I am trying to understand CouchDB network traffic with Wireshark and find it very difficult.
A simple transaction with plain-text content seems to result in many lines in Wireshark, most of them being not more than unparsed binary data:
44270 > terabase [PSH ACK] Seq=1411 Ack=2369 Win=16195 Len=27 [...]
00:00:00:1b:00:00:2a:6b:00:10:03:00:00:00:00:00:00:00:1c:00:00:00:00:03:21:00:1e
Packet data is decoded up to the TCP level, but not at the CouchDB level.
Is there any Wireshark plugin to understand CouchDB traffic ?
CouchDB traffic is just HTTP traffic to a JSON API; even if Wireshark doesn't catch the fact that it's HTTP, the traffic should still be really quite readable.
A TCP ACK packet (the one pasted in your question) is never going to be terribly enlightening, though; you're interested in the data within the TCP connection. Try right-clicking one of the packets and "Follow TCP stream" - a window will come up with all of the data from the connection, color-coded by request and response.