This document summarizes the state of Cassandra in 2011. It discusses that Cassandra is used across many industries including financial, social media, advertising, and healthcare. It highlights advantages like linear scalability, large datasets, and tunable consistency levels. The document outlines updates in versions like 0.7, 0.8, and goals for 1.0 around compaction and repair. It previews upcoming features in CQL and the roadmap for improved ease of use, triggers, and analytics with Brisk.

1. State of Cassandra 2011
Jonathan Ellis
Apache Chair
CTO
DataStax

2. Job Trends from Indeed.com
2

3. Customer and Verticals
• Financial
• Social Media
• Advertising
• Entertainment
• Energy
• E-tail
• Health care
• Government
3

4. Why?
Why?
4
4

5. 5

6. Why Cassandra?
Why
Cassandra?
6
6

7. Better technology
• Multi-master, multi-DC
• Linearly scalable
• Larger-than-memory datasets
• Best-in-class performance (not just writes!)
• Fully durable
• Integrated caching
• Tuneable consistency
7

8. Tunable Consistency
WRITE READ
Level Level
ANY
ONE ONE
LOCAL_QUORUM LOCAL_QUORUM
QUORUM QUORUM
ALL ALL

9. Generalizes Easily to Multi-DC
9

10. 0.7
• CREATE COLUMN FAMILY
• Expiring columns (TTL)
• Secondary (column) indexes
• Efficient streaming
1
0

11. 0.8
• CQL
• Counters
• Automatic memtable tuning
• New bulk load interface
1
1

12. A performance retrospective
1
2

13. October 8, 2011
Road to 1.0
13

14. Theme: polish
• Repair
• Compaction
• Optimize reads for update-heavy workloads
• CQL 1.1
1
4

15. Repair
• Consistency is checked per-ColumnFamily but data
is transferred per-Keyspace
• Merkle trees requests are sent en masse, but may
not execute start at the same time
1
5

16. Compression
• Rows-per-block or blocks-per-row
1
6

17. Read Performance: Compaction
1
7

18. Level-based Compaction
• SSTables are non-overlapping within a level
• Bounds the number that can contain a given row
L2: 1000 MB
L1: 100 MB
L0: newly flushed
1
8

19. Read performance: maxtimestamp
• Sort sstables by maximum (client-provided)
timestamp
• Only merge sstables until we have the columns
request
• Allows pre-merging highly fragmented rows without
waiting for compaction
1
9

20. CQL
cqlsh> SELECT * FROM users WHERE state='UT' AND birth_date > 1970;!
KEY | birth_date | full_name | state |
bsanderson | 1975 | Brandon Sanderson | UT |
2
0

21. CQL 1.1
• ALTER
• Counter support
• TTL support
• Compound columns
• Prepared statements
2
1

22. Post-1.0
• Ease of use
• Ease of use
• Ease of use
2
2

23. Post-1.0 features
• “Native” CQL transport
• Triggers
• Entity groups
• Smarter range queries
2
3

24. Brisk
• Analytics for your
realtime data
without ETL
• Widens scope of
Cassandra’s
applicability
• Also: Solandra
2
4

25. Questions
Ques/ons?
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25