12 Things About 12c Release 2 for Developers

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WE
ARE
SHOWING
CODING SAMPLES
SO IF YOU HAVE PASSED
THE AGE OF TWENTY THEN YOU SHOULD PROBABLY THINK
ABOUT SITTING RIGHT UP CLOSE TO THE FRONT OF THE ROOM BECAUSE OTHERWISE YOU MIGHT MISS OUT
A N D I F Y O U C A N R E A D T H I S, T H E N Y O U S H O U L D L E A V E B E C A U S E Y O U H A V E S U P E R P O W E R S A N D Y O U S H O U L D B E I N A N A V E N G E R S M O V I E N O T L E A R N I N G A B O U T I N F O R M A T I O N T E C H N O L O G Y. :-)

@connor_mc_d connormcdonald.wordpress.com

https://www.youtube.com/c/ConnorMcDonaldOracle
https://www.facebook.com/connor.mcdonald42

12 things Devs will love about 12.2
Connor McDonald
Developer Advocate
November 2017

why me ?

https://asktom.oracle.com

18c

why you ?

12.2!12.2!
12.2!12.2!
12.2!

reality
18

SQL> select * from v$version;
BANNER
----------------------------------------------------------
Oracle8i Enterprise Edition Release 8.1.7.4.0 - Production
PL/SQL Release 8.1.7.4.0 - Production
CORE 8.1.7.0.0 Production
TNS for HPUX: Version 8.1.7.4.0 - Production
NLSRTL Version 3.4.1.0.0 - Production

BANNER
----------------------------------------------------------

you still should be here
23

there's a lot in 12.2

get started right now

install nothing

https://cloud.oracle.com/tryit

install something

http://tinyurl.com/ora122vm

install lots :-)

http://www.oracle.com/technetwork/database/enterprise-edition/downloads/index.html

before we get started

Safe Harbor Statement
The following is intended to outline our general product direction. It is intended for
information purposes only, and may not be incorporated into any contract. It is not a
commitment to deliver any material, code, or functionality, and should not be relied upon
in making purchasing decisions. The development, release, and timing of any features or
functionality described for Oracle’s products remains at the sole discretion of Oracle.
35

test ! Test ! TEST !

licensing

time is short ...

asktom.oracle.com

longer names

128 bytes

cool

SQL> create table MY_TABLE
2 (
3 LONGER_COLUMNS_ARE_BETTER_BECAUSE_THEY_GIVE_MORE_MEANING DATE
4 );
Table created.

the ol' days

"can I get a CSV of the chart of accounts?"

SQL> select table_name
2 from user_tables;
TABLE_NAME
------------------------------
T001B
T003
T004
T009
T010O
T010P
T012
T014
T077S
T880
…
Permitted Posting Periods
Document types
Chart of accounts
Fiscal year variants
Posting periods
Posting Period Names
House banks
Credit control area
Account group (G/L accounts)
Global company data
...

and...

SQL> create table FINALISED_ANNUAL_BUDGET_STATS
2 ( budget_seq int,
3 fiscal_year int,
...
...
24 );
Table created.
SQL> alter table FINALISED_ANNUAL_BUDGET_STATS
2 add constraint FINALISED_ANNUAL_BUDGET_STATS_PK
3 primary key ( budget_seq );
add constraint FINALISED_ANNUAL_BUDGET_STATS_PK
*
ERROR at line 2:
ORA-00972: identifier is too long

but...

SQL> create table MY_TABLE
2 (
3 "SomeRidiculousPieceOfNonsenseBySomeDude
WhoWantsToAlignTheDatabaseWithHisDotNetCodingStyle" DATE
4 );
Table created.
SQL> select column_name,num_distinct,avg_col_len, num_nulls
2 from all_tab_cols
3 where table_name = upper('&table_name')
4 order by column_id;
Enter value for table_name: MY_TABLE
COLUMN_NAME
------------------------------
SomeRidiculousPieceOfNonsenseBySomeDudeWhoWantsToAlignWithHisDotNetCodi
ngStyle NUM_DISTINCT AVG_COL_LEN NUM_NULLS
------------ ----------- ----------

have some fun :-)

SQL> create or replace
2 trigger ddl_trigger
3 before create or alter on demo.SCHEMA
4 declare
5 l_obj varchar2(128);
6 l_power int;
7 begin
8 l_obj := ora_dict_obj_name;
9
10 select count(*)
11 into l_power
12 from dba_role_privs
13 where grantee = user
14 and granted_role = 'SENIOR_DEV';
15
16 if l_power = 0 and length(l_obj) > 30 then
17 raise_application_error(-20000,'Identifier "'||l_obj||'" is too long');
18 end if;
19 end;
Trigger created.

