On 01.02.22 15:40, Peter Eisentraut wrote:
On 12.01.22 11:20, Julien Rouhaud wrote:
Since you mentioned that this patch depends on the SHOW_ALL_RESULTS psql patch which is still being worked on, I'm not expecting much activity here until the prerequirements are done.  It also seems better to mark this patch as Waiting
on Author as further reviews are probably not really needed for now.

Well, a review on the general architecture and approach would have been useful.  But I understand that without the psql work, it's difficult for a reviewer to even get started on this patch.  It's also similarly difficult for me to keep updating it.  So I'll set it to Returned with feedback for now and take it off the table.  I want to get back to it when the prerequisites are more settled.

Now that the psql support for multiple result sets exists, I want to revive this patch. It's the same as the last posted version, except now it doesn't require any psql changes or any weird test modifications anymore.

(Old news: This patch allows declaring a cursor WITH RETURN in a procedure to make the cursor's data be returned as a result of the CALL invocation. The procedure needs to be declared with the DYNAMIC RESULT SETS attribute.)
From 80311214144fba40006dea54817956c3e92110ce Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <pe...@eisentraut.org>
Date: Fri, 14 Oct 2022 09:01:17 +0200
Subject: [PATCH v5] Dynamic result sets from procedures

Declaring a cursor WITH RETURN in a procedure makes the cursor's data be
returned as a result of the CALL invocation.  The procedure needs to
be declared with the DYNAMIC RESULT SETS attribute.

Discussion: 
https://www.postgresql.org/message-id/flat/6e747f98-835f-2e05-cde5-86ee444a7...@2ndquadrant.com
---
 doc/src/sgml/catalogs.sgml                    | 10 +++
 doc/src/sgml/information_schema.sgml          |  3 +-
 doc/src/sgml/plpgsql.sgml                     | 27 +++++-
 doc/src/sgml/protocol.sgml                    | 19 +++++
 doc/src/sgml/ref/alter_procedure.sgml         | 12 +++
 doc/src/sgml/ref/create_procedure.sgml        | 14 +++
 doc/src/sgml/ref/declare.sgml                 | 34 +++++++-
 src/backend/catalog/information_schema.sql    |  2 +-
 src/backend/catalog/pg_aggregate.c            |  3 +-
 src/backend/catalog/pg_proc.c                 |  4 +-
 src/backend/catalog/sql_features.txt          |  2 +-
 src/backend/commands/functioncmds.c           | 79 +++++++++++++++--
 src/backend/commands/portalcmds.c             | 23 +++++
 src/backend/commands/typecmds.c               | 12 ++-
 src/backend/parser/gram.y                     | 18 +++-
 src/backend/tcop/postgres.c                   | 61 ++++++++++++-
 src/backend/tcop/pquery.c                     |  6 ++
 src/backend/utils/errcodes.txt                |  1 +
 src/backend/utils/mmgr/portalmem.c            | 48 +++++++++++
 src/bin/pg_dump/pg_dump.c                     | 16 +++-
 src/include/catalog/pg_proc.h                 |  6 +-
 src/include/commands/defrem.h                 |  1 +
 src/include/nodes/parsenodes.h                |  1 +
 src/include/parser/kwlist.h                   |  2 +
 src/include/utils/portal.h                    | 14 +++
 src/interfaces/libpq/fe-protocol3.c           |  6 +-
 src/pl/plpgsql/src/expected/plpgsql_call.out  | 78 +++++++++++++++++
 src/pl/plpgsql/src/pl_exec.c                  |  6 ++
 src/pl/plpgsql/src/pl_gram.y                  | 58 +++++++++++--
 src/pl/plpgsql/src/pl_unreserved_kwlist.h     |  2 +
 src/pl/plpgsql/src/sql/plpgsql_call.sql       | 46 ++++++++++
 .../regress/expected/create_procedure.out     | 85 ++++++++++++++++++-
 src/test/regress/sql/create_procedure.sql     | 61 ++++++++++++-
 33 files changed, 719 insertions(+), 41 deletions(-)

diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 00f833d210e7..16dbe93e2246 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -6020,6 +6020,16 @@ <title><structname>pg_proc</structname> Columns</title>
       </para></entry>
      </row>
 
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>prodynres</structfield> <type>int4</type>
+      </para>
+      <para>
+       For procedures, this records the maximum number of dynamic result sets
+       the procedure may create.  Otherwise zero.
+      </para></entry>
+     </row>
+
      <row>
       <entry role="catalog_table_entry"><para role="column_definition">
        <structfield>pronargs</structfield> <type>int2</type>
diff --git a/doc/src/sgml/information_schema.sgml 
b/doc/src/sgml/information_schema.sgml
index 350c75bc31ef..5fc9dc22aeff 100644
--- a/doc/src/sgml/information_schema.sgml
+++ b/doc/src/sgml/information_schema.sgml
@@ -5885,7 +5885,8 @@ <title><structname>routines</structname> Columns</title>
        <structfield>max_dynamic_result_sets</structfield> 
<type>cardinal_number</type>
       </para>
       <para>
-       Applies to a feature not available in 
<productname>PostgreSQL</productname>
+       For a procedure, the maximum number of dynamic result sets.  Otherwise
+       zero.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/plpgsql.sgml b/doc/src/sgml/plpgsql.sgml
index d85f89bf3033..58a997e15eef 100644
--- a/doc/src/sgml/plpgsql.sgml
+++ b/doc/src/sgml/plpgsql.sgml
@@ -3128,7 +3128,7 @@ <title>Declaring Cursor Variables</title>
      Another way is to use the cursor declaration syntax,
      which in general is:
 <synopsis>
-<replaceable>name</replaceable> <optional> <optional> NO </optional> SCROLL 
</optional> CURSOR <optional> ( <replaceable>arguments</replaceable> ) 
</optional> FOR <replaceable>query</replaceable>;
+<replaceable>name</replaceable> <optional> <optional> NO </optional> SCROLL 
</optional> CURSOR <optional> <optional> WITH RETURN </optional> ( 
<replaceable>arguments</replaceable> ) </optional> FOR 
<replaceable>query</replaceable>;
 </synopsis>
      (<literal>FOR</literal> can be replaced by <literal>IS</literal> for
      <productname>Oracle</productname> compatibility.)
@@ -3136,6 +3136,10 @@ <title>Declaring Cursor Variables</title>
      scrolling backward; if <literal>NO SCROLL</literal> is specified, backward
      fetches will be rejected; if neither specification appears, it is
      query-dependent whether backward fetches will be allowed.
+     If <literal>WITH RETURN</literal> is specified, the results of the
+     cursor, after it is opened, will be returned as a dynamic result set; see
+     <xref linkend="sql-declare"/> for details.  (<literal>WITHOUT
+     RETURN</literal> can also be specified but has no effect.)
      <replaceable>arguments</replaceable>, if specified, is a
      comma-separated list of pairs <literal><replaceable>name</replaceable>
      <replaceable>datatype</replaceable></literal> that define names to be
@@ -3194,7 +3198,7 @@ <title>Opening Cursors</title>
      <title><command>OPEN FOR</command> 
<replaceable>query</replaceable></title>
 
 <synopsis>
-OPEN <replaceable>unbound_cursorvar</replaceable> <optional> <optional> NO 
</optional> SCROLL </optional> FOR <replaceable>query</replaceable>;
+OPEN <replaceable>unbound_cursorvar</replaceable> <optional> <optional> NO 
</optional> SCROLL </optional> <optional> WITH RETURN </optional> FOR 
<replaceable>query</replaceable>;
 </synopsis>
 
        <para>
@@ -3212,8 +3216,9 @@ <title><command>OPEN FOR</command> 
<replaceable>query</replaceable></title>
         substituted is the one it has at the time of the 
<command>OPEN</command>;
         subsequent changes to the variable will not affect the cursor's
         behavior.
-        The <literal>SCROLL</literal> and <literal>NO SCROLL</literal>
-        options have the same meanings as for a bound cursor.
+        The options <literal>SCROLL</literal>, <literal>NO SCROLL</literal>,
+        and <literal>WITH RETURN</literal> have the same meanings as for a
+        bound cursor.
        </para>
 
        <para>
@@ -3590,6 +3595,20 @@ <title>Returning Cursors</title>
 COMMIT;
 </programlisting>
        </para>
+
+       <note>
+        <para>
+         Returning a cursor from a function as described here is a separate
+         mechanism from declaring a cursor <literal>WITH RETURN</literal>,
+         which automatically produces a result set for the client if the
+         cursor is left open when returning from the procedure.  Both
+         mechanisms can be used to achieve similar effects.  The differences
+         are mainly how the client application prefers to manage the cursors.
+         Furthermore, other SQL implementations have other programming models
+         that might map more easily to one or the other mechanism when doing a
+         migration.
+        </para>
+       </note>
      </sect3>
    </sect2>
 
diff --git a/doc/src/sgml/protocol.sgml b/doc/src/sgml/protocol.sgml
index 5fdd429e05d3..f11295168636 100644
--- a/doc/src/sgml/protocol.sgml
+++ b/doc/src/sgml/protocol.sgml
@@ -959,6 +959,25 @@ <title>Extended Query</title>
     an empty query string), ErrorResponse, or PortalSuspended.
    </para>
 
