AD104 - LotusScript Tips and Tricks. Wai-ki Yip, Development Manager/Senior Developer Raphael Savir, Senior IT Specialist

Size: px

Start display at page:

Download "AD104 - LotusScript Tips and Tricks. Wai-ki Yip, Development Manager/Senior Developer Raphael Savir, Senior IT Specialist"

Tyrone Mathews
5 years ago
Views:

1 AD104 - LotusScript Tips and Tricks Wai-ki Yip, Development Manager/Senior Developer Raphael Savir, Senior IT Specialist

3 Agenda for the Session Purpose - Focus on Performance Tips Architectural Overview of LotusScript Tips/Techniques Control the life time of Notes objects Others Say a few words on the usage of profile documents Conclusion

4 Focus on Performance In the past, we have focused this session mostly on new/cool features Would like to focus this particular session on developing high performance LotusScript Raphael is a Senior IT specialist has been called to many customer sites to diagnose problems found many cases of poorly performing code

5 Purpose of this session To help developers to Diagnose problems Pinpoint some of the potential problem areas Share some experience in the proper usage of LotusScript

6 Real Life Samples We have been looking at many LotusScript samples they work, in general but they take a long time to run take a lot of system resources the worst code have taken down the entire system Point out the issues for LotusScript developers to look out for

7 An Example - Deleting all docs in a view Do While Not(doc is Nothing) count = count+1 set doc = vw.getnextdocument(doc) Redim Preserve arr(ubound(arr)+1 Set arr(ubound(arr)) = doc if count = then goto StopScript Loop 'then loop again to remove all docs in the array

8 Example Expand array one element at a time Not scalable - have problems when you have a large number of documents Create server problem - use up all server resources A better way to accomplish this is by doing NotesViewEntryCollection vec = vw.allentries vec.removeall TRUE Take almost no time to execute

9 Approach Provide an overview of the LotusScript architecture Explain how it functions in Notes Point out a few important areas Binding and reference to Notes objects Interface to the data in Notes objects

10 LotusScript Architecture Overview LotusScript is BASIC (very close to VB/VBA) an embedded full function scripting language full function programming language embedded in a host environment scripting

11 LotusScript as a full function programming language BASIC (VB/VBA compatible) Provides language syntax for data types and its manipulation data manipulation (addition, subtraction,...) string manipulation (concat, left, right, mid,...) control flow (for, if then ) functional abstraction (sub, function) data abstractions (type, classes)

12 LotusScript as a full function programming language It is rich enough to Allow you to freely express the logic of your application But it also gives you all the ropes to hang yourself

13 Simple LotusScript program Dim session as New NotesSession Dim db as NotesDatabase Dim doccollection as NotesDocumentCollection Set db = session.currentdatabase Set collection = db.unprocesseddocuments Forall doc in doccollection 'process the notes document 'your application logic... End Forall

14 LotusScript as a scripting language Efficient mechanism to "glue" data and functionalities from many different places together Access external objects Product objects (e.g., front end/backend classes) Access other external objects COM, Java Access external functions Win32 API Extension mechanism

15 LotusScript as Glue Notes/Domino Database LootusScript as Glue MS Office Internet

16 LotusScript as an embedding component Designed to run within some other applications Memory usage model need to fit in Efficient interface to host Execution within the Notes run time environment Front end (a.k.a., client application) Server (a.k.a., server application)

17 Embedding LotusScript in Notes Notes Environment Session Object LotusScript Virtual Machine stack frame Document Collection database object Document Object Document Object Document Object symbol table Heap

18 How does it work? Session and Current Database objects are created when the agent starts Others are created as needed by the application new forall refvar The product objects are usually large and take time to create LotusScript holds only reference to object As long as a reference is held, it will stay in memory

19 What it boils down to: The application developer needs to understand how to use the language constructs to control the objects how to use the appropriate objects for the appropriate operations Otherwise, your application may tie up a lot of resources unnecessarily take a long time to run cause your application, and other applications on same server to slow down to an unacceptable level (classic situation when you need Raphael on site)

20 LifeTime of the Notes Object General Rules Notes objects are quite large create only when you need them delete if you don't need them anymore save if you think you are going to reuse them Only exception is the NotesSession Object Current Database Object Current Object in the argument of the event raised these are all created when the agent starts to run

21 Object creation Creation - LotusScript new dim session as new NotesSession assign an object set doc = anotherdoc forall reference forall doc in doccollection LotusScript instructs Notes to create the object holds a reference to it, set reference count appropriately