SQL> conn junior_dev/junior_dev@db122pdb
Connected.
SQL> create table EMPLOYEES ( empno int , dept int);
Table created.
SQL> create table EMPLOYEE_RATINGS_BENEFITS_BEFORE_SALARY_REVIEW
2 ( empno int, dept int );
create table EMPLOYEE_RATINGS_BENEFITS_BEFORE_SALARY_REVIEW
*
ERROR at line 1:
ORA-04088: error during execution of trigger 'CONNOR.DDL_TRIGGER'
ORA-00604: error occurred at recursive SQL level 1
ORA-20000: Identifier "EMPLOYEE_RATINGS_BENEFITS_BEFORE_SALARY_REVIEW" is too long
ORA-06512: at line 16

SQL> conn connor/*******@db122pdb
Connected.
SQL> alter table DEMO.EMPLOYEES add
2 constraint EMPLOYEES_CROSS_DIVISION_DEPARTMENTS_FK foreign key
3 ( dept ) references DEMO.CROSS_DIVISION_DEPARTMENTS ( dept ) ;
Table altered.

PL/SQL resolved expressions

longer names

2 procedure process_tab is
3 l_tab varchar2(30);
4 begin
5 select table_name
6 into l_tab
7 from user_tables
8 where ...

SQL> exec process_tab;
ORA-06502: PL/SQL: numeric or value
error: character string buffer too
small

12.2

expression in place of literal

SQL> declare
2 c_var_length constant pls_integer := 30;
3 l_str varchar2(c_var_length);
4 begin
5 null;
6 end;
7 /
PL/SQL procedure successfully completed.

must be resolvable at compile time
SQL
function

SQL> declare
2 c_var_length constant pls_integer := to_number('30');
4 begin
5 null;
6 end;
7 /
l_str varchar2(c_var_length);
*
ERROR at line 3:
ORA-06550: line 3, column 25:
PLS-00491: numeric literal required

SQL> declare
2 c_var_length constant pls_integer := 30;

3 l_str varchar2(ora_max_name_len);
4 begin

start today

3
4 $if DBMS_DB_VERSION.VER_LE_12_1 $then
5 l_str varchar2(30);
6 $else
7 l_str varchar2(ora_max_name_len);
8 $end
9
10 begin

"Wasn't I just supposed to use ..."

user_tables.table_name%type

Yes ... but

3 l_str varchar2( );
4 begin
5 select owner||'.'||table_name
6 into l_str
7 from all_tables
8 where ...
9
?

3 l_str varchar2(2*ora_max_name_len+1);
4 begin
5 select owner||'.'||table_name
6 into l_str
7 from all_tables
8 where ...
9

So ... let's try that again

longer names

compile time resolvable sizes

SQL> desc STORE_SALES
Name Type
--------------------------------------------------------------------------------- ----------
SALES_PK NUMBER(38)
DATE_AT_WHICH_CUSTOMER_CAME_INTO_THE_STOP DATE
DATE_AT_WHICH_CUSTOMER_CAME_LEFT_THE_STOP DATE
DURATION_CUSTOMER_SPENT_BROWSING_SALES_CATALOG_BEFORE_ASKING_FOR_ASSISTANCE_MINS NUMBER(38)
ITEM_THAT_CUSTOMER_PURCHASED VARCHAR2(50)
AMOUNT_CUSTOMER_TENDERED_TO_CASHIER_IN_50DOLLAR_NOTES NUMBER(38)
AMOUNT_CUSTOMER_TENDERED_TO_CASHIER_IN_COINS_IN_TOTAL_CENTS NUMBER(38)
LENGTH_IN_MILLIMETERS_OF_THE_RECEIPT_WE_PRINTED_FOR_THE_CUSTOMER NUMBER(38)
AVERAGE_LENGTH_OF_SHOELACE_OF_STORE_ASSISTANT_THAT_HELPED_THE_CUSTOMER NUMBER(38)
...
...
...