+   <para>
+    Executing a portal may give rise to a <firstterm>dynamic result set
+    sequence</firstterm>.  That means the command contained in the portal
+    created additional result sets beyond what it normally returns.  (The
+    typical example is calling a stored procedure that creates dynamic result
+    sets.)  Dynamic result sets are issued after whatever response the main
+    command issued.  Each dynamic result set begins with a RowDescription
+    message followed by zero or more DataRow messages.  (Since, as explained
+    above, an Execute message normally does not respond with a RowDescription,
+    the appearance of the first RowDescription marks the end of the primary
+    result set of the portal and the beginning of the first dynamic result
+    set.)  The CommandComplete message that concludes the Execute message
+    response follows <emphasis>after</emphasis> all dynamic result sets.  Note
+    that dynamic result sets cannot, by their nature, be decribed prior to the
+    execution of the portal.  Multiple executions of the same prepared
+    statement could result in dynamic result sets with different row
+    descriptions being returned.
+   </para>
+
    <para>
     At completion of each series of extended-query messages, the frontend
     should issue a Sync message.  This parameterless message causes the
diff --git a/doc/src/sgml/ref/alter_procedure.sgml 
b/doc/src/sgml/ref/alter_procedure.sgml
index 20a623885f74..76b9425a08b5 100644
--- a/doc/src/sgml/ref/alter_procedure.sgml
+++ b/doc/src/sgml/ref/alter_procedure.sgml
@@ -34,6 +34,7 @@
 
 <phrase>where <replaceable class="parameter">action</replaceable> is one 
of:</phrase>
 
+    DYNAMIC RESULT SETS <replaceable 
class="parameter">dynamic_result_sets</replaceable>
     [ EXTERNAL ] SECURITY INVOKER | [ EXTERNAL ] SECURITY DEFINER
     SET <replaceable class="parameter">configuration_parameter</replaceable> { 
TO | = } { <replaceable class="parameter">value</replaceable> | DEFAULT }
     SET <replaceable class="parameter">configuration_parameter</replaceable> 
FROM CURRENT
@@ -157,6 +158,17 @@ <title>Parameters</title>
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term><literal>DYNAMIC RESULT SETS <replaceable 
class="parameter">dynamic_result_sets</replaceable></literal></term>
+
+    <listitem>
+     <para>
+      Changes the dynamic result sets setting of the procedure.  See <xref
+      linkend="sql-createprocedure"/> for more information.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><literal><optional> EXTERNAL </optional> SECURITY 
INVOKER</literal></term>
     <term><literal><optional> EXTERNAL </optional> SECURITY 
DEFINER</literal></term>
diff --git a/doc/src/sgml/ref/create_procedure.sgml 
b/doc/src/sgml/ref/create_procedure.sgml
index 03a14c868458..1c99b00eef8b 100644
--- a/doc/src/sgml/ref/create_procedure.sgml
+++ b/doc/src/sgml/ref/create_procedure.sgml
@@ -24,6 +24,7 @@
 CREATE [ OR REPLACE ] PROCEDURE
     <replaceable class="parameter">name</replaceable> ( [ [ <replaceable 
class="parameter">argmode</replaceable> ] [ <replaceable 
class="parameter">argname</replaceable> ] <replaceable 
class="parameter">argtype</replaceable> [ { DEFAULT | = } <replaceable 
class="parameter">default_expr</replaceable> ] [, ...] ] )
   { LANGUAGE <replaceable class="parameter">lang_name</replaceable>
+    | DYNAMIC RESULT SETS <replaceable 
class="parameter">dynamic_result_sets</replaceable>
     | TRANSFORM { FOR TYPE <replaceable 
class="parameter">type_name</replaceable> } [, ... ]
     | [ EXTERNAL ] SECURITY INVOKER | [ EXTERNAL ] SECURITY DEFINER
     | SET <replaceable class="parameter">configuration_parameter</replaceable> 
{ TO <replaceable class="parameter">value</replaceable> | = <replaceable 
class="parameter">value</replaceable> | FROM CURRENT }
@@ -176,6 +177,19 @@ <title>Parameters</title>
      </listitem>
     </varlistentry>
 
+    <varlistentry>
+     <term><literal>DYNAMIC RESULT SETS <replaceable 
class="parameter">dynamic_result_sets</replaceable></literal></term>
+
+     <listitem>
+      <para>
+       Specifies how many dynamic result sets the procedure returns (see
+       <literal><link linkend="sql-declare">DECLARE</link> WITH
+       RETURN</literal>).  The default is 0.  If a procedure returns more
+       result sets than declared, a warning is raised.
+      </para>
+     </listitem>
+    </varlistentry>
+
     <varlistentry>
      <term><literal>TRANSFORM { FOR TYPE <replaceable 
class="parameter">type_name</replaceable> } [, ... ] }</literal></term>
 
diff --git a/doc/src/sgml/ref/declare.sgml b/doc/src/sgml/ref/declare.sgml
index bbbd335bd0bf..a6ff2567ea3b 100644
--- a/doc/src/sgml/ref/declare.sgml
+++ b/doc/src/sgml/ref/declare.sgml
@@ -27,7 +27,8 @@
  <refsynopsisdiv>
 <synopsis>
 DECLARE <replaceable class="parameter">name</replaceable> [ BINARY ] [ 
ASENSITIVE | INSENSITIVE ] [ [ NO ] SCROLL ]
-    CURSOR [ { WITH | WITHOUT } HOLD ] FOR <replaceable 
class="parameter">query</replaceable>
+    CURSOR [ { WITH | WITHOUT } HOLD ] [ { WITH | WITHOUT } RETURN ]
+    FOR <replaceable class="parameter">query</replaceable>
 </synopsis>
  </refsynopsisdiv>
 
@@ -131,6 +132,22 @@ <title>Parameters</title>
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term><literal>WITH RETURN</literal></term>
+    <term><literal>WITHOUT RETURN</literal></term>
+    <listitem>
+     <para>
+      This option is only valid for cursors defined inside a procedure.
+      <literal>WITH RETURN</literal> specifies that the cursor's result rows
+      will be provided as a result set of the procedure invocation.  To
+      accomplish that, the cursor must be left open at the end of the
+      procedure.  If multiple <literal>WITH RETURN</literal> cursors are
+      declared, then their results will be returned in the order they were
+      created.  <literal>WITHOUT RETURN</literal> is the default.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><replaceable class="parameter">query</replaceable></term>
     <listitem>
@@ -323,6 +340,21 @@ <title>Examples</title>
    See <xref linkend="sql-fetch"/> for more
    examples of cursor usage.
   </para>
+
+  <para>
+   This example shows how to return multiple result sets from a procedure:
+<programlisting>
+CREATE PROCEDURE test()
+LANGUAGE SQL
+AS $$
+DECLARE a CURSOR WITH RETURN FOR SELECT * FROM tbl1;
+DECLARE b CURSOR WITH RETURN FOR SELECT * FROM tbl2;
+$$;
+
+CALL test();
+</programlisting>
+   The results of the two cursors will be returned in order from this call.
+  </para>
  </refsect1>
 
  <refsect1>
diff --git a/src/backend/catalog/information_schema.sql 
b/src/backend/catalog/information_schema.sql
index 18725a02d1fb..7b440e761377 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -1593,7 +1593,7 @@ CREATE VIEW routines AS
              CASE WHEN p.proisstrict THEN 'YES' ELSE 'NO' END END AS 
yes_or_no) AS is_null_call,
            CAST(null AS character_data) AS sql_path,
            CAST('YES' AS yes_or_no) AS schema_level_routine,
-           CAST(0 AS cardinal_number) AS max_dynamic_result_sets,
+           CAST(p.prodynres AS cardinal_number) AS max_dynamic_result_sets,
            CAST(null AS yes_or_no) AS is_user_defined_cast,
            CAST(null AS yes_or_no) AS is_implicitly_invocable,
            CAST(CASE WHEN p.prosecdef THEN 'DEFINER' ELSE 'INVOKER' END AS 
character_data) AS security_type,
diff --git a/src/backend/catalog/pg_aggregate.c 
b/src/backend/catalog/pg_aggregate.c
index 0d0daa69b340..a8f0967d3d9d 100644
--- a/src/backend/catalog/pg_aggregate.c
+++ b/src/backend/catalog/pg_aggregate.c
@@ -640,7 +640,8 @@ AggregateCreate(const char *aggName,
                                                         PointerGetDatum(NULL), 
/* proconfig */
                                                         InvalidOid,    /* no 
prosupport */
                                                         1, /* procost */
-                                                        0);    /* prorows */
+                                                        0,     /* prorows */
+                                                        0);    /* prodynres */
        procOid = myself.objectId;
 
