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
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5
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
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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
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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 |
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0
21. CQL 1.1
• ALTER
• Counter support
• TTL support
• Compound columns
• Prepared statements
2
1