postgres.git / summary / log / commit / refs

commit    29aabbc432693b3fcda287b953c832d62dda7946
Author:   Fujii Masao <fujii@postgresql.org>
Date:     Tue Sep 30 14:52:28 2025 +0000
First released in: 13.23, 14.20, 15.15, 16.11, 17.7, 18.1

    pgbench: Fix error reporting in readCommandResponse().
    
    pgbench uses readCommandResponse() to process server responses.
    When readCommandResponse() encounters an error during a call to
    PQgetResult() to fetch the current result, it attempts to report it
    with an additional error message from PQerrorMessage(). However,
    previously, this extra error message could be lost or become incorrect.
    
    The cause was that after fetching the current result (and detecting
    an error), readCommandResponse() called PQgetResult() again to
    peek at the next result. This second call could overwrite the libpq
    connection's error message before the original error was reported,
    causing the error message retrieved from PQerrorMessage() to be
    lost or overwritten.
    
    This commit fixes the issue by updating readCommandResponse()
    to use PQresultErrorMessage() instead of PQerrorMessage()
    to retrieve the error message generated when the PQgetResult()
    for the current result causes an error, ensuring the correct message
    is reported.
    
    Backpatch to all supported versions.
    
    Author: Yugo Nagata <nagata@sraoss.co.jp>
    Reviewed-by: Chao Li <lic@highgo.com>
    Reviewed-by: Fujii Masao <masao.fujii@gmail.com>
    Discussion: https://postgr.es/m/20250925110940.ebacc31725758ec47d5432c6@sraoss.co.jp
    Backpatch-through: 13


 src/bin/pgbench/pgbench.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 031939b29eb..fa15c84ba8d 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -3356,7 +3356,7 @@ readCommandResponse(CState *st, MetaCommand meta, char *varprefix)
 				st->num_syncs--;
 				if (st->num_syncs == 0 && PQexitPipelineMode(st->con) != 1)
 					pg_log_error("client %d failed to exit pipeline mode: %s", st->id,
-								 PQerrorMessage(st->con));
+								 PQresultErrorMessage(res));
 				break;
 
 			case PGRES_NONFATAL_ERROR:
@@ -3366,7 +3366,7 @@ readCommandResponse(CState *st, MetaCommand meta, char *varprefix)
 				if (canRetryError(st->estatus))
 				{
 					if (verbose_errors)
-						commandError(st, PQerrorMessage(st->con));
+						commandError(st, PQresultErrorMessage(res));
 					goto error;
 				}
 				/* fall through */
@@ -3375,7 +3375,7 @@ readCommandResponse(CState *st, MetaCommand meta, char *varprefix)
 				/* anything else is unexpected */
 				pg_log_error("client %d script %d aborted in command %d query %d: %s",
 							 st->id, st->use_file, st->command, qrynum,
-							 PQerrorMessage(st->con));
+							 PQresultErrorMessage(res));
 				goto error;
 		}
 


[parent: b5f898944d12]