DF14: Faster SOQL? Yes, Please

By John Tan (@johntansfdc) and Chris Peterson (@ca_peterson) at Dreamforce '14

This presentation was recorded and can be watched at http://dreamforce.vidyard.com/watch/4MfH1Hne0EV76ChTjSWfbQ

Transcript

1. Faster SOQL? Yes, please!
   John Tan
   Architect Evangelist, salesforce.com
   @johntansfdc
   Chris Peterson
   Force.com MVP
   Senior Developer, FinancialForce.com
   @ca_peterson
   

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3. Your company uses Salesforce/
   Force.com …
   

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4. You are a developer or architect …
   

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5. You want to ensure your queries
   perform …
   

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6. Debug Logs
   

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7. Agenda
   1.  Selective Filters
   2.  Query Plan Tool Demos
   

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8. Query Plan Tool in Developer Console
   

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9. John Tan
   Architect Evangelist, salesforce.com
   

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10. Developers Community
    http://bit.ly/Arch_Core_Resources
    

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11. Cheat sheet
    http://bit.ly/Query_Cheat_Sheet
    

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12. Chris Peterson
    Force.com MVP
    Senior Developer, FinancialForce.com
    

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13. Query Plan API
    http://bit.ly/Query_Plan_API
    

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14. Selective filters
    

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15. What is the Force.com query optimizer?
    Generates the most efficient query based on:
    •  Statistics
    •  Indexes / Skinny Tables
    •  Sharing
    

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16. Basic Algorithm
    •  Pre-query engine
    •  Chooses the most selective filter from the WHERE clause
    •  Determine the best leading table/index to drive the query
    Query optimizer will make the best choice best on the filters in your query.
    

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17. Best Practice: One+ Selective Filter Per SOQL statement
    

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18. Selective Filters: Four Components
    1.  Filters - add filters to reduce data
    2.  Operators - avoid 2 inefficient filter operators
    3.  Thresholds – ensure filter meets selectivity threshold
    4.  Index Creation - index the filter field
    

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19. Fields that often make good filters
    •  Date fields
    •  Picklists
    •  Fields with wide and even distribution of values
    

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20. Non-Deterministic Formula Fields Aren’t Good Filters
    •  Can’t index
    •  For example:
    –  References related object
    –  CASE(MyUser__r.UserType__c,1,”Gold”,”Silver”)
    –  Create separate field and use trigger to populate
    Force.com SOQL Best Practices: Nulls and Formula Fields
    

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21. Avoid negative operators
    Query for reciprocal values instead
    ✖ Status != 'closed'
    ✔ Status IN ('open', 'in progress')
    

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22. Avoid filters with a leading % wildcard
    CONTAINS or LIKE ‘%searchstring%’
    ✖ CONTAINS ('district') / LIKE '%district%'
    ✔ STARTS WITH ('district') / LIKE 'district%'
    

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23. Standard Index Selectivity Threshold
    A standard index is selective when it returns:
    •  < 30% of the first 1 million records
    •  < 15% of returned records after the first 1 million records
    •  No more than 1 million total records
    

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24. Standard Index Selectivity Threshold
    For 750,000 Account records
    •  < 30% of the first 1 million records
    •  750,000 x .30 = 225,000
    

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25. Standard Index Selectivity Threshold
    For 3,500,000 Account records
    •  < 30% of the first 1 million records
    •  < 15% of returned records after the first 1 million records
    •  (1,000,000 x .30) + (2,500,000 x .15) = 675,000
    

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26. Standard Index Selectivity Threshold
    Over 5,600,000 Account records
    •  No more than 1 million records
    •  1,000,000
    

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27. Custom Index Selectivity Threshold
    A custom index is selective when it returns:
    •  < 10% of the first million records
    •  < 5% of returned records after the first million records
    •  No more than 333,333 records
    

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28. Standard Fields With Indexes
    •  Id
    •  Name
    •  OwnerId
    •  CreatedDate
    •  SystemModstamp
    •  RecordType
    •  Master-detail fields
    •  Lookup fields
    

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29. Custom Indexes
    •  Discover common filter conditions
    •  Determine selective fields in those conditions
    •  Request custom indexes
    

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30. A filter condition is selective when …
    … it uses an optimizable operator
    … it meets the selectivity threshold
    … selective fields have indexes
    

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31. Demos
    

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32. Query Plan Tool in Developer Console
    

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33. Optimizations
    

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34. AND conditions
    WHERE FirstName__c = 'Jane' AND LastName__c = 'Doe' AND City__c
    = 'San Francisco'
    Step 1 – Allow each index to still be considered if they return < 2X selectivity threshold
    Step 2 – INTERSECTION of all indexes must meet *selectivity threshold
    Step 3 – Use composite index join to drive query
    *If all indexes are standard indexes, use standard index selectivity threshold. Otherwise, use the custom index selectivity threshold
    

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35. AND conditions
    Composite index join – MyUser object 100,000 total records
    

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36. AND conditions
    Composite index join – MyUser object 100,000 total records
    

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37. 2-column index
    For this simple example, it makes more sense to have Customer Support create a 2-column index.
    

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38. OR conditions
    WHERE FirstName__c = 'Jane' OR LastName__c = 'Doe' OR City__c =
    'San Francisco'!
    Step 1 – Each field must be indexed and meet selectivity threshold
    Step 2 – UNION of all the indexes must meet *selectivity threshold
    Step 3 – Use union to drive query
    *If all indexes are standard indexes, use standard index selectivity threshold. Otherwise, use the custom index selectivity threshold
    

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39. OR conditions
    Union - MyUser object 100,000 total records
    

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40. Sort Optimization
    ORDER BY CreatedDate LIMIT 100
    Step 1 – ORDER BY on date or number field
    Step 2 – Bound results with LIMIT clause
    * May have to add CreatedDate <> null explicitly to WHERE clause
    

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41. Summary
    

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42. Summary
    •  Query optimizer generates the most efficient query possible
    •  1+ selective filters per SOQL statement
    •  Test with > 10K records
    

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43. Links
    

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44. Links
    •  Architect Core Resources – http://bit.ly/Arch_Core_Resources
    •  Query cheat sheet – http://bit.ly/Query_Cheat_Sheet
    •  Query Plan API wiki - http://bit.ly/Query_Plan_API
    •  Sort Optimization blog - http://bit.ly/Sort_Optimization
    

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46. Q & A
    

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