La vita nella corsia di sorpasso; A tutta velocità, XPages!

La vita nella corsia di
sorpasso
Ulrich Krause, Milano, 27 Settembre 2013
A tutta velocità, XPages!

Life in the Fast Lane – Full Speed XPages!
About: me
Administrator /Developer since 1993
Senior Software Architect at BCC
OpenNTF Contributor
OpenNTF Board of Directors
Blog http://www.eknori.de
IBM Champion 2011/2012/2013
Notes Forum (http://www.atnotes.de)

Agenda
What factors affect Performance?
Java vs. JavaScript
ViewNavigator vs. GetNextDocument
Stringbuilder vs. Concat (+)
JSF Lifecycle Listener
Partial Update / Partial Execute
Variable Resolver
Tools

XPages Request

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

Hardware
Main Memory
• Limit defined by the operating system
•  Scalability
CPU
• Cores / Clock / Cache
•  Poor response time
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 heap size & garbage collector
• CPU time, competition between threads, gives slower response
times
• Threads, limited to 40 by default

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.

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,addre
ss=8000

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
Use 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
When using 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

JavaScript/CSS Aggregation

XPages PreLoad
XPagesPreload=1
New Feature in Notes / Domino 8.5.3
Works on 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 PreLoad
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

XPages PreLoad (cont.)
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.
• 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.

Scoped Variables (cont.)
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

JSF Lifecycle

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%20Master
class

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
Can be thought of as global variables
Value can be computed dynamically or on page
load
• You can use ${javascript:@Today()} and run it once rather than
running a function each time.
Can be scoped to any level that datasources can
• XPage, Custom Control or Panel
• Set a dataContext in a panel in a repeat control to avoid multiple
references to a NotesDocument's item
Is Referenced using EL
• At no point in the references do you run SSJS
• Not having to go through the SSJS parser

DataContext - Pitfall
Do not bind data context variables dynamically.
• They will be recomputed again and again, even when in partial
execution mode and if they are not in use

DataContext - Pitfall

Partial Refresh / Update (Pro)
Reduced control processing in the render response
phase
• Means less work on the server
• RenderResponse 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 Refresh / Update (Cons)
Refreshing more than one target ID in a single
partial refresh event
• http://www.timtripcony.com/blog.nsf/d6plinks/TTRY-84B6VP

Partial Execution
Reduced 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.

Partial Execution (cont.)
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 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
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
computationMost properties, like CSS “style” are only computed
in the RenderResponse phase
Edit Box and input “value” properties are used in
Data Processing phases and RenderResponse
phase
Data Source properties are computed during
RenderResponse
• Results are cached for the next request's Data Processing and
InvokeApplication phases

Minimize work in rendered / visible
computationThe 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 other 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 complex and 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

Image Sprites
Use CSS Image Sprites
• If you have multiple small images, make a single larger image
containing the smaller images
• Use CSS to display only 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_im
g

XPages Toolbox
XPages based Application
• Runs on the Domino server or the Notes client
• An NSF needs to be installed on the server/Notes client
• A profiler jar file should be added to the JVM launch options
Measures CPU performance and memory
allocation
Available from OpenNTF.org
• Free open source project
• http://www.openntf.org/internal/home.nsf/project.xsp?action=openDo
cument&name=XPages%20Toolbox
Extended in 8.5.2 to support backend classes
profiling

XPages Toolbox

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

Heapdump / Javadump Analyzer

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

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 objectsUse the Eclipse Java
debugger.
• In Dominonotes.ini add these 2 options:
• JavaEnableDebug=1
• JavaDebugOptions=transport=dt_socket,server=y,suspend=n,address=
8000

Optimization – Step By Step

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

XAgent – SSJS – UNID from Item
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
loop the collection and get the JSON from an item
on the document. JSON is calculated on document
save

XAgent – SSJS - SingleItem

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

StringBuilder vs String.concat
When to use StringBuilder over '+' (String.concat())
?
• use StringBuilder whenever you assemble a String in a loop
• Keep in mind that '+' isn't always a good idea
http://kaioa.com/node/59

XAgent – SSJS – ViewNavigator +
StringBuilderloop 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

XAgent – Java

Themes
Single document containing references to all your
CSS resources
• resource sections reference the CSS files
• 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

Themes
Create your own themes from scratch.
• Extending an existing theme will include extra stylesheets and styles
that you might not need.
Be prepared to spend more time writing css though

Load Resources from Themes
Global Application / Configuration properties

Feedback
ulrich_krause@bcc.biz
Questions ?

La vita nella corsia di sorpasso; A tutta velocità, XPages!

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