Sessions, Counters, and Rate Limits

Keep common application state beside each workload and share it when requests can reach several instances.

Store a serialized session with an expiration:

SET session:123 '{"user":42}' EX 3600
GET session:123

Use the same session key across workloads. Decide whether losing it should log the user out or require recovery from tiered storage.

Use INCR for a count instead of a client-side read followed by SET:

INCR views:article:42

Several workloads accessing the counter make it shared state. Measure that access pattern at the intended topology.

A fixed-window counter can use a key containing the window identifier, such as rate:user:42:2026-09-15T12:30. Increment the key and compare the returned count with the limit. Expire old windows so they do not accumulate.

Use SSI transactions for multi-command decisions: read the count, check the limit in your application, then update and commit. Lua is not required. Test concurrent requests and retry confirmed conflicts. Decide whether network failures should reject requests or permit them. Non-transactional counters accepting writes during a partition do not by themselves enforce a strict global admission limit.

Read transaction semantics and disconnected operation before relying on a cross-region limit.