You cannot run it on Mac with Container

https://github.com/crystal-lang/crystal/issues/11761

https://github.com/crystal-lang/distribution-scripts/issues/125

Workaround

brew install crystal librdkafka
docker compose -f docker-compose.local.yml up -d
cd crystal
shards install

Build

crystal build consumer.cr \
    --release \
    --no-debug \
    -o consumer

Run

./consumer

x86/64

Bench

docker compose exec -it postgres psql -U bench -d bench -c "SELECT event_type, COUNT(*) as total_events, MIN(id) as first_id, MAX(id) as last_id, MIN(event_ts) as first_event_time, MAX(event_ts) as last_event_time, MIN(created_at) as first_created, MAX(created_at) as last_created FROM kiosk_events GROUP BY event_type ORDER BY event_type;"

output:

event_type   |total_events|first_id|last_id|first_event_time       |last_event_time        |first_created          |last_created           |
-------------+------------+--------+-------+-----------------------+-----------------------+-----------------------+-----------------------+
crystal-visit|     1499001|       1|1499001|2024-11-27 22:33:10.728|2025-11-26 22:37:12.403|2025-11-26 22:38:19.131|2025-11-26 22:38:34.185|
ruby-visit   |     1500000| 1499002|2999001|2025-11-26 22:41:46.000|2025-11-26 22:42:08.000|2025-11-26 22:41:46.000|2025-11-26 22:42:08.000|

Time Summary - Processing ~1.5M events

Crystal Consumer

• Total events: 1,499,001
• Processing time: ~15 seconds
  • Start: 22:38:19
  • End: 22:38:34
• Rate: ~99,933 events/second

Ruby Consumer

• Total events: 1,500,000
• Processing time: ~22 seconds
  • Start: 22:41:46
  • End: 22:42:08
• Rate: ~68,181 events/second

Performance Comparison

• Crystal is ~46% faster than Ruby
• Crystal processed the same amount of events in 7 seconds less
• Throughput ratio: Crystal is 1.46x faster

---

Time Summary - Processing ~50.5M events

event_type   |total_events|first_id|last_id  |first_event_time       |last_event_time        |first_created          |last_created           |
-------------+------------+--------+---------+-----------------------+-----------------------+-----------------------+-----------------------+
crystal-visit|    50500000|       1| 88421000|2024-11-27 22:51:17.266|2025-11-26 22:56:09.600|2025-11-26 22:51:19.709|2025-11-26 23:00:40.427|
ruby-visit   |    50500000|  726001|101000000|2025-11-26 22:51:27.000|2025-11-26 23:03:50.000|2025-11-26 22:51:27.000|2025-11-26 23:03:50.000|

Crystal Consumer

• Total events: 50,500,000
• Processing time: ~9 minutes 21 seconds (561 seconds)
  • Start: 22:51:19
  • End: 23:00:40
• Rate: ~90,016 events/second

Ruby Consumer

• Total events: 50,500,000
• Processing time: ~12 minutes 23 seconds (743 seconds)
  • Start: 22:51:27
  • End: 23:03:50
• Rate: ~67,970 events/second

Performance Comparison

• Crystal is ~32% faster than Ruby
• Crystal processed the same amount of events in ~3 minutes less
• Throughput ratio: Crystal is 1.32x faster