Star98

Two Generations of Client / Server Performance Testing

Steven J. Oubre

MedicaLogic, Inc.

May 7, 1998

Client / Server Performance Testing2

Mission Statement

The mission of MedicaLogic is to develop, marketand support electronic medical records products for the office and clinic that enables cliniciansto deliver higher quality care at lower cost and in teamwork with strategic partners, to deliver a comprehensive EMR solution across the continuum of care.


Product Architecture

LogicianCore EMR

Standard Hardware/Network

Oracle RDMS

StandardScreenDesigns

ClinicalPaths &Outcomes(Enc. Forms,Reports)

KnowledgeBases

LinkLogicEDI Interface

Data InterchangeTo/From OtherSystemsvia HL7/ASTMor ANSI Stds

Indius C++ Class Library

MLI C++ Class Library

Microsoft WindowsDesktop OSStandard Server OS


Appointments

Reviewstatus

In-officeencounter

Update probs, meds;enter orders, services;

create note

Readflag

View contexttake action

Remove, reply,or forward flag

Unsigneddocuments

Review andsign document

Clinical Workflows Flags


How many?

User Workstations

Server Under Test

How many workstationscan be used with a server with acceptableperformance?


Scalability Testing

• Server characterization (memory, disk space, processor speed needed for a given size clinic to run product with acceptable performance.)

• Recommended computer configurations per release for our customers

Objectives:


Alternative Strategies and Factors

•External Lab vs. Load Testing Tool

• Requirement: 500 workstations with multiple servers supporting our supported OS’s via Ethernet 10/100Base-T.

•Factors we considered:

• to perform each release

•Amount of expertise gained at MLI

•Decision: Compuware’s QALoad Load Testing Tool


Player Controllers

QALoadConductor

Server Under Test

Compuware QALoad

Actual Clients

EmulatedClients


QALoad/Client SimulationsClient to

server call:

(SQL)

Keyboard, Mouse &

Display

To network & servers

QALoad/CS simulatesthese “middleware” functions

UserInterface

ApplicationLogic

Middleware

Logician running


Script Capture & ConversionScript Capture & Conversion

Test Planning Test Planning

Test Runs, Analysis & ReportingTest Runs, Analysis & Reporting

Parameterization & DebuggingParameterization & Debugging

Project Phases


Test Planning

• Define a typical encounter in a clinic including roles within the clinic.

• Front Desk, Nurse, and Doctor


QALoad Scripting

Client WS

Select xxxx from yyy

Update aaaa with zzz

Trace File

QALoad/Client-ServerScript

QALoad/WinScripts

Server


Patient Encounter.DAT000-00-0001

000-00-0002

Patient Encounter Script 2 GET_DATA socsecno = “000-00-0002”


Scripts & Data Pools

Patient Encounter.C GET_DATA strncpy( socsecno, VAR1_DATA, 11 ); socsecno[11] = '\0';




Performance Bottlenecks

• Improper / poor disk configurations on database server

• “Under-powered” database server hardware

• Sub-optimal lan / wan configurations

• Poor database / application tuning

• Is the cost to correct these problems for you or your customers worth it?


Common RAID Levels

• RAID 0 - Disk Striping without parity; very fast but no data protection

• RAID 1 - Disk Mirroring; very good data protection but requires 2X number of disks to hold same data

• RAID 0+1 - Mirrored Stripe; fast and reliable

• RAID 5 - Disk Stripe with parity; not quite as fast as 0+1 and reliability is limited

• Cost vs. Performance- In general, RAID 0+1 gives the best performance

but at the cost of the number of drives (and controllers?) needed to implement.


Hardware vs. Software RAID

• Hardware RAID implementations are generally faster due to RAID I/O and management being offloaded from server OS but are more expensive.

• Ability to perform software RAID implementations exist in Netware and NT (and other NOS’s) without the additional cost of hardware RAID controller(s).

• Cost vs. Performance- Depends on how mission critical the database

server is. Hardware solutions are available with added fault tolerance and high availability options.


Splitting Database Files

• It has been known for some time that splitting Oracle data files across multiple disk devices can improve performance.

• Not immediately clear is how the different Oracle data files should be deployed on different disk devices.- The key issue is to minimize head contentions

for reads and writes.

- Oracle has several white papers available on this and related issues.


Lan / Wan Configurations

• Know what your network loads and bandwidths are.- Proper network segmentation improves overall

performance and minimizes collisions

• MedicaLogic has published a WAN Planning Guide for our customer use based on network load testing performed inhouse.- Connection speeds tested range from 28.8Kbps

to 100Mbit/s including Frame Relay and ISDN connections

• Alternative connection solution(s)- Windows Terminal Server / Citrix MetaFrame


Single DB 3-tier System

MetaFrame Serverw/Logician

PClow-endPC

WyseCruisePad® winTermweb

browser

WAN (T1+ bandwidth) Screen update traffic

10Mbit LAN

Oracle Logician Server

100Mbit LANSQLNet traffic(ATM or Gigabit Ethernet later)


Clinic A

Main Campus

Clinic B



Database / Application Tuning• Tuning helps achieve improved database

performance– Use of Oracle OCI instead of ODBC for database

communications– Increase use of host variables, cursors, and indexing

to reduce SQL query parsing – Reduce and eliminate the number of redundant

queries

– Modify Oracle database schema to minimize table contentions

• SQL_AREA cache hit ratio in Oracle measures this level of performance (a recommended ratio is 95%)- This is Oracle’s area for client-submitted SQL

statements

• An application with a cache hit ratio of 38% translates to Oracle having to fully parse and validate a SQL statement over 62% of the time - highly CPU intensive

Star98

Documents

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