The document provides a non-technical guide to understanding technical concepts that impact e-commerce site performance, stability, and conversion. It emphasizes the importance of caching, indexing, and managing changes to minimize downtime and enhance user experience, highlighting that poor performance can lead to significant revenue loss. Additionally, it outlines best practices for deploying updates, emphasizing careful planning, testing, and avoiding changes during peak times.

1. Have you cleared the
cache?
A non-technical guide to technical concepts and
their impact on stability, performance & conversion

2. Who am I?
l Stephen McNairn ...in a past life.
l Project Manager at • Marketing Manager
Session Digital l Intro to E-commerce
l Certified Scrum
l Business focused
Master
l Feel your pain!
l Warner Music,
Dreams, Missguided,
Football League
Magento projects

3. Aim
l Share some lessons learned
l Promote site stability and protect conversion
l Explain key technical concepts
l Using that knowledge to drive business decisions
l Share standard processes and best practice

4. Topics
l Platform stability is crucial
l Load
l Caching and Indexing
l Magento Flat Tables
l Magento Content Staging Stores
l Managing change
l Sharing, Q & A

5. Apologies!
l No silver bullet
l I am not technical
l I will use bad metaphors
l I will over simplify
l “The brain is very much like a big computer”

6. Performance and Stability
l 23% of dissatisfied online shoppers attributed [this] to the
Web site being too slow or taking too long to render.
l Another 17% reported dissatisfaction due to site crashes
or error messages they received.
l 1/3 of shoppers who abandoned a recent shopping
session were dissatisfied with a retail site’s performance.
eCommerce Web Site Performance Today (Forrester Consulting)

7. Performance and Stability
l 79% of online shoppers who experience a dissatisfying
visit are likely to no longer buy from that site.
l 46% of dissatisfied online shoppers are more likely to
develop a negative perception of the company
l 44% will tell their friends and family about the experience.
eCommerce Web Site Performance Today (Forrester Consulting)

8. Performance and Stability
l When a site experiences an outage, 9% of online
customers permanently abandon the site, and 48% of site
users establish a relationship with a competitor.
Jupiter Research
l There is a nearly 50% relationship between performance
and site abandonment - i.e., a 10% decrease in site
[performance] leads to a 5% increase in site
abandonment.
Zona

9. We know poor performance and
down-time impacts revenue…
…why do we put good
performance at risk?

10. The Internet!

11. Load

12. Under Heavy Load

13. Know your limits
Do: Avoid:
l Know your capacity l Too much load
l Load test l Mailing the world at
l GA real-time
once
l Changes at peak
l Plan your campaigns
l Plan your growth
times
l Hope it will cope
l Give yourself
headroom

14. Cache

15. Hot cache!

16. Magento Cache Management

17. What does each line do
• Configuration: Everything you manage in the configuration in System>>Configuration
• Layout: Front end layout rules (layout.XML). How the page is laid out
• Block HTML: More template info. Front end HTML generated by blocks (.phtml)
• Translations: Core translations (so if you change locale)
• Collections: Collections are requests to the DB regarding product info (ie. sort, view all)
• EAV types: DB information - particularly related to attributes, attributes sets, names values etc
• Web services: API - How and what Magento use to speaks to 3rd party applications
• Class rewrites: When you extend Magento you rewrite classes. Magento caches details of
where and what you have rewritten.
• FPC – Full page Cache – Enterprise only – The actual pages of your site
• Catalog Images and JavaScript/CSS only need refreshed if you have made front end design
changes
• Flush Magento Cache: Completely empties all Magento cache lines so they can be rebuilt
• Flush Cache storage. Completely empties all caches (inc. Magento, sessions, memcache etc.)

18. Have you cleared the Cache?
l No! You've refreshed the relevant cache lines
l Avoid flushing the cache or cache storage (unless you
want to annoy customers).
l Up-to-date caches are good...
l ...be not afraid of the invalid cache
l Refreshing cache is change
l Change at peak is risky!

19. There's a hole in my bucket

20. The Magento DB

21. The Magento DB
• Horribly complex!
• Not a spread-sheet
• EAV (Entity attribute value)
• Flexible (new attributes, values)
• Finding data is complex
• DB bottlenecks cause performance

22. Data structure

23. Indexed data

24. Index Management

25. Issues resolved by Indexing
• Products not displaying
• Product not in correct category
• Out-of-stock products not visible
• Redirects not working
• Products appear at incorrect price
• Products not appearing in search results
You may also need to refresh page or block cache

26. “Have you updated the index?”
l Up to date indexes are good
l ...but be not afraid of the out-of-date-index
l Indexing is an intensive process (URLs)
l Extenuated on multi-store
l Use auto-update carefully
l Indexing is change
l Change at peak is risky

