Oracle Audio Technologies A86828-01 User Manual
Oracle9i Application Server
Oracle HTTP Server powered by Apache Performance Guide
Release 1.0.2 for AIX-Based Sys te m s, C om paq Tru64 UNIX, HP 9000 Series HP-UX,
Linux Intel, an d Sun Solaris Intel
October 2000
Part No. A86828-01
Oracle9i Application Server Oracle HTTP Server powered by Apache Performance Guide, Release 1.0.2
Part No. A86828-01
Copyright © 2000, Oracle Corporation. All rights reserved.
Authors: Pallavi Bhowmik, and Julia Pond.
Contributors: Corinne Arne, Rupesh Das, Danielle Higgins, Prashanth Joshi, Rajesh
Konanganparambath, Saurabh Pandey, and Sriram V.R. Nagaraja Rao .
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This product includes software developed b y th e A pache Group for use in the Apache HTTP server project
(http://www.apache.org/).
This product includes software developed by the OpenSSL project for use in the OpenSSL Toolkit
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This product includes software developed by Ralf S. Engelschall (rse@engelschall.com) for use in the mod_ssl
project (http://www.modssl.org/).
Contents
Send Us Your Comments.................................................................................................................. vii
Preface............................................................................................................................................................ ix
1 Performance Overview
Performance Terms............................................................................................................................. 1-2
What is Performance Tuning? .......................................................................................................... 1-2
Response Time.............................................................................................................................. 1-3
System Throughput...................................................................................................................... 1-4
Wait Time....................................................................................................................................... 1-4
Critical Resources......................................................................................................................... 1-5
Effects of Excessive Demand....................................................................................................... 1-6
Adjustments to Relieve Problems.............................................................................................. 1-6
Setting Performance Targets............................................................................................................. 1-7
Setting User Expectations.................................................................................................................. 1-7
Evaluating Performance .................................................................................................................... 1-7
Performance Methodology ............................................................................................................... 1-8
Factors in Improving Performance............................................................................................ 1-9
Architecture........................................................................................................................................ 1-10
2 Monitoring Your Web Server
Monitoring Processor Use................................................................................................................. 2-2
Using the sar Utility (AIX, HP-UX, Intel Solaris)..................................................................... 2-2
Using the top Utility ..................................................................................................................... 2-3
iii
Monitoring the Web Server............................................................................................................... 2-3
Using the mod_status Utility...................................................................................................... 2-4
Logging Server Statistics to a File............................................................................................... 2-6
Monitoring JServ Processes.............................................................................................................. 2-8
3 Sizing and Configuration
Sizing your Hardware and Resources............................................................................................. 3-1
Understanding Concurrent Users and User Population ............................................................. 3-1
Determining CPU Requirements.................................................................................................... 3-3
Secure Sockets Layer Impact on CPU Requirements.............................................................. 3-3
Determining Memory Requirements.............................................................................................. 3-3
Memory for Non-HTTP Server Software and Operating System ......................................... 3-4
HTTP Server Memory Requirements ........................................................................................ 3-4
JServ Memory Requirements...................................................................................................... 3-4
Determining Java Heap Size....................................................................................................... 3-4
Servlet and OracleJSP pages Memory Requirements.............................................................. 3-5
Number of JServ Processes.......................................................................................................... 3-6
4 Optimizing HTTP Server Performance
TCP Tuning .......................................................................................................................................... 4-2
Linux Tunables........................................................ ..... ................................................................. 4-4
MaxClients ........................................................................................................................................... 4-9
SSL Session Caching........................................................................................................................ 4-10
Impact of Logging............................................................................................................................. 4-10
HTTP/1.1............................................................................................................................................. 4-11
Persistent Connections............................................................................................................... 4-11
Apache Versions...................................................... ...... ..... ...... ......................................................... 4-14
5 Optimizing Apache JServ
JServ Overview.................................................................................................................................... 5-2
Optimizing Servlet Performance..................................................................................................... 5-3
Loading Servlet Classes............................................................................................................... 5-3
Automatic Class Reloading......................................................................................................... 5-3
Load Balancing.............................................................................................................................. 5-4
iv
Using Single Thread Model Servlets.......................................................................................... 5-7
What is OracleJSP?............................................................................................................................. 5-8
OracleJSP Page Performance Tuning.............................................................................................. 5-8
Impact of Session Management.................................................................................................. 5-8
Developer Mode .................................. ...... ...... ............................................................................. 5-9
Buffering ........................................................................................................................................ 5-9
Enhancing OracleJSP Performance............................................................................................ 5-9
Index
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Send Us Your Comments
Oracle9i Application Server, Oracle HTTP Server powered by Apache Performance Guide,
Release 1.0.2
Part No. A86828-01
Oracle Corporation welcomes your comments and suggestions on the quality and usefulness of this
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vii
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Audience
Assumptions
Conventions
Preface
This guide is written for Oracle Internet Application Server 8i developers and
system administrators who are responsible for configuring and tuning the Oracle
HTTP Server powered by Apache.
