions
PARTITION_NAME STATUS
------------------------------ -------
P01 USABLE
P02 USABLE
P03 USABLE
P05 USABLE
P06 USABLE
P07 USABLE
...

awesome for ILM

handling old data

2009 2010 2011 2012
SQL> alter table SALES move partition SALES_2009
2 COMPRESS;

2009 2010 2011 2012
SQL> alter table SALES move partition SALES_2009
2 TABLESPACE CRAPPY_OLD_DISK;
SQL> alter tablespace CRAPPY_OLD_DISK READ ONLY;
RMAN

combine with deferred segments

2009 2010 2011 2012
SQL> alter index SALES_IX partition SALES_IX_2009
2 UNUSABLE;

or in 12c

2009 2010 2011 2012
SQL> alter table SALES modify partition SALES_2009
2 INDEXING OFF;

or the opposite

2009 2010 2011 2012
SQL> alter table SALES modify partition SALES_2012
2 INDEXING OFF;
2012

handling new data

2010 2011 201220132013
SQL> alter table SALES exchange
2 partition SALES_2013 with
3 table NEW_SALES;

local = goodlocal = good

global = badglobal = bad

nope :-)

different usage models

2009 2010 2011 2012
SQL> select *
2 from SALES
3 where CUSTOMER = 123;
123 123 123 123
SQL> create index SALES_IX on SALES ( CUSTOMER ) LOCAL;

or worse...

2009 2010 2011 2012
SQL> select *
2 from SALES
CAR TAXI
NWFB MTR
CAR TAXI
NWFB MTR
CAR TAXI
NWFB MTR
CAR TAXI
NWFB MTR

explain plan

SQL> select * from SALES
2 where CUSTOMER= 123;
----------------------------------------------------------------------
| Id | Operation | Name |Pstart | Pstop |
----------------------------------------------------------------------
| 1 | PARTITION RANGE ALL | | 1 | 13 |
| 2 | TABLE ACCESS BY LOCAL INDEX ROWID| SALES | 1 | 13 |
|* 3 | INDEX RANGE SCAN | SALES_IX| 1 | 13 |
----------------------------------------------------------------------

2009 2010 2011 2012
SQL> select *
2 from SALES
123123123123
SQL> create index SALES_IX on SALES ( CUSTOMER ) LOCAL;

"so global for index lookups then"....

nope :-)

2009 2010 2011 2012
SQL> select *
2 from SALES
3 where CUSTOMER = 123
4 and YEAR = 2010;
123

careful design

application compromises
eg unique keys

more partitioning options

SALES
SQL> create index SALES_IX ON SALES ( CUSTOMER )
2 global
3 partition by ....

2009 2010 2011 2012
SQL> create index SALES_IX
2 on SALES ( location, empno )
3 global partition by range ( location )
4 ( partition p0 values less than (1),
6 partition p1 values less than (2),
...
12 partition pmax values less than (maxvalue)
13 );

rare ....

...one special case

hash partitioned index

recall: hash partitioned tables

concurrencyASSM

indexes a problem
ascending key

hash partitioned indexes

SQL> create index SALES_PK on SALES( TXN_ID )
2 global partition by hash ( TXN_ID )
3 partitions 8
4 /
Index created.

Part 3
partition queries

partition pruning

query efficiency =
data required /
data scanned

6 )
8 (
10 (TIMESTAMP' 2010-01-01 00:00:00'),
12 (TIMESTAMP' 2010-02-01 00:00:00'),
14 (TIMESTAMP' 2010-03-01 00:00:00'),
...
...
26 (TIMESTAMP' 2011-01-01 00:00:00')
27 );
Table created.
monthly
partitions

SQL> insert /*+ APPEND */ into DEMO
2 select trunc(sysdate,'YYYY')+rownum/( 1000000 / 360 ),
3 rownum,
4 rownum,
5 mod(rownum,1000)
6 from dual
7 connect by level <= 1000000
8 /
1m rows over
360 days

