At Burt we use Cassandra for a little bit of everything. We have a graph database, a tracing system, a stream processing engine and a document store that uses it for storage, and of course, we use it for time series too – but with a twist. Cassandra works great for all of these use cases, but not out of the box. We've learned the hard way what not to do, and what to do instead.

1. CASSANDRA
FOR ALL
THE THINGS
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2. CASSANDRA
FOR ALL
THE THINGS
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3. THEO
Chief Architect at Burt
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4. THEO
Cassandra MVP and original author of the DataStax Ruby driver
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5. CASSANDRA
FOR ALL
THE THINGS*
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6. CASSANDRA
FOR ALL
THE THINGS*
* where it makes sense
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7. CASSANDRA
FTW
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8. BIG TABLE
partitions as sorted maps
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9. DYNAMO
availability and simple ops
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10. LOGS AS STORAGE
optimized for writes
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11. CASSANDRA
FTW
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12. CONVERSION
TRACKING
$ $ $ $ $
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13. ATTRIBUTION
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$

14. ATTRIBUTION
90s 5s
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30s
$

15. visitor ID
timestamp timestamp timestamp
event event event

16. visitor ID
visitor ID
timestamp timestamp timestamp
event event event
timestamp timestamp timestamp
event event event
visitor ID
visitor ID
timestamp timestamp timestamp
event event event
timestamp timestamp timestamp
event event event
visitor ID
timestamp timestamp timestamp
event event event
➔

17. 1/10,000
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18. TTL
automatic windowing
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19. ANALYTICS
precomputed cubes
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20. SELECT
category,
author,
device_type,
COUNT(*) AS pageviews,
AVG(duration) AS duration
FROM pageviews
GROUP BY 1, 2, 3
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21. SELECT
category,
author,
device_type,
COUNT(*) AS pageviews,
AVG(duration) AS duration
FROM pageviews
GROUP BY 1, 2, 3
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22. SELECT
category,
author,
device_type,
COUNT(*) AS pageviews,
AVG(duration) AS duration
FROM pageviews
GROUP BY 1, 2, 3
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23. date + cube
slice + time slice + time slice + time
metrics metrics metrics

24. “sports”, “Sue”, “tablet”
date + cube
slice + time slice + time slice + time
metrics metrics metrics
category, author, device type

25. date + cube
slice + time slice + time slice + time
metrics metrics metrics
{pageviews: 234, duration: 2451.45}

26. COUNTERS
at 2M increments per second they’re not cost-effective ×
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27. WIDE ROWS FAIL
cardinality kills
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28. “sports”, “Sue”, “tablet”
date + cube
slice + time slice + time slice + time
metrics metrics metrics

30. remember when we
thought this was a problem?

31. date +
cube +
shard
slice + time slice + time slice + time
metrics metrics metrics
H(slice) mod 12

32. TIME SERIES
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33. cube +
slice + metric
time time time
value value value
cube
slice slice slice

34. NARROW ROWS
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35. cube + slice +
epoch + metric
time + version time + version time + version
value value value
cube + epoch
slice slice slice
time/1000

36. NARROW ROWS
enables parallel reads
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37. SELECT
category,
device_type,
COUNT(*) AS pageviews,
AVG(duration) AS duration
FROM pageviews
WHERE category = “sports”
GROUP BY 1, 2, 3

38. category +
device type
culture +
computer
culture +
tablet
news +
computer
news +
tablet
news +
mobile
sports +
computer
sports +
tablet
sports +
mobile

39. supports wildcard on device type
category +
device type
culture +
computer
culture +
tablet
news +
computer
news +
tablet
news +
mobile
sports +
computer
sports +
tablet
sports +
mobile
device type +
category
computer +
culture
computer +
news
computer +
sports
mobile +
news
mobile +
sports
tablet +
culture
tablet +
news
tablet +
sports
supports wildcard on category

40. TRANSIENT STATE
➔ ➔
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41. session ID
timestamp timestamp timestamp
data data data
shard
session ID session ID session ID
H(session ID) mod 360

42. WIDE ROWS FAIL
(again)
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43. shard 9
NFNJ0U NFNJ13 NFNJ0Y NFNJ1L NFNJ16 NFNJ0U NFNJ1C NFNJ20 NFNJ0U NFNJ2L NFNJ2S NFNJ2D NFNJ2U NFNJ1X NFNJ4C NFNJ1O NFNJ1A NFNJ29 × × × × × × × × × × × × × × × ×

44. session ID
timestamp timestamp timestamp
data data data
shard
session ID session ID session ID

45. session ID
timestamp timestamp timestamp
data data data
shard + slot
session ID session ID session ID

46. session ID
timestamp timestamp timestamp
data data data
shard + slot
session ID session ID session ID
day-of-year mod 30

47. shard 9
slot 1 × × ×
shard 9
slot 3
NFNJ6Z NFNJ73 NFNJ7B NFNJ72 NFNJ7N NFNJ74 NFNJ6Z NFNJ8C NFNJ7N NFNJ88 NFNJ83 NFNJ94 NFNJ8Z NFNJ7P NFNJA3 × × × × × ×
shard 9
slot 2
NFNJ58 NFNJ5H NFNJ5C NFNJ5E NFNJ68 NFNJ6H NFNJ68 NFNJ5M NFNJ64 NFNJ6H NFNJ6C NFNJ5U NFNJ5K NFNJ84 NFNJ7Y NFNJ62 NFNJ70 NFNJ74 NFNJ6Q × × × × × × × × × × × × × × × ×

48. AND MORE
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49. GRAPHS
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50. TRACES
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51. KEY/VALUE
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52. CASSANDRA
FOR ALL
THE THINGS
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53. @iconara
burtcorp.com
architecturalatrocities.com