The talk discusses the health and engagement of the Apache Cassandra community, focusing on measures of community activity, user engagement challenges, and the impact of DataStax's withdrawal. It highlights the need for improved documentation and user experiences while revealing that a significant portion of engineers contribute to the project more than once. The speaker emphasizes the vibrant community but acknowledges challenges in maintaining growth and user satisfaction.

1. Apache Cassandra
Community Health
NGCC 2017
Ben Bromhead

2. Agenda
● What this talk is, what it is not
● Bias
● Data, Anecdotes and Observations
● Final thoughts

3. What this talk is
● A chance to look at some (arbitrary) measures about our community
● A chance for me to talk about my personal and corporate experience in the
community
● A chance to reflect
● A chance to celebrate

4. What this talk is not
● Blaming, Finger pointing etc
● A definitive state of the community
● This is not the way things have always been and always will be
● A roadmap / plan to fix things

5. Bias
● Using Cassandra since 2012
● Active since 2013
● I am not a committer or a PMC member
● I have a leadership and ownership position in a company with direct
commercial interest in the Apache Cassandra project
● My company is in competition with others that have an interest/influence in
the Apache Cassandra project
● We also have informal and formal partnerships with other companies that
have direct interest/influence on the Apache Cassandra project

6. Each measure of an Open Source projects health is a brush stroke,
not the whole picture
Methodology

7. Methodology
● Code Activity
● Release history
● User community
● longevity
● surrounding ecosystem
● db-engines popularity ranking*
*vanity metric

8. Code Activity
● Volume and timeliness of commits
○ Proxy for community activity
● As projects mature / stabilize, volume can reduce
○ Shift to incremental features, bug fixes etc
○ Cyclical following project approach to versions
● Who works on what, when and how often
○ Governance can impact volume and timeliness

13. Release Activity
● Push and pull between releasing new features and stability for users
○ Proxy for community maturity
● Databases tend to favor stability
○ New ones still have a lot of features to ship!
○ 9 years old, Cassandra is still a baby
○ 1.0 was only released 6 years ago
● A regular, consistent release cadence indicates maturity
○ Can be as long or short between features
○ Generally reflects mature development processes, release infra

14. Release Activity
Branch Previous Release Previous Release
Time Delta from
previous
Current Release Current Release
Time Delta from
previous
3.x 3.10 4 Months 3.11.0 5 Months
3.0 3.0.14 1 Months 3.0.14 2 Months
2.2 2.2.9 5 Months 2.2.10 4 Months
2.1 2.1.17 4 Months 2.1.18 4 Months
Cassandra 3.11.1 (unreleased) elapsed time - 3 Months, 3 days

15. User Community
● Hardest to measure
○ Previous examinations are measures of <1% who use Cassandra
○ Public measures of community generally only include 10% (those who engage)
● Use a diversity of measures
● Will include some commercial measures
● Will include some qualitative data

18. Apache Cassandra (search term) vs AWS DynamoDB (search term)

19. Apache Cassandra (topic) vs DynamoDB (search term)

20. DB-Engines

21. Longevity
● Cassandra is often considered a “winner” when looking at the NoSQL cohort
from the late 2000’s
● Large user base focused primarily in USA and Europe
● Top 1% of Apache Cassandra users are heavily invested in it
● A number of companies looking to take a similar approach
● Community health and engagement with users/new contributors is a
challenge

22. Ecosystem
Direct - Consulting companies, Support providers, Managed Service providers
OEM - C* as the embedded data store for their core product.
Integrations - OSS integrations with other big/fast data
Startups - Companies targeting Cassandra with their initial product release

23. Commercial Performance
● Instaclustr performance
○ 100%+ CAGR whole business
○ Significantly better growth for our Cassandra support line of business
● Other players in the space all appear to be growing well and rapidly
○ Datastax
○ Scylla
○ Consulting groups

24. Datastax withdrawal
● It has happened
○ Definite reduction in commits / time / jira comments from DS employed committers
○ Awesome individual contributions from DS employed committers who are passionate about
Apache Cassandra
● How users viewed it
○ It appears to be a very binary thing in the wider community
○ Seen as a clear fork
● Perception Impact (survey conducted by Instaclustr)
○ 20% say it's a negative
○ 60% say it doesn’t matter
○ 20% say it’s a positive

25. User Discussions - Bad
● Datastax withdrawal rattled a few Cassandra evaluators, polarised some
users towards Apache Cassandra as well
● Long tail of old advice, cargo culting, bad documentation, tick-tock is causing
first time adopters to struggle with the “right” way to run Cassandra.
● Performance issues and half finished features

26. User Discussions - Good
● Cassandra is part of the standard developer toolbelt. We now see second and
third generation deployments due to cross pollination
● I would argue that a significant % of the global population interacts with a C*
backed service on a daily basis!
● Passionate community who are excited about solving these challenges
● Existing large users who did not have a heavy investment in Cassandra now
feel like they have the opportunity and responsibility to be better community
citizens

27. Community Challenges - Summary
From our perspective the Cassandra community faces two challenges:
● Filling the gap left by Datastax withdrawal, this is primarily related to
resources and time.
● Improving first (n) time experiences
○ Documentation
○ Development
○ Deployment
○ Operations
○ Contributors
45% of engineers who submit and have a patch accepted will submit a second
one!

28. Questions?