Apex Algorithms: Tips and Tricks (Dreamforce 2014)

Apex Algorithms: Tips and Tricks (Dreamforce 2014)

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  Apex Algorithms: Tips& Tricks Mary Scotton Developer Evangelist salesforce.com @rockchick322004 Gonzalo Abruna Developer & Analyst 4C Consulting (Belgium) @GonzaloAbruna
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  Agenda •  Top CoderChallenge •  Optimize SOQL queries •  How to optimize an algorithm: tips & tricks •  Summary •  References •  Q&A
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  Use to uce a video, A,etc. Use Case: Mother-Son Bowling Event Assign each attendee to 1 of 30 lanes, ordered by grade
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  Place er or go in eaof ered ntally Gonzalo Abruna Developer & Analyst, 4C Consulting (Belgium)
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  Optimize SOQL queries SOQLLimits •  100 SOQL queries per transaction (200 if transaction is asynchronous) •  50.000 rows retrieved by SOQL queries •  120 seconds maximum SOQL query run time
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  Optimize SOQL queries DataModel
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  Optimize SOQL queries Requirements:Sample Scenario •  Query all the Contacts that have worked for an Account, via join object •  For those Contacts, get all the Accounts they have worked for
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  Optimize SOQL queries Solution#1 •  Upsides –  Easy to implement •  Downsides –  Many loops –  Many SOQLs –  Bad performance
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  Optimize SOQL queries Solution#2 •  Upsides –  Less SOQL queries –  Less loops (important for complex algorithms) •  Downsides –  Not much better than Solution #1 –  SOQL Limit: “In a SOQL query with parent-child relationship sub-queries, each parent-child relationship counts as an additional query. These types of queries have a limit of three times the number for top-level queries. The row counts from these relationship queries contribute to the row counts of the overall code execution. In addition to static SOQL statements, calls to the following methods count against the number of SOQL statements issued in a request.”
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  Optimize SOQL queries Solution#3 •  Upsides –  The most efficient –  Less SOQL queries –  Less loops (important for complex algorithms) •  Downsides –  Data structures may be required to represent the data
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  Representing the Data • Upsides –  Avoids unnecessary loops –  Direct access to the records –  Easier to handle than lists without key •  Downsides –  Be careful with null pointer exceptions and reference to null object –  Maps are not ordered Solution #3, Part 2: Using Map<Id, List<sObject>>
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  How to Optimizean Algorithm •  Use Map<Id, sObject> in SOQL queries List<Account> listAccounts = [SELECT Id, Name FROM Account]; Map<Id, Account> mapAccounts = new Map<Id, Account>([SELECT Id, Name FROM Account]); •  Estimate how big your data is & test empty values scenario •  Avoid unnecessary loops: try to reuse loops without losing readability of code Top Tricks
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  How to Optimizean Algorithm •  Put conditions in SOQL queries, not in if statements List<Account> listAccounts = [SELECT Id, Name, Type FROM Account]; for(Account acc : listAccounts){ if(acc.Type == ‘Prospect’){…} } VS List<Account> listAccounts = [SELECT Id, Name, Type FROM Account WHERE Type = ‘Prospect’]; Top Tricks
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  How to Optimizean Algorithm •  Query only the fields that you need •  Try to avoid putting formula fields on a WHERE clause •  Parent-Child SOQL to avoid loops –  Example: get the three newest Contacts per Account Top Tricks
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  Summary •  Every algorithmis different •  Think before coding •  Be aware of limits •  Readability of code is important •  Complex algorithms can be broken down into smaller and easier (divide & conquer) •  The place of an algorithm is critical
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  References •  Developer blogshttps://developer.salesforce.com/blogs/ •  Force.com Apex developer guide. http://www.salesforce.com/us/developer/docs/apexcode/ salesforce_apex_language_reference.pdf •  Appelman, Dan. Advanced Apex Programming. http://advancedapex.com •  Douglas, Jeff. Blog. http://blog.jeffdouglas.com •  Altman, Jesse. Blog. http://jessealtman.com •  Bob Buzzard Blog. http://bobbuzzard.blogspot.be •  Carlberg, Reid. Blog. http://reidcarlberg.com
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  Mary Scotton Developer Evangelist salesforce.com @rockchick322004 GonzaloAbruna Developer & Analyst 4C Consulting (Belgium) @GonzaloAbruna