---------------------------------------------------------------
---------------------------------------------------------------
---------------------------------------------------------------

2 where TRUNC(TSTAMP) = to_date('01-JUN-2010');
------------------------------------------------------------
------------------------------------------------------------
| 1 | PARTITION RANGE ALL| | 10000 | 1 | 13 |
------------------------------------------------------------

works with binds too

2 where TSTAMP = :b1;
---------------------------------------------------------------
---------------------------------------------------------------
| 1 | PARTITION RANGE SINGLE| | 1 | KEY | KEY |
|* 2 | TABLE ACCESS FULL | DEMO | 1 | KEY | KEY |
---------------------------------------------------------------

lots of power

2 where TSTAMP between to_date('12-JAN-2010')
3 and to_date('07-FEB-2010')
4 or TSTAMP between to_date('03-JUN-2010')
5 and to_date('06-AUG-2010');
-----------------------------------------------------------
-----------------------------------------------------------
| 0 | SELECT STATEMENT | | 240K| | |
| 1 | PARTITION RANGE OR| | 240K|KEY(OR)|KEY(OR)|
|* 2 | TABLE ACCESS FULL| DEMO | 240K|KEY(OR)|KEY(OR)|
-----------------------------------------------------------

limitations of explain plan

SQL> alter table DEMO move partition P08 tablespace USERS;
Table altered.
SQL> alter tablespace USERS offline;
Tablespace altered.
SQL> select count(*) from DEMO
3 to_date('01-DEC-2010'));
COUNT(*)
----------
1234
July

SQL> select count(*) from DEMO
3 to_date('01-JUL-2010'));
select count(*) from DEMO
*
ERROR at line 1:
ORA-00376: file 4 cannot be read at this time
ORA-01110: data file 4: 'C:ORACLEDB12USERS01.DBF'

interval partition idiosyncracy

INTERVAL = 1 million potential partitions

6 )
8 INTERVAL( NUMTOYMINTERVAL(1,'MONTH'))
9 (
10 PARTITION P00 VALUES LESS THAN
11 (TIMESTAMP' 2010-01-01 00:00:00')
12 );
Table created.

SQL> select * from DEMO; --empty
------------------------------------------------------------
------------------------------------------------------------
| 1 | PARTITION RANGE ALL| | 1 | 1 |1048575|
| 2 | TABLE ACCESS FULL | DEMO | 1 | 1 |1048575|
------------------------------------------------------------

NO OP pruning

--------------------------------------------------------------
--------------------------------------------------------------
| 1 | PARTITION RANGE EMPTY| | 1 |INVALID|INVALID|
|* 2 | TABLE ACCESS FULL | DEMO | 1 |INVALID|INVALID|
--------------------------------------------------------------

pruning composites

6 )
7 PARTITION BY RANGE (tstamp)
9 SUBPARTITION TEMPLATE
10 (SUBPARTITION d1 VALUES (1),
13 SUBPARTITION d4 VALUES (4))
14 (
16 (TIMESTAMP' 2010-01-01 00:00:00'),
18 (TIMESTAMP' 2010-02-01 00:00:00'),
19 ....

SQL> select * from COMP
2 where TSTAMP = to_date('01-JUN-2010')
3 and DEPTNO = 2;
---------------------------------------------------------------
---------------------------------------------------------------
| 2 | PARTITION LIST SINGLE| | 1 | 2 | 2 |
|* 3 | TABLE ACCESS FULL | COMP | 1 | 26 | 26 |
---------------------------------------------------------------

pruning by subquery

SQL> select e.deptno, max(d.empno)
2 from demo d, scott.emp e
3 where d.tstamp = e.hiredate
4 and e.sal < 10000
5 group by e.deptno;
-----------------------------------------------------------------
| Id | Operation | Name | Pstart| Pstop |
-----------------------------------------------------------------
| 1 | HASH GROUP BY | | | |
|* 2 | HASH JOIN | | | |
| 3 | PART JOIN FILTER CREATE | :BF0000 | | |
|* 4 | TABLE ACCESS FULL | EMP | | |
| 5 | PARTITION RANGE JOIN-FILTER| |:BF0000|:BF0000|
| 6 | TABLE ACCESS FULL | DEMO |:BF0000|:BF0000|
-----------------------------------------------------------------

huh ?