        /*
diff --git a/src/backend/catalog/pg_proc.c b/src/backend/catalog/pg_proc.c
index a9fe45e34714..667ddf289dc2 100644
--- a/src/backend/catalog/pg_proc.c
+++ b/src/backend/catalog/pg_proc.c
@@ -95,7 +95,8 @@ ProcedureCreate(const char *procedureName,
                                Datum proconfig,
                                Oid prosupport,
                                float4 procost,
-                               float4 prorows)
+                               float4 prorows,
+                               int dynres)
 {
        Oid                     retval;
        int                     parameterCount;
@@ -314,6 +315,7 @@ ProcedureCreate(const char *procedureName,
        values[Anum_pg_proc_proretset - 1] = BoolGetDatum(returnsSet);
        values[Anum_pg_proc_provolatile - 1] = CharGetDatum(volatility);
        values[Anum_pg_proc_proparallel - 1] = CharGetDatum(parallel);
+       values[Anum_pg_proc_prodynres - 1] = Int32GetDatum(dynres);
        values[Anum_pg_proc_pronargs - 1] = UInt16GetDatum(parameterCount);
        values[Anum_pg_proc_pronargdefaults - 1] = 
UInt16GetDatum(list_length(parameterDefaults));
        values[Anum_pg_proc_prorettype - 1] = ObjectIdGetDatum(returnType);
diff --git a/src/backend/catalog/sql_features.txt 
b/src/backend/catalog/sql_features.txt
index da7c9c772e09..eb8a2465e853 100644
--- a/src/backend/catalog/sql_features.txt
+++ b/src/backend/catalog/sql_features.txt
@@ -486,7 +486,7 @@ T433        Multiargument GROUPING function                 
YES
 T434   GROUP BY DISTINCT                       YES     
 T441   ABS and MOD functions                   YES     
 T461   Symmetric BETWEEN predicate                     YES     
-T471   Result sets return value                        NO      
+T471   Result sets return value                        NO      partially 
supported
 T472   DESCRIBE CURSOR                 NO      
 T491   LATERAL derived table                   YES     
 T495   Combined data change and retrieval                      NO      
different syntax
diff --git a/src/backend/commands/functioncmds.c 
b/src/backend/commands/functioncmds.c
index e6fcfc23b931..1f2400854312 100644
--- a/src/backend/commands/functioncmds.c
+++ b/src/backend/commands/functioncmds.c
@@ -72,6 +72,7 @@
 #include "utils/guc.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
+#include "utils/portal.h"
 #include "utils/rel.h"
 #include "utils/snapmgr.h"
 #include "utils/syscache.h"
@@ -513,7 +514,8 @@ compute_common_attribute(ParseState *pstate,
                                                 DefElem **cost_item,
                                                 DefElem **rows_item,
                                                 DefElem **support_item,
-                                                DefElem **parallel_item)
+                                                DefElem **parallel_item,
+                                                DefElem **dynres_item)
 {
        if (strcmp(defel->defname, "volatility") == 0)
        {
@@ -589,12 +591,28 @@ compute_common_attribute(ParseState *pstate,
 
                *parallel_item = defel;
        }
+       else if (strcmp(defel->defname, "dynamic_result_sets") == 0)
+       {
+               if (!is_procedure)
+                       goto function_error;
+               if (*dynres_item)
+                       errorConflictingDefElem(defel, pstate);
+
+               *dynres_item = defel;
+       }
        else
                return false;
 
        /* Recognized an option */
        return true;
 
+function_error:
+       ereport(ERROR,
+                       (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
+                        errmsg("invalid attribute in function definition"),
+                        parser_errposition(pstate, defel->location)));
+       return false;
+
 procedure_error:
        ereport(ERROR,
                        (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
@@ -731,7 +749,8 @@ compute_function_attributes(ParseState *pstate,
                                                        float4 *procost,
                                                        float4 *prorows,
                                                        Oid *prosupport,
-                                                       char *parallel_p)
+                                                       char *parallel_p,
+                                                       int *dynres_p)
 {
        ListCell   *option;
        DefElem    *as_item = NULL;
@@ -747,6 +766,7 @@ compute_function_attributes(ParseState *pstate,
        DefElem    *rows_item = NULL;
        DefElem    *support_item = NULL;
        DefElem    *parallel_item = NULL;
+       DefElem    *dynres_item = NULL;
 
        foreach(option, options)
        {
@@ -792,7 +812,8 @@ compute_function_attributes(ParseState *pstate,
                                                                                
  &cost_item,
                                                                                
  &rows_item,
                                                                                
  &support_item,
-                                                                               
  &parallel_item))
+                                                                               
  &parallel_item,
+                                                                               
  &dynres_item))
                {
                        /* recognized common option */
                        continue;
@@ -840,6 +861,11 @@ compute_function_attributes(ParseState *pstate,
                *prosupport = interpret_func_support(support_item);
        if (parallel_item)
                *parallel_p = interpret_func_parallel(parallel_item);
+       if (dynres_item)
+       {
+               *dynres_p = intVal(dynres_item->arg);
+               Assert(*dynres_p >= 0); /* enforced by parser */
+       }
 }
 
 
@@ -1051,6 +1077,7 @@ CreateFunction(ParseState *pstate, CreateFunctionStmt 
*stmt)
        Form_pg_language languageStruct;
        List       *as_clause;
        char            parallel;
+       int                     dynres;
 
        /* Convert list of names to a name and namespace */
        namespaceId = QualifiedNameGetCreationNamespace(stmt->funcname,
@@ -1075,6 +1102,7 @@ CreateFunction(ParseState *pstate, CreateFunctionStmt 
*stmt)
        prorows = -1;                           /* indicates not set */
        prosupport = InvalidOid;
        parallel = PROPARALLEL_UNSAFE;
+       dynres = 0;
 
        /* Extract non-default attributes from stmt->options list */
        compute_function_attributes(pstate,
@@ -1084,7 +1112,7 @@ CreateFunction(ParseState *pstate, CreateFunctionStmt 
*stmt)
                                                                &isWindowFunc, 
&volatility,
                                                                &isStrict, 
&security, &isLeakProof,
                                                                &proconfig, 
&procost, &prorows,
-                                                               &prosupport, 
&parallel);
+                                                               &prosupport, 
&parallel, &dynres);
 
        if (!language)
        {
@@ -1285,7 +1313,8 @@ CreateFunction(ParseState *pstate, CreateFunctionStmt 
*stmt)
                                                   PointerGetDatum(proconfig),
                                                   prosupport,
                                                   procost,
-                                                  prorows);
+                                                  prorows,
+                                                  dynres);
 }
 
 /*
@@ -1362,6 +1391,7 @@ AlterFunction(ParseState *pstate, AlterFunctionStmt *stmt)
        DefElem    *rows_item = NULL;
        DefElem    *support_item = NULL;
        DefElem    *parallel_item = NULL;
+       DefElem    *dynres_item = NULL;
        ObjectAddress address;
 
        rel = table_open(ProcedureRelationId, RowExclusiveLock);
@@ -1405,7 +1435,8 @@ AlterFunction(ParseState *pstate, AlterFunctionStmt *stmt)
                                                                         
&cost_item,
                                                                         
&rows_item,
                                                                         
&support_item,
-                                                                        
&parallel_item) == false)
+                                                                        
&parallel_item,
+                                                                        
&dynres_item) == false)
                        elog(ERROR, "option \"%s\" not recognized", 
defel->defname);
        }
 
@@ -1467,6 +1498,8 @@ AlterFunction(ParseState *pstate, AlterFunctionStmt *stmt)
        }
        if (parallel_item)
                procForm->proparallel = interpret_func_parallel(parallel_item);
+       if (dynres_item)
+               procForm->prodynres = intVal(dynres_item->arg);
        if (set_items)
        {
                Datum           datum;
@@ -2138,6 +2171,17 @@ ExecuteDoStmt(ParseState *pstate, DoStmt *stmt, bool 
atomic)
        OidFunctionCall1(laninline, PointerGetDatum(codeblock));
 }
 