SQL> select table_name,
2 listagg(column_name, ',') within group
3 (order by column_id) cols
4 from user_tab_columns
5 group by table_name;
*
ERROR at line 1:
ORA-01489: result of string concatenation is too long

tough to solve

SQL> select
2 column_name,
3 ( select listagg(column_name,',') within group ( order by column_id )
4 from all_tab_columns
5 where table_name = 'EMP'
6 and owner = 'SCOTT'
7 and column_id <= a.column_id ) cols
8 from all_tab_columns a
9 where table_name = 'EMP'
10 and owner = 'SCOTT'
11 order by column_id;
COLUMN_NAME COLS
------------------------------ ----------------------------------------------------
EMPNO EMPNO
ENAME EMPNO,ENAME
JOB EMPNO,ENAME,JOB
MGR EMPNO,ENAME,JOB,MGR
HIREDATE EMPNO,ENAME,JOB,MGR,HIREDATE
SAL EMPNO,ENAME,JOB,MGR,HIREDATE,SAL
COMM EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM
DEPTNO EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO
8 rows selected.

first principles
pipeline function

12.2

improved overflow handling

2 listagg(column_name, ',' on overflow truncate)
3 within group (order by column_id) cols
TABLE_NAME COLS
------------- ------------------------------------------------------------
STORE_SALES SALES_PK,DATE_AT_WHICH_CUSTOMER_CAME_INTO_THE_STOP,DATE_AT_W
HICH_CUSTOMER_CAME_LEFT_THE_STOP,DURATION_CUSTOMER_SPENT_BRO
WSING_SALES_CATALOG_BEFORE_ASKING_FOR_ASSISTANCE_IN_MINS,ITE
,LENGTH_IN_MILLIMETERS_OF_THE_RECEIPT_WE_PRINTED_FOR_THE_CUS
[snip]
TIME_SPENT_WHILST_REFOLDING_ITE...(2378)

plus you get control

2 listagg(column_name, ',' on overflow truncate '[more]')
TABLE_NAME COLS
------------- ------------------------------------------------------------
[snip]
TIME_SPENT_WHILST_REFOLDING_ITE[more](2378)

2 listagg(column_name,','
3 on overflow truncate '[more]' without count)
TABLE_NAME COLS
------------- ------------------------------------------------------------
[snip]
TIME_SPENT_WHILST_REFOLDING_ITE[more]

2 listagg(column_name,','
3 on overflow truncate '' without count)
TABLE_NAME COLS
------------- ------------------------------------------------------------
[snip]
TIME_SPENT_WHILST_REFOLDING_ITE

QTFWBC

queries that finish without bloody crashing

SQL> insert into MY_TABLE
2 select *
3 from MY_WHOPPING_GREAT_FAT_TABLE;
100
MY_WHOPPING_GREAT_FAT_TABLE;

2 select *
Elapsed: 06:12:34.00
106

2 select *
Elapsed: 06:12:34.00
ERROR at line 1:
ORA-01847: day of month must be between 1 and last day of month
107

ooooooo
o !

and then we do this :-)

SQL> select count(*) from MY_TABLE;
COUNT(*)
----------
0
111

12.2

validate_conversion

SQL> select CREATED_DATE
CREATED_DATE
--------------------
01-FEB-2016
12-MAR-2012
54-AUG-2013
09-SEP-2014
23-OCT-2012
...
...
114

SQL> select to_date(created_date, 'dd-mon-yyyy')
2 from MY_WHOPPING_GREAT_FAT_TABLE
3 where validate_conversion(
4 created_date as date, 'dd-MON-yyyy'
5 ) = 1;
TO_DATE(C
---------
01-FEB-16
12-MAR-12
09-SEP-14
23-OCT-12
115

