1. Solving the C20K Problem:
PHP Performance and Scalability
Kuassi Mensah, Group Product Manager
Oracle Corporation

2. The C20K Problem

3. Genesis: the C10K Problem
• Circa 2003: “How to write a server which can handle
10.000 parallel connections”
• http://www.kegel.com/c10k.html

4. The C20K Problem
• Can a single commodity database server handle 20K
simultaneous PHP users?
…

5. Solving C20K with Built­In Database
Mechanisms in PHP
• Database Resident Connection Pool
• Query Change Notification
• Client­side Query Result Cache
• Scaling with Stored Procedures
• Database Built­in Partitioning
• Scaling Very Complex Queries
• Scaling Queries with Advanced Data Compression
• Database Failover
• Case Study: Community Connect

6. <Insert Picture Here>
Database Resident
Connection Pool

7. PHP Lacks Proper Connection Pool
Current choices:
2. Persistent Connections
• Connection not automatically closed at
script completion
• Fast for subsequent connections but
holds resources when application idle
⇒ Over­allocation – Waste of system resources
• Non Persistent Connections
• Connection closed at script completion
⇒ High connect times
⇒ Unnecessary connect/disconnect CPU load

8. Database Resident Connection Pool
Dedicated servers
Connection Connection
( DB handle) Broker
Session
Session
Session
(User Handle)
1 Session
(User Handle)
Session
(User Handle)
(User Handle)
Oracle Net (User Handle)
2
• Pool of dedicated servers
• (1) Server allocated/locked on Appl. Connect
• (2) Direct server access after handoff
• (3) Server released on Appl. ConnClose .
• No man­in­the­middle, low latency

9. Database Resident Connection Pool
• Pools a set of dedicated servers on each database
instance
• Designed primarily for process systems (PHP)
1/ Just Change the Connect String
<?php
$c = oci_pconnect("phpweb", "phpweb", "//localhost/orcl:pooled");
$s = oci_parse($c, 'select * from employees');
oci_execute($s);
oci_fetch_all($s, $res);
var_dump($res);
?>
2/ Zero code change: change TNS alias
• Currently in OCI, C/C++, PHP (OCI8), Python

10. DRCP in Action – PHP Connection
Pooled Database
Servers
PHP 3 Busy Server
Idle Server
PGA memory
oci Session memory
_ pco
n nec
t()
35k Idle Server
Apache Processes 1 2 .
.
35k
ct(
) .
ne
c on Connection
i_p
PHP oc
Broker

11. DRCP in Action – Closing Connection
Pooled Database
Servers
oci_close() Busy Server
PHP
PGA memory
Connection Session memory
Broker
Idle Server
35k
Apache Processes
4
.
.
PHP 35k
oci_close()
.

12. DRCP in Action – After Close
Pooled Database
Servers
Idle Server
PHP
PGA memory
Connection Session memory
socket Broker
connection
35k Idle Server
Apache Processes 5 .
.
PHP 35k
.
socket
connection

13. Configuring and Starting DRCP
• Configure the Pool (Optional)
SQL> execute dbms_connection_pool.configure_pool(pool_name
=> 'SYS_DEFAULT_CONNECTION_POOL',
minsize => 4,
maxsize => 40,
incrsize => 2,
session_cached_cursors => 20,
inactivity_timeout => 300,
max_think_time => 600,
max_use_session => 500000,
max_lifetime_session => 86400);
• Start the pool
SQL> execute dbms_connection_pool.start_pool();

14. C20K, Yes We Did!
PHP DRCP Benchmark
• PHP script
• connect, query, disconnect, sleep 1 second
• Database Server
• Dual CPU Intel P4/Xeon ­­ 3.00GHz ­ 2GB RAM
• 32bit Red Hat Enterprise Linux 4
• DRCP
• 100 pooled servers, one connection broker
• 0.5% nb users simultaneously active
• PHP Hosts
• 3 machines similar to Db Server
• Apache
• PHP DRCP Whitepaper: http://tinyurl.com/554cz4

15. C20K, Yes We Did!
PHP DRCP Benchmark ­ Throughput

16. C20K, Yes We Did!
PHP DRCP Benchmark ­ Memory

17. <Insert Picture Here>
Query Change Notification

18. Built­in Query Change Notification
Problem to solve:
Be notified when changes in the database invalidates
an existing query result set
2.Upon Change
(DMLImpacting
<?php
the result set)
… Callout
4.Invalidate cache
5.repopulate cache
…
?>
1. Register
3.Automatic the query
Custom cache Notification
(Java or PL/SQL database job
as noificaion handler)

