Another year goes by, and most likely, another data access framework has been invented. It will claim to be the fastest, smartest way to talk to the database, and just like all those that came before it, it will not be. Because the best database access tool has been there for more than 30 years now, and that is PL/SQL. Although we all sometimes fall prey to the mindset of “Oh look, a shiny new tool, we should start using it," the performance and simplicity of PL/SQL remain unmatched. This session looks at the failings of other data access languages, why even a cursory knowledge of PL/SQL will make you a better developer, and how to get the most out of PL/SQL when it comes to database performance.

1. 1
Connor McDonald
bit.ly/techguysong

2. PL/SQL - still super cool
Connor McDonald
Database Advocate
Copyright © 2019 Oracle and/or its affiliates.

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Me
youtube bit.ly/youtube-connor
blog connor-mcdonald.com
twitter @connor_mc_d
400+ posts mainly on database & development
250 technical videos, new uploads every week
rants and raves on tech and the world :-)

7. 7
etc...
facebook bit.ly/facebook-connor
linkedin bit.ly/linkedin-connor
instagram bit.ly/instagram-connor
slideshare bit.ly/slideshare-connor

8. 8 8https://asktom.oracle.com

9. 9https://asktom.oracle.com/officeho

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before we begin

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some ground rules...

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this is not

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successful applications

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my definition of success

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meets business objectives

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meets performance objectives
(really a business objective)

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meets development objectives
(really a business objective)

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meets security objectives
(really a business objective)

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let's be real...

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make more, spend less

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PL/SQL should help achieve this for you

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the motivation

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let's look at real life ...

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"We'd never do that .... that's stupid"

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but everyone does ... :-(

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no matter what platform

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no matter what direction

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which leads to ...

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"The database is slow"

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is PL/SQL the solution ?

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remember definition of success

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performance, maintenance, security

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a small digression

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utopia

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SmartDB

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https://dzone.com/articles/the-smartdb-resource-center

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utopia, n:
"an imagined a place or state of things in which everything is perfect."

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100%
% people using
any form of SmartDB

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#FAIL

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100%
% closeness to full SmartDB

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#FAIL

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forget philosophy...focus on success

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can even small PL/SQL investment help ?

51. performance

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evolving to PL/SQL ...

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.. bit by bit

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my app = primary key lookup

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SQL> create or replace
2 function simplepk(i int) return int is
3 res int;
4 begin
5 select pk
6 into res
7 from parse_demo
8 where pk = i;
9 return res;
10 end;
SimplePK

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"PL/SQL is more expensive"

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irony

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"More layers...more expensive"

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my app = a simple API

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SQL> create or replace
2 procedure simpleapi(i1 int, i2 int, o1 out int, o2 out int, o3 out int) is
3 begin
4 select region_id into o1 from customer where id = i1;
5
6 for i in ( select order_id from cust_orders where cust_id = i2 )
7 loop
8 o2 := i.order_id;
9 end loop;
10
11 select count(*) into o3 from order_items where order_id = o2;
12 end;
SimpleAPI

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let's make it "real"

65. sb_client
sb_server

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the best java (et al) can do

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it is not just latency

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we'll come back to why shortly...

69. development
build
maintenance

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benefit #1

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"Crash Early"
"A dead program normally does a lot less damage than a crippled one."

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C:src> type MyApp.java
...
...
PreparedStatement s =
con.prepareStatement("select any piece of old crap from dual");
...
...
C:src> javac SimplePKcache.java
[no errors]

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SQL> create or replace
2 procedure MY_PROC is
3 begin
...
...
24 select any piece of old crap from dual;
...
...
75 end;
76 /
Warning: Procedure created with compilation errors.

