Life In The FastLane: Full Speed XPages

Life In The Fast Lane
Full Speed XPages
March , 21. – 22. 2013
Faculty Club, Leuven, Belgium

Ulrich Krause, BCC Unternehmensberatung GmbH
Matthew Fyleman, We4IT

About: Matthew Fyleman
 Lotus Notes/Domino Developer since 1993
 Senior Developer at We4IT GmbH

 Recently focused entirely on XPages
development
 Working on We4IT's XPages framework
 Also on Offline capabilities for We4IT’s mobile
framework

About: Ulrich Krause
 Lotus Notes/Domino Developer since 1993
 Senior Software Architect at BCC

 OpenNTF Contributor
 OpenNTF Board of Directors
 IBM Champion 2011/2012/2013
 Blog http://www.eknori.de
 Notes Forum (http://www.atnotes.de)

Agenda
 Performance, what factors affect it?
 Java vs. JavaScript
 Looping through Documents, ViewNavigator vs.
GetNextDocument
 Stringbuilder vs. Concat (+)
 JSF Lifecycle Listener
 Partial Update / Partial Execute
 Variable Resolver
 Tools

Hardware
 The hardware used has a significant influence on performance.
There are 3 key elements:
• CPU
• Main Memory
• Hard Disk

Hardware
 CPU
• Cores / Clock / Cache
•  Poor response time

 Main Memory
• Limit defined by the operating system
•  Scalability

 Weak CPU AND Low Memory
• Poor overall performance
• Poor response times
• Server "hangs"

Network
 Latency
• Time taken for data transmission between multiple computers on a
network
 Bandwidth
• Rate of transmission of data

 Greater Bandwidth
+ Lower Latency
--------------------------------
= Better Connection

Client & Browser
 Hardware
 How many data requests / responses are transmitted
 How much data is transferred (size)
 Caching of resources
 How much CSJS runs
 Size / complexity of the CSS
 Complexity of the site structure

Limiting factors on performance
 Browser / HTTP server
• Network latency – distance/time to server. Bandwidth – size of files.
• Browser limits on concurrent downloads; <= IE7 allows 2 downloads, IE8
allows 6
 HTTP Server / App Server
• HTTP Server JVM memory allocation (heap size) & garbage collector
• CPU time, competition between threads, gives slower response times
• Threads, limited to 40 by default, configurable in Domino Administrator
 App Server / Domino context
• Read design elements from the NSF (XPage .class files, form structure, etc)
• Backend API calls may be expensive, especially for large data sets.
• Design elements may be network requests.

Limiting factors on performance
 Servlet / Lifecycle
• Restore control tree – file system read. Control tree locking – no
concurrent access.
• Rendered re-evaluated for every control for most phases

 Browser/Client JavaScript/Dojo
• Inline JavaScript blocks insertion of later HTML elements into the DOM
tree
• Dojo does AJAX requests for .js files for dojo modules that are not loaded

General Performance Options
 notes.ini
• HTTPJVMMaxHeapSizeSet=1
• HTTPJVMMaxHeapSize=256M
• Should be set to ¼ of the available RAM
 Domino Administrator
• HTTP server "Enable logging to" disabled
• HTTP server thread count – defaults to 40
 Remember, enabling the debugger affects performance
• JavaEnableDebug=1
• JavaDebugOptions=transport=dt_socket,server=y,suspend=n,address=8000
• JavascriptEnableDebug=1 ( Version 9 )

Reducing Memory Utilization
 xsp.persistence.mode=
 Defines the persistence mode for the JSF pages
• file: All the pages are persisted on disk
• fileex: All the pages are persisted on disk except the current one, which
stays in memory
• <else>: All the pages stay in memory (tree mode)

XPages Design Optimizations
 Simple actions vs links or button with window.location JS
 Reduce server phase processing
• Use partial update where possible
• Use partial execute where possible
• Use disableValidators & immediate event

