This document discusses how to solve the C20K problem of handling 20,000 simultaneous PHP users on a single database server using built-in database mechanisms in PHP. It describes how database resident connection pooling, query change notification, client-side query result caching, scaling with stored procedures, database partitioning, and fast application notification can be used to improve performance and scalability. Configuring these features and case studies demonstrating their effectiveness in achieving the C20K goal are provided.

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