19. <Insert Picture Here>
Client­Side Query Result Cache

20. MemCached
query = "select name, address, phone, acctbal from custumer,
nation where c_nationkey= n_nationkey;
key = md5($query);
If (serval=$memcache->get($key) {
res = oci_execute($query)
ser = serialize($res); Problems
memcache->set($key, $ser); • Cache Invalidation
} • Additional
res = unserialize($serval); Memcached Servers
MemCached
PHP
Database

21. Built­in Client Query Result Cache
$query = "select /*+ RESULT_CACHE */ name,
address, phone, acctbal from customer, nation
where c_nationkey=n_nationkey;
PHP
Database
• May be Faster than Memcached !
• No additional cache server(s) but process level cache
• Automatic Cache Invalidation
• Transparent OCI, PHP, Ruby, ODP.Net, ODBC, JDBC

22. Configuring Client Query Result Cache
1/ Configure the Cache
Database Server Configuration (init.ora)
client_result_cache_size=200M
client_result_cache_lag=5000
Client Configuration (sqlnet.ora)
OCI_QUERY_CACHE_SIZE=200M
OCI_QUERY_CACHE_MAXROWS=20
2/ Caching the Result Set
Using Hints
select /*+ result_cache */ * from employees
Alternatively, at Table level
alter table emp result_cache (mode force);

23. Client Query Result Cache
5­8 x Faster
900%
800%
700%
600%
500%
400%
300%
200%
100%
0%
10 100 1000

24. <Insert Picture Here>
Scaling with Stored Procedures

25. Stored Procedures instead of Multiple
Unique Statements
Unique Statements Stored Procedures (PL/SQL or Java)
PHP PHP
Stored Procedure
Call
Calls
Java
JDBC
Calls
SQL SQL
Faster, up to 10X!

26. PHP Bulk Insert
function do_transactional_insert($conn, $array)
{
$s = oci_parse($conn,
'insert into ptab (pdata) values (:bv)');
oci_bind_by_name($s, ':bv', $v, 20, SQLT_CHR);
foreach ($array as $v)
$r = oci_execute($s, OCI_DEFAULT);
oci_commit($con);
}
Elapsed time: 8 millisec

27. PHP Bulk Insert with Stored Procedure
function do_bulk_insert($conn, $array)
{
$s = oci_parse($conn,
'begin mypkg.myproc(:c1); end;');
oci_bind_array_by_name($s, ":c1", $array,
count($array), -1, SQLT_CHR);
oci_execute($s);
}
Elapsed time: 2 millisec (4X speed up; may vary!)

28. PL/SQL Stored Proc. (Bulk insert)
create or replace package mypkg as
type arrtype is table of varchar2(20)
index by pls_integer;
procedure myproc(p1 in arrtype);
end mypkg;
create or replace package body mypkg as
procedure myproc(p1 in arrtype) is
begin
forall i in indices of p1
insert into ptab values (p1(i));
end myproc;
end mypkg;

29. Using Java Stored Procedures in PHP
• Secure Credit­Card Processing • Implement Parsers for various File
using JSSE Formats (txt, zip, xml, binary)
• Custom Alert applications that • Implement Image Transformation and
monitor business data Format Conversion (GIF, PNG,
• Sending emails with attachment JPEG, etc)
from within the database
• Implement database­resident Content
• Produce PDF files from Result
Set Management System
• Execute external OS commands • HTTP Call­Out
and external procedures • JDBC Call­Out
• Implement Md5 CRC • RMI Call­Out to SAP
• Publish Repository Content to • Web Services Call­Out
Portal
• Messaging across Tiers
• Portable Logistic Applications
• RESTful Database Web Services*
• Db Resident Lucene*
* http://marceloochoa.blogspot.com/