CAST extended

SQL> select SALARY,
2 cast(SALARY as number
3 DEFAULT -1 ON CONVERSION ERROR) conv_sal
SALARY CONV_SAL
---------- ----------
120000 120000
172125 172125
128000 128000
125,000 -1
99500 99500
...
...
117

SQL> select SALARY,
2 TO_NUMBER(SALARY
3 DEFAULT -1 ON CONVERSION ERROR) conv_sal
SALARY CONV_SAL
---------- ----------
120000 120000
172125 172125
128000 128000
125,000 -1
99500 99500
118
TO_DATE
TO_NUMBER
TO_TIMESTAMP
etc

column level collation

SQL> select *
2 from customers
3 where cust_name = 'ADAMS';
COUNTRY CREATED CUST_NAME
------------ --------- ---------------------
AUS 08-NOV-16 ADAMS

looks great... until

SQL> select *
2 from customers
3 where upper(cust_name) = 'ADAMS';
------------ --------- ------------
AUS 07-NOV-16 Adams
AUS 08-NOV-16 ADAMS
AUS 09-NOV-16 adams

SQL> select * from customers

SQL> select column_name
2 from user_ind_columns
3 where index_name = 'CUST_IX';
COLUMN_NAME
------------------------------
CUST_NAME
-------------------------------------------------------
| Id | Operation | Name | Rows | Bytes |
-------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 152 |
|* 1 | TABLE ACCESS FULL| CUSTOMERS | 1 | 152 |
-------------------------------------------------------

SQL> create index cust_ix
2 on customers ( cust_name );
Index created.
SQL> create index cust_ix2
2 on customers ( upper(cust_name) );
Index created.

DML slower
more contention
more redo/undo space

"not my problem"

SQL> alter table customers shrink space;
*
ERROR at line 1:
ORA-10631: SHRINK clause should not be specified for this object

12.2

column level collation

SQL> CREATE TABLE CUSTOMERS
2 (
3 COUNTRY VARCHAR2(128),
4 CREATED DATE,
5 CUST_NAME VARCHAR2(150) COLLATE BINARY_CI
6 );
Table created.
"case insenstive"

SQL> create index cust_ix
2 on customers ( cust_name);
Index created.
SQL> set autotrace traceonly explain
-----------------------------------------------------------------
| Id | Operation | Name | Rows |
-----------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 |
| 1 | TABLE ACCESS BY INDEX ROWID BATCHED| CUSTOMERS | 1 |
|* 2 | INDEX RANGE SCAN | CUST_IX | 1 |
-----------------------------------------------------------------

"big deal"

------------ --------- ----------------
AUS 07-NOV-16 Adams
AUS 08-NOV-16 ADAMS
AUS 09-NOV-16 adams

binary_ci
------------ --------- ----------------
AUS 07-NOV-16 Adams
AUS 08-NOV-16 ADAMS
AUS 09-NOV-16 adams

binary_ai
------------ --------- ----------------
AUS 07-NOV-16 Adams
AUS 08-NOV-16 ADAMS
AUS 09-NOV-16 adams
AUS 10-NOV-16 adáms
adáms

column | table | user

SQL> alter table people default collation binary_ai;
new columns only

key point

SQL> alter table people default collation binary_ai;
*
ERROR at line 1:
ORA-43929: Collation cannot be specified if
parameter MAX_STRING_SIZE=STANDARD

deprecated code

"huh?"

deprecate your code

column collation

2 package customer_pkg as
3
4 cursor get_customers(p_name varchar2) is
5 select * from customers
6 where upper(customer_name) = upper(p_name);
7
8 ...

3
4 --
5 -- do not use
6 --
10
11 --
12 -- fixed with CI collation
13 --
14 cursor get_cust_ci(p_name varchar2) is
16 where customer_name = p_name;

new pragma

6
7 pragma deprecate(get_customers,'Use get_cust_ci');
8
9 cursor get_cust_ci(p_name varchar2) is
11 where customer_name = p_name;

SQL> alter system set
2 plsql_warnings = enable:(6019,6020,6021,6022)';

