The document summarizes new features and improvements in Apache Cassandra 2.1, including enhanced performance, lightweight transactions, collection indexing, improved counters, incremental repair, and a new row cache. It also discusses Cassandra's use at eBay to power mission-critical features for hundreds of millions of users daily.

1. State of Cassandra 2014
Jonathan Ellis
Project Chair, Apache Cassandra
CTO, DataStax
©2014 DataStax Confidential. Do not distribute without consent.

2. 2.1 http://cassandra.apache.org/download/

5. Cluster cluster = Cluster.builder()
.addContactPoint("127.0.0.1")
.withRetryPolicy(
DefaultRetryPolicy.INSTANCE)
.withLoadBalancingPolicy(
new TokenAwarePolicy(
new DCAwareRoundRobinPolicy()))
.build();
Session session = cluster.connect("demo");
cluster = Cluster(
contact_points=['127.0.0.1'],
load_balancing_policy=TokenAwarePolicy(
DCAwareRoundRobinPolicy(
local_dc='datacenter1')),
default_retry_policy = RetryPolicy())
session = cluster.connect('demo’)
Cluster cluster = Cluster.Builder()
.AddContactPoints("127.0.0.1")
.WithRetryPolicy(
DowngradingConsistencyRetryPolicy.INSTANCE)
.WithLoadBalancingPolicy(
new TokenAwarePolicy(
new RoundRobinPolicy())
.Build();
ISession session = cluster.Connect("demo");

6. Cassandra’s peer to peer architecture,
linear scalability and multi data center
active-active deployment enable mission
critical eBay features for hundreds of
millions users every day.
Feng Qu, principal DBA at eBay Inc

8. Client Coordinator
40%
busy
90%
busy
30%
busy

9. Client Coordinator
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busy
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busy
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busy

10. Client Coordinator
40%
busy
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busy
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busy

11. Client Coordinator
40%
busy
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busy
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Xbusy

12. Client Coordinator
40%
busy
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busy
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Xbusy

13. Client Coordinator
40%
busy
90%
busy
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Xbusy

14. Client Coordinator
40%
busy
90%
busy
30%
Xbusy success

19. “One of the great things about
NoSQL is the ability to iterate
on one's data model as one's
business requires it.”
“Everything in one place is
convenient until it fails. If you
want to scale and be highly
available, use Cassandra.”
Matt Asay
MongoDB
Adrian Cockcroft
Battery Ventures

22. 2.1: Performance

23. Read performance, 2.0 vs 2.1

24. Reads, post-compaction (2.0)

25. Reads, post-compaction (2.1)

26. Write performance, 2.0 vs 2.1

27. Competitive performance

28. Competitive performance
https://github.com/jbellis/YCSB

29. 2.1: Data modeling

30. Lightweight transactions

31. Lightweight transactions
INSERT INTO users
(username, name, email,
password, created_date)
VALUES ('pmcfadin',
'Patrick McFadin',
['patrick@datastax.com'],
'ba27e03fd9...',
'2011-06-20 13:50:00')
IF NOT EXISTS;

32. Lightweight transactions
INSERT INTO users
(username, name, email,
password, created_date)
VALUES ('pmcfadin',
'Patrick McFadin',
['patrick@datastax.com'],
'ba27e03fd9...',
'2011-06-20 13:50:00')
IF NOT EXISTS;
INSERT INTO users
(username, name, email,
password, created_date)
VALUES ('pmcfadin',
'Patrick McFadin',
['patrick@datastax.com'],
'ea24e13ad9...',
'2011-06-20 13:50:01')
IF NOT EXISTS;

33. Lightweight transactions
INSERT INTO users
(username, name, email,
password, created_date)
VALUES ('pmcfadin',
'Patrick McFadin',
['patrick@datastax.com'],
'ba27e03fd9...',
'2011-06-20 13:50:00')
IF NOT EXISTS;
[applied]
-----------
True
INSERT INTO users
(username, name, email,
password, created_date)
VALUES ('pmcfadin',
'Patrick McFadin',
['patrick@datastax.com'],
'ea24e13ad9...',
'2011-06-20 13:50:01')
IF NOT EXISTS;

34. Lightweight transactions
[applied] | username | created_date | name
-----------+----------+----------------+----------------
False | pmcfadin | 2011-06-20 ... | Patrick McFadin
INSERT INTO users
(username, name, email,
password, created_date)
VALUES ('pmcfadin',
'Patrick McFadin',
['patrick@datastax.com'],
'ba27e03fd9...',
'2011-06-20 13:50:00')
IF NOT EXISTS;
[applied]
-----------
True
INSERT INTO users
(username, name, email,
password, created_date)
VALUES ('pmcfadin',
'Patrick McFadin',
['patrick@datastax.com'],
'ea24e13ad9...',
'2011-06-20 13:50:01')
IF NOT EXISTS;

35. Static columns (2.0.6)
CREATE TABLE bills (
user text,
balance int static,
expense_id int,
amount int,
description text,
paid boolean,
PRIMARY KEY (user, expense_id)
);