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benefit #2

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the lazy way is the optimal way

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rs = stmt.executeQuery(
"select ename from emp where empno = " + v_empno );
while(rs.next()) {
v_ename = rs.getInt(1);
}
PreparedStatement pstmt =
con.prepareStatement("select ename from emp where empno = ?");
pstmt.setInt(1, v_empno);
rs = pstmt.executeQuery();
while(rs.next()) {
v_ename = rs.getInt(1);
}

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building SQL by concatenation

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you'll get hacked

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select ename
from emp
where empno = 6543
select ename
from emp
where empno = 6543
and 1=0
union all
select table_name
from all_tables
where table_name like '%SECURITY%'
select ename
from emp
where empno = 6543
and 1=0
union all
select username
from app_security
where ...
rs = stmt.executeQuery(
"select ename from emp where empno = " + v_empno );

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begin
select ename
into v_ename
from emp
where empno = v_empno;
begin
dbms_sql.parse(
v_cur,
'select ename from emp where empno = '||v_empno,
dbms_sql.native );
dbms_sql.define_column(v_cur, 1, v_ename, 30);
l_status := dbms_sql.execute(v_cur);
while ( dbms_sql.fetch_rows(v_cur) > 0 ) loop
dbms_sql.column_value(v_cur, 1, v_ename);
end loop;

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begin
execute immediate
'select ename from emp where empno = '||v_empno
into v_ename;

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"We're safe... we use an ORM"

83. https://snyk.io/blog/sequelize-orm-npm-library-found-vulnerable-to-sql-injection-attacks/

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not just static versus dynamic

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back to performance

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procedure GET_EMPS_FOR_JOB(p_job varchar2) is
begin
for i in (
select ename
from emp
where job = p_job
)
loop
...
end loop;
SQL> select ename from emp where job = 'SALES'

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SELECT ENAME
FROM EMP
WHERE JOB = :B1
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 1 0.00 0.00 0 0 0 0
Execute 10000 0.17 0.14 0 0 0 0
Fetch 10000 0.07 0.09 24 20000 0 40000
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 20001 0.25 0.24 24 20000 0 40000

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SELECT ENAME
FROM EMP
WHERE JOB = :B1
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 1 0.00 0.00 0 0 0 0
Execute 10000 0.17 0.14 0 0 0 0
Fetch 10000 0.07 0.09 24 20000 0 40000
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 20001 0.25 0.24 24 20000 0 40000

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PreparedStatement pstmt =
con.prepareStatement("select ename from emp where empno = ?");
pstmt.setString(1,v_job);
rs = pstmt.executeQuery();
while(rs.next()) {
v_ename = rs.getInt(1);
}
pstmt.close();
SQL> select ename from emp where job = 'SALES'

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select ename
from emp
where job = :1
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 10000 0.06 0.10 0 0 0 0
Execute 10000 0.14 0.15 0 0 0 0
Fetch 40000 0.12 0.10 24 40000 0 40000
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 50000 0.32 0.37 24 40000 0 40000

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select ename
from emp
where job = :1
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 10000 0.06 0.10 0 0 0 0
Execute 10000 0.14 0.15 0 0 0 0
Fetch 40000 0.12 0.10 24 40000 0 40000
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 50000 0.32 0.37 24 40000 0 40000

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OracleDataSource ods = new OracleDataSource();
ods.setImplicitCachingEnabled( true );
Properties cacheProps = new Properties();
cacheProps.put( "MaxStatementsLimit", "50" );
ods.setConnectionCacheProperties( cacheProps );
PreparedStatement pstmt =
con.prepareStatement("select ename from emp where empno = ?");
pstmt.setFetchSize(100);
pstmt.setString(1,v_job);
rs = pstmt.executeQuery();
while(rs.next()) {
v_ename = rs.getInt(1);
}
pstmt.close();
SQL> select ename from emp where job = 'SALES'

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"It's good enough for me"

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totally fine but ...

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benefit #3

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no application is 100% complete

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data loading, data patching

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archival, adhoc query

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a common build criticism

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"No private sandbox"

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true ... in the past

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115

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<= 3 pluggables
19c

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Oracle XE

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100% free

109. development
build
maintenance

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benefits #1

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free dependency analysis

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SQL> desc DBA_DEPENDENCIES
Name Null? Type
----------------------------- -------- --------------------
OWNER NOT NULL VARCHAR2(128)
NAME NOT NULL VARCHAR2(128)
TYPE VARCHAR2(19)
REFERENCED_OWNER VARCHAR2(128)
REFERENCED_NAME VARCHAR2(128)
REFERENCED_TYPE VARCHAR2(19)
REFERENCED_LINK_NAME VARCHAR2(128)
DEPENDENCY_TYPE VARCHAR2(4)

