v2-0001-psql-Add-support-for-prepared-stmt-with-extended-.patch

From 7c616373487734f60cd0012f78a9e889852675b4 Mon Sep 17 00:00:00 2001
From: Anthonin Bonnefoy <anthonin.bonnefoy@gmail.com>
Date: Wed, 1 Nov 2023 10:45:12 +0100
Subject: [PATCH v2] psql: Add support for prepared stmt with extended protocol

Currently, only unnamed prepared statement is supported by psql with the
\bind command so it's not possible to test named statement creation and
execution through extended protocol.

This commit introduces three additional commands: \parse, \bindx and
\close.
\parse creates a prepared statement using extended protocol.
\bindx binds and execute an existing prepared statement using extended
protocol.
\close closes an existing prepared statement using extended protocol.
---
 doc/src/sgml/ref/psql-ref.sgml     |  86 ++++++++++++++++++++++
 src/bin/psql/command.c             | 111 +++++++++++++++++++++++++++++
 src/bin/psql/common.c              |  28 +++++++-
 src/bin/psql/help.c                |   4 ++
 src/bin/psql/settings.h            |   6 ++
 src/bin/psql/tab-complete.c        |   6 +-
 src/test/regress/expected/psql.out |  46 ++++++++++++
 src/test/regress/sql/psql.sql      |  24 +++++++
 8 files changed, 306 insertions(+), 5 deletions(-)

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index cc7d797159..b4551b516e 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -916,6 +916,35 @@ INSERT INTO tbl1 VALUES ($1, $2) \bind 'first value' 'second value' \g
        </listitem>
       </varlistentry>
 
+      <varlistentry id="app-psql-meta-command-bindx">
+       <term><literal>\bindx</literal> <replaceable class="parameter">prepared_statement_name</replaceable> [ <replaceable class="parameter">parameter</replaceable> ] ... </term>
+
+       <listitem>
+        <para>
+        <literal>\bindx</literal> is equivalent to <literal>\bind</literal>,
+         except that it takes the name of an explicit existing prepared
+         statement as first parameter.
+        </para>
+
+        <para>
+         Example:
+<programlisting>
+PREPARE stmt1 AS INSERT INTO tbl1 VALUES ($1, $2);
+\bindx stmt1 'first value' 'second value' \g
+</programlisting>
+        </para>
+
+        <para>
+         This command causes the extended query protocol (see <xref
+         linkend="protocol-query-concepts"/>) to be used, unlike normal
+         <application>psql</application> operation, which uses the simple
+         query protocol. So this command can be useful to test the extended
+         query protocol from psql.
+        </para>
+
+       </listitem>
+      </varlistentry>
+
       <varlistentry id="app-psql-meta-command-c-lc">
         <term><literal>\c</literal> or <literal>\connect [ -reuse-previous=<replaceable class="parameter">on|off</replaceable> ] [ <replaceable class="parameter">dbname</replaceable> [ <replaceable class="parameter">username</replaceable> ] [ <replaceable class="parameter">host</replaceable> ] [ <replaceable class="parameter">port</replaceable> ] | <replaceable class="parameter">conninfo</replaceable> ]</literal></term>
         <listitem>
@@ -1037,6 +1066,35 @@ INSERT INTO tbl1 VALUES ($1, $2) \bind 'first value' 'second value' \g
         </listitem>
       </varlistentry>
 
+      <varlistentry id="app-psql-meta-command-close">
+       <term><literal>\close</literal> [ <replaceable class="parameter">prepared_statement_name</replaceable> ] </term>
+
+       <listitem>
+        <para>
+        Closes the specified prepared statement. Without argument, closes the unnamed statement.
+        If no prepared statement exists with this name, the operation is a no-op.
+        </para>
+
+        <para>
+         Example:
+<programlisting>
+PREPARE stmt1 AS SELECT $1;
+\close stmt1 \g
+</programlisting>
+        </para>
+
+        <para>
+         This command causes the extended query protocol (see <xref
+         linkend="protocol-query-concepts"/>) to be used, unlike normal
+         <application>psql</application> operation, which uses the simple
+         query protocol. So this command can be useful to test the extended
+         query protocol from psql.
+        </para>
+
+       </listitem>
+      </varlistentry>
+
+
       <varlistentry id="app-psql-meta-commands-copy">
         <term><literal>\copy { <replaceable class="parameter">table</replaceable> [ ( <replaceable class="parameter">column_list</replaceable> ) ] }
         <literal>from</literal>
@@ -2779,6 +2837,34 @@ lo_import 152801
         </listitem>
       </varlistentry>
 