SQL> alter procedure PROCESS_CUSTOMERS compile;
SP2-0804: Procedure created with compilation warnings
LINE/COL ERROR
-------- -----------------------------------------------------------
1/1 PLW-05018: unit PROCESS_CUSTOMERS omitted optional AUTHID
clause; default value DEFINER used
7/9 PLW-06020: reference to a deprecated entity:
GET_CUSTOMERS declared in unit CUSTOMER_PKG[2,10].
Use get_cust_ci instead

one month later

SQL> alter system set
2 plsql_warnings = error:(6019,6020,6021,6022)';

SQL> alter procedure PROCESS_CUSTOMERS compile;
SP2-0804: Procedure created with compilation errors
LINE/COL ERROR
-------- -----------------------------------------------------------
1/1 PLW-05018: unit PROCESS_CUSTOMERS omitted optional AUTHID
clause; default value DEFINER used
GET_CUSTOMERS declared in unit CUSTOMER_PKG[2,10].
Use get_cust_ci instead

external tables

ext_emp

SQL> create table ext_emp (
2 empno number(4),
3 ename varchar2(10),
4 job varchar2(9),
5 mgr number(4),
6 hiredate date,
7 sal number(7,2),
8 comm number(7,2),
9 deptno number(2)
10 )
11 organization external
12 ( type oracle_loader
13 default directory TMP
14 access parameters
15 ( records delimited by newline
16 fields terminated by ','
17 missing field values are null
18 ( empno,ename,job,mgr,hiredate,sal,comm,deptno )
19 )
20 location ('emp20161001.dat'));
Table created.

SQL> select * from ext_emp;
select * from ext_emp
*
ERROR at line 1:
ORA-29913: error in executing ODCIEXTTABLEFETCH callout
ORA-30653: reject limit reached

easy fix

2 empno number(4),
...
12 ( type oracle_loader
13 default directory TMP
14 access parameters
15 ( records delimited by newline
16 fields terminated by ','
17 missing field values are null
18 ( empno,ename,job,mgr,hiredate,sal,comm,deptno )
19 )
20 location ('emp20161001.dat'))
21 REJECT LIMIT UNLIMITED;
Table created.

it's ddl

ITIL :-(

service
call
help
desk
problem
recordDONE !

12.2

query time modification

SQL> select * from ext_emp
2 external modify ( reject limit unlimited );
EMPNO ENAME JOB MGR HIREDATE SAL
---------- ---------- --------- ---------- --------- ---------- ---
7499 ALLEN SALESMAN 7698 20-FEB-81 1600
7521 WARD SALESMAN 7698 22-FEB-81 1250
7566 JONES MANAGER 7839 02-APR-81 2975
...
7902 FORD ANALYST 7566 03-DEC-81 3000
7934 MILLER CLERK 7782 23-JAN-82 1300
13 rows selected.

file names

2 empno number(4),
...
20 location ('emp20161001.dat'))
Table created.

SQL> select * from ext_emp
2 external modify ( location ('emp20161002.dat') );
EMPNO ENAME JOB MGR HIREDATE SAL
---------- ---------- --------- ---------- --------- ---------- ---
7902 FORD ANALYST 7566 03-DEC-81 3000
7934 MILLER CLERK 7782 23-JAN-82 1300
7566 JONES MANAGER 7839 02-APR-81 2975
...
7499 ALLEN SALESMAN 7698 20-FEB-81 1600
7521 WARD SALESMAN 7698 22-FEB-81 1250
8 rows selected.

select * from ext_tab external modify (
[ default directory ]
[ location ]
[ access parameters ]
[ reject limit ]
);

ACCOUNTING,KING,PRESIDENT,5000
ACCOUNTING,MILLER,CLERK,1300
181

<department name="ACCOUNTING">
<employees>
<employee>
<ename>KING</ename>
<job>PRESIDENT</job>
<sal>5000</sal>
</employee>
<employee>
<ename>MILLER</ename>
<job>CLERK</job>
<sal>1300</sal>
</employee>
</employees>
</department>
182

{ "NAME" :"ACCOUNTING"
, "EMPLOYEES" : [
{"ENAME" : "KING",
"JOB" : "PRESIDENT",
"SAL" : 5000
},
{"ENAME" : "MILLER",
"JOB" : "CLERK",
"SAL" : 1300
}]
}
183