 Minimize work in rendered / visible computations
• Use variable resolver

 Repeats & Views
• Use viewEntry.getColumnValue instead of viewEntry.getDocument.getColumn
• Use Domino View data source dataCache property where possible

XPages Design Optimizations
 Load-time vs Runtime
• Using loaded vs rendered
• ExtLib Dynamic Content
– allows partial re-loading so more use of load-time optimizations

 Loading resources in the browser
• CSS & browser JS
– extract to separate files. Minify & compress files

• Images
– use correct size & format. Use CSS Image Sprites as possible

JavaScript/CSS Aggregation
 Groups many DOJO, CSS / JS files into a single file
• Less requests from the browser to the server
• Performance improvements on networks with high latency
• Enhanced performance parsing CSS / JS
• Fewer connections to the server
On the Server: xsp.properties:
xsp.resources.aggregate=true

XPages Pre-Load
 XPagesPreload=1
 New Feature in Notes / Domino 8.5.3
 Server and Client

 Java classes from the XPages runtime plug-ins
• loaded from a fixed list of runtime classes ( 435 in ND 8.5.3 )
• com.ibm.xsp.core, common utility, JS wrapper, FSF runtime classes

 Java classes referenced in *-faces.config.xml
• XPages control renderer, data sources, complex types

XPages Pre-Load
• XPagesPreloadDB=Server!!Db.nsf/XPage.xsp, myLocalDb.nsf
• Works at the application level

• The application is loaded on the client / server startup into memory. This
happens even when the application is first opened in the browser
• For each entry in the notes.ini variable, an XPage URL is generated and
sent to the server
• The application is loaded, and the HTML generated
• The XPages runtime discards the HTML, but retains the application in
memory

Scoped Variables
 applicationScope
• Are visible for all users of one application. Expires some time after the last user
used an applicationScope variable.
That means applicationScope variables are NOT persistent forever.
 sessionScope
• Is valid through the session of the current user. A user session expires after
some time of inactivity. Uses don't have access to the sessionScope variables of
other users.
 viewScope
• Is visible for views on the current page only. Useful for transporting a search
query to a view.
 requestScope
• Is valid through one request of the current user. That includes refreshing of a
page.

Caching with Application Scope

XPages Lifecycle Listener
 What happens in each phase of the JSF lifecycle?

Ulrich Krause: http://openntf.org/XSnippets.nsf/snippet.xsp?id=a-simple-lifecyclelistener-

XPages Masterclass

http://www.openntf.org/internal/home.nsf/project.xsp?action=openDocument&name=XPages%20Masterclass

When to Execute - # vs $
 #
• Executed every time the page is rendered
• Use for values that are likely to change
 $
• Executed when the page is first loaded
• Use for values that don't change

DataContext
 dataContexts can be thought of as global variables
 dataContext's value can be computed dynamically or on page
load
• So you can use ${javascript:@Today()} and run it once rather than running
a function each time.
 dataContexts can be scoped to any level that datasources can
• XPage, Custom Control or Panel
• you can set a dataContext in a panel in a repeat control, to avoid multiple
references to a NotesDocument's item
 dataContexts are referenced using EL
• So at no point in the references do you run SSJS, so it's not having to go
through the SSJS parser

DataContext - Pitfall
 Issue with data context variables if they are bound dynamically.
• They will be recomputed again and again, even when in Partial Execution
mode and if they are not in use (http://hasselba.ch/blog/?p=1112)

Partial Refresh / Update (Pro)
 Reduced control processing in the render response phase
• Means less work on the server
– render response is the most intensive phase

 Smaller response from server.
• means reduced network usage

 Better browser experience
• rest of the page is still visible while waiting for a response
• inserting small sections into the page is much faster than reloading a full page.