+      <varlistentry id="app-psql-meta-command-parse">
+        <term><literal>\parse <replaceable class="parameter">prepared_statement_name</replaceable></literal></term>
+        <listitem>
+        <para>
+        Creates a prepared statement for the next query execution.
+        </para>
+
+        <para>
+         Example:
+<programlisting>
+SELECT $1 \parse stmt1 \g
+</programlisting>
+        </para>
+
+        <para>
+         This command causes the extended query protocol (see <xref
+         linkend="protocol-query-concepts"/>) to be used, unlike normal
+         <application>psql</application> operation, which uses the simple
+         query protocol. A <xref linkend="protocol-message-formats-Parse"/>
+         message will be issued by this command so it can be useful to
+         test the extended query protocol from psql. This command affects
+         only the next query executed; all subsequent queries will use the
+         simple query protocol by default.
+        </para>
+
+        </listitem>
+      </varlistentry>
+
       <varlistentry id="app-psql-meta-command-password">
         <term><literal>\password [ <replaceable class="parameter">username</replaceable> ]</literal></term>
         <listitem>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 9ad911e28d..8044fc1dee 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -64,10 +64,14 @@ static backslashResult exec_command(const char *cmd,
 									PQExpBuffer previous_buf);
 static backslashResult exec_command_a(PsqlScanState scan_state, bool active_branch);
 static backslashResult exec_command_bind(PsqlScanState scan_state, bool active_branch);
+static backslashResult exec_command_bindx(PsqlScanState scan_state, bool active_branch,
+										  const char *cmd);
 static backslashResult exec_command_C(PsqlScanState scan_state, bool active_branch);
 static backslashResult exec_command_connect(PsqlScanState scan_state, bool active_branch);
 static backslashResult exec_command_cd(PsqlScanState scan_state, bool active_branch,
 									   const char *cmd);
+static backslashResult exec_command_close(PsqlScanState scan_state, bool active_branch,
+									   const char *cmd);
 static backslashResult exec_command_conninfo(PsqlScanState scan_state, bool active_branch);
 static backslashResult exec_command_copy(PsqlScanState scan_state, bool active_branch);
 static backslashResult exec_command_copyright(PsqlScanState scan_state, bool active_branch);
@@ -116,6 +120,8 @@ static backslashResult exec_command_lo(PsqlScanState scan_state, bool active_bra
 static backslashResult exec_command_out(PsqlScanState scan_state, bool active_branch);
 static backslashResult exec_command_print(PsqlScanState scan_state, bool active_branch,
 										  PQExpBuffer query_buf, PQExpBuffer previous_buf);
+static backslashResult exec_command_parse(PsqlScanState scan_state, bool active_branch,
+										  const char* cmd);
 static backslashResult exec_command_password(PsqlScanState scan_state, bool active_branch);
 static backslashResult exec_command_prompt(PsqlScanState scan_state, bool active_branch,
 										   const char *cmd);
@@ -311,12 +317,16 @@ exec_command(const char *cmd,
 		status = exec_command_a(scan_state, active_branch);
 	else if (strcmp(cmd, "bind") == 0)
 		status = exec_command_bind(scan_state, active_branch);
+	else if (strcmp(cmd, "bindx") == 0)
+		status = exec_command_bindx(scan_state, active_branch, cmd);
 	else if (strcmp(cmd, "C") == 0)
 		status = exec_command_C(scan_state, active_branch);
 	else if (strcmp(cmd, "c") == 0 || strcmp(cmd, "connect") == 0)
 		status = exec_command_connect(scan_state, active_branch);
 	else if (strcmp(cmd, "cd") == 0)
 		status = exec_command_cd(scan_state, active_branch, cmd);
+	else if (strcmp(cmd, "close") == 0)
+		status = exec_command_close(scan_state, active_branch, cmd);
 	else if (strcmp(cmd, "conninfo") == 0)
 		status = exec_command_conninfo(scan_state, active_branch);
 	else if (pg_strcasecmp(cmd, "copy") == 0)
@@ -378,6 +388,8 @@ exec_command(const char *cmd,
 	else if (strcmp(cmd, "p") == 0 || strcmp(cmd, "print") == 0)
 		status = exec_command_print(scan_state, active_branch,
 									query_buf, previous_buf);
+	else if (strcmp(cmd, "parse") == 0)
+		status = exec_command_parse(scan_state, active_branch, cmd);
 	else if (strcmp(cmd, "password") == 0)
 		status = exec_command_password(scan_state, active_branch);
 	else if (strcmp(cmd, "prompt") == 0)
@@ -471,6 +483,7 @@ exec_command_bind(PsqlScanState scan_state, bool active_branch)
 		int			nalloc = 0;
 