+static List *procedure_stack;
+
+Oid
+CurrentProcedure(void)
+{
+       if (!procedure_stack)
+               return InvalidOid;
+       else
+               return llast_oid(procedure_stack);
+}
+
 /*
  * Execute CALL statement
  *
@@ -2177,6 +2221,7 @@ ExecuteCallStmt(CallStmt *stmt, ParamListInfo params, 
bool atomic, DestReceiver
        AclResult       aclresult;
        FmgrInfo        flinfo;
        CallContext *callcontext;
+       int                     prodynres;
        EState     *estate;
        ExprContext *econtext;
        HeapTuple       tp;
@@ -2217,6 +2262,8 @@ ExecuteCallStmt(CallStmt *stmt, ParamListInfo params, 
bool atomic, DestReceiver
        if (((Form_pg_proc) GETSTRUCT(tp))->prosecdef)
                callcontext->atomic = true;
 
+       prodynres = ((Form_pg_proc) GETSTRUCT(tp))->prodynres;
+
        ReleaseSysCache(tp);
 
        /* safety check; see ExecInitFunc() */
@@ -2277,7 +2324,18 @@ ExecuteCallStmt(CallStmt *stmt, ParamListInfo params, 
bool atomic, DestReceiver
 
        /* Here we actually call the procedure */
        pgstat_init_function_usage(fcinfo, &fcusage);
-       retval = FunctionCallInvoke(fcinfo);
+
+       procedure_stack = lappend_oid(procedure_stack, fexpr->funcid);
+       PG_TRY();
+       {
+               retval = FunctionCallInvoke(fcinfo);
+       }
+       PG_FINALLY();
+       {
+               procedure_stack = list_delete_last(procedure_stack);
+       }
+       PG_END_TRY();
+
        pgstat_end_function_usage(&fcusage, true);
 
        /* Handle the procedure's outputs */
@@ -2338,6 +2396,13 @@ ExecuteCallStmt(CallStmt *stmt, ParamListInfo params, 
bool atomic, DestReceiver
                         fexpr->funcresulttype);
 
        FreeExecutorState(estate);
+
+       CloseOtherReturnableCursors(fexpr->funcid);
+
+       if (list_length(GetReturnableCursors()) > prodynres)
+               ereport(WARNING,
+                               
errcode(ERRCODE_WARNING_ATTEMPT_TO_RETURN_TOO_MANY_RESULT_SETS),
+                               errmsg("attempt to return too many result 
sets"));
 }
 
 /*
diff --git a/src/backend/commands/portalcmds.c 
b/src/backend/commands/portalcmds.c
index 9902c5c5669a..c42f88f2ddda 100644
--- a/src/backend/commands/portalcmds.c
+++ b/src/backend/commands/portalcmds.c
@@ -24,6 +24,7 @@
 #include <limits.h>
 
 #include "access/xact.h"
+#include "commands/defrem.h"
 #include "commands/portalcmds.h"
 #include "executor/executor.h"
 #include "executor/tstoreReceiver.h"
@@ -140,6 +141,28 @@ PerformCursorOpen(ParseState *pstate, DeclareCursorStmt 
*cstmt, ParamListInfo pa
                        portal->cursorOptions |= CURSOR_OPT_NO_SCROLL;
        }
 
+       /*
+        * For returnable cursors, remember the currently active procedure, as
+        * well as the command ID, so we can sort by creation order later.  If
+        * there is no procedure active, the cursor is marked as WITHOUT RETURN.
+        * (This is not an error, per SQL standard, subclause "Effect of 
opening a
+        * cursor".)
+        */
+       if (portal->cursorOptions & CURSOR_OPT_RETURN)
+       {
+               Oid                     procId = CurrentProcedure();
+
+               if (procId)
+               {
+                       portal->procId = procId;
+                       portal->createCid = GetCurrentCommandId(true);
+               }
+               else
+               {
+                       portal->cursorOptions &= ~CURSOR_OPT_RETURN;
+               }
+       }
+
        /*
         * Start execution, inserting parameters if any.
         */
diff --git a/src/backend/commands/typecmds.c b/src/backend/commands/typecmds.c
index 33b64fd2793b..942cbfa93f92 100644
--- a/src/backend/commands/typecmds.c
+++ b/src/backend/commands/typecmds.c
@@ -1775,7 +1775,8 @@ makeRangeConstructors(const char *name, Oid namespace,
                                                                 
PointerGetDatum(NULL), /* proconfig */
                                                                 InvalidOid,    
/* prosupport */
                                                                 1.0,   /* 
procost */
-                                                                0.0);  /* 
prorows */
+                                                                0.0,   /* 
prorows */
+                                                                0);    /* 
prodynres */
 
                /*
                 * Make the constructors internally-dependent on the range type 
so
@@ -1840,7 +1841,8 @@ makeMultirangeConstructors(const char *name, Oid 
namespace,
                                                         PointerGetDatum(NULL), 
/* proconfig */
                                                         InvalidOid,    /* 
prosupport */
                                                         1.0,   /* procost */
-                                                        0.0);  /* prorows */
+                                                        0.0,   /* prorows */
+                                                        0);    /* prodynres */
 
        /*
         * Make the constructor internally-dependent on the multirange type so
@@ -1884,7 +1886,8 @@ makeMultirangeConstructors(const char *name, Oid 
namespace,
                                                         PointerGetDatum(NULL), 
/* proconfig */
                                                         InvalidOid,    /* 
prosupport */
                                                         1.0,   /* procost */
-                                                        0.0);  /* prorows */
+                                                        0.0,   /* prorows */
+                                                        0);    /* prodynres */
        /* ditto */
        recordDependencyOn(&myself, &referenced, DEPENDENCY_INTERNAL);
        pfree(argtypes);
@@ -1922,7 +1925,8 @@ makeMultirangeConstructors(const char *name, Oid 
namespace,
                                                         PointerGetDatum(NULL), 
/* proconfig */
                                                         InvalidOid,    /* 
prosupport */
                                                         1.0,   /* procost */
-                                                        0.0);  /* prorows */
+                                                        0.0,   /* prorows */
+                                                        0);    /* prodynres */
        /* ditto */
        recordDependencyOn(&myself, &referenced, DEPENDENCY_INTERNAL);
        pfree(argtypes);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 94d5142a4a06..029d86fa30f1 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -689,7 +689,7 @@ static Node *makeRecursiveViewSelect(char *relname, List 
*aliases, Node *query);
        DATA_P DATABASE DAY_P DEALLOCATE DEC DECIMAL_P DECLARE DEFAULT DEFAULTS
        DEFERRABLE DEFERRED DEFINER DELETE_P DELIMITER DELIMITERS DEPENDS DEPTH 
DESC
        DETACH DICTIONARY DISABLE_P DISCARD DISTINCT DO DOCUMENT_P DOMAIN_P
-       DOUBLE_P DROP
+       DOUBLE_P DROP DYNAMIC
 
        EACH ELSE ENABLE_P ENCODING ENCRYPTED END_P ENUM_P ESCAPE EVENT EXCEPT
        EXCLUDE EXCLUDING EXCLUSIVE EXECUTE EXISTS EXPLAIN EXPRESSION
@@ -736,7 +736,7 @@ static Node *makeRecursiveViewSelect(char *relname, List 
*aliases, Node *query);
 
        RANGE READ REAL REASSIGN RECHECK RECURSIVE REF REFERENCES REFERENCING
        REFRESH REINDEX RELATIVE_P RELEASE RENAME REPEATABLE REPLACE REPLICA
-       RESET RESTART RESTRICT RETURN RETURNING RETURNS REVOKE RIGHT ROLE 
ROLLBACK ROLLUP
+       RESET RESTART RESTRICT RESULT RETURN RETURNING RETURNS REVOKE RIGHT 
ROLE ROLLBACK ROLLUP
        ROUTINE ROUTINES ROW ROWS RULE
 
        SAVEPOINT SCHEMA SCHEMAS SCROLL SEARCH SECOND_P SECURITY SELECT 
SEQUENCE SEQUENCES
@@ -8512,6 +8512,10 @@ common_func_opt_item:
                                {
                                        $$ = makeDefElem("parallel", (Node *) 
makeString($2), @1);
                                }
+                       | DYNAMIC RESULT SETS Iconst
+                               {
+                                       $$ = makeDefElem("dynamic_result_sets", 
(Node *)makeInteger($4), @1);
+                               }
                ;
 
 createfunc_opt_item:
@@ -12401,6 +12405,12 @@ cursor_options: /*EMPTY*/                              
        { $$ = 0; }
 opt_hold: /* EMPTY */                                          { $$ = 0; }
                        | WITH HOLD                                             
{ $$ = CURSOR_OPT_HOLD; }
                        | WITHOUT HOLD                                  { $$ = 
0; }
+                       | WITH HOLD WITH RETURN                 { $$ = 
CURSOR_OPT_HOLD | CURSOR_OPT_RETURN; }
+                       | WITHOUT HOLD WITH RETURN              { $$ = 
CURSOR_OPT_RETURN; }
+                       | WITH HOLD WITHOUT RETURN              { $$ = 
CURSOR_OPT_HOLD; }
+                       | WITHOUT HOLD WITHOUT RETURN   { $$ = 0; }
+                       | WITH RETURN                                   { $$ = 
CURSOR_OPT_RETURN; }
+                       | WITHOUT RETURN                                { $$ = 
0; }
                ;
 
