BLPOPBlocking left pop across one or more lists (effect logged as LPOP).
| Syntax | BLPOP key [key ...] timeout |
| Group | list |
| Arity | -3 |
| Since | 1.0.0 |
| Flags | write, blocking |
| Complexity | O(1) to serve; the park is O(1) and waiters are woken FIFO per key |
| Redis compatibility | differs: on a multi-shard server the multi-key form does not honour Redis's left-to-right key priority — keys on the connection's own shard are served before remote ones |