22 Object Deletion Deletion - LotusScript delete delete doc assign something into it set doc = someotherdoc next iteration in forall forall doc in doccollection reference variable is out of scope Rule - if the reference count is 0, it instructs Notes to delete the object

23 Tip#1: Don't create object unless you need it dim count as integer count = 0 dim x(10000) as NotesDocument forall doc in doccollection set x(count) = doc count = count + 1 end forall Depends on the number of documents in the collection

24 Tip #1 This piece of script is not scalable and could bring the system to its knees Since the object reference is stored in the array x, all NotesDocument objects are created and remained in memory Ask yourself - how many objects are there at any time? If you have more than 100, you need to examine your application's logic

25 Tip# 2: Use forall to enumerate collection forall doc in doccollection 'process your document end forall Keep one document object active at one time The previous object is deleted as soon as it executes the forall statement at the top

26 Releasing objects Notes object has a reference count When the reference count goes to 0, the object will be deleted. The resources are free. LotusScript does not do garbage collection like Java. There is no delay. We have experimented with delayed notification Every 10 statements At the end of each SUB Does not work out

27 Tip #3: Pass the object reference in If you will call subs/functions frequently that need to lookup similar information, pass in the object reference this example has many subs (one shown) which all get a handle to a Keywords view this is inefficient Sub Sub1 ( ts as String ) Dim dbpath as String Dim s as New NotesSession Set db = s.currentdatabase Set view = db.getview ( "(Keywords)" ) Set doc = view.getdocumentbykey ( ts ) dbpath = doc.dbpath ( 0 ) ' do some work End Sub

28 Tip #3: Pass the object reference in (cont.) Instead, pass the view reference to each sub Sub Initialize Dim s as New NotesSession Set db = s.currentdatabase Set view = db.getview ( "(Keywords)" ) Call Sub1 ( view ) Call Sub2 ( view ) etc.

29 Tip #3: Pass the object reference in (cont.) Other variation Save an object reference in the GLOBAL section Accessible by all SUBs Advantage Don't delete and recreate the same object again and again

30 Tip #4: Use objects that are readily available to you Because it is expensive to create objects, some of commonly used objects are readily available to you NotesViewEntryCollection vec = vw.allentries NotesDocumentCollection ndc = db.alldocuments NotesDocumentCollection ndc = db.unprocesseddocuments NotesViewColumnArray nvw = vw.columns Also remember that there is a CurrentObject passing to you as part of an event

31 Tip #4: Use objects that are readily available to you (cont'd) Operations are designed to efficiently operate on all documents in the collection For example, NotesViewEntryCollection vec = vw.allentries vec.removeall TRUE No document object needs to be created

32 Tip #5: How to retrieve document data without opening the document Expensive to have a document object. Summary data Buffer holding just the minimum document data to show in a view Loaded when a view is opened When you create the view object, Column values are loaded already Use NotesViewEntry.ColumnValues To get the values directly

33 Tip #6: Temp variables In LotusScript, it is highly preferable to use temporary variables that are held in memory to hold values, instead of directly referencing databases or documents See code on the left (better) and right (worse) below for examples VarViews = db.views Forall v in VarViews print v.name End Forall Dim i as integer Do While i <= ubound ( db.views ) Print db.views(i).name i = i + 1 Loop

34 Tip #6 LotusScript needs to resolve the field name of the object. The process involves string comparison and is relatively slow. If it is saved the data in a variable, it is far more efficient

35 Tip #7: Multi-value fields vs. Single value fields It is inefficient to have many hidden programmatic fields stored on a document for example, if you need to store 100 bits of information, 1's and 0's, do not make 100 fields each containing a single 1 or 1 instead, make a single multi-value field that contains 100 numbers, 1's and 0's you can read this single field into memory and then read/write the various values you need the document will not need to retain the excess 99 fields

36 Tip #7 Each field access takes time 100 different fields will take 100 times longer to access the value. Even if the fields are not used, it will take longer for the document to load

37 Tip #8: How to efficient retrieve data in a view Always best to access data that is already displayed in a view ; columnnumber) doc.columnvalues ( ColumnNumber ) As long as the view is reasonably well constructed, indexing times will be on the order of 100ms every 15 minutes, much less concern than extra LS execution time, especially if your code is in form events

38 Lookups (cont.) If you have a lot of data to lookup (e.g., 10 fields of information), you can optimize your view and lookups View has two columns Column 1 is the sort key, as small as possible Column 2: Field1 + "~" + Field2 + "~" + Field3... "^") if multi-value fields Optionally, Column 2 could reference a field which has already performed this calculation Code lookups then perform only one lookup x = doc.columnvalues ( 1 ) - subscript starts at zero Then use x ( i ) to get the various field values

