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BP 206
Let's Give Your LotusScript a Tune-Up

Craig Schumann – Senior Developer, Teamstudio

Jens-B. Augustiny, CEO, LIGONET GmbH

Who is who?

Craig Schumann, Senior Developer at Teamstudio

Teamstudio is a producer of Development and Administration tools
for IBM Lotus Notes and Domino


Jens-B. Augustiny, CEO at LIGONET GmbH

Ligonet is a small but active Busines Partner located in Switzerland

2

Agenda
 What do you mean it's slow?

 Where do performance problems show up

 Where the heck is that coming from?

 Tips and tools to weed out the slow bits

 Don't want to go through that again!

 Tips for avoiding slowness in the first place

3

What do you mean it's slow?

4

Bad performance... what exactly do we
mean?

The application is bad ....

Delivery time vs response time ....

Impossible to work with this application

This workflow has to be improved in any case!

Who has never heard these comments?

First and foremost - Make sure you are addressing the right problem.

5

Performance of WHAT?
 Perceived Performance
 The user is feeling that the application is not giving the expected
output
 Rather difficult to define, hence rather difficult to analyze
 Possible fixes:
 Better user training - Explain the functionality to the
users
 Enhance the experience - More information on
screen during processing or data entry
 Streamline the experience - Change the process
flow

User experience can greatly influence how fast an application seems to
work. If it is frustrating or takes a long time to enter data, users may
report this as bad performance.
7

Real performance ....
..... or rather the lack of it ....

 Bottlenecks, that can be verified by timing
 Almost impossible to anticipate
 Differences between testing and production environment
 Any conclusion without actual timing data is pure speculation
 Timing may influence the result

 It is important to have empirical data before you start changing anything.
Just like with end users, developers have preconceived notions about
what the source of the problem might be

8

Example

Running the same functionality four times: list all the views of
names.nsf

2 parameters are changed: The loop logic and the way that we
access the DB properties


Which of the four variants is the fastest?

Why is your choice the fastest?

9

Core code for the examples

10

Timing results
First run

Second run (caching)

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Conclusion

Results may surprise you

Metering should be done in a realistic environment

The amount of data and its structure has to be realistic; most testing
environments are insufficient

Approach of analysis has to be very, very systematic e.g. by
narrowing down the points of problem

12

Where the heck is that coming from?

So you need actual numbers to justify the work to
speed something up..... where are those supposed
to come from?

13

Timing with Now

Example:
BaseTime = Now
[.... your code goes here ... ]
Print “Time used: “ & Now – BaseTime

Advantages Disadvantages

Requires changing of code
Bad placement falsifies the result
Simple and cheap Insufficient timing resolution

14

High Resolution Timing - GetThreadInfo()

Bruce Perry once published an undocumented way to use a high
resolution timer

http://searchdomino.techtarget.com/tip/1,289483,sid4_gci895240,00.html?FromTaxonomy=%2Fpr%2F283841

stc = GetThreadInfo(LSI_THREAD_TICKS) ' get the starting tick
count
'[....the code you want To Time...]
'get the final tick count
ftc = GetThreadInfo(LSI_THREAD_TICKS)
'get the ticks per second
tps = GetThreadInfo(LSI_THREAD_TICKS_PER_SEC)
'final tick count minus starting tick count divided by ticks
per second yields duration.
t = (ftc - stc) / tps
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High Resolution Timing - GetThreadInfo()

Advantages Disadvantages
Requires changing of code
Bad placement falsifies the result
Relatively Simple to implement Makes use of undocumented functions
Better resolution than using 'Now'


A bit more tricky to use

GetThreadInfo() is not guaranteed to work on all versions of Lotus
Notes

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How to communicate the results

PRINT to the status bar (client) or the log.nsf (server)

Better:

Output to a document

Output to a profile document

Output into an analysis database ..... sorry ....
application

17

Example - Make it reusable
Class debugTimer
Private Start As Variant
Private fnName As String

Sub New( fn As String )
Set Start = Now
fnName = fn
End Sub
Sub Delete
Print fnName & " took " & Now-Start & " seconds to complete."
End Sub
End Class

18

Example - Make it reusable
Sub Initialize()
Dim fnTime As New debugTimer( GetThreadInfo(LSI_THREAD_PROC) )
Dim i As Integer

While i < 1000
Print i
i = i + 1
Wend

End Sub

19

Built in profiling

Introduced in Lotus Notes / Domino 7
® ® ®


Only for agents and Web Services

Java and LotusScript

Activation in the properties of the Agent or Service

Access to the results by right-clicking on the Agent or Service

There are only results for pure Notes-Objects, no information for
your own code

20

Built in profiling - Example
Sub Initialize
Dim db As New NotesDatabase( "", "names.nsf" )
i = 0
Dim s As String
For i = 0 To UBound(db.views)
s =db.Views(i).name
Print s
Next
End Sub

21


Run your
agent

22


23

Teamstudio Profiler

Timing of functions

Timing of code line-by-line

Plethora of additional analysis information available

Server and Client

LotusScript only

Application is slowed down a lot

You have to pay for it

24

Teamstudio Profiler - Example

25

Don't want to go through that again!