12.1
184

alter table T
add constraint t_chk
check
(
my_doc is JSON
)
185

extraction
186

SQL> select json_value(my_doc,
2 '$.ACCOUNTING.EMPLOYEES[0].ENAME') as ename
3 from t;
ENAME
----------
KING
187

dot notation
188

SQL> select t.my_doc.ACCOUNTING.EMPLOYEES.ENAME emps,
2 t.my_doc.ACCOUNTING.EMPLOYEES.JOB jobs,
3 t.my_doc.ACCOUNTING.EMPLOYEES.SAL sals
4 from T t;
EMPS JOBS SALS
-------------------- ------------------- ---------------
[KING,MILLER] [PRESIDENT,CLERK] [5000,1300]
189

12.2
190

generation
191

{
"department": "Accounting",
"employees": [
{
"name": "Shelley,Higgins",
"job": "Accounting Manager"
},
{
"name": "William,Gietz",
"job": "Public Accountant"
}
]
}

{"newJSONfunctions": [
"json_array",
"json_object",
"json_arrayagg",
"json_objectagg"
] }

SQL> select
2 json_array(department_id, department_name) depts
3 from hr.departments
4 where department_id > 200;
DEPTS
--------------------------------------------------------
[210,"IT Support"]
[220,"NOC"]
[230,"IT Helpdesk"]
[240,"Government Sales"]
[250,"Retail Sales"]
[260,"Recruiting"]
[270,"Payroll"]
7 rows selected.

SQL> select
2 json_object(
3 'DeptID' is department_id,
4 'Name' is department_name) depts
5 from hr.departments
6 where department_id > 200;
DEPTS
------------------------------------------------
{"DeptID":210,"Name":"IT Support"}
{"DeptID":220,"Name":"NOC"}
{"DeptID":230,"Name":"IT Helpdesk"}
{"DeptID":240,"Name":"Government Sales"}
{"DeptID":250,"Name":"Retail Sales"}
{"DeptID":260,"Name":"Recruiting"}
{"DeptID":270,"Name":"Payroll"}
7 rows selected.

SQL> select json_object(
2 'department' value d.department_name,
3 'employees' value json_arrayagg(
4 json_object(
5 'name' value first_name||','||last_name,
6 'job' value job_title
7 )))
8 from hr.departments d, hr.employees e, hr.jobs j
9 where d.department_id = e.department_id
10 and e.job_id = j.job_id
11 and d.department_id = 110
12 group by d.department_name;

... and more JSON goodies
json_exists
GeoJSON
JSON Partitioning
In-Memory support
JSON Data Guide
Materialized Views
Search index

SQL> desc ORDERS
NAME TYPE
------------------ -----------
ORDER_DETAILS BLOB
{"date": "2016-05-03 10:40:36",
"loyaltyCardNo": 1230,
"location": {
"city": "Dallas",
"state": "TX”},
"salesAmount": 7.55,
"order": [ {
"item": "Espresso”, ... }
}

SQL> SELECT JSON_DATAGUIDE(o.order_details) FROM orders o;
JSON_DATAGUIDE(O.ORDER_DETAILS)
----------------------------------------------------------------------
[ {"o:path": "$.date", "type": "string", "o:length": 32 },
{"o:path": "$.order", "type": "array", "o:length": 256 },
{"o:path": "$.location", "type": "object", "o:length": 32},
{"o:path": "$.location.city", "type": "string", "o:length": 8},
...
...
{ "o:path": "$.salesAmount", "type": "number", "o:length": 4 },
{ "o:path": "$.loyaltyCardNo","type": "number", "o:length": 8}]

one row...

one
lousy

can really spoil your day :-(

SQL> select owner,
2 count(*) as cnt
3 from t
4 where owner like 'S%'
5 group by owner;
SQL> select num_rows
2 from user_tables
3 where table_name = 'T';
NUM_ROWS
-----------
7014272505

SQL> create materialized view log on T
2 with rowid (owner,object_id)
3 including new values;
Materialized view log created.
SQL> create materialized view T_MV
2 refresh fast on demand
3 enable query rewrite
4 as
5 select owner,
6 sum(object_id) as sum_obj,
7 count(object_id) as cnt_obj,
8 count(*) as cnt
9 from t
10 group by owner;
Materialized view created.

