This patch introduces support for a `tcp_syn_count` parameter in libpq, allowing control over the number of SYN retransmissions when initiating a connection.
The primary goal is to prevent the walreceiver from getting stuck resending SYNs for an extended period, up to `net.ipv4.tcp_syn_retries` (127 seconds by default), in the event of network disruptions.
Thanks for bringing this up and providing this straightforward patch. Configuring this TCP setting on the WAL receiver side will give us more precise control over connections, specifically over replication behaviour. This is especially important in Kubernetes environments with operators like CloudNativePG, where modifying this setting at a lower level may not be feasible due to separation of duties and permission constraints.
