Atomic

A bounded Redis Lua script combines reads and writes without interleaving, but not with automatic rollback.

Redis Lua scripts run without interleaving

A Redis Lua script can read data, make a decision, and update it without another client’s command interleaving between those steps. It does not mean every statement succeeds, that earlier writes are undone after an error, or that the result is automatically durable. ...

WATCH protects a read-dependent transaction while EXEC runs its accepted queue without interleaving.

MULTI EXEC runs a batch of commands as one

MULTI/EXEC prevents another client’s commands from interleaving while the queued commands execute. That alone does not protect a value read earlier in the application. If two buyers read the same stock count and later write their own calculated value, wrapping each SET in a transaction can still lose an update. ...