Prevent dupe participation in same experiment - Githubissues

assaf / vanity

Experiment Driven Development for Ruby

http://vanity.labnotes.org

MIT License

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Prevent dupe participation in same experiment #336

Closed pihman closed 6 years ago

pihman commented 6 years ago

Fixes a race condition that leads to multiple participant records for the same experiment/identity. This could even lead to users w/ participation records in two different segments!!!

Thread A: ab_test(:my_experiment) => seen=0 Thread B: ab_test(:my_experiment) => seen=1

Solution:

Add a unique index on vanity_participants(experiment_id, identity) (convert the existing index).
Gracefully handle DUP_VAL_ON_INDEX errors when creating participant records.

pihman commented 6 years ago

dupe PR