39 Lookups (cont.) Regardless of how you lookup your data, try to do it only one time If multiple keyword fields, for example, then have them reference a field on the form that performs the lookup just once Or use a profile document to perform the calculation and then read from that into your keyword fields to minimize the frequency or LS equivalent code

40 Tip #9: Comparing ways to get a document collection Full Text Search View - GetAlldocumentByKey View - GetdocumentByKey Database Search

41 db.ftsearch db.ftsearch requires that a full text index be present, and up to date syntax can be a bit trickier to use limit of 5000 results in ND6, ND6.5

42 view.getalldocumentsbykey view.getalldocumentsbykey and db.ftsearch are consistently the fastest methods for acquiring a small collection of documents view.getalldocumentsbykey requires a view views generally index very quickly make the view hidden and streamlined consider a sorted one-column view that has "1" as the formula in that column dc = view.getalldocumentsbykey ( "1" ) will then return the view if you only need to update a simple value, or remove all, then you can use nvc = view.allentries

43 view.getdocumentbykey view.getdocumentbykey is fast use view.autoupdate = False makes method faster allows set doc = view.getnextdocument ( doc ) even if you have just removed the previous doc from the view

44 db.search db.search is not a fast way to get a small collection generally, the larger the database, in terms of documents and size, the longer it takes db.search to return even one document db.search becomes competitive as the collection size increases previous tests indicate approximately 5-10% of the documents in a database but... you don't need a full text index, and you don't need a view in order to use this method, so very handy especially with ad hoc queries and queries against other database over which you have little control

45 Tip # 10 - Error Processing On Error GoTo ErrHandler... average = total / count ErrHandler 'The intention is to write the error handler later Resume when count is 0, it is an infinite loop

46 Tip #11 - Unrestricted Goto Basic was designed in the 60s before the concept of structured programming Goto statement is included for compatibility reason Avoid using it if possible You may get into problems even in seemingly benign situations

47 Tip #11 On Error GoTo ErrHandler... an error occurs Handled: Errhandler... Goto Handled Errhandler is actually a block with a new stack frame You get stack overflow after encountering a number of errors

48 Tip #12: Avoid Conversion Data Type conversions are expensive Avoid using variants and declare all your variables explicitly For I = 1 to Next I I is a variant unless you dim it takes longer to execute - about 10x

49 Tip #12 explicit typing will help dim I as integer For I = 1 to Next I

50 Tip #13 - String handling differences between LotusScript and Notes LotusScript internally represents all strings as UNICODE (UTF16) Notes/Domino represents all string as LMBCS So, whenever there is a data string going through the interface, we have to call a translation routine to convert between LMBCS and UNICODE It is quite expensive

51 Tip #13 - String Processing You want to pull the string out into LotusScript and complete processing before you put it back into Notes Don't do x.result = x.result + "my new text" x.result = mid$(x.result, 2, 4) Instead dim result as string result = x.result do all your string manipulation in LotusScript x.result = result

52 Tip #14 - Remote Debugger Setting A Domino 6 feature Allow you to remotely debug your LotusScript agent on the server Turn it off on the server if you don't need it It has a time out setting waiting for the client debugger to attach e.g., 20 seconds agents running on the server will be stopped at the beginning for 20 seconds every STOP statement will wait for 20 seconds

53 Tip #15: A few words on Profile Documents set by one author... settings...

54 Tip #15 Intention for profile doc Set by one Use by many Performance comes from Per thread cache Multiple updates Efficient but it will take time to propage the change from one cache to the other cache

55 Help is on the way Problem detection Time out for particular agent Memory errors in the agent log Crash your system Domino 7 - agent health monitor Track runaway/expensive agents Track down which calls are expensive

56 Other LotusSphere Sessions AD105 - Who is Misbehaving? Monitoring Lotus Domino Server Agents Julie Kadashevich, J. Cooper Mon 1:30 Swan 1/4 AD106 - Lotus Domino Objects: Overview and Update J. Cooper Tues 10:30 Swan 5/6 BOF - LotusScript Y & B Hampton Wed 7 am

LotusScript Optimization:

LotusScript Optimization: Improving Application Reliability, Speed and the End User Experience By Teamstudio, Inc. Teamstudio, Inc. 900 Cummings Center Suite 326T Beverly MA, 01915 Phone: 800.632.9787