There are many sources of information on configuring and tuning web servers,
Apache in particular. This guide refers to those sources when expedient, and, where
practical, quantifies the performance gains resulting from configuration actions
found in those sources. Any recommendations not validated by our in-house testing
are cited as such, with attribution to the origina l source.
All of our in-house tests were run on a dedicated 100 Mbps network, in order to
achieve repeatable test results. Your results wil l vary based on network
configuration and contention characteristics.
This manual uses the following typographical conventions:
Convention Example Explanation
bold tnsnames.ora
runInstaller
www .oracle.com
Identifies file names,
utilities,
processes,
and URLs
ix
Convention Example Explanation
italics file1 Identifies a variable in text; replace this place
holder with a specific value or string.
angle brackets <filename> Identifies a variable in code; replace this
place holder with a specific value or string.
courier owsctl start wrb Text to be entered exactly as it appears. Also
used for functions.
square brackets [-c string]
[on|off]
Identifies an optional item.
Identifies a choice of optional items, each
separated by a verti c al bar (|), any one
option can be specified.
braces {yes|no} Identifies a choice of mandatory items, each
ellipses n,... Indicates that the preceding item can be
The term, Oracle Server, refers to the database server product from Oracle
Corporation.
The term, oracle, refers to an executable or account by that name.
The term, oracle, refers to the owner of the Oracle software.
Oracle Services and Support
A wide range of information about Oracle products and global services is available
from:
■ http://www.oracle.com
The sections below provide URLs for selected services.
Oracle Support Services
Technical Support contact information worldwide is listed at:
■ http://www.oracle.com/support
Templates are provided to help you prepare information about your problem before
you call. You will also need your CSI number (if applicable) or complete contact
details, including any special project information.
separated by a verti c al bar (|).
repeated any number of times.
x
Product and Documentation
For U.S.A customers, Oracle Store is at:
■ http://store.oracle.com
Links to Stores in other countries are provided from this site.
Product documentation can be found at:
■ http://docs.oracle.com
Customer Service
Global Customer Service contacts are listed at:
■ http://www.oracle.com/support
Education and Training
Training information and worldwide schedules are available from:
■ http://education.oracle.com
Oracle Technology Network
Register with the Oracle Technology Network (OTN) at:
■ http://technet.oracle.com
OTN delivers technical papers, code samples, product documentation, self-service
developer support, and Oracle key developer products to enable rapid
development and deployment of application built on Oracle technology.
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Contents
1
Performance Overview
This chapter discusses performance and tuning concepts, and briefly describes
Oracle9i Application Server architecture.
■ Performance Terms
■ What is Performance Tuning?