 /*****************************************************************************
@@ -16722,6 +16732,7 @@ unreserved_keyword:
                        | DOMAIN_P
                        | DOUBLE_P
                        | DROP
+                       | DYNAMIC
                        | EACH
                        | ENABLE_P
                        | ENCODING
@@ -16867,6 +16878,7 @@ unreserved_keyword:
                        | RESET
                        | RESTART
                        | RESTRICT
+                       | RESULT
                        | RETURN
                        | RETURNS
                        | REVOKE
@@ -17267,6 +17279,7 @@ bare_label_keyword:
                        | DOMAIN_P
                        | DOUBLE_P
                        | DROP
+                       | DYNAMIC
                        | EACH
                        | ELSE
                        | ENABLE_P
@@ -17454,6 +17467,7 @@ bare_label_keyword:
                        | RESET
                        | RESTART
                        | RESTRICT
+                       | RESULT
                        | RETURN
                        | RETURNS
                        | REVOKE
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 27dee29f420b..e60fca128a1e 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -33,6 +33,7 @@
 #include "access/xact.h"
 #include "catalog/pg_type.h"
 #include "commands/async.h"
+#include "commands/defrem.h"
 #include "commands/prepare.h"
 #include "common/pg_prng.h"
 #include "jit/jit.h"
@@ -1072,6 +1073,7 @@ exec_simple_query(const char *query_string)
                Portal          portal;
                DestReceiver *receiver;
                int16           format;
+               ListCell   *lc;
 
                pgstat_report_query_id(0, true);
 
@@ -1233,7 +1235,7 @@ exec_simple_query(const char *query_string)
                MemoryContextSwitchTo(oldcontext);
 
                /*
-                * Run the portal to completion, and then drop it (and the 
receiver).
+                * Run the portal to completion, and then drop it.
                 */
                (void) PortalRun(portal,
                                                 FETCH_ALL,
@@ -1243,10 +1245,34 @@ exec_simple_query(const char *query_string)
                                                 receiver,
                                                 &qc);
 
-               receiver->rDestroy(receiver);
-
                PortalDrop(portal, false);
 
+               /*
+                * Run portals for dynamic result sets.
+                */
+               foreach (lc, GetReturnableCursors())
+               {
+                       Portal          dynportal = lfirst(lc);
+
+                       if (dest == DestRemote)
+                               SetRemoteDestReceiverParams(receiver, 
dynportal);
+
+                       PortalRun(dynportal,
+                                         FETCH_ALL,
+                                         true,
+                                         true,
+                                         receiver,
+                                         receiver,
+                                         NULL);
+
+                       PortalDrop(dynportal, false);
+               }
+
+               /*
+                * Drop the receiver.
+                */
+               receiver->rDestroy(receiver);
+
                if (lnext(parsetree_list, parsetree_item) == NULL)
                {
                        /*
@@ -2058,6 +2084,7 @@ exec_execute_message(const char *portal_name, long 
max_rows)
        const char *sourceText;
        const char *prepStmtName;
        ParamListInfo portalParams;
+       ListCell   *lc;
        bool            save_log_statement_stats = log_statement_stats;
        bool            is_xact_command;
        bool            execute_is_fetch;
@@ -2194,6 +2221,34 @@ exec_execute_message(const char *portal_name, long 
max_rows)
                                                  receiver,
                                                  &qc);
 
+       /*
+        * Run portals for dynamic result sets.
+        */
+       foreach (lc, GetReturnableCursors())
+       {
+               Portal dyn_portal = lfirst(lc);
+
+               if (dest == DestRemoteExecute)
+                       SetRemoteDestReceiverParams(receiver, dyn_portal);
+
+               PortalSetResultFormat(dyn_portal, 1, &portal->dynamic_format);
+
+               SendRowDescriptionMessage(&row_description_buf,
+                                                                 
dyn_portal->tupDesc,
+                                                                 
FetchPortalTargetList(dyn_portal),
+                                                                 
dyn_portal->formats);
+
+               PortalRun(dyn_portal,
+                                 FETCH_ALL,
+                                 true,
+                                 true,
+                                 receiver,
+                                 receiver,
+                                 NULL);
+
+               PortalDrop(dyn_portal, false);
+       }
+
        receiver->rDestroy(receiver);
 
        /* Done executing; remove the params error callback */
diff --git a/src/backend/tcop/pquery.c b/src/backend/tcop/pquery.c
index 5aa5a350f387..d2e55501325a 100644
--- a/src/backend/tcop/pquery.c
+++ b/src/backend/tcop/pquery.c
@@ -641,6 +641,8 @@ PortalSetResultFormat(Portal portal, int nFormats, int16 
*formats)
                                         errmsg("bind message has %d result 
formats but query has %d columns",
                                                        nFormats, natts)));
                memcpy(portal->formats, formats, natts * sizeof(int16));
+
+               portal->dynamic_format = 0;
        }
        else if (nFormats > 0)
        {
@@ -649,12 +651,16 @@ PortalSetResultFormat(Portal portal, int nFormats, int16 
*formats)
 
                for (i = 0; i < natts; i++)
                        portal->formats[i] = format1;
+
+               portal->dynamic_format = format1;
        }
        else
        {
                /* use default format for all columns */
                for (i = 0; i < natts; i++)
                        portal->formats[i] = 0;
+
+               portal->dynamic_format = 0;
        }
 }
 
diff --git a/src/backend/utils/errcodes.txt b/src/backend/utils/errcodes.txt
index 62418a051ac7..c20722e6bbdd 100644
--- a/src/backend/utils/errcodes.txt
+++ b/src/backend/utils/errcodes.txt
@@ -83,6 +83,7 @@ Section: Class 01 - Warning
 # do not use this class for failure conditions
 01000    W    ERRCODE_WARNING                                                
warning
 0100C    W    ERRCODE_WARNING_DYNAMIC_RESULT_SETS_RETURNED                   
dynamic_result_sets_returned
+0100E    W    ERRCODE_WARNING_ATTEMPT_TO_RETURN_TOO_MANY_RESULT_SETS         
attempt_to_return_too_many_result_sets
 01008    W    ERRCODE_WARNING_IMPLICIT_ZERO_BIT_PADDING                      
implicit_zero_bit_padding
 01003    W    ERRCODE_WARNING_NULL_VALUE_ELIMINATED_IN_SET_FUNCTION          
null_value_eliminated_in_set_function
 01007    W    ERRCODE_WARNING_PRIVILEGE_NOT_GRANTED                          
privilege_not_granted
diff --git a/src/backend/utils/mmgr/portalmem.c 
b/src/backend/utils/mmgr/portalmem.c
index 3a161bdb88d1..e27e082a618f 100644
--- a/src/backend/utils/mmgr/portalmem.c
+++ b/src/backend/utils/mmgr/portalmem.c
@@ -1289,3 +1289,51 @@ ForgetPortalSnapshots(void)
                elog(ERROR, "portal snapshots (%d) did not account for all 
active snapshots (%d)",
                         numPortalSnaps, numActiveSnaps);
 }
+
+static int
+cmp_portals_by_creation(const ListCell *a, const ListCell *b)
+{
+       Portal          pa = lfirst(a);
+       Portal          pb = lfirst(b);
+
+       return pa->createCid - pb->createCid;
+}
+
+List *
+GetReturnableCursors(void)
+{
+       List       *ret = NIL;
+       HASH_SEQ_STATUS status;
+       PortalHashEnt *hentry;
+
+       hash_seq_init(&status, PortalHashTable);
+
+       while ((hentry = (PortalHashEnt *) hash_seq_search(&status)) != NULL)
+       {
+               Portal          portal = hentry->portal;
+
+               if (portal->cursorOptions & CURSOR_OPT_RETURN)
+                       ret = lappend(ret, portal);
+       }
+
+       list_sort(ret, cmp_portals_by_creation);
+
+       return ret;
+}
+
+void
+CloseOtherReturnableCursors(Oid procid)
+{
+       HASH_SEQ_STATUS status;
+       PortalHashEnt *hentry;
+
+       hash_seq_init(&status, PortalHashTable);
+
+       while ((hentry = (PortalHashEnt *) hash_seq_search(&status)) != NULL)
+       {
+               Portal          portal = hentry->portal;
+
+               if (portal->cursorOptions & CURSOR_OPT_RETURN && portal->procId 
!= procid)
+                       PortalDrop(portal, false);
+       }
+}
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index bd9b066e4eb8..e6d17aedc345 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -11573,6 +11573,7 @@ dumpFunc(Archive *fout, const FuncInfo *finfo)
        char       *prorows;
        char       *prosupport;
        char       *proparallel;
+       int                     prodynres;
        char       *lanname;
        char      **configitems = NULL;
        int                     nconfigitems = 0;
@@ -11640,10 +11641,17 @@ dumpFunc(Archive *fout, const FuncInfo *finfo)
 