27. Caching and Indexing
l They make Magento perform better
l Keep them up-to-date
l Updating them can cause performance issues:
l Cache changes will impact front end, more at peak
l Indexing can cause additional load on the DB
l Don’t flush – Do refresh
l Choose appropriate times to update cache and index or
wait for auto-updates

28. www.mymagestore.com/admin
• Intensive Processes
• Can contribute to performance issues
• Separate admin server does help server load
• Separate admin server does not reduce impact on DB
• /admin can cause chaos

29. Flat tables
System>>Configuration>>Catalog>>Frontend

30. Flat tables
Benefits: Be aware:
• Gives the front-end a • >1000 products
single table for products • Must be periodically rebuilt
• Gives the front-end a for changes to appear
single table for categories • Run after other indexes
• Improves F/E performance updated
• Can reduce DB locks • Another index to maintain
• Can reduce /admin impact
on front end

31. Staging Websites
• Enterprise Edition only
• Uses Magento multi-store
architecture
• Requires minimal
development work
• Highly recommended
• It works!

32. Staging Websites
Features Benefits
• New store view you • More controlled work flow
access through admin • Separates admin
• Preview catalogue, maintenance from front
content and config end store
changes • Publish changes at best
• Simple control of merge, time for front end
back up and roll-back • Reduce need for cache
• Can schedule merges and indexing
(e.g. sales)

33. Maintenance
• An unmaintained Magento platform will be slower
• Admin processes take longer
• Front end processes slower
• Use default Magento log clearing
• Deploy custom maintenance script to improve standard
• Clean up sales flat quotes table
• Examples in the community

34. Change Management
New features and fixes
• 4,500,000 lines of code in Magento
• Bad code will lead to instability/poor performance
Your decisions should be made based on protecting the
quality of that code.

35. Agile
Release early,
Release often

36. The Fear
Do not release
anything.
Ever.

37. Easing the Fear…
Good Source control Safe Deployment Process
l Manage “Versions” of • Have one!
your code • Avoid hot fix!
l Track changes • Should be automated
l Avoid the disappearing • No manually copying
feature! • Don’t deploy at peak
l Collaborative • Ask your dev team
l Helps roll back • Capistrano
l Ask your dev team
l GIT, SVN

38. Planning change
• Define a release schedule
• Avoid hot-fixing
• Use the release plan to protect your code
• Can it wait until the next release?
• Always discuss risk vs. business value
• Need to hot fix? What’s the business value?
• Can the blue button wait?

39. Planning change
• When defining new features consider business value
• Improve sales
• Improve business process
• Improve customer experience
• Resolve immediate critical issue
• Document business value as part of requirement:
• BDD, Gherkin
• User stories
• 1,2,3,4,5

40. Value Based Planning
Long term
• Invest based on business value
Medium term
• Priorities based on business value
Short term
• Release based on business value
• Risk vs. Business Value
• Only hot-fix critical issues

41. Testing – Final acceptance
• Don’t just test the new features
• Don’t avoid manual testing
• Test list of key processes
• Admin tasks
• Front end journeys
• Trust your sense of smell

42. Test the checkout
• Test the checkout
• Test the checkout
• Test the checkout
• Test the checkout
• Test the checkout
• Test the checkout
• Test the checkout
• Test the checkout
• Test the checkout

43. Agile
Release early,
Release often

44. A recommendation…
Do not release
anything…
…on a Friday

45. Example 1
You biggest selling product is incorrectly priced and
you’re selling it for £16.99 (should be £18.99). You
discover this a 4pm and you expect to sell 100 units in
the next hour.

46. Example 2
Promotional campaign is scheduled to 500,000 users
offering free delivery.
A high response rate is expected.
2 days before launch it is suggested that the servers
may not be able to cope with extra traffic levels…
(Forecast response x audience) + standard traffic level

47. Example 3
The CEO demands the “home” link in the navigation to
be green. He has been asking for it for the last week
and it must go live NOW!
It is in a release with one other fix but the release has
not been fully tested.

48. Summary
• Stability = happy customers = revenue
• Know your platforms load capacity
• Consider load in campaign and growth planning
• Avoid changes at peak
• Deployments, catalogue updates, cache and indexing
• Avoid impact of business processes on front end
• Use flat tables
• Use content staging stores
• Use maintenance scripts

49. Summary
• Change is risky
• Minimise the risk of releasing code
• Automated deployment
• Source control
• Define a release schedule.
• Avoid hot-fixing
• Always test the checkout!
• Define every features business value
• Use business value in all your planning and decisions
• Don’t release on a Friday!

50. Any questions?