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Software Development at Mercari #ioi2018

Software Development at Mercari #ioi2018

Programming for a competition and programming for work are similar.
In both cases, programming is about solving problems.

Yuichiro SAITO

September 07, 2018

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  1. Software Development at Mercari Yuichiro Saito (@koemu) International Olympiad in

    Informatics Sep 7th, 2018
  2. • Slides are uploaded on Speaker Deck (check the pinned

    post my Twitter @koemu_s) • Feel free to record and/or share this presentation on social media! • Have questions? ◦ Q&A time after presentation ◦ Visit us at the Mercari booth (in the hallway between the main entrance and Capio) ◦ Contact me at [email protected] 2 Before we begin
  3. Programming is about solving problems 3


    Improve yourself Improve society 4
  5. Me ↓ 5

  6. Me ↓ 6

  7. Mercari’s Mission Create value in a global marketplace where anyone

    can buy & sell 7
  8. 8 Reduce Waste, Create Value →

  9. 9 Mercari app, similar product recommendations Product pages show related

    items. Problem: Loads too slow
  10. 10 1. Identify Issue 2. Solve Issue 3. Measure Results

    As an engineer...
  11. 1. Identify Issue - Used monitoring software to confirm breakdown

    of latency of each process - Latency of access to the database was several times higher compared to other functions - Identified that the backend application was recursively retrieving product attributes 11
  12. 2. Solve Issue Incorporated a cache system when accessing the

    database - Saves product attributes to memory - Maintain memory space using Least Recently Used (LRU) algorithm 12 How memcached works. Image from: https://zenmachine.wordpress.com/2008/12/03/50/ More on the LRU algorithm: https://github.com/memcached/memcached/wiki/UserInternals
  13. 3. Measure Results - Significantly decreased access to database (shown

    in purple below) - Improved latency by 30%! 13 Released at 2:35 PM ↓
  14. ➔ Performance optimization 14 Impact

  15. ➔ Better customer experience 15 Impact

  16. ➔ More completed transactions 16 Impact

  17. ➔ Less waste, more value 17 Impact

  18. This is the future you can create. 18

  19. Q&A Time Please raise your hand if you have questions!

  20. We’re hiring! For further questions, visit us at the Mercari

    Booth. Link to slides pinned on Twitter (@koemu_s) 20
  21. Credits Images from 「いらすとや」 https://www.irasutoya.com/ English Translation by Sherry Zhang