 		pset.bind_params = NULL;
+		pset.stmtName = NULL;
 
 		while ((opt = psql_scan_slash_option(scan_state, OT_NORMAL, NULL, false)))
 		{
@@ -490,6 +503,51 @@ exec_command_bind(PsqlScanState scan_state, bool active_branch)
 	return status;
 }
 
+/*
+ * \bindx -- set query parameters for an existing prepared statement
+ */
+static backslashResult
+exec_command_bindx(PsqlScanState scan_state, bool active_branch,
+				   const char* cmd)
+{
+	backslashResult status = PSQL_CMD_SKIP_LINE;
+
+	if (active_branch)
+	{
+		char	   *opt;
+		int			nparams = 0;
+		int			nalloc = 0;
+
+		pset.bind_params = NULL;
+		pset.stmtName = NULL;
+
+		opt = psql_scan_slash_option(scan_state, OT_NORMAL, NULL, false);
+		if (!opt)
+		{
+			pg_log_error("\\%s: missing required argument", cmd);
+			status = PSQL_CMD_ERROR;
+			free(opt);
+		} else {
+			pset.stmtName = opt;
+			pset.bind_flag = true;
+
+			while ((opt = psql_scan_slash_option(scan_state, OT_NORMAL, NULL, false)))
+			{
+				nparams++;
+				if (nparams > nalloc)
+				{
+					nalloc = nalloc ? nalloc * 2 : 1;
+					pset.bind_params = pg_realloc_array(pset.bind_params, char *, nalloc);
+				}
+				pset.bind_params[nparams - 1] = opt;
+			}
+			pset.bind_nparams = nparams;
+		}
+	}
+
+	return status;
+}
+
 /*
  * \C -- override table title (formerly change HTML caption)
  */
@@ -640,6 +698,27 @@ exec_command_cd(PsqlScanState scan_state, bool active_branch, const char *cmd)
 	return success ? PSQL_CMD_SKIP_LINE : PSQL_CMD_ERROR;
 }
 
+/*
+ * \close -- close a previously prepared statement
+ */
+static backslashResult
+exec_command_close(PsqlScanState scan_state, bool active_branch, const char *cmd)
+{
+	backslashResult status = PSQL_CMD_SKIP_LINE;
+
+	if (active_branch)
+	{
+		char	   *opt = psql_scan_slash_option(scan_state,
+												 OT_NORMAL, NULL, false);
+		pset.stmtName = opt;
+		pset.close_flag = true;
+	}
+	else
+		ignore_slash_options(scan_state);
+
+	return status;
+}
+
 /*
  * \conninfo -- display information about the current connection
  */
@@ -2093,6 +2172,38 @@ exec_command_print(PsqlScanState scan_state, bool active_branch,
 	return PSQL_CMD_SKIP_LINE;
 }
 
+/*
+ * \parse -- parse query
+ */
+static backslashResult
+exec_command_parse(PsqlScanState scan_state, bool active_branch,
+				   const char* cmd)
+{
+	backslashResult status = PSQL_CMD_SKIP_LINE;
+
+	if (active_branch)
+	{
+		char	   *opt = psql_scan_slash_option(scan_state,
+												 OT_NORMAL, NULL, false);
+		pset.stmtName = NULL;
+		if (!opt)
+		{
+			pg_log_error("\\%s: missing required argument", cmd);
+			status = PSQL_CMD_ERROR;
+			free(opt);
+		}
+		else
+		{
+			pset.stmtName = opt;
+			pset.parse_flag = true;
+		}
+	}
+	else
+		ignore_slash_options(scan_state);
+
+	return status;
+}
+
 /*
  * \password -- set user password
  */
diff --git a/src/bin/psql/common.c b/src/bin/psql/common.c
index 76e01b02a3..2e853b71c4 100644
--- a/src/bin/psql/common.c
+++ b/src/bin/psql/common.c
@@ -1241,16 +1241,34 @@ sendquery_cleanup:
 		pset.gsavepopt = NULL;
 	}
 