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SQL> create or replace
2 procedure MY_PROC is
3 v_ename scott.emp.ename%type;
4 begin
5 select ename
6 into v_ename
7 from scott.emp
8 where 1=0;
9 end;
10 /
SQL> select name, referenced_name
2 from dba_dependencies
3 where name = 'MY_PROC';
NAME REFERENCED_NAME
-------------------- -------------------------------------
MY_PROC STANDARD
MY_PROC EMP

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a common maintenance criticism

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"Deployment means down time"

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packages

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break the invalidation chain

118. proc A proc B proc C proc D
pack A pack B pack C pack D
body A body B body C body D

119. 11g and beyond

120. pack A pack B pack C pack D
body A body B body C
body D

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12c and beyond

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edition based redefinition

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procedure MY_PROC is
begin
...
... "v1 code"
...
end;
procedure MY_PROC is
begin
...
... "v2 code"
...
end;

124. security

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benefit #1

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the opportunity of better security

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SQL> select username, program from v$session;
USERNAME PROGRAM
-------------------- ----------------------------
MY_SCHEMA JDBC Thin Client
MY_SCHEMA JDBC Thin Client
MY_SCHEMA JDBC Thin Client
MY_SCHEMA JDBC Thin Client
MY_SCHEMA JDBC Thin Client
MY_SCHEMA JDBC Thin Client
...
...

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TABLES
MY_SCHEMA

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there isn't a limit on schemas

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least privilege is the best privilege

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nothing connects to the data owner ... ever

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ins,upd,del,sel privs
APP_CONNECTING
TABLES
MY_SCHEMA

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execute privs
APP_CONNECTING
TABLES
MY_SCHEMA
PL/SQL

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select privs
execute privs
APP_CONNECTING
TABLES
MY_SCHEMA
PL/SQL

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benefit #2 - corollary

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execute privs
APP_CONNECTING
TABLES
MY_SCHEMA
PL/SQL

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triggers

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triggers are hard

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putting theory into practice

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customer example

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development team
C++
C#
no Oracle experience
no database experience !

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C#, C++ ESB Tuxedo
Weblogic

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public static void RaceStarted(int race_id)
{
...
}
public static void HorseScratched(int race_id, int horse_id)
{
...
}
public static void NewCustomer(int cust_seq, ...)
{
...
}
public static void DepositIntoAccount(int ...)
{
...
}

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plus hundreds more...

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PROCEDURE customer_bet(
p_transaction_ts IN timestamp
,p_bet_type IN bet.bet_type%TYPE
,p_store IN bet.store%TYPE
,p_accountnum IN bet.bet_account_num%TYPE
,p_amount IN bet.amount%TYPE
...
);
PROCEDURE pay_winner(
p_transaction_ts IN timestamp
,p_bet_seq IN bet.bet_seq%TYPE
,p_bet_type IN bet.bet_type%TYPE
,p_store IN bet.store%TYPE
,p_accountnum IN bet.bet_account_num%TYPE
,p_amount_to_pay IN bet.paid_payout%TYPE
,p_amount_to_refund IN bet.paid_refunds%TYPE
...
);

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that's it!

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the benefits can be addictive

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pl/sql c#

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"We added one procedure to solve one problem,
then another procedure to solve another problem,
and very quickly...now they want PLSQL everywhere"
- Office Hours, June 2019

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addressing some common criticisms

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"PL/SQL is not object oriented"

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OO principles

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PL/SQL

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"We don't have PL/SQL skills"

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procedural language

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if-then-else, loop, subroutines, parameters

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"We struggle with SQL"

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"We struggle with good PL/SQL"

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it ... doesn't ... matter

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utopia

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wrap up

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it doesn't have to be a war

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it doesn't have to be utopia

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PL/SQL is easy to learn, easy to write

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good wins for small effort

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kick starts the journey to big wins

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Thank you
youtube bit.ly/youtube-connor
blog connor-mcdonald.com
twitter @connor_mc_d