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Open Unique ID Generator (Snowflake) →Open Instagram Feed →

Unique ID Generator (Snowflake) vs Instagram Feed

Unique ID Generator (Snowflake)

Unique ID Generator (Snowflake)

64-bit, roughly time-sortable IDs minted locally on each node: timestamp + worker id + per-ms sequence, no coordination on the hot path.

Components (4)

App Server
ID Generator A
ID Generator B
Coordination Service

Headline numbers

Lifespan from epoch~69 years
Max worker nodes1,024
Max IDs per node per second~4.096M

Instagram Feed

Instagram Feed

Fan-out on write vs read, ranking, CDN.

Components (10)

Mobile Client
CDN
API Gateway
Feed Service
Post Service
Kafka
Fan-out Worker
Redis
Postgres
S3

Headline numbers

Posts / sec (avg)~3,000/sec
Feed read QPS~58,000/sec
Fan-out writes / sec~600,000/sec

Key differences

Only in Unique ID Generator (Snowflake)

None.

In both

Service

Only in Instagram Feed

Mobile Client
CDN
API Gateway
Kafka
Redis
Postgres
S3

Flow shape

Unique ID Generator (Snowflake) flows

Generator boots and claims a worker id2 steps
Generate an ID (bit composition)2 steps
Two generators mint in the same millisecond4 steps
⚠ Sequence overflows within one millisecond3 steps
⚠ Clock moves backward (NTP correction)3 steps

Instagram Feed flows

Post a photo (fan-out on write)7 steps
Open feed (precomputed timeline)5 steps
⚠ Fan-out Worker is down7 steps
⚠ Timeline cache flushed (Redis restart)4 steps