From 1eaed7dc94359315c80f8a38e4b2b158cecf1b06 Mon Sep 17 00:00:00 2001
From: Dmitrii Bondar <d.bondar@postgrespro.ru>
Date: Tue, 27 Jan 2026 08:29:46 +0700
Subject: [PATCH] Remove synchronous prepare from pgbench

Pgbench waits for the result of a prepare packet synchronously
when the prepared protocol flag is provided. For this reason
it is impossible to use it with some poolers (such as PgBouncer)
in the session pooling mode.
It is replaced by the full sequence of parse/bind/execute/sync
packets. This behaviour is similar to pgbench with the extended
protocol flag.
---
 src/bin/pgbench/pgbench.c                    | 22 ++++++++--
 src/bin/pgbench/t/001_pgbench_with_server.pl |  1 -
 src/interfaces/libpq/exports.txt             |  1 +
 src/interfaces/libpq/fe-exec.c               | 46 ++++++++++++++++++++
 src/interfaces/libpq/libpq-fe.h              |  9 ++++
 5 files changed, 74 insertions(+), 5 deletions(-)

diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 58735871c17..8e11bc39de2 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -3179,12 +3179,26 @@ sendCommand(CState *st, Command *command)
 	{
 		const char *params[MAX_ARGS];
 
-		prepareCommand(st, st->command);
 		getQueryParams(&st->variables, command, params);
 
-		pg_log_debug("client %d sending %s", st->id, command->prepname);
-		r = PQsendQueryPrepared(st->con, command->prepname, command->argc - 1,
-								params, NULL, NULL, 0);
+		if (!st->prepared)
+			allocCStatePrepared(st);
+
+		if (!st->prepared[st->use_file][st->command])
+		{
+			r = PQsendPBES(st->con, command->prepname,
+						   command->argv[0], command->argc - 1, NULL,
+						   params, NULL, NULL, 0);
+			if (!r)
+				pg_log_error("%s", PQerrorMessage(st->con));
+			st->prepared[st->use_file][st->command] = true;
+		}
+		else
+		{
+			pg_log_debug("client %d sending %s", st->id, command->prepname);
+			r = PQsendQueryPrepared(st->con, command->prepname, command->argc - 1,
+									params, NULL, NULL, 0);
+		}
 	}
 	else						/* unknown sql mode */
 		r = 0;
diff --git a/src/bin/pgbench/t/001_pgbench_with_server.pl b/src/bin/pgbench/t/001_pgbench_with_server.pl
index b7685ea5d20..c047b5d0460 100644
--- a/src/bin/pgbench/t/001_pgbench_with_server.pl
+++ b/src/bin/pgbench/t/001_pgbench_with_server.pl
@@ -1231,7 +1231,6 @@ my @errors = (
 		2,
 		[
 			qr{ERROR:  syntax error},
-			qr{prepared statement .* does not exist}
 		],
 		q{-- SQL syntax error
     SELECT 1 + ;
diff --git a/src/interfaces/libpq/exports.txt b/src/interfaces/libpq/exports.txt
index dbbae642d76..ebebbacd5cd 100644
--- a/src/interfaces/libpq/exports.txt
+++ b/src/interfaces/libpq/exports.txt
@@ -210,3 +210,4 @@ PQgetAuthDataHook         207
 PQdefaultAuthDataHook     208
 PQfullProtocolVersion     209
 appendPQExpBufferVA       210
+PQsendPBES                210
\ No newline at end of file
diff --git a/src/interfaces/libpq/fe-exec.c b/src/interfaces/libpq/fe-exec.c
index 203d388bdbf..bef103ac3f3 100644
--- a/src/interfaces/libpq/fe-exec.c
+++ b/src/interfaces/libpq/fe-exec.c
@@ -1682,6 +1682,52 @@ PQsendQueryPrepared(PGconn *conn,
 						   resultFormat);
 }
 
+/* PQsendPBES
+ *		Like PQsendQueryPrepared, but prepare a query
+ */
+int
+PQsendPBES(PGconn *conn,
+		   const char *stmtName,
+		   const char *query,
+		   int nParams,
+		   const Oid *paramTypes,
+		   const char *const *paramValues,
+		   const int *paramLengths,
+		   const int *paramFormats,
+		   int resultFormat)
+{
+	if (!PQsendQueryStart(conn, true))
+		return 0;
+
+	/* check the arguments */
+	if (!stmtName)
+	{
+		libpq_append_conn_error(conn, "statement name is a null pointer");
+		return 0;
+	}
+	if (!query)
+	{
+		libpq_append_conn_error(conn, "command string is a null pointer");
+		return 0;
+	}
+	if (nParams < 0 || nParams > PQ_QUERY_PARAM_MAX_LIMIT)
+	{
+		libpq_append_conn_error(conn, "number of parameters must be between 0 and %d",
+								PQ_QUERY_PARAM_MAX_LIMIT);
+		return 0;
+	}
+
+	return PQsendQueryGuts(conn,
+						   query,
+						   stmtName,
+						   nParams,
+						   paramTypes,
+						   paramValues,
+						   paramLengths,
+						   paramFormats,
+						   resultFormat);
+}
+
 /*
  * PQsendQueryStart
  *	Common startup code for PQsendQuery and sibling routines
diff --git a/src/interfaces/libpq/libpq-fe.h b/src/interfaces/libpq/libpq-fe.h
index 905f2f33ab8..772583dcea9 100644
--- a/src/interfaces/libpq/libpq-fe.h
+++ b/src/interfaces/libpq/libpq-fe.h
@@ -525,6 +525,15 @@ extern int	PQsendQueryPrepared(PGconn *conn,
 								const int *paramLengths,
 								const int *paramFormats,
 								int resultFormat);
+extern int	PQsendPBES(PGconn *conn,
+					   const char *stmtName,
+					   const char *query,
+					   int nParams,
+					   const Oid *paramTypes,
+					   const char *const *paramValues,
+					   const int *paramLengths,
+					   const int *paramFormats,
+					   int resultFormat);
 extern int	PQsetSingleRowMode(PGconn *conn);
 extern int	PQsetChunkedRowsMode(PGconn *conn, int chunkSize);
 extern PGresult *PQgetResult(PGconn *conn);
-- 
2.52.0