Partial Refresh / Update (Cons)
 Dependancy outside of the partial update area
• Other areas of the control tree are not processed,so any SSJS scripts in those
other controls will not be run.
• Enabling Partial Update where it was previously full update may lead to
functional problems
 Only one area may be partial updated by default
• In CSJS you can schedule later partial updates of related areas, but any
concurrent requests will wait for exclusive access to the server-side control
tree before processing on the server

http://www.timtripcony.com/blog.nsf/d6plinks/TTRY-
84B6VP

Partial Execution
 Reduced control processing in the 3 data-processing phases
• Means less work on the server, faster response times

 Dependancy on Edit Box values outside of the exec area
• Submitted values from Edit Boxes and/or other input controls in other areas of
the control tree are not processed, so any control values and document fields
in those other areas will not be updated. Enabling Partial Exec where it was
previously full execution may lead to functional problems where values are
out-of date in the onclick script or in the redisplayed page.

 onclick Event Handler must be in the exec area
• The applyRequestValues phase prepares for the invokeApplication phase.The
onclick simple action or SSJS script won't occur if outside the partial exec area

Partial Execution
 execMode only added in 8.5.1 (not in 8.5.0)
 execId slightly difficult to select in Designer
• Select your button, in the Outline view, toggle open the button, select the child
Event Handler control, then set the execId property on the Event Handler.
• [Better UI proposed in Notes/Domino Next – in the Events tab]

disableValidators / immediate
 disableValidators
• JSF life cycle through all phases (1-6)
• But requests will not validate the data
• Converters continue to work.
• Items in documents will be updated
• Sven Hasselbach - "Disable all validators at once" (
http://hasselba.ch/blog/?p=1106)
• Immediate
• JSF Lifecycle processes only phases (1, 2, 6)
• No data processing
• Items in documents are not updated
• Onclick event handler scripts and render response calculations are
performed

Minimize work in rendered / visible computation
 Most properties, like CSS “style” are only computed in the
renderResponse
 Edit Box and input “value” properties are used in Data Processing
phases & renderResponse
 Data Source properties are computed during renderResponse &
results are cached for the next request's Data Processing &
invokeApplication phases

Minimize work in rendered / visible computation
 The rendered property is computed in all 5 lifecycle phases
 Avoid re-computing values in every rendered property

• @DbLookup, @DbColumn, getDocumentByKey
• In the rendered property, save the computed boolean to a viewScope
variable

Using loaded vs rendered
 Loaded
• is only computed once in the createView phase
• not re-computed in the 5 usual phases
• false means the control is not created. So it can never be rendered.
• true means the control is added to the control tree.
• You can still compute rendered when loaded evaluates to true.

 Compute the loaded property on conditions
• where you could compute the rendered property and save it to the view
scope
• it would never need to be recomputed for the rest of the interaction with
this page

Images
 Use correct file type depending on content
• JPEG for complexed detailed images

• PNG/GIF for simple images, fonts, transparencies
• Use the HTML <img> tag “width” and “height” attributes

• For faster HTML layout in the browser
• Size the image to size you intend to use
• Resizing using html attributes height and width will delay the rendering of your
page
• Images larger than necessary will waste bandwidth

CSS Image Sprites
 Use CSS Image Sprites
• If you have multiple small images, make a single larger image containing
the smaller images
• And use CSS to display just the relevant subset image at a location in the
page
• For semantically significant sprites, provide an accessibility “title” attribut
(as sprites don't use the IMG “alt” attribute, but you still want to assist
blind users)
• There's no specific XPages support for sprites, but they're used in the
XPages OneIU themes

CSS Image Sprite Sample

http://www.w3schools.com/css/tryit.asp?filename=trycss_sprites_img

XPages Toolbox
 XPages based Application
• Runs on the Domino server or the Notes client
• An NSF needs to be installed on the Domino server/Notes client
• A profiler jar file should be added to the JVM launch options

 Measures the CPU performance and the memory allocation
 Available from OpenNTF.org
• Free open source project
• Search for “XPages Toolbox”
 Extended in 8.5.2 to support Backend classes profiling
http://www.openntf.org/internal/home.nsf/project.xsp?action=openDocument&name=XPages%20Toolbox

XPages Toolbox
 Generate a heap dump of the JVM running in the HTTP task
• A button in the XPages profiler generates the heap dump
• From the Domino console