30. <Insert Picture Here>
Database Built­in Partitioning

31. Built­in Partitioning
Orders
Line
Inventory Items
Orders Jan
Orders
Feb
Back Pick Orders
Orders Lists
Mar

32. <Insert Picture Here>
Scaling Very Complex SQL
Queries

33. Scaling Very Complex SQL Queries
Problem to Solve: Query Sales and Quantity by Year,
Department, Class and Country
The SQL Query
SELECT SUM(s.quantity) AS quantity, SUM(s.sales) AS sales,
t.calendar_year_name, p.department_name, c.class_name,
cu.country_name
FROM times t, products p, channels c, customers cu,
sales_fact s
WHERE p.item_key = s.product AND s.day_key = t.day_key AND
s.channel = c.channel_key AND
s.customer = cu.customer_key
GROUP BY p.department_name, t.calendar_year_name,
c.class_name, cu.country_name;

34. Built­in OLAP Engine
PHP

35. Cube Organized Materialized Views
Transparent to SQL Queries
SQL Query Materialized Views
Region Date
Query
Rewrite
Product Channel
Automatic OLAP Cube
Refresh

36. <Insert Picture Here>
Scaling with Advanced Data
Compression

37. Scaling w. Advanced Data Compression
Going Green
2500
Storage
2000
Reduction
More than 70% (up to 4X)
Compression Storage Savings
1500
MB
No Compression 1000
500
0
Table Scan Performance DML Performance
Less than
0.4 40
3% Overhead
2.5 x Faster
0.3 (seconds) 30
(seconds)
Time
Time
0.2 20
0.1 10
0 0

38. Database Failover

39. Oracle Database 11g RAC
Shared Disk Architecture

40. Fast Application Notification of Events
• Pub/Sub Event Notification (AQ based)
• High Availability feature for PHP with RAC or Data­
Guard­with­physical­standby
• When DB node or network fails
• Database generates FAN events
• PHP error returned without TCP timeout delay
• PHP application reconnect to surviving instance
• OCI8 1.3.1 Beta supports FAN

41. Database Failover – Application View
Fast Connection Failover
Invalid Connections Valid Connections
Inst x Inst y

42. Configuring Fast Application
Notification for PHP
• High Availability feature with RAC or DG
• Usable with or without DRCP
• Available from Oracle 10gR2
• OCI8 1.3 supports FAN
5.Tell DB to broadcast FAN Events
SQL> execute
dbms_service.modify_service(service_name =>'SALES',
aq_ha_notifications =>TRUE);
6.Subscribe to FAN events
Example: Configure PHP for OCI8 to listen for FAN events
oci8.events = On
7.Application to Re­connect

43. Database Failover in PHP
When DB node or network fails
• Database generates FAN events
• Oracle error returned without TCP timeout delay
• PHP application is not blocked for TCP timeout – it can
immediately reconnect to surviving DB instance
$conn = doConnect();
$err = doSomeWork($conn);
if (isConnectionError($err)) {
// reconnect, find what was committed, and retry
$conn = doConnect();
$err = checkApplicationStateAndContinueWork($conn);
}
if ($err)
handleError($err);

44. C(N*20)K Using DRCP and RAC
• Scale your database horizontally to N*C20K with N
RAC nodes!!
• DRCP starts on all RAC instances
• Same pool limits apply to each individual RAC
instance
• min, max
• number of brokers
• max connections per broker
• DRCP connections benefit from TNS Listener
connection load balancing across RAC instances
www.oracle.com/technology/tech/php/pdf/php­scalability­ha­twp.pdf

45. <Insert Picture Here>
Case Study
Community Connect Inc.

46. Xtreme Scalability
Web Scale PHP Deployment
BlackPlanet.com
• 19+ million users
• 500+ millions pages views
per month
• 100+ web servers
• 10+ databases (incl. RAC)
• ~ 50,000 conc. Users
• Case Studied by Gartner
http://tinyurl.com/dg6rxm

47. Oracle Technology Network
PHP Developer Center
• Free
• Articles
• Install guides
• Underground PHP
and Oracle Manual
• Online forum
• PHP RPMs
• Oracle JDeveloper
10g PHP extension
otn.oracle.com/php

48. Oracle Resources
• Free Oracle Techology Network (OTN)
PHP Developer Center
otn.oracle.com/php
• Underground PHP and Oracle Manual
• Whitepapers, Articles, FAQs, links to blogs, JDeveloper
PHP Extension, PHP RPMs
• Information
kuassi.mensah@oracle.com
christopher.jones@oracle.com
• SQL and PL/SQL Questions
asktom.oracle.com
• ISVs and hardware vendors
oraclepartnernetwork.oracle.com

49. Q & A
Thank You
49