bloom filters
243

The Bloom filter...is a space-efficient
probabilistic data structure that is
used to test whether an element is
a member of a set.
- Wikipedia
244

"b" bits
"h" hash functions

b0
b1
b2
b3
b4
b5
b6
b7
h1
h2
h3
data

b0
b1
b2
b3
b4
b6
b7
h1
h2
h3
data
b5

b0
b1
b2
b3
b4
b5
b6
b7
h1
h2
h3
data

b0
b1
b2
b3
b4
b5
b6
b7
h1
h2
h3
matching
data?

b0
b1
b2
b3
b4
b5
b6
b7
h1
h2
h3
matching
data?
do the "real" work

b0
b1
b2
b3
b4
b5
b6
b7
h1
h2
h3
matching
data?

metaphor

"phone in advance"

"Are you serious !? Try in 6 months"

"There's a few seats left..."

false positives possible

false negatives impossible

other partitioning benefits

partition wise join

"big deal"
join the partitions
join the table

our last metaphor :-)

match the pairs

SQL> select ...
2 from SOCKS n, SOCKS s
3 where n.STYLE_SIZE = s.STYLE_SIZE
----------------------------------------------------------------
| Id | Operation | Name | Pstart| Pstop |
----------------------------------------------------------------
|* 1 | HASH JOIN | | | |
| 4 | TABLE ACCESS FULL | WHITE | 1 | 2 |
| 6 | TABLE ACCESS FULL | BLACK | 1 | 2 |
----------------------------------------------------------------

SQL> select d.*, d2.*
2 from DEMO d, DEMO2 d2
3 where d.TSTAMP = d2.TSTAMP;
-------------------------------------------------------------
-------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1003K| | |
| 1 | PARTITION RANGE ALL| | 1003K| 1 | 13 |
|* 2 | HASH JOIN | | 1003K| | |
| 3 | TABLE ACCESS FULL| DEMO | 1000K| 1 | 13 |
| 4 | TABLE ACCESS FULL| DEMO2 | 1000K| 1 | 13 |
-------------------------------------------------------------

wrap up
276

lots of potential ...
277

benefits in many places
278

"yeah but"

the two O's
"Oh crap ... we will need an Outage"

partition existing table
12.2

SQL> create table T as
2 select d.*
3 from dba_Objects d,
4 ( select 1 from dual
5 connect by level <= 20 )
6 where d.object_id is not null;
Table created.
SQL> create index IX on t ( object_id );
Index created.
SQL> create index IX2 on t ( created, object_name );
Index created.

SQL> alter table T modify
2 partition by range (object_id) interval (10000)
3 (
4 partition p1 values less than (20000) compress
5 ) online
6 including rows where created > date '2010-01-01'
7 update indexes
8 ( ix local tablespace new_idx_ts,
9 ix2 global partition by range (created)
10 (
11 partition ix2_p1 values less than (date '2016-08-01'),
12 partition ix2_p2 values less than (maxvalue)
13 )
14 );
Table altered.

did you notice ?
285

SQL> create table HKOUG_PRESENTATION
2 ( ...
3 ...
4 ...
5 )
6 PARTITION BY LIST (topic)
7 (
8 PARTITION PART1 VALUES ('TABLES'),
9 PARTITION PART2 VALUES ('INDEXES'),
10 PARTITION PART3 VALUES ('QUERIES')
11 );
11 /
Table created.

Thank you for your time
youtube tinyurl.com/connor-tube
blog connor-mcdonald.com
twitter @connor_mc_d

Partitioning 101

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