ハマったところ 表参道.rb #44 / into a problem

Railsアプリ運用時にハマったときの体験です

Transcript

1. ϋϚͬͨͱ͜Ζ
   දࢀಓ.rb #44 2019/3/7
   

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2. ࣗݾ঺հ
   • Piece of Cake, Inc.
   
   • দ࡚ ܒ࣏ (·͖ͭ͟ ͚͍͡)
   
   • αʔόαΠυ݉ΠϯϑϥΤϯδχΞ
   
   • 2019೥1݄͔Β
   

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3. Ruby΍Railsͷਂ෵͸
   ೷͖·ͤΜm(_ _)m
   

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4. ϋϚͬͨࣄྫͷ͝঺հ
   

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5. uniq
   

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6. uniq
   • ͖͔͚ͬRails 4.2 -> 5.1΁ͷΞοϓάϨʔυ͕࠷ॳͷ࢓ࣄ
   
   • deprecated 5.0 -> 5.1ΑΓ
   
   • distinctʹॻ͖׵͑Δඞཁ͕͋Δ
   
   • uniqΛ͋Δఔ౓ݕࡧ͍͕ͯͨ͠ɺͱ͋ΔՕॴͰॻ͖׵͑
   ࿙Ε͕͋ͬͨ
   

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7. uniq
   • ActiveRecord::RelationʹͯuniqΛ࢖͏ͱSELECT
   DISTINCT… ͱ DISTINCTจʹม͑ͯ͘ΕΔػೳ
   
   • Rails 5.1͔ΒɺActiveRecord::Relation͸EnumerableΛ
   includeͯ͠ରԠ͢ΔΑ͏ʹͳͬͨͷͰɺArrayΛฦ͢
   

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8. uniq
   • ى͖ͨ໰୊ -> SELECT id FROM… ʹͯऔಘͨ͠IDΛݩʹ
   ϨίʔυΛݕࡧ͢ΔΫΤϦ͕͋ͬͨ
   
   • uniqͰɺDISTINCT͕ޮ͍ͨͱ͖͸ɺidͷ਺͕ߜΓࠐ·Εͯ
   ͍ͨ
   

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9. uniq
   • طଘͷΫΤϦ͸n✕n✕n…(௚ੵ)ɺDISTINCT͕༗ޮʹͳΒͳ
   ͍ͱऔಘ͢ΔϨίʔυ਺͕૿͑ΔΑ͏ʹͳ͍ͬͯͨ
   
   • EXPLAINͰ࣮ߦͯ͠ɺΫΤϦύϑΥʔϚϯε݁ՌΛݟͯ
   ͋ͱͰڍಈΛ֬ೝͰ͖ͨ
   

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10. uniq
    • Rails 5.1͔Βɺuniqͦͷ΋ͷͷϝιου͸׆༻Ͱ͖Δͷͩ
    ͕ɺArrayͱͯ͠ฦͬͯ͘Δ
    
    • Rails 5.0 -> 5.1ΞοϓάϨʔυ࣌ʹ͸Ϩίʔυ਺ͷগͳ͍
    ؀ڥͰಈ࡞֬ೝΛ͢ΔͨΊɺಈ࡞ʹؔͯ͠໰୊͸ΈΒΕͣ
    

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11. uniq
    • Production deployޙɺҰ෦Controller#ActionͷϨεϙϯε
    λΠϜ͕େ͖͘ͳΔ
    
    • unicornͷϓϩηε͕൓Ԡ͠ͳ͘ͳΔ
    
    • ଞͷunicornϓϩηε͕ଞͷϦΫΤετΛॲཧ͠Α͏ͱ͠
    ͯɺಉ͡Controller#ActionͷॲཧΛ࣮ߦͯ͠͠·͏
    

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12. uniq
    • ໰୊ͱͳΔController#ActionΛ௥͍ͬͯ͘ͱɺuniqͱॻ͔
    Ε͍ͯͨɻ
    
    • uniq͔Βdistinctʹஔ͖׵͑Δͱ໰୊͕ࢭΜͩ
    

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13. deprecatedͱܯࠂ͞Εͨޙ΋
    Ҿ͖ଓ͖࢖͑Δϝιουʹ͸
    ஫ҙ͠Α͏
    

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14. Rails Update࣌ʹ
    Upgrade GuideΛݟΑ͏
    

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15. ଞ (աڈͷܦݧ)
    

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16. ଞ (աڈͷܦݧ)
    • INDEXΛࢥͬͨΑ͏ʹ࢖ͬͯ͘Ε͍ͯͳ͍͜ͱ͕Θ͔ͬͨ
    ͷͰɺFORCE INDEXΛ࢖͏Α͏ʹվળ͢Δ
    
    • SELECT … FOR UPDATE Λൃߦதɺ͏͔ͬΓtransaction
    block಺ʹ ଞαʔϏε ΁ͷAPIΞΫηεΛߦ͏ॲཧΛೖΕͯ
    ͠·͏
    
    • ଞαʔϏεͷϦΫΤετॲཧʹࣦഊ͠ߦLOCKΛѲͬͨ·
    ·ʹͳΓঃʑʹϦΫΤετʹ٧·͍ͬͯ͘ͳͲ
    

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17. ऴΘΓ
    

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18. ࢀߟ
    • ActiveRecord::Relation distinct method (Rails 4.2)
    
    • https://github.com/rails/rails/blob/v4.2.11/activerecord/
    lib/active_record/relation/query_methods.rb#L776
    
    • ActiveRecord::Relation (Rails 5.1) -> include Enumerable
    
    • https://github.com/rails/rails/blob/v5.1.6.1/activerecord/
    lib/active_record/relation.rb
    

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19. ࢀߟ
    • ΠϯσοΫεώϯτͷߏจ (FORCE INDEX)
    
    • https://dev.mysql.com/doc/refman/5.6/ja/index-hints.html
    
    • ϩοΫಡΈऔΓ (SELECT … FOR UPDATE)
    
    • https://dev.mysql.com/doc/refman/5.6/ja/innodb-locking-
    reads.html
    

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20. ࢀߟ
    • Rails Upgrade Guide (೔ຊޠ൛)
    
    • https://railsguides.jp/upgrading_ruby_on_rails.html
    

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