Router: maxQueueSize

Java pending connection-request queue limit.

Type: Integer. Default: 0.

Meaning

In Java, the maximum pending connection requests held when a backend connection pool cannot immediately supply a connection.

maxQueueSize: 0

Disables this pool’s pending-request queue. It does not disable retry/alternate-host handling or guarantee that every busy request fails immediately. If the proxy cannot acquire a connection through its allowed attempts, the request can fail with service unavailable.

The template and Portal description say that 0 means “there is queued requests”. Read this as no queued requests; zero is the queue limit.

maxQueueSize: 20

Allows up to twenty waiting connection requests in the Java pool. This can absorb a short burst but adds memory use and waiting time. The ordinary request deadline still limits how long a queued request can wait. Tune only after checking backend capacity and connection failures; a large queue can worsen latency under sustained overload.

Rust support: accepted as a compatibility property, but the current gateway does not wire it to a Pingora pending-request queue.

See Router configuration for Portal/values.yml syntax, runtime compatibility, and source references.