SQL> select owner, count(*)
2 from t
4 group by owner;
--------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)|
--------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 2 | 26 | 3 (0)|
|* 1 | MAT_VIEW REWRITE ACCESS FULL| T_MV | 2 | 26 | 3 (0)|
--------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - filter("T_MV"."OWNER" LIKE 'S%')

hero

until ...

SQL> insert into t
2 values ( ... , ... , ..., ..... );
1 row created.
SQL> commit;
Commit complete.

2 from t
4 group by owner;
----------------------------------------------------------------
----------------------------------------------------------------
| 0 | SELECT STATEMENT | | 2 | 10 | 14M (1)|
| 1 | HASH GROUP BY | | 2 | 10 | 14M (1)|
|* 2 | TABLE ACCESS FULL| T | 574M| 2738M| 14M (1)|
----------------------------------------------------------------

2 procedure KILL_MY_CPU_MIXED_WITH_PRAYER is
3 begin
4 loop
5 dbms_mview.refresh('T_MV');
6 end loop;
7 end;
8 /
Procedure created.

12.2

real time refresh

on commit

SQL> create materialized view T_MV
2 refresh fast on demand
3 enable query rewrite
4 enable on query computation
5 as
6 select owner,
7 sum(object_id) as sum_obj,
8 count(object_id) as cnt_obj,
9 count(*) as cnt
10 from t
11 group by owner;
Materialized view created.

2 from t
4 group by owner;
---------------------------------------------------------------------------
---------------------------------------------------------------------------
|* 1 | MAT_VIEW REWRITE ACCESS FULL| T_MV | 2 | 26 | 3 (0)|
---------------------------------------------------------------------------
as before

SQL> insert into t
2 values ( ... , ... , ..., ..... );
1 row created.
SQL> commit;
Commit complete.

SQL> select owner, count(*) cnt
2 from t
4 group by owner;
OWNER CNT
------------------------------ ----------
SYS 50941
SI_INFORMTN_SCHEMA 8
SYSTEM 482
Elapsed: 00:00:01.41
SQL> select /*+ NO_REWRITE */ owner, count(*) cnt
2 from t
4 group by owner;
OWNER CNT
------------------------------ ----------
SYS 50941
SYSTEM 482

how ?

we didn't refresh the mview
SQL> select owner, count(*) as cnt
2 from t
4 group by owner;
OWNER CNT
------------------------------ ----------
SYS 50941
SYSTEM 482
SQL> select owner, cnt
2 from T_MV
3 where owner like 'S%';
OWNER CNT
------------------------------ ----------
SYS 50940
SYSTEM 482

SQL> select owner,
2 count(*) as cnt
3 from t
5 group by owner;

-----------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------
| 1 | VIEW | | 4 | 316 | 15 (20)|
| 2 | UNION-ALL | | | | |
|* 3 | FILTER | | | | |
|* 4 | HASH JOIN OUTER | | 2 | 184 | 6 (17)|
|* 5 | MAT_VIEW ACCESS FULL | T_MV | 2 | 46 | 2 (0)|
| 6 | VIEW | | 1 | 69 | 4 (25)|
| 7 | HASH GROUP BY | | 1 | 88 | 4 (25)|
|* 8 | TABLE ACCESS FULL | MLOG$_T | 1 | 88 | 3 (0)|
| 9 | VIEW | | 2 | 158 | 9 (23)|
| 10 | UNION-ALL | | | | |
|* 11 | FILTER | | | | |
| 12 | NESTED LOOPS OUTER | | 1 | 102 | 4 (25)|
| 13 | VIEW | | 1 | 79 | 4 (25)|
|* 14 | FILTER | | | | |
| 15 | HASH GROUP BY | | 1 | 88 | 4 (25)|
|* 17 | INDEX UNIQUE SCAN | I_SNAP$_T_MV | 1 | 23 | 0 (0)|
| 18 | NESTED LOOPS | | 1 | 105 | 5 (20)|
| 19 | VIEW | | 1 | 82 | 4 (25)|
| 20 | HASH GROUP BY | | 1 | 88 | 4 (25)|
|* 22 | MAT_VIEW ACCESS BY INDEX ROWID| T_MV | 1 | 23 | 1 (0)|
|* 23 | INDEX UNIQUE SCAN | I_SNAP$_T_MV | 1 | | 0 (0)|
-----------------------------------------------------------------------------------------

what about direct queries ?