36. Static columns + LWT
CREATE TABLE bills (
user text,
balance int static,
expense_id int,
amount int,
description text,
paid boolean,
PRIMARY KEY (user, expense_id)
);
BEGIN BATCH
UPDATE bills SET balance = -116 WHERE user='user1' IF balance = 84;
INSERT INTO bills (user, expense_id, amount, description, paid)
VALUES ('user1', 2, 200, 'hotel room', false);
APPLY BATCH;

37. Atomic log appends with LWT
CREATE TABLE log (
log_name text,
seq int static,
logged_at timeuuid,
entry text,
primary key (log_name, logged_at)
);
INSERT INTO log (log_name, seq)
VALUES ('foo', 0);

38. Atomic log appends with LWT
BEGIN BATCH
UPDATE log SET seq = 1
WHERE log_name = 'foo'
IF seq = 0;
INSERT INTO log (log_name, logged_at, entry)
VALUES ('foo', now(), 'test');
APPLY BATCH;

39. User defined types
CREATE TYPE address (
street text,
city text,
zip_code int,
phones set<text>
)
CREATE TABLE users (
id uuid PRIMARY KEY,
name text,
addresses map<text, frozen<address>>
)
SELECT id, name, addresses.city, addresses.phones FROM users;
id | name | addresses.city | addresses.phones
--------------------+----------------+--------------------------
63bf691f | jbellis | Austin | {'512-4567', '512-9999'}

40. Collection indexing
CREATE TABLE songs (
id uuid PRIMARY KEY,
artist text,
album text,
title text,
data blob,
tags set<text>
);
CREATE INDEX song_tags_idx ON songs(tags);
SELECT * FROM songs WHERE tags CONTAINS 'blues';
id | album | artist | tags | title
----------+---------------+-------------------+-----------------------+------------------
5027b27e | Country Blues | Lightnin' Hopkins | {'acoustic', 'blues'} | Worrying My Mind

41. 2.1: Operations

42. Counters, 2.0

43. Counters, 2.0
1. Node A, increment by 1
Memtable
A0 1 1
Commitlog
A0 1 1
Value: 1

44. Counters, 2.0
2. Node A, increment by 1
Commitlog
A0 1 1
A0 1 1
Memtable
A0 2 2
Value: 2
1. Node A, increment by 1
Memtable
A0 1 1
Commitlog
A0 1 1
Value: 1

45. Counters, 2.0
2. Node A, increment by 1
Commitlog
A0 1 1
A0 1 1
Memtable
A0 2 2
Value: 2
1. Node A, increment by 1
Memtable
A0 1 1
Commitlog
A0 1 1
Value: 1
3. Node A, decrement by 2
Memtable
A0 3 0
Value: 0
Commit Log
A0 1 1
A0 1 1
A0 1 -2

46. Counters, 2.1

47. Counters, 2.1
1. Node A, increment by 1
Memtable
A0 1 1
Commitlog
A0 1 1
Value: 1

48. Counters, 2.1
2. Node A, increment by 1
Commitlog
A0 1 1
A0 2 2
Memtable
A0 2 2
Value: 2
1. Node A, increment by 1
Memtable
A0 1 1
Commitlog
A0 1 1
Value: 1

49. Counters, 2.1
2. Node A, increment by 1
Commitlog
A0 1 1
A0 2 2
Memtable
A0 2 2
Value: 2
1. Node A, increment by 1
Memtable
A0 1 1
Commitlog
A0 1 1
Value: 1
3. Node A, decrement by 2
Memtable
A0 3 0
Value: 0
Commit Log
A0 1 1
A0 2 2
A0 3 0

50. (low contention)

51. (high contention)

52. Regular repair

53. Regular repair

54. Regular repair

55. Incremental repair

56. Implications for LCS (and STCS)
bin/nodetool upgradesstables
tools/bin/sstablerepairedset --is-repaired
bin/nodetool repair
bin/nodetool repair -inc

57. The new row cache
CREATE TABLE notifications (
target_user text,
notification_id timeuuid,
source_id uuid,
source_type text,
activity text,
PRIMARY KEY (target_user, notification_id)
)
WITH CLUSTERING ORDER BY (notification_id DESC)
AND caching = 'rows_only'
AND rows_per_partition_to_cache = '3';

58. The new row cache
target_user notification_id source_id source_type activity
nick e1bd2bcb- d972b679- photo tom liked
nick 321998c- d972b679- photo jake commented
nick ea1c5d35- 88a049d5- user mike created account
nick 5321998c- 64613f27- photo tom commented
nick 07581439- 076eab7e- user tyler created account
mike 1c34467a- f04e309f- user tom created account

59. The new row cache
target_user notification_id source_id source_type activity
nick e1bd2bcb- d972b679- photo tom liked
nick 321998c- d972b679- photo jake commented
nick ea1c5d35- 88a049d5- user mike created account
nick 5321998c- 64613f27- photo tom commented
nick 07581439- 076eab7e- user tyler created account
mike 1c34467a- f04e309f- user tom created account

60. The new row cache
target_user notification_id source_id source_type activity
nick e1bd2bcb- d972b679- photo tom liked
nick 321998c- d972b679- photo jake commented
nick ea1c5d35- 88a049d5- user mike created account
nick 5321998c- 64613f27- photo tom commented
nick 07581439- 076eab7e- user tyler created account
mike 1c34467a- f04e309f- user tom created account

61. 2.1: Testing & QA