From dd5eca055d484af41eb6d50d6eeea7cb065d450c Mon Sep 17 00:00:00 2001 From: Heikki Linnakangas Date: Fri, 3 Jul 2026 14:57:35 +0300 Subject: [PATCH] Fix tracing of BackendKeyData and CancelRequest BackendKeyData length was increased from 4 bytes to a variable-length length (up to 256 bytes) in a460251f0a. However, pqTrace still traces it as a 4 bytes key, leading to a "mismatched message length" warning message. The same issue impacts the tracing of CancelRequest. This patch fixes the issue by using pqTraceOutputNchar instead of pqTraceOutputInt32 in both cases. Author: Anthonin Bonnefoy Discussion: https://www.postgresql.org/message-id/CAO6_Xqo6gTv9=76H=k2qDRFU+KHuBiY2S=bQynEr6J8gS7L6xA@mail.gmail.com Backpatch-through: 18 --- src/interfaces/libpq/fe-trace.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/src/interfaces/libpq/fe-trace.c b/src/interfaces/libpq/fe-trace.c index fae5b47e551..f97319c5d96 100644 --- a/src/interfaces/libpq/fe-trace.c +++ b/src/interfaces/libpq/fe-trace.c @@ -452,11 +452,12 @@ pqTraceOutput_CopyOutResponse(FILE *f, const char *message, int *cursor) } static void -pqTraceOutput_BackendKeyData(FILE *f, const char *message, int *cursor, bool regress) +pqTraceOutput_BackendKeyData(FILE *f, const char *message, int *cursor, int length, + bool regress) { fprintf(f, "BackendKeyData\t"); pqTraceOutputInt32(f, message, cursor, regress); - pqTraceOutputInt32(f, message, cursor, regress); + pqTraceOutputNchar(f, length - *cursor + 1, message, cursor, regress); } static void @@ -762,7 +763,8 @@ pqTraceOutputMessage(PGconn *conn, const char *message, bool toServer) /* No message content */ break; case PqMsg_BackendKeyData: - pqTraceOutput_BackendKeyData(conn->Pfdebug, message, &logCursor, regress); + pqTraceOutput_BackendKeyData(conn->Pfdebug, message, &logCursor, + length, regress); break; case PqMsg_NoData: fprintf(conn->Pfdebug, "NoData"); @@ -876,7 +878,8 @@ pqTraceOutputNoTypeByteMessage(PGconn *conn, const char *message) pqTraceOutputInt16(conn->Pfdebug, message, &logCursor); pqTraceOutputInt16(conn->Pfdebug, message, &logCursor); pqTraceOutputInt32(conn->Pfdebug, message, &logCursor, regress); - pqTraceOutputInt32(conn->Pfdebug, message, &logCursor, regress); + pqTraceOutputNchar(conn->Pfdebug, length - logCursor, message, + &logCursor, regress); } else if (version == NEGOTIATE_SSL_CODE) {