                if (fout->remoteVersion >= 140000)
                        appendPQExpBufferStr(query,
-                                                                
"pg_get_function_sqlbody(p.oid) AS prosqlbody\n");
+                                                                
"pg_get_function_sqlbody(p.oid) AS prosqlbody,\n");
                else
                        appendPQExpBufferStr(query,
-                                                                "NULL AS 
prosqlbody\n");
+                                                                "NULL AS 
prosqlbody,\n");
+
+               if (fout->remoteVersion >= 160000)
+                       appendPQExpBufferStr(query,
+                                                                "prodynres\n");
+               else
+                       appendPQExpBufferStr(query,
+                                                                "0 AS 
prodynres\n");
 
                appendPQExpBufferStr(query,
                                                         "FROM 
pg_catalog.pg_proc p, pg_catalog.pg_language l\n"
@@ -11688,6 +11696,7 @@ dumpFunc(Archive *fout, const FuncInfo *finfo)
        prorows = PQgetvalue(res, 0, PQfnumber(res, "prorows"));
        prosupport = PQgetvalue(res, 0, PQfnumber(res, "prosupport"));
        proparallel = PQgetvalue(res, 0, PQfnumber(res, "proparallel"));
+       prodynres = atoi(PQgetvalue(res, 0, PQfnumber(res, "prodynres")));
        lanname = PQgetvalue(res, 0, PQfnumber(res, "lanname"));
 
        /*
@@ -11806,6 +11815,9 @@ dumpFunc(Archive *fout, const FuncInfo *finfo)
        if (proisstrict[0] == 't')
                appendPQExpBufferStr(q, " STRICT");
 
+       if (prodynres > 0)
+               appendPQExpBuffer(q, " DYNAMIC RESULT SETS %d", prodynres);
+
        if (prosecdef[0] == 't')
                appendPQExpBufferStr(q, " SECURITY DEFINER");
 
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 76310d4cc9a1..c5d2f5beba82 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -76,6 +76,9 @@ CATALOG(pg_proc,1255,ProcedureRelationId) BKI_BOOTSTRAP 
BKI_ROWTYPE_OID(81,Proce
        /* see PROPARALLEL_ categories below */
        char            proparallel BKI_DEFAULT(s);
 
+       /* maximum number of dynamic result sets */
+       int32           prodynres BKI_DEFAULT(0);
+
        /* number of arguments */
        /* Note: need not be given in pg_proc.dat; genbki.pl will compute it */
        int16           pronargs;
@@ -211,7 +214,8 @@ extern ObjectAddress ProcedureCreate(const char 
*procedureName,
                                                                         Datum 
proconfig,
                                                                         Oid 
prosupport,
                                                                         float4 
procost,
-                                                                        float4 
prorows);
+                                                                        float4 
prorows,
+                                                                        int 
dynres);
 
 extern bool function_parse_error_transpose(const char *prosrc);
 
diff --git a/src/include/commands/defrem.h b/src/include/commands/defrem.h
index 56d2bb661612..84591a529bc7 100644
--- a/src/include/commands/defrem.h
+++ b/src/include/commands/defrem.h
@@ -57,6 +57,7 @@ extern ObjectAddress CreateTransform(CreateTransformStmt 
*stmt);
 extern void IsThereFunctionInNamespace(const char *proname, int pronargs,
                                                                           
oidvector *proargtypes, Oid nspOid);
 extern void ExecuteDoStmt(ParseState *pstate, DoStmt *stmt, bool atomic);
+extern Oid     CurrentProcedure(void);
 extern void ExecuteCallStmt(CallStmt *stmt, ParamListInfo params, bool atomic, 
DestReceiver *dest);
 extern TupleDesc CallStmtResultDesc(CallStmt *stmt);
 extern Oid     get_transform_oid(Oid type_id, Oid lang_id, bool missing_ok);
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 633e7671b3ea..ef10e2ff78dd 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2899,6 +2899,7 @@ typedef struct SecLabelStmt
 #define CURSOR_OPT_INSENSITIVE 0x0008  /* INSENSITIVE */
 #define CURSOR_OPT_ASENSITIVE  0x0010  /* ASENSITIVE */
 #define CURSOR_OPT_HOLD                        0x0020  /* WITH HOLD */
+#define CURSOR_OPT_RETURN              0x0040  /* WITH RETURN */
 /* these planner-control flags do not correspond to any SQL grammar: */
 #define CURSOR_OPT_FAST_PLAN   0x0100  /* prefer fast-start plan */
 #define CURSOR_OPT_GENERIC_PLAN 0x0200 /* force use of generic plan */
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index ccc927851cb9..9cf45a02d3f9 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -144,6 +144,7 @@ PG_KEYWORD("document", DOCUMENT_P, UNRESERVED_KEYWORD, 
BARE_LABEL)
 PG_KEYWORD("domain", DOMAIN_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("double", DOUBLE_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("drop", DROP, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("dynamic", DYNAMIC, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("each", EACH, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("else", ELSE, RESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("enable", ENABLE_P, UNRESERVED_KEYWORD, BARE_LABEL)
@@ -353,6 +354,7 @@ PG_KEYWORD("replica", REPLICA, UNRESERVED_KEYWORD, 
BARE_LABEL)
 PG_KEYWORD("reset", RESET, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("restart", RESTART, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("restrict", RESTRICT, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("result", RESULT, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("return", RETURN, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("returning", RETURNING, RESERVED_KEYWORD, AS_LABEL)
 PG_KEYWORD("returns", RETURNS, UNRESERVED_KEYWORD, BARE_LABEL)
diff --git a/src/include/utils/portal.h b/src/include/utils/portal.h
index aeddbdafe56a..eed9bb372dbc 100644
--- a/src/include/utils/portal.h
+++ b/src/include/utils/portal.h
@@ -132,6 +132,16 @@ typedef struct PortalData
        SubTransactionId activeSubid;   /* the last subxact with activity */
        int                     createLevel;    /* creating subxact's nesting 
level */
 
+       /*
+        * Procedure that created this portal.  Used for returnable cursors.
+        */
+       Oid                             procId;
+       /*
+        * Command ID where the portal was created.  Used for sorting returnable
+        * cursors into creation order.
+        */
+       CommandId               createCid;
+
        /* The query or queries the portal will execute */
        const char *sourceText;         /* text of query (as of 8.4, never 
NULL) */
        CommandTag      commandTag;             /* command tag for original 
query */
@@ -160,6 +170,8 @@ typedef struct PortalData
        TupleDesc       tupDesc;                /* descriptor for result tuples 
*/
        /* and these are the format codes to use for the columns: */
        int16      *formats;            /* a format code for each column */
+       /* Format code for dynamic result sets */
+       int16           dynamic_format;
 
        /*
         * Outermost ActiveSnapshot for execution of the portal's queries.  For
@@ -248,5 +260,7 @@ extern void PortalHashTableDeleteAll(void);
 extern bool ThereAreNoReadyPortals(void);
 extern void HoldPinnedPortals(void);
 extern void ForgetPortalSnapshots(void);
+extern List *GetReturnableCursors(void);
+extern void CloseOtherReturnableCursors(Oid procid);
 