SQL> select /*+ FRESH_MV */ owner, cnt
2 from T_MV
3 where owner like 'S%';
OWNER CNT
------------------------------ ----------
SYSTEM 482
SYS 50940
owner, cnt
50941

almost correct SQL

background

don't you hate ...

ALERT: Batch load failed
Batch process ended in error.
Module: Financial Reconcilation
Issue: Yearly total
Expected: $7,102,231.76
Actual: $7,102,231.32

$7,100,000
$8,200,000
$7,700,000

sometimes ...

close enough ...

... is good enough

the hardest work for a database ...

SQL> select count(distinct ...) cdist
2 from my_super_massive_table;
CDIST
-------
12
Elapsed: 01:32:17.00

12.1

SQL> select approx_count_distinct(...) cdist
CDIST
-------
12
Elapsed: 00:12:43.00

but ...

SQL> select count(*)
2 from user_source
3 where upper(text) like '%COUNT(%DISTINCT%';
COUNT(*)
----------
1723

"I don't think so"

12.2

SQL> alter session set approx_for_count_distinct = true;
Session altered.
SQL> select count(distinct ...)
approx_count_distinct(...)

more functions
approx_median
approx_percentile
approx_count_distinct_detail
to_approx_...

more confidence

SQL> select department,
2 approx_median(salary deterministic) med_sal
3 from employees
4 group by department
5 order by department;
DEPARTMENT MED_SAL
---------- -------------
10 4400
20 6000
30 2765
40 6500

SQL> select
2 department,
3 approx_median(salary deterministic, 'ERROR_RATE') err
4 from employees
DEPARTMENT ERR
---------- -------------
10 .002718282
20 .021746255
30 .021746255
40 .002718282
50 .019027973
60 .019027973

SQL> select
2 department,
3 approx_median(salary, 'CONFIDENCE') conf
4 from employees
DEPARTMENT CONF
---------- -------------
10 .997281718
20 .999660215
30 .999660215
40 .997281718
50 .999611674
60 .999611674
70 .997281718

partitioning

10g and earlier

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

11g

interval partitioning

SQL> create table SALES
2 ( cal_year date,
3 txn_is int
4 )
5 partition by range ( cal_year )
6 interval ( numtoyminterval(1,'YEAR') )
7 (
8 partition p_low values less than ( date '2000-01-01' )
9 );
Table created.

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)
9 (
10 partition male values ('M'),
11 partition female values ('F')
12 );
Table created.

SQL> insert into PEOPLE
3 values ( 1,'Connor','McDonald','U');
insert into PEOPLE *
ERROR at line 1:
ORA-14400: inserted partition key does not map to any partition

12.2

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
2 from user_tab_partitions
3 where table_name = 'PEOPLE';
PARTITION_NAME
-------------------------------------------------
FEMALE
MALE
SYS_P661

existing tables

SQL> alter table PEOPLE set partitioning automatic;
Table altered.
SQL> alter table PEOPLE set partitioning manual;
Table altered.

save the largest for last

LOBs

1997

securefile LOBs

2007

LOBs are cool

securefile LOBs are cooler
compression
de-duplication
encryption
write cache

until ...

n(databases) > 1

SQL> create table t ( id int, c clob );
Table created.
SQL> insert into t values (1,rpad('x',32000,'x'));
1 row created.
SQL> select *
2 from t;
ID C
---------- --------------------------------------------
1 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

SQL> select *
2 from t@db11;
ERROR:
ORA-22992: cannot use LOB locators selected from remote tables

12.2

SQL> select *
2 from t@db122;
ID C
---------- --------------------------------------------
1 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

http://docs.oracle.com/database/122/ADLOB/distributed-LOBs.htm

wrap up

there's a lot in 12.2

lots not covered today

plenty to excite
291

never too soon to start
292

asktom.oracle.com

12 Things About 12c Release 2 for Developers

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