trace_connection_negotiation

Definition PG 18 manual

No dedicated definition was found in this manual. The parameter’s presence and values come from the metadata snapshot identified above.

How it works

trace_connection_negotiation logs details from the pre-authentication connection negotiation path, providing evidence for protocol, encryption, and handshake debugging before normal authentication logs are available.

It is a server-start setting, so enabling it affects subsequent connection handshakes cluster-wide until restart. It does not alter authentication rules or make negotiation succeed.

Handshake logs can be high-volume and reveal network or client capability details. Use a controlled reproduction and protect the resulting server logs. Its postmaster context fixes the value at server start; changing it requires a restart.

Operational considerations

Leaving trace_connection_negotiation enabled after the bounded diagnostic or recovery task.

Running the experiment on the only copy of production data.

Underestimating log, core-file, temporary-file, WAL, CPU, or connection-slot amplification.

Treating a server that merely starts or completes a query as proof that data and behavior are correct.

Workload guidance

OLAP: Long analytical runs can amplify trace_connection_negotiation's debug overhead and artifacts. Prefer standard EXPLAIN and statistics first, and isolate any developer experiment from normal users.

OLTP: Do not tune production OLTP with trace_connection_negotiation. Enable it only for a bounded reproduction with an owner, log/disk budget, rollback condition, and evidence-capture plan; restore the default immediately afterward.

SMALL: Keep trace_connection_negotiation at its upstream default. A small host has less spare CPU, disk, connection, and log capacity for developer instrumentation.