From 6ec578e60101c3c02533f99715945a0400fb3286 Mon Sep 17 00:00:00 2001 From: Alvaro Herrera Date: Wed, 31 Mar 2021 20:11:51 -0300 Subject: [PATCH] Remove setvbuf() call from PQtrace() It's misplaced there -- it's not libpq's output stream to tweak in that way. In particular, POSIX says that it has to be called before any other operation on the file, so if a stream previously used by the calling application, bad things may happen. Put setvbuf() in libpq_pipeline for good measure. Also, reduce fopen(..., "w+") to just fopen(..., "w") in libpq_pipeline.c. It's not clear that this fixes anything, but we don't use w+ anywhere. Per complaints from Tom Lane. Discussion: https://postgr.es/m/3337422.1617229905@sss.pgh.pa.us --- src/interfaces/libpq/fe-trace.c | 2 -- src/test/modules/libpq_pipeline/libpq_pipeline.c | 7 +++++-- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/src/interfaces/libpq/fe-trace.c b/src/interfaces/libpq/fe-trace.c index ca59c183182..9a4595f5c87 100644 --- a/src/interfaces/libpq/fe-trace.c +++ b/src/interfaces/libpq/fe-trace.c @@ -40,8 +40,6 @@ PQtrace(PGconn *conn, FILE *debug_port) if (debug_port == NULL) return; - /* Make the trace stream line-buffered */ - setvbuf(debug_port, NULL, _IOLBF, 0); conn->Pfdebug = debug_port; conn->traceFlags = 0; } diff --git a/src/test/modules/libpq_pipeline/libpq_pipeline.c b/src/test/modules/libpq_pipeline/libpq_pipeline.c index 081a84f8248..7aa78662653 100644 --- a/src/test/modules/libpq_pipeline/libpq_pipeline.c +++ b/src/test/modules/libpq_pipeline/libpq_pipeline.c @@ -1319,10 +1319,13 @@ main(int argc, char **argv) /* Set the trace file, if requested */ if (tracefile != NULL) { - trace = fopen(tracefile, "w+"); - + trace = fopen(tracefile, "w"); if (trace == NULL) pg_fatal("could not open file \"%s\": %m", tracefile); + + /* Make it line-buffered */ + setvbuf(trace, NULL, _IOLBF, 0); + PQtrace(conn, trace); PQtraceSetFlags(conn, PQTRACE_SUPPRESS_TIMESTAMPS | PQTRACE_REGRESS_MODE);