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Common problems

Tooling is a must for existing applications and performance
problems, but even better would be not to create the problem to
being with!


Some of these are just rookie mistakes, others are just careless.

So first up.....

GetNthDocument!

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GetNthDocument()

Running through a Doc-Collection with GetNThDocument(n) is a lot
slower than getting the first doc with GetFirstDocument and then
going through the collection by GetNextDocument (doc)


Much has been said about this ... mostly all can be read online


http://bobzblog.com/tuxedoguy.nsf/dx/getnth-revisited-helpful-function-or-spawn-of-
the-devil

http://www.lotusgeek.com/LotusGeek/LotusGeekBlog.nsf/d6plinks/ROLR-7HHPER

Be familiar with the limitations of the API you are using. There are no
bad functions, but not every function is appropriate for all situations.

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Check your loop logic

found=False

Do Until (selected_doc Is Nothing)
If (selected_doc.Form(0)="fa_Term") Then
found=True
End If
Set selected_doc=term_collection.GetNextDocument(selected_doc)
Loop

Set selected_doc=term_collection.GetFirstDocument()

If Not(found=True) Then
MessageBox NO_TERM_DOCUMENTS_SELECTED_TO_DELETE, 16,
DELETE_ERROR
Exit Sub
End If

29

and fix your bugs....
found=False

Do Until (selected_doc Is Nothing)
If (selected_doc.Form(0)="fa_Term") Then
found=True
' loop should short circuit here!!
End If
Set selected_doc=term_collection.GetNextDocument(selected_doc)
Loop

Set selected_doc=term_collection.GetFirstDocument()

If Not(found=True) Then
MessageBox NO_TERM_DOCUMENTS_SELECTED_TO_DELETE, 16,
DELETE_ERROR
Exit Sub
End If

30

Fix your bugs - Code Rot

Fact - Code changes over time. Requirements change, better ways
of doing things are discovered.

Make sure your code changes are complete before moving on other
wise performance suffers
Sub Queryopen(...)
Dim session As New NotesSession
Set db = session.currentdatabase
Set view = db.getview("People")

Set ProfileDoc = db.getprofiledocument("PickerView")
' ProfileDoc.Pview = "People"
End Sub

 The variable 'view' is never used anywhere on the form.
NotesDatabase.GetView() is an expensive call to make on a QueryOpen.
Especially if it is never used.

31

Careful with nested IFs

Unlike languages like C and Java LotusScript always evaluates all
conditions in an if statement.

x = 1
If x = 0 And checkresult( res ) = 0 Then
'do some stuff
End If

Checkresult() will always be called. Performance problems can easily be
masked in seemingly simple statements like this.

32

Careful with nested IFs – The Fix

The correct statement is the following:

x = 1
If x = 0 Then
If checkresult( res ) Then
'do some stuff
End If
End If
Checkresult() will only be called when the first statement is true.

33

Variables – Variant is slower

 Besides being breeding grounds for bugs the
Variant data type is inherently slower than typed
variables.

 LotusScript will have to figure out the type at
some point and provide a conversion to the
correct type.

 Don't be lazy! Use Option Declare

34

Loops – Some are faster than others
Forall through arrays much faster than For ..... Next
For ... Next is faster than Do ..... Loop or While ..... Wend

35

Left overs....

Access to selected documents is faster by accessing them through a
view instead of a document collection

Access to Notes object through a temporary variable is faster than
accessing them every time through the property of another Notes
object

36

Summary
 There are technical and non-technical reasons for performance
issues
 If the issue is technical, any statement without metering is pure
speculation
 There are no two identical cases
 Systematic top down analysis is very, very important
 Sometimes the redesign of the application is the best way to remove
the issues
 There are some best practices

37

Thank you!

Questions?
Maybe there are even answers ..... :-)

Craig Schumann - Teamstudio
craig_schuman@teamstudio.com
www.teamstudio.com

Jens-B. Augustiny - LIGONET GmbH
augustiny.j@ligonet.ch
www.ligonet.ch

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Legal Disclaimer
© IBM Corporation 2009. All Rights Reserved.

The information contained in this publication is provided for informational purposes only. While efforts were made to verify the completeness and accuracy of the information contained in this publication, it is provided AS IS
without warranty of any kind, express or implied. In addition, this information is based on IBM’s current product plans and strategy, which are subject to change by IBM without notice. IBM shall not be responsible for any
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Performance is based on measurements and projections using standard IBM benchmarks in a controlled environment. The actual throughput or performance that any user will experience will vary depending upon many
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BP206 - Let's Give Your LotusScript a Tune-Up

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BP206 - Let's Give Your LotusScript a Tune-Up

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