• tell http xsp heapdump (triggers com.ibm.jvm.Dump.HeapDump())
• tell http xsp javadump (triggers com.ibm.jvm.Dump.JavaDump())

 Analyze the heap dump using the Eclipse memory analyzer
• http://www.eclipse.org/mat/
• http://www.ibm.com/developerworks/java/jdk/tools/dtfj.html

More Tools
 Print statements
• In rendered/visible computations to see how often executed
– print("panel2 evaluating rendered property");
• In the XPages root control events:
– before/afterPageLoad, afterRestoreView, before/afterRenderResponse.
• Custom control root events:
– before/afterPageLoad.
• In the document data source events:
– queryNewDocument, postSaveDocument, etc.

 Task Manager and/or Process Explorer
• Shows CPU usage & process memory usage as it happens
• Heap memory usage will be a subset of process memory, but heap dumps are
only a snapshot

More Tools
 Browser developer tools
• for watching network transactions, partial updates, response times
• BROWSER: Firebug, Developer Tools
• XPiNC: FirebugLite from ExtLib

 Java / Javascript Debugging
• Degrades performance but can inspect objects, step into code.
• Use the Eclipse Java debugger.
• In Dominonotes.ini add these 2 options:
• JavaEnableDebug=1
• JavaDebugOptions=transport=dt_socket,server=y,suspend=n,address=8000

Demo - Step-By-Step Optimization

XAgent – SSJS
 Get all „Contacts“ into a NotesDocumentCollection, loop the collection and build the
JSON by reading the values from items in the document

XAgent – SSJS – UNID from Item
 Get all „Contacts“ into a NotesDocumentCollection, loop the collection and build the
JSON by reading the values from items in the document. Also UNID is stored in
document

XAgent – SSJS – UNID from Item

XAgent – SSJS - SingleItem
 Get all „Contacts“ into a NotesDocumentCollection, loop the collection and get the
JSON from an item on the document. The JSON is calculated on document save

XAgent – SSJS – ViewNavigator
 loop thru a view and get the JSON from a view column.

XAgent – SSJS – ViewNavigator

StringBuilder vs String.concat
 Concatenation of Strings is very easy in Java - all you need is a '+‘
 Each time you append something via '+' (String.concat()) a new
String is created, the old stuff is copied, the new stuff is
appended, and the old String is thrown away.
The bigger the String gets the longer it takes - there is more to
copy and more garbage is produced.
 Accordingly to Arno Unkrig the optimal strategy is to use
String.concat() for 2 or 3 operands, and StringBuilder for 4 or
more operands
String text= System.out.println("x:"+x+" y:"+y);
"line 1n"+
"line 2n"+
"line 3";

StringBuilder vs String.concat
 When to use StringBuilder over '+' (String.concat()) ?
• use StringBuilder whenever you assemble a String in a loop
• Just keep in mind that '+' isn't always a good idea

http://kaioa.com/node/59

XAgent – SSJS – ViewNavigator + StringBuilder
 loop thru a view and get the JSON from a view column. Use a StringBuilder to concat
the JSON

XAgent – SSJS – ViewNavigator + StringBuilder

XAgent – Java
 loop thru a view and get the JSON from a view column. Use a StringBuilder to concat
the JSON + use Java instead of SSJS

Themes
 Single Document Containing References to all your CSS Resources
• resource sections reference the CSS files used
• control section define what CSS classes are applied to specific controls
 XML Based and Easy To Learn
• creating a new theme document prefills sample content
 Can Extend Other Themes
• <theme extends="webstandard">
• will automatically include all the resource and control definitions from that
theme built-in themes
• webstandard, notes, oneUI

Themes
 Create your own themes from scratch.
 Creating a theme that extends from the webstandard or another
supplied theme will include extra stylesheets and styles that you
might not need.
 Be prepared to spend more time writing css though

Load Resources from Theme
 Global Application / Configuration properties

Life In The FastLane: Full Speed XPages

Life In The FastLane: Full Speed XPages

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