-	/* clean up after \bind */
+	/* clean up after \bind or \bindx */
 	if (pset.bind_flag)
 	{
 		for (i = 0; i < pset.bind_nparams; i++)
 			free(pset.bind_params[i]);
 		free(pset.bind_params);
+		free(pset.stmtName);
 		pset.bind_params = NULL;
+		pset.stmtName = NULL;
 		pset.bind_flag = false;
 	}
 
+	/* clean up after \parse */
+	if (pset.parse_flag)
+	{
+		free(pset.stmtName);
+		pset.stmtName = NULL;
+		pset.parse_flag = false;
+	}
+
+	/* clean up after \close */
+	if (pset.close_flag)
+	{
+		free(pset.stmtName);
+		pset.stmtName = NULL;
+		pset.close_flag = false;
+	}
+
 	/* reset \gset trigger */
 	if (pset.gset_prefix)
 	{
@@ -1433,8 +1451,14 @@ ExecQueryAndProcessResults(const char *query,
 	else
 		INSTR_TIME_SET_ZERO(before);
 
-	if (pset.bind_flag)
+	if (pset.bind_flag && pset.stmtName == NULL)
 		success = PQsendQueryParams(pset.db, query, pset.bind_nparams, NULL, (const char *const *) pset.bind_params, NULL, NULL, 0);
+	else if (pset.bind_flag && pset.stmtName != NULL)
+		success = PQsendQueryPrepared(pset.db, pset.stmtName, pset.bind_nparams, (const char *const *) pset.bind_params, NULL, NULL, 0);
+	else if (pset.close_flag)
+		success = PQsendClosePrepared(pset.db, pset.stmtName);
+	else if (pset.parse_flag)
+		success = PQsendPrepare(pset.db, pset.stmtName, query, 0, NULL);
 	else
 		success = PQsendQuery(pset.db, query);
 
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index 4e79a819d8..bb2e66c109 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -165,6 +165,9 @@ slashUsage(unsigned short int pager)
 
 	HELP0("General\n");
 	HELP0("  \\bind [PARAM]...       set query parameters\n");
+	HELP0("  \\bindx STMT_NAME [PARAM]...\n"
+		  "                         set query parameters for an existing prepared statement\n");
+	HELP0("  \\close STMT_NAME       close an existing prepared statement\n");
 	HELP0("  \\copyright             show PostgreSQL usage and distribution terms\n");
 	HELP0("  \\crosstabview [COLUMNS] execute query and display result in crosstab\n");
 	HELP0("  \\errverbose            show most recent error message at maximum verbosity\n");
@@ -312,6 +315,7 @@ slashUsage(unsigned short int pager)
 			  "                         connect to new database (currently no connection)\n");
 	HELP0("  \\conninfo              display information about current connection\n");
 	HELP0("  \\encoding [ENCODING]   show or set client encoding\n");
+	HELP0("  \\parse STMT_NAME       create a prepared statement\n");
 	HELP0("  \\password [USERNAME]   securely change the password for a user\n");
 	HELP0("\n");
 
diff --git a/src/bin/psql/settings.h b/src/bin/psql/settings.h
index 505f99d8e4..4048c45ebf 100644
--- a/src/bin/psql/settings.h
+++ b/src/bin/psql/settings.h
@@ -100,6 +100,12 @@ typedef struct _psqlSettings
 								 * protocol */
 	int			bind_nparams;	/* number of parameters */
 	char	  **bind_params;	/* parameters for extended query protocol call */
+	bool		close_flag;		/* one-shot request to close a prepared statement using
+								 * extended query protocol */
+	bool		parse_flag;		/* one-shot request to parse query using extended query
+								 * protocol */
+	char	   *stmtName;		/* prepared statement name used for extended query
+								 * protocol commands */
 	bool		crosstab_flag;	/* one-shot request to crosstab result */
 	char	   *ctv_args[4];	/* \crosstabview arguments */
 