■ Setting Performance Targets
■ Setting User Expectations
■ Evaluating Performance
■ Performance Methodology
■ Architecture
Performance Overview 1-1
Performan ce Terms
Performance Terms
Following are performance terms used in this book:
concurrency The ability to handle multiple requests simulta neously.
latency The time that one system component spends waiting for
response time The time between the submission of a request and the
scalability The ability of a system to provide throughput in
Threads and processes are examples of concurrency
mechanisms.
another component in order to complete the entire task.
Latency can be defined as wasted time. In networking
discussions, latency is defined as the travel time of a
packet from source to destination.
completion of the response.
proportion to, and limited only by, available hardware
resources.
A scalable system is one that can handle increasing
numbers of requests without adversely affecting response
time and throughput.
service time The time between the initiation and completion of the
response to a request.
think time The time the user is not engaged in actual use of the
processor.
throughput The number of requests processed per unit of time.
wait time The time between the submission of the request and
initiation of the response.
What is Performance Tuning?
Performance must be built in. You must anticipate performance requirements
during application analysis and design, and balance the costs and benefits of
optimal performance (see "Setting Performance Targets" on page 1-7). This section
introduces some fundamental concepts:
■ Response Time
■ System Throughput
1-2 Oracle HTTP Server powered by Apache Performance Guide
Response Time
What is Performance Tuning?
■ Wait Time
■ Critical Resources
■ Effects of Excessive Demand
■ Adjustments to Relieve Problems
Because response time equals service time plus wait time, you can increase
performance in this area by:
■ Reducing wait time
■ Reducing service time
Figure 1–1 illustrates ten independent tasks competin g for a single resource.
Figure 1–1 Sequential processing of independent tasks
In this example, only task 1 runs without waiting. Task 2 must wait until task 1 has
completed; task 3 must wait until tasks 1 and 2 have completed, and so on.
(Although the figure shows the independent tasks as the same size, the size of the
tasks will vary .)
Performance Overview 1-3
What is Performance Tuning?
In parallel processing with multiple resources, more resources are available to the
tasks. Each independent task executes immediately using its own resource: no wait
time is involved.
System Throughput
System throughput is the amount of work accomplished in a given amount of time.
You can increase throughput by:
■ Reducing service time
■ Reducing overall response time by increasing the amount of scarce resources
available. For example, if the system is CPU bound, and you can add more
CPUs.
Wait Time
While the service time for a task may stay the same, wait time will lengthen with
increased contention. If many users are waiting for a service that takes one second,
the tenth user must wait 9 seconds. Figure 1–2 shows the relationship between wait
time and resource contention.
Figure 1–2 Wait time rising with increased contention for a resource
1-4 Oracle HTTP Server powered by Apache Performance Guide
Critical Resources
Resources such as CPU, memory, I/O capacity, and network bandwidth are key to
reducing service time. Adding resources incr eases thr oughput and r educes response
time. Performance depends on these factors:
■ How many resources are available?
■ How many clients need the resource?
■ How long must they wait for the resource?
■ How long do they hold the resource?
Figure 1–3 shows that as the number of units requested rises, the time to service
completion rises.
Figure 1–3 Time to service completion vs. demand rate
What is Performance Tuning?
To manage this situation, you have two options:
■ Limit demand rate to maintain acceptable response times
■ Add resources
Performance Overview 1-5
What is Performance Tuning?
Effects of Excessive Demand
Excessive demand increases response time and reduces throughput, as shown in
Figure 1–4. If there is any possibility of the demand rate exceeding the achievable
throughput, a demand limiter (such as MaxClients in the Oracle HTTP Server and
security.maxConnections in JServ) is essential. Look at the possible demands that
may be placed on the system and design the application or configure the system
with these cons traints in mind.
Figure 1–4 Increased Demand/Reduced Throughput
Adjustments to Relieve Problems
Performance problems can be relieved by making adjustments in the following
areas:
unit consumption Reducing the resource (CPU, memory)
consumption of each request can improve
performance. This might be achieved by
pooling and caching.
functional demand Rescheduling or redistributing the work
will relieve some problems.
capacity Increasing or reallocating resources (e.g.,
CPUs) relieves some problems.
