Capacity estimation

5000 users per year
50 new discussions created a day ==> 18 K discussions/year
500 users post an average of 15 comments a day --> 7.500 comments per day ==> 2,7 M comments/year
Each user engaged in an average of 10 discussions
1,5 mean different devices used by each user
Assuming 10% ussers logged in: 7.500 comments/day * 500 users * 1,5 devices/user --> 5,5 M notifications/day ==> 7 notifications/sec

Summary

Estimated growth: 10x

Summary

This section provides a detailed storage estimation for the graph database.

Data Types: Standard sizes are assumed (Long/Timestamp: 8 bytes, Boolean: 1 byte, String: average length + overhead). IDs are stored as 16-byte UUIDs.
Database Overhead: Graph databases add significant overhead for managing relationships, indexes, and internal data structures. A conservative overhead factor of 2.5x the raw data size is used for the final estimation.
Growth: Year 3 figures are estimated at a 10x scale of Year 1 data, a common assumption for a successful growing service.

User Node:
- id (16 B) + name (avg 50 B) + preferences_reply_notifications (1 B) = ~67 Bytes
Discussion Node:
- id (16 B) + title (avg 150 B) + creation_date (8 B) + author_id (16 B) + author_name (avg 50 B) + last_update_date (8 B) = ~248 Bytes
Comment Node:
- id (16 B) + content (avg 300 B) + creation_date (8 B) + author_id (16 B) + author_name (avg 50 B) + last_update_date (8 B) + discussion_id (16 B) = ~414 Bytes
Device Node:
- id (16 B) + login_date (8 B) + type (avg 10 B) = ~34 Bytes

Users: 5,000 nodes * 67 B/node = 0.34 MB
Discussions: 18,000 nodes * 248 B/node = 4.46 MB
Comments: 2,700,000 nodes * 414 B/node = 1,117.8 MB
Devices: 5,000 users * 1.5 devices/user = 7,500 nodes * 34 B/node = 0.26 MB
Total Node Storage: ~1,123 MB (~1.12 GB)
HAS_COMMENT Edges: 2,700,000 edges * 40 B/edge = 108 MB
FOLLOWS_DISCUSSION Edges: 5,000 users * 10 follows/user = 50,000 edges * 48 B/edge = 2.4 MB
USES_DEVICE Edges: 7,500 edges * 40 B/edge = 0.3 MB
Total Edge Storage: ~111 MB
Total Raw Data (Year 1): 1,123 MB + 111 MB = 1,234 MB (~1.23 GB)

Primary Indexes: On id for all nodes.
Secondary Indexes: On author_id (Discussions, Comments) and discussion_id (Comments).
A conservative estimate for index size is 30% of the total raw data size.
Index Storage (Year 1): 1.23 GB * 0.30 = ~0.37 GB

Total Estimated Storage (Year 1): ~4.0 GB

Total Estimated Storage (Year 3): ~40.0 GB