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Lotuscript for large systems
 

Lotuscript for large systems

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    Lotuscript for large systems Lotuscript for large systems Presentation Transcript

    • LotusScript SurvivalTips for Large Systems Bill Buchan hadsl.com
    • Agenda• Introduction• What do we need?• Logging• Performance• Code Reuse• Weirdness
    • Introduction• I am: • Bill Buchan, CEO, hadsl • LotusScript expert since 1997, Large systems experience
    • Direction?• Lets consider the following slide...
    • Whats New In LotusScript?This page is left intentionally blank
    • Whats new in LotusScript?• The Class libraries have generally grown with each release • Leveraging feature-specific stuff such as ID Vault in 8.5.0
    • What does this mean?• LotusScript is still an invaluable tool in your armoury for creating Business Logic • Its easy, its multi-platform• Its NOT the future in terms of Client or Web • Check out all the xPages sessions here • No excuses
    • What do we need?• Large environments need: • Stability • Scalability• If you cant measure it, you cant manage it• You want to do more, with less time and less people
    • What do we need?• Stable performance • We cant keep adding new servers every time we add a new application/database instance • We cant let a single application wreak havoc on our systems
    • What do we need?• Code Reuse. Of course. • We have less resources doing more work • We need to test more effectively
    • Logging• Why do logging? • As a rule of thumb, if its scheduled, critical, or running in someplace you cant immediately check, you need logging• You need to know: • When and where did it start, stop • Was it successful
    • Logging• If something happens, and you find out from the users • You have failed
    • Logging• Lots of solutions available • For instance, use ‘msgbox’ to log to the console. • Admins hate this • It’ll never be acted upon
    • Logging Solutions• Check out OpenLog at OpenNTF • Add two lines of code, and you have a comprehensive log • Free and Easy• No excuses
    • SuperLogging• Consider Performance • Opening a notes database - even from Script - opens the default view • Log database views can get large • It can be slow
    • SuperLogging• Why not • Create a new document and populate as normal • Stamp it with start and stop times - handy for measuring load • Add Server, Database, Agent and User • But then use notesdocument.send()
    • SuperLogging• Sending log documents by email means: • The process is not waiting for you to save the log document (and update the views) - huge performance increase • The log database need not be local • The user processes do NOT need access to the log database
    • SuperLogging• Once you start emailing in Log Documents, you can do more: • Spot when agents DONT trigger a log document - and do something about it • Spot when NEW agents start creating logs
    • SuperLogging• Remember, ALL code has to log accurately • LotusScript, Java, xPages • Javascript?
    • Performance• We application developers can create fantastic applications• And we can create horrible ones • Ones that really kill servers.• Lets talk about...
    • Performance:Views• Your application needs views. Of course it does. But does it need them all?• ‘Click-sort’ columns are evil• Use more ‘Categorised’ views
    • Performance:Views• How can I tell the size of a view? • Admin client, select database, Tools, Manage Views
    • Performance:Views
    • Performance:Views
    • Performance:Views• Create as few views as possible• Don’t use Click-sort on columns unless absolutely necessary. Each click-sort column creates another copy of the view
    • Performance:Agents• Scheduled Agents have to be well-behaved • Agent Manager doesnt really do a great job in killing runaway agents • It certainly doesnt throttle agents which consume lots of CPU • And it only runs one or two agents at a time
    • Performance:Agents• So how to we minimise our Agent Footprint? • Write them to fit the potential size of your application • If there are lots of documents to process, let the agent run multiple times
    • Performance:Agents• Use Agent Profiling to find out how long your agents take against a representative quantity of documents • ‘It worked in testing’ is not an excuse. • Its an admission your testing wasn’t rigorous enough
    • Performance:Agents• To enable Agent Profiling, check the ‘Profile This agent’ in Agent Properties.• Once its ran, you can view which calls its made, and how much time it took
    • Performance:Agents
    • Performance:Agents• You can see • When the agent ran • Where it ran • Where it spent time• Invaluable for performance tuning
    • Performance:Agents• Now. Lets take it one step further • How about collecting ALL agent profiles from ALL databases and storing them in a database? • NOT recommended for production environments