1-6 Oracle HTTP Server powered by Apache Performance Guide
Setting Performance Targets
Whether you are designing or maintaining a system, you should set specific
performance goals so that you know how and what to optimize. If you alter
parameters without a specific goal in mind, you can waste time tuning your s ystem
without significant gain.
An example of a specific performance goal is an order entry response time under
three seconds. If the application does not meet that goal, identify the cause (for
example, I/O contention), and take corrective action. During development, test the
application to determine if it meets the designed performance goals.
Tuning usually involves a series of trade-offs. Once you have determined the
bottlenecks, you may have to modify performance in some other areas to achieve
the desired results. For example, if I/O is a problem, you may need to purchase
more memory or more disks. If a purchase is not possible, you may have to limit the
concurrency of the system to achieve the desired performance. However, if you
have clearly defined goals for performance, the decision on what to trade for higher
performance is simpler because you have identified the most important areas.
Setting User Expectations
Evaluating Performance
Application developers, database administrators, and system administrators must
be careful to set appropriate performance expectations for users. When the system
carries out a particularly complicated operation, response time may be slower than
when it is performing a simple operation. Users should be made aware of which
operations might take longer.
Evaluating Performance
With clearly defined performance goals, you can readily determine when
performance tuning has been successful. Success depends on the functional
objectives you have established with the user community, your ability to measure
whether or not the criteria are being met, and your ability to take corrective action
to overcome any exceptions.
Ongoing performance monitoring enables you to maintain a well tuned system.
Keeping a history of the application’s performance over time enables you to make
useful comparisons. With data about actual resource consumption for a range of
loads, you can conduct objective scalabilit y studies and from these predict the
resource requirements for anticipated load volumes.
Performance Overview 1-7
Performance Methodology
Performance Methodology
Achieving optimal effectiveness in your system requires planning, monitoring, and
periodic adjustment. The first step in performance tuning is to determine the goals
you need to achieve and to design effective usage of available technology into your
applications. After implementing your system, it is necessary to periodically
monitor and adjust your system For example, you might want to ensure that 90% of
the users experience response times no greater than 5 seconds and the maximum
response time for all users is 20 seconds. Usually, it’s not that simple. Your
application may include a variety of operations with differing characteristics and
acceptable response times. You will need to set measurable goals for each of these.
Figure 1–5 Adjusting Capacity and Functional Demand
You w ill also need to determine variances in the load. For example, users might
access the system heavily between 9:00am and 10:00am and then again between
1:00pm and 2:00pm. If your peak load occurs on a regular basis, for example, daily
or weekly, the conventional wisdom is to configure and tune systems to meet your
peak load requirements. The lucky users who access the application in off-time will
typically achieve better response times than your peak-time users. If your peak load
is infrequent, you may be willing to tolerate higher response times at peak loads for
the cost savings of smaller hardware configurations.
1-8 Oracle HTTP Server powered by Apache Performance Guide
Factors in Improving Performance
Performance spans several areas:
■ Application design: Designing applications that efficiently utilize hardware
resources and handle increasing numbers of users effectively.
■ Sizing and configuration: Determining the type of hardware needed to support
your performance goals. See Chapter 3, "Sizing and Configuration".
■ Parameter tuning: Setting configurable parameters to achieve the best
performance for your application. See Chapter 5, "Optimizing Apache JServ"
and Chapter 4, "Optimizing HTTP Server Performance".
■ Performance monitoring: Determining what hardware resources are being used
by your application and what response time your users are experiencing. See
Chapter 2, "Monitoring Your Web Server".
■ Troubleshooting: Diagnosing why an applica tion is using excessive hardware
resources, or why the response time exceeds the desired limit.
Performance Methodology
Performance Overview 1-9
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