ZEO Client Timeout
If a ZEO client is configured with multiple server addresses, it will only failover to a new server address if it is disconnected from its current server. This mechanism doesn't cope with soft failures, i.e. a failure that does not disconnect the client but does prevent it from making progress.
It might be possible to let the client timeout if it decides the server is too slow to respond. Then it could failover to one of the other servers.
There are a bunch of complications to consider if we decided to add this feature:
- What if the failed server is still accepting connections? Then the client is likely to reconnect to it.
- How do you tell the difference between a slow server and a failed server?
- If the read_only_fallback option is enabled and the failed server was a read-write server, how do you decide when to reconnect to it?