 #endif                                                 /* PORTAL_H */
diff --git a/src/interfaces/libpq/fe-protocol3.c 
b/src/interfaces/libpq/fe-protocol3.c
index f001137b7692..0fa4c9537bd1 100644
--- a/src/interfaces/libpq/fe-protocol3.c
+++ b/src/interfaces/libpq/fe-protocol3.c
@@ -324,10 +324,8 @@ pqParseInput3(PGconn *conn)
                                        {
                                                /*
                                                 * A new 'T' message is treated 
as the start of
-                                                * another PGresult.  (It is 
not clear that this is
-                                                * really possible with the 
current backend.) We stop
-                                                * parsing until the 
application accepts the current
-                                                * result.
+                                                * another PGresult.  We stop 
parsing until the
+                                                * application accepts the 
current result.
                                                 */
                                                conn->asyncStatus = 
PGASYNC_READY;
                                                return;
diff --git a/src/pl/plpgsql/src/expected/plpgsql_call.out 
b/src/pl/plpgsql/src/expected/plpgsql_call.out
index 1ec6182a8da8..1c8872a75470 100644
--- a/src/pl/plpgsql/src/expected/plpgsql_call.out
+++ b/src/pl/plpgsql/src/expected/plpgsql_call.out
@@ -466,3 +466,81 @@ BEGIN
 END;
 $$;
 NOTICE:  <NULL>
+-- dynamic result sets
+CREATE TABLE cp_test2 (a int);
+INSERT INTO cp_test2 VALUES (1), (2), (3);
+CREATE TABLE cp_test3 (x text, y text);
+INSERT INTO cp_test3 VALUES ('abc', 'def'), ('foo', 'bar');
+CREATE PROCEDURE pdrstest1(x int)
+LANGUAGE plpgsql
+DYNAMIC RESULT SETS 2
+AS $$
+DECLARE
+  c1 CURSOR WITH RETURN (y int) FOR SELECT a * y AS ay FROM cp_test2;
+  c2 CURSOR WITH RETURN FOR SELECT * FROM cp_test3;
+BEGIN
+  OPEN c1(x);
+  IF x > 1 THEN
+    OPEN c2;
+  END IF;
+END;
+$$;
+CALL pdrstest1(1);
+ ay 
+----
+  1
+  2
+  3
+(3 rows)
+
+CALL pdrstest1(2);
+ ay 
+----
+  2
+  4
+  6
+(3 rows)
+
+  x  |  y  
+-----+-----
+ abc | def
+ foo | bar
+(2 rows)
+
+CREATE PROCEDURE pdrstest2(x int)
+LANGUAGE plpgsql
+DYNAMIC RESULT SETS 2
+AS $$
+DECLARE
+  c1 refcursor;
+  c2 refcursor;
+BEGIN
+  OPEN c1 WITH RETURN FOR SELECT a * x AS ax FROM cp_test2;
+  IF x > 1 THEN
+    OPEN c2 SCROLL WITH RETURN FOR SELECT * FROM cp_test3;
+  END IF;
+END;
+$$;
+CALL pdrstest2(1);
+ ax 
+----
+  1
+  2
+  3
+(3 rows)
+
+CALL pdrstest2(2);
+ ax 
+----
+  2
+  4
+  6
+(3 rows)
+
+  x  |  y  
+-----+-----
+ abc | def
+ foo | bar
+(2 rows)
+
+DROP TABLE cp_test2, cp_test3;
diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c
index a64734294805..07d21ad8ed79 100644
--- a/src/pl/plpgsql/src/pl_exec.c
+++ b/src/pl/plpgsql/src/pl_exec.c
@@ -4776,6 +4776,12 @@ exec_stmt_open(PLpgSQL_execstate *estate, 
PLpgSQL_stmt_open *stmt)
                elog(ERROR, "could not open cursor: %s",
                         SPI_result_code_string(SPI_result));
 
+       if (portal->cursorOptions & CURSOR_OPT_RETURN)
+       {
+               portal->procId = estate->func->fn_oid;
+               portal->createCid = GetCurrentCommandId(true);
+       }
+
        /*
         * If cursor variable was NULL, store the generated portal name in it,
         * after verifying it's okay to assign to.
diff --git a/src/pl/plpgsql/src/pl_gram.y b/src/pl/plpgsql/src/pl_gram.y
index f7cf2b4b899a..e5e9222d3ec3 100644
--- a/src/pl/plpgsql/src/pl_gram.y
+++ b/src/pl/plpgsql/src/pl_gram.y
@@ -212,7 +212,7 @@ static      void                    
check_raise_parameters(PLpgSQL_stmt_raise *stmt);
 %type <datum>  getdiag_target
 %type <ival>   getdiag_item
 
-%type <ival>   opt_scrollable
+%type <ival>   opt_scrollable opt_with_return
 %type <fetch>  opt_fetch_direction
 
 %type <ival>   opt_transaction_chain
@@ -352,6 +352,8 @@ static      void                    
check_raise_parameters(PLpgSQL_stmt_raise *stmt);
 %token <keyword>       K_WARNING
 %token <keyword>       K_WHEN
 %token <keyword>       K_WHILE
+%token <keyword>       K_WITH
+%token <keyword>       K_WITHOUT
 
 %%
 
@@ -529,7 +531,7 @@ decl_statement      : decl_varname decl_const decl_datatype 
decl_collate decl_notnull
                                                plpgsql_ns_additem($4->itemtype,
                                                                                
   $4->itemno, $1.name);
                                        }
-                               | decl_varname opt_scrollable K_CURSOR
+                               | decl_varname opt_scrollable K_CURSOR 
opt_with_return
                                        { plpgsql_ns_push($1.name, 
PLPGSQL_LABEL_OTHER); }
                                  decl_cursor_args decl_is_for decl_cursor_query
                                        {
@@ -573,12 +575,12 @@ decl_statement    : decl_varname decl_const decl_datatype 
decl_collate decl_notnull
                                                curname_def->parseMode = 
RAW_PARSE_PLPGSQL_EXPR;
                                                new->default_val = curname_def;
 
-                                               new->cursor_explicit_expr = $7;
-                                               if ($5 == NULL)
+                                               new->cursor_explicit_expr = $8;
+                                               if ($6 == NULL)
                                                        
new->cursor_explicit_argrow = -1;
                                                else
-                                                       
new->cursor_explicit_argrow = $5->dno;
-                                               new->cursor_options = 
CURSOR_OPT_FAST_PLAN | $2;
+                                                       
new->cursor_explicit_argrow = $6->dno;
+                                               new->cursor_options = 
CURSOR_OPT_FAST_PLAN | $2 | $4;
                                        }
                                ;
 
@@ -596,6 +598,20 @@ opt_scrollable :
                                        }
                                ;
 
+opt_with_return :
+                                       {
+                                               $$ = 0;
+                                       }
+                               | K_WITH K_RETURN
+                                       {
+                                               $$ = CURSOR_OPT_RETURN;
+                                       }
+                               | K_WITHOUT K_RETURN
+                                       {
+                                               $$ = 0;
+                                       }
+                               ;
+
 decl_cursor_query :
                                        {
                                                $$ = read_sql_stmt();
@@ -2003,6 +2019,10 @@ stmt_execsql     : K_IMPORT
                                        {
                                                $$ = make_execsql_stmt(K_MERGE, 
@1);
                                        }
+                               | K_WITH
+                                       {
+                                               $$ = make_execsql_stmt(K_WITH, 
@1);
+                                       }
                                | T_WORD
                                        {
                                                int                     tok;
@@ -2125,6 +2145,30 @@ stmt_open                : K_OPEN cursor_variable
                                                                tok = yylex();
                                                        }
 
+                                                       /* same for 
opt_with_return */
+                                                       if (tok_is_keyword(tok, 
&yylval,
+                                                                               
           K_WITH, "with"))
+                                                       {
+                                                               tok = yylex();
+                                                               if 
(tok_is_keyword(tok, &yylval,
+                                                                               
                   K_RETURN, "return"))
+                                                               {
+                                                                       
new->cursor_options |= CURSOR_OPT_RETURN;
+                                                                       tok = 
yylex();
+                                                               }
+                                                       }
+                                                       else if 
(tok_is_keyword(tok, &yylval,
+                                                                               
           K_WITHOUT, "without"))
+                                                       {
+                                                               tok = yylex();
+                                                               if 
(tok_is_keyword(tok, &yylval,
+                                                                               
                   K_RETURN, "return"))
+                                                               {
+                                                                       
new->cursor_options |= 0;
+                                                                       tok = 
yylex();
+                                                               }
+                                                       }
+
                                                        if (tok != K_FOR)
                                                                yyerror("syntax 
error, expected \"FOR\"");
 
@@ -2579,6 +2623,8 @@ unreserved_keyword        :
                                | K_USE_VARIABLE
                                | K_VARIABLE_CONFLICT
                                | K_WARNING
+                               | K_WITH
+                               | K_WITHOUT
                                ;
 