    • Performance:Agents• Recipe: • Take ‘TriggerHappy’ from OpenNTF • Have it listen to ALL document saves on the server • If the form is called "$BEProfileR7" • Forward the document to another database
    • Performance:Agents• For more information on this, visit: • http://www.billbuchan.com/ imported-20091119232548/2010/2/2/ universal-agent-profiling-in-domino.html • URL is in IBM Standard Download Notation.
    • Performance:Agents• A common scenario • We build an agent to examine a lot of documents, and update a few of them, every night. • The database grows • Your admin kills you.
    • Performance:Agents• Remember: • Agent Manager is like a crumbly old relative - Everyone loves him • But he’s quite shaky on his feet • And smells• Don’t abuse him
    • Performance:Agents• Changing the maximum agent run-time on the server document is CHEATING
    • Performance:Agents• Re-architect the agent • It starts up, figures out how long it has to run, and works out its termination time. • Maximum time minus 2 mins • Keep working till expiry time • Have the agent run a few times - say every 10 mins for 3 hours overnight
    • Performance:Agents• So: • Own & Understand your agent performance • Don’t abuse agent manager • Don’t let it kill your system
    • Code Re-use• Dont reinvent the wheel every time • That leaves far too little time for the pub • Oh - and it means re-testing from scratch every time• Be Lazy
    • Code Re-use• So • If your an old-fashioned script guy, create a standard script library that encapsulates: • Standard Logging • Configuration lookup
    • Code Re-Use• If your a little bored with this (and who isnt?) • Create a LotusScript class which encapsulates all boring logic • Extend this class in your own code for the business logic • Simplify the target code
    • Code Re-use• For example:class baseClass Public Sub logMsg(msg as String) ‘ do stuff end sub public sub raiseError() ‘ do stuff end subend class
    • Code Re-useclass myLogicClass as baseclass Private Function myStuff(waffle as String) on error goto errorhandler call logMsg(“hello world”) ‘ Do stuff exitFunction: exit function errorhandler: call me.raiseError() resume exitFunction end functionend class
    • Code Re-use• Remove the responsibility for • Logging • Error handling • Other boring stuff• From your business logic
    • Weirdness• Sometimes, we have to walk on the wild side • Just sometimes, we like to stroke our misshapen little ego • Or we actually have a business reason • Whatever
    • Weirdness: Lists • Use lists - they’re not hard.Dim Pres list as StringPres(“George”) = “Bush”Pres(“Bill”) = “Clinton”Print “Georges’s last name is: “ + Pres(“George” )if not isElement(Pres(“Chad”)) then _ print “Chad wasn’t found”forall thisPres in Pres Print listtag(thisPres) + “ “ + thisPresend forall
    • Weirdness:C-API• LotusScript never does everything. Sometimes you have to call out to C-API • What is C-API? • Over 700 functions that you can get to using C code • Downside: Creating & Supporting code on every platform you support. Eugh.
    • Weirdness: C-API • So how can the lazy programmer call C-API functions from LotusScript?Declare Function W32_NSFGetServerLatency LibLIB_W32 Alias {NSFGetServerLatency} (_ Byval ServerName As Lmbcs String, _ Byval Timeout As Long, _ retClientToServerMS As Long, _ retServerToClientMS As Long, _ ServerVersion As Integer) As Integer
    • Weirdness: C-API • Now lets exploit this declarationPublic Function getServerLatency _ (strServer As String) AsLong Dim nnServer As New NotesName(strServer) Dim ToServer As Long, fromServer As Long Dim ver As Integer Dim timeout As Long timeout = 1000 1000ms == 1 second Call W32_NSFGetServerLatency(nnServer.Can onical,_ timeout, _ toServer, fromServer, ver) Return both directional latencies added togeth er getServerLatency = fromServer + ToServerEnd Function
    • Weirdness: C-API• Now do this for every function, and every platform you wish to support. • Euch
    • Weirdness: Execute • You all know how to do ‘Evaluate’ right?Dim V as variantV = evaluate( “ @Name( [CN]; @UserName ) “ )print V(0) ‘ Result is ‘Bill Buchan’
    • Weirdness: Execute• Boring. Lets write some code to write some code Dim S as String S = “ msgbox | Hello World | “ V = execute ( S )
    • Weirdness: Execute• What is this doing? • We can populate a string with valid Lotusscript Code • And then execute it.• Why on earth would this be useful? • We could, for instance, generate our platform specific C-API calls
    • Weirdness: C-API• Check out the ls2capi.com web site• And check out my ls2capi database on • http://hadsl.com/hadsl.nsf/Documents/ LS2CAPI+-+Calling+Notes+C-API+from +LotusScript!OpenDocument• Step through it in the debugger.. ;-)
    • Conclusion• Use these techniques to deal with large systems • Minimise, Simplify and Productionalise your code• Learn xPages