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 09914165e4..43595da6f9 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -1712,8 +1712,8 @@ psql_completion(const char *text, int start, int end)
 	/* psql's backslash commands. */
 	static const char *const backslash_commands[] = {
 		"\\a",
-		"\\bind",
-		"\\connect", "\\conninfo", "\\C", "\\cd", "\\copy",
+		"\\bind", "\\bindx",
+		"\\connect", "\\conninfo", "\\C", "\\cd", "\\close", "\\copy",
 		"\\copyright", "\\crosstabview",
 		"\\d", "\\da", "\\dA", "\\dAc", "\\dAf", "\\dAo", "\\dAp",
 		"\\db", "\\dc", "\\dconfig", "\\dC", "\\dd", "\\ddp", "\\dD",
@@ -1730,7 +1730,7 @@ psql_completion(const char *text, int start, int end)
 		"\\if", "\\include", "\\include_relative", "\\ir",
 		"\\list", "\\lo_import", "\\lo_export", "\\lo_list", "\\lo_unlink",
 		"\\out",
-		"\\password", "\\print", "\\prompt", "\\pset",
+		"\\parse", "\\password", "\\print", "\\prompt", "\\pset",
 		"\\qecho", "\\quit",
 		"\\reset",
 		"\\s", "\\set", "\\setenv", "\\sf", "\\sv",
diff --git a/src/test/regress/expected/psql.out b/src/test/regress/expected/psql.out
index 4f3fd46420..a290d573f8 100644
--- a/src/test/regress/expected/psql.out
+++ b/src/test/regress/expected/psql.out
@@ -98,6 +98,47 @@ two | 2
    1 |   2
 (1 row)
 
+-- \parse (extended query protocol)
+SELECT 1 \parse '' \g
+SELECT 2 \parse stmt1 \g
+SELECT $1 \parse stmt2 \g
+SELECT $1, $2 \parse stmt3 \g
+-- \bindx (extended query protocol)
+\bindx '' \g
+ ?column? 
+----------
+        1
+(1 row)
+
+\bindx stmt1 \g
+ ?column? 
+----------
+        2
+(1 row)
+
+\bindx stmt2 'foo' \g
+ ?column? 
+----------
+ foo
+(1 row)
+
+\bindx stmt3 'foo' 'bar' \g
+ ?column? | ?column? 
+----------+----------
+ foo      | bar
+(1 row)
+
+-- \close (extended query protocol)
+\close \g
+\close stmt2 \g
+\close stmt2 \g
+select name, statement from pg_prepared_statements order by name;
+ name  |   statement    
+-------+----------------
+ stmt1 | SELECT 2 
+ stmt3 | SELECT $1, $2 
+(2 rows)
+
 -- \bind (extended query protocol)
 SELECT 1 \bind \g
  ?column? 
@@ -129,6 +170,11 @@ ERROR:  cannot insert multiple commands into a prepared statement
 -- bind error
 SELECT $1, $2 \bind 'foo' \g
 ERROR:  bind message supplies 1 parameters, but prepared statement "" requires 2
+-- bindx error
+\bindx stmt2 'baz' \g
+ERROR:  prepared statement "stmt2" does not exist
+\bindx stmt3 'baz' \g
+ERROR:  bind message supplies 1 parameters, but prepared statement "stmt3" requires 2
 -- \gset
 select 10 as test01, 20 as test02, 'Hello' as test03 \gset pref01_
 \echo :pref01_test01 :pref01_test02 :pref01_test03
diff --git a/src/test/regress/sql/psql.sql b/src/test/regress/sql/psql.sql
index c997106b9f..399810ca3e 100644
--- a/src/test/regress/sql/psql.sql
+++ b/src/test/regress/sql/psql.sql
@@ -45,6 +45,27 @@ SELECT 1 as one, 2 as two \g (format=csv csv_fieldsep='\t')
 SELECT 1 as one, 2 as two \gx (title='foo bar')
 \g
 
+-- \parse (extended query protocol)
+
+SELECT 1 \parse '' \g
+SELECT 2 \parse stmt1 \g
+SELECT $1 \parse stmt2 \g
+SELECT $1, $2 \parse stmt3 \g
+
+-- \bindx (extended query protocol)
+
+\bindx '' \g
+\bindx stmt1 \g
+\bindx stmt2 'foo' \g
+\bindx stmt3 'foo' 'bar' \g
+
+-- \close (extended query protocol)
+
+\close \g
+\close stmt2 \g
+\close stmt2 \g
+select name, statement from pg_prepared_statements order by name;
+
 -- \bind (extended query protocol)
 
 SELECT 1 \bind \g
@@ -58,6 +79,9 @@ SELECT foo \bind \g
 SELECT 1 \; SELECT 2 \bind \g
 -- bind error
 SELECT $1, $2 \bind 'foo' \g
+-- bindx error
+\bindx stmt2 'baz' \g
+\bindx stmt3 'baz' \g
 
 -- \gset
 
-- 
2.39.3 (Apple Git-145)