 %%
diff --git a/src/pl/plpgsql/src/pl_unreserved_kwlist.h 
b/src/pl/plpgsql/src/pl_unreserved_kwlist.h
index ee2be1b212b4..daf0b1081de0 100644
--- a/src/pl/plpgsql/src/pl_unreserved_kwlist.h
+++ b/src/pl/plpgsql/src/pl_unreserved_kwlist.h
@@ -109,3 +109,5 @@ PG_KEYWORD("use_column", K_USE_COLUMN)
 PG_KEYWORD("use_variable", K_USE_VARIABLE)
 PG_KEYWORD("variable_conflict", K_VARIABLE_CONFLICT)
 PG_KEYWORD("warning", K_WARNING)
+PG_KEYWORD("with", K_WITH)
+PG_KEYWORD("without", K_WITHOUT)
diff --git a/src/pl/plpgsql/src/sql/plpgsql_call.sql 
b/src/pl/plpgsql/src/sql/plpgsql_call.sql
index 502839834803..9ace9d4e0676 100644
--- a/src/pl/plpgsql/src/sql/plpgsql_call.sql
+++ b/src/pl/plpgsql/src/sql/plpgsql_call.sql
@@ -436,3 +436,49 @@ CREATE PROCEDURE p1(v_cnt int, v_Text inout text = NULL)
   RAISE NOTICE '%', v_Text;
 END;
 $$;
+
+
+-- dynamic result sets
+
+CREATE TABLE cp_test2 (a int);
+INSERT INTO cp_test2 VALUES (1), (2), (3);
+CREATE TABLE cp_test3 (x text, y text);
+INSERT INTO cp_test3 VALUES ('abc', 'def'), ('foo', 'bar');
+
+CREATE PROCEDURE pdrstest1(x int)
+LANGUAGE plpgsql
+DYNAMIC RESULT SETS 2
+AS $$
+DECLARE
+  c1 CURSOR WITH RETURN (y int) FOR SELECT a * y AS ay FROM cp_test2;
+  c2 CURSOR WITH RETURN FOR SELECT * FROM cp_test3;
+BEGIN
+  OPEN c1(x);
+  IF x > 1 THEN
+    OPEN c2;
+  END IF;
+END;
+$$;
+
+CALL pdrstest1(1);
+CALL pdrstest1(2);
+
+CREATE PROCEDURE pdrstest2(x int)
+LANGUAGE plpgsql
+DYNAMIC RESULT SETS 2
+AS $$
+DECLARE
+  c1 refcursor;
+  c2 refcursor;
+BEGIN
+  OPEN c1 WITH RETURN FOR SELECT a * x AS ax FROM cp_test2;
+  IF x > 1 THEN
+    OPEN c2 SCROLL WITH RETURN FOR SELECT * FROM cp_test3;
+  END IF;
+END;
+$$;
+
+CALL pdrstest2(1);
+CALL pdrstest2(2);
+
+DROP TABLE cp_test2, cp_test3;
diff --git a/src/test/regress/expected/create_procedure.out 
b/src/test/regress/expected/create_procedure.out
index 46c827f9791c..b3802bd7c1db 100644
--- a/src/test/regress/expected/create_procedure.out
+++ b/src/test/regress/expected/create_procedure.out
@@ -375,9 +375,92 @@ ALTER ROUTINE cp_testfunc1a RENAME TO cp_testfunc1;
 ALTER ROUTINE ptest1(text) RENAME TO ptest1a;
 ALTER ROUTINE ptest1a RENAME TO ptest1;
 DROP ROUTINE cp_testfunc1(int);
+-- dynamic result sets
+CREATE TABLE cp_test2 (a int);
+INSERT INTO cp_test2 VALUES (1), (2), (3);
+CREATE TABLE cp_test3 (x text, y text);
+INSERT INTO cp_test3 VALUES ('abc', 'def'), ('foo', 'bar');
+CREATE PROCEDURE pdrstest1()
+LANGUAGE SQL
+DYNAMIC RESULT SETS 2
+AS $$
+DECLARE c1 CURSOR WITH RETURN FOR SELECT * FROM cp_test2;
+DECLARE c2 CURSOR WITH RETURN FOR SELECT * FROM cp_test3;
+$$;
+CALL pdrstest1();
+ a 
+---
+ 1
+ 2
+ 3
+(3 rows)
+
+  x  |  y  
+-----+-----
+ abc | def
+ foo | bar
+(2 rows)
+
+CREATE PROCEDURE pdrstest2()
+LANGUAGE SQL
+DYNAMIC RESULT SETS 1
+AS $$
+CALL pdrstest1();
+DECLARE c3 CURSOR WITH RETURN FOR SELECT * FROM cp_test2 WHERE a < 2;
+$$;
+CALL pdrstest2();
+ a 
+---
+ 1
+(1 row)
+
+CREATE PROCEDURE pdrstest3(INOUT a text)
+LANGUAGE SQL
+DYNAMIC RESULT SETS 1
+AS $$
+DECLARE c4 CURSOR WITH RETURN FOR SELECT * FROM cp_test2;
+SELECT a || a;
+$$;
+CALL pdrstest3('x');
+ a  
+----
+ xx
+(1 row)
+
+ a 
+---
+ 1
+ 2
+ 3
+(3 rows)
+
+-- test the nested error handling
+CREATE TABLE cp_test_dummy (a int);
+CREATE PROCEDURE pdrstest4a()
+LANGUAGE SQL
+DYNAMIC RESULT SETS 1
+AS $$
+DECLARE c5a CURSOR WITH RETURN FOR SELECT * FROM cp_test_dummy;
+$$;
+CREATE PROCEDURE pdrstest4b()
+LANGUAGE SQL
+DYNAMIC RESULT SETS 1
+AS $$
+CALL pdrstest4a();
+$$;
+DROP TABLE cp_test_dummy;
+CALL pdrstest4b();
+ERROR:  relation "cp_test_dummy" does not exist
+LINE 2: DECLARE c5a CURSOR WITH RETURN FOR SELECT * FROM cp_test_dum...
+                                                         ^
+QUERY:  
+DECLARE c5a CURSOR WITH RETURN FOR SELECT * FROM cp_test_dummy;
+
+CONTEXT:  SQL function "pdrstest4a" during startup
+SQL function "pdrstest4b" statement 1
 -- cleanup
 DROP PROCEDURE ptest1;
 DROP PROCEDURE ptest1s;
 DROP PROCEDURE ptest2;
-DROP TABLE cp_test;
+DROP TABLE cp_test, cp_test2, cp_test3;
 DROP USER regress_cp_user1;
diff --git a/src/test/regress/sql/create_procedure.sql 
b/src/test/regress/sql/create_procedure.sql
index 75cc0fcf2a6c..c3970726a6e0 100644
--- a/src/test/regress/sql/create_procedure.sql
+++ b/src/test/regress/sql/create_procedure.sql
@@ -242,12 +242,71 @@ CREATE USER regress_cp_user1;
 DROP ROUTINE cp_testfunc1(int);
 
 
+-- dynamic result sets
+
+CREATE TABLE cp_test2 (a int);
+INSERT INTO cp_test2 VALUES (1), (2), (3);
+CREATE TABLE cp_test3 (x text, y text);
+INSERT INTO cp_test3 VALUES ('abc', 'def'), ('foo', 'bar');
+
+CREATE PROCEDURE pdrstest1()
+LANGUAGE SQL
+DYNAMIC RESULT SETS 2
+AS $$
+DECLARE c1 CURSOR WITH RETURN FOR SELECT * FROM cp_test2;
+DECLARE c2 CURSOR WITH RETURN FOR SELECT * FROM cp_test3;
+$$;
+
+CALL pdrstest1();
+
+CREATE PROCEDURE pdrstest2()
+LANGUAGE SQL
+DYNAMIC RESULT SETS 1
+AS $$
+CALL pdrstest1();
+DECLARE c3 CURSOR WITH RETURN FOR SELECT * FROM cp_test2 WHERE a < 2;
+$$;
+
+CALL pdrstest2();
+
+CREATE PROCEDURE pdrstest3(INOUT a text)
+LANGUAGE SQL
+DYNAMIC RESULT SETS 1
+AS $$
+DECLARE c4 CURSOR WITH RETURN FOR SELECT * FROM cp_test2;
+SELECT a || a;
+$$;
+
+CALL pdrstest3('x');
+
+-- test the nested error handling
+CREATE TABLE cp_test_dummy (a int);
+
+CREATE PROCEDURE pdrstest4a()
+LANGUAGE SQL
+DYNAMIC RESULT SETS 1
+AS $$
+DECLARE c5a CURSOR WITH RETURN FOR SELECT * FROM cp_test_dummy;
+$$;
+
+CREATE PROCEDURE pdrstest4b()
+LANGUAGE SQL
+DYNAMIC RESULT SETS 1
+AS $$
+CALL pdrstest4a();
+$$;
+
+DROP TABLE cp_test_dummy;
+
+CALL pdrstest4b();
+
+
 -- cleanup
 
 DROP PROCEDURE ptest1;
 DROP PROCEDURE ptest1s;
 DROP PROCEDURE ptest2;
 
-DROP TABLE cp_test;
+DROP TABLE cp_test, cp_test2, cp_test3;
 
 DROP USER regress_cp_user1;

base-commit: 39b8c293fcde1d845da4d7127a25d41df53faab5
-- 
2.37.3

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