How the WATCH command works on the client side

[ajzach]

Hi, I wanted to know if the WATCH command has any special behavior considering that if I run several WATCH commands from different threads (which share the same client), executing MULTI/EXEC will perform an UNWATCH on all of them.

[barshaul]

Yes, it will perform UNWATCH on all of them since all threads will share the same server connections. The client utilizes a single multiplexed connection per cluster node, meaning that all watch commands and multi-exec commands will be executed through the same connection. This setup can lead to interactions between threads due to the shared state of the connection. To avoid issues with commands that alter the connection’s state (e.g., blocking commands, WATCH), it is necessary to create separate clients for each execution.

[barshaul]

Updated the connection management section with WATCH/UNWATCH:
https://github.com/valkey-io/valkey-glide/wiki/General-Concepts#connection-management