Subject: POC: PLpgSQL FOREACH IN JSON ARRAY

From: Pavel Stehule <[email-masked]>
Date: Sat, 28 Feb 2026 08:10:53 +0100

Hi

I wrote PoC for previously proposed plpgsql statement FOREACH IN JSON ARRAY

It looks like:

do $$
declare x int;
begin
  foreach x in json array '[1,2,3,4]'
  loop
    raise notice 'x: %', x;
  end loop;
end;
$$

do $$
declare x int; y int;
begin
  foreach x, y in json array '[{"x": 100, "y": 1000}, {"y": 1000, "x":
100}]'
  loop
    raise notice 'x: %, y: %', x, y;
  end loop;
end
$$

My first motivation for this patch is performance. This is faster (3 - 4 x)
than using FOR IN SELECT FROM json_array_elements, because there is no
overhead of SQL executor. Second motivation is a little bit better
readability, because inside plpgsql' statements we have info about used
variables and we can use it.

The behavior is very similar to FOREACH IN ARRAY with one significant
difference - the values of JSON objects are assigned to the composite
variable or lists of variables by names (not by position). It made this
decision because jsonb doesn't preserve the position of the field in
object, and then assignment based on position cannot work.

The code is relatively short now - about 400 lines +/- and the code is
simple without risks.

There are some open questions - mainly if default mode for mapping json
fields to plpgsql variables should be in lax or strict mode. Now, it is
something between (cast errors are raised) - it is consistent
with jsonb_populate_record - but it should not be the final design. I
cannot say what is better - currently implemented behavior is consistent
with common plpgsql behaviour, but SQL/JSON is different. I can imagine
that default behaviour will be lax, and with some optional clauses we can
push behave to strict mode. I have no strong opinion about it. Maybe I
prefer the current "strict" behaviour a little bit, because it is more
"safe", but it is only my personal opinion. But again, I have no strong
opinion about this question and I very much invite any discussion about it.

This is proof of concept patch - casting between plpgsql arrays and json
arrays is not supported, documentation and regress tests are minimalistic,
but it is good enough for testing and good enough for decision, if this
feature is wanted or not (or if it needs some modifications).

This is a new feature (and proprietary feature). There should not be any
compatibility issues.

What do you think about this feature?

Regards

Pavel
From c9f041e5408351961425eabeef161c4b72b93d1c Mon Sep 17 00:00:00 2001
From: "[email-masked]" <[email-masked]>
Date: Mon, 23 Feb 2026 12:53:44 +0100
Subject: [PATCH] FOREACH scalar IN JSON ARRAY

this patch introduce FOREACH scalar_var IN JSON ARRAY. The design is based
on behave of jsonb_array_elements functions. In this case, FOREACH enforce
casting to target type (because we know target type) and try to reduce
IO casting. Attention: IO casting can be more strict, then casting based
on cast functions.

DECLARE t int;
BEGIN
  -- this can work because we use cast numeric -> int
  FOREACH t IN JSON ARRAY '[1,2,3.14]'
  LOOP

  -- this fails, because IO cast is used, and integer input function
  -- allows only digits
  FOREAC t IN JSON ARRAY '[1,2,3,"3.14"]'
  LOOP

Conceptual question is if casting should be strict like "old" PostgreSQL
json function or lax as "new" SQL/JSON functions? I can imagine lax mode
as default with possibility to switch to strict mode (this is not implemented
now):

  FOREACH t IN JSON ARRAY '[1,2,3]' ERROR ON EMPTY ERROR ON ERROR
  LOOP
    ...

The performance (best case for iteration over 1000 fields array) is about
4x better than when FOR IN SELECT jsonb_array_elements is used.
---
 doc/src/sgml/plpgsql.sgml                     |  63 ++++
 src/backend/utils/adt/jsonb_util.c            |   1 +
 src/pl/plpgsql/src/Makefile                   |   2 +-
 .../plpgsql/src/expected/plpgsql_foreach.out  | 119 +++++++
 src/pl/plpgsql/src/meson.build                |   1 +
 src/pl/plpgsql/src/pl_comp.c                  |   4 +-
 src/pl/plpgsql/src/pl_exec.c                  | 296 +++++++++++++++++-
 src/pl/plpgsql/src/pl_funcs.c                 |  29 ++
 src/pl/plpgsql/src/pl_gram.y                  |  39 ++-
 src/pl/plpgsql/src/pl_unreserved_kwlist.h     |   1 +
 src/pl/plpgsql/src/plpgsql.h                  |  35 ++-
 src/pl/plpgsql/src/sql/plpgsql_foreach.sql    |  89 ++++++
 12 files changed, 669 insertions(+), 10 deletions(-)
 create mode 100644 src/pl/plpgsql/src/expected/plpgsql_foreach.out
 create mode 100644 src/pl/plpgsql/src/sql/plpgsql_foreach.sql

diff --git a/doc/src/sgml/plpgsql.sgml b/doc/src/sgml/plpgsql.sgml
index 561f6e50d63..c11f44676bf 100644
--- a/doc/src/sgml/plpgsql.sgml
+++ b/doc/src/sgml/plpgsql.sgml
@@ -2780,6 +2780,69 @@ NOTICE:  row = {10,11,12}
     </para>
    </sect2>
 
+   <sect2 id="plpgsql-foreach-json-array">
+    <title>Looping through JSON arrays</title>
+
+    <para>
+     The <literal>FOREACH</literal> loop is much like a <literal>FOREACH</literal> loop,
+     but instead of iterating through elements of the array,
+     it iterates through the elements of an JSON array value
+     (expression is internaly casted to jsonb type).
+
+<synopsis>
+<optional> &lt;&lt;<replaceable>label</replaceable>&gt;&gt; </optional>
+FOREACH <replaceable>target</replaceable> IN JSON ARRAY <replaceable>expression</replaceable> LOOP
+    <replaceable>statements</replaceable>
+END LOOP <optional> <replaceable>label</replaceable> </optional>;
+</synopsis>
+    </para>
+
+    <para>
+     Target can be scalar variable, composite variable or list of
+     scalar variables. When variable is not scalar, then assigned value
+     should be a JSON object and the JSON attributes are assigned by names.
+
+<programlisting>
+CREATE FUNCTION scan_rows(jsonb) RETURNS void AS $$
+DECLARE
+  x int;
+BEGIN
+  FOREACH x IN JSON ARRAY $1
+  LOOP
+    RAISE NOTICE 'row = %', x;
+  END LOOP;
+END;
+$$ LANGUAGE plpgsql;
+
+SELECT scan_rows('[1,2,3]');
+NOTICE:  row = 1
+NOTICE:  row = 2
+NOTICE:  row = 3
+
+CREATE FUNCTION scan_rows(jsonb) RETURNS void AS $$
+DECLARE
+  x int; y varchar;
+BEGIN
+  FOREACH x, y IN JSON ARRAY $1
+  LOOP
+    RAISE NOTICE 'x: %, y: %', x, y;
+  END LOOP;
+END;
+$$ LANGUAGE plpgsql;
+
+SELECT scan_rows('[{},{"x":10},{"y":"Hi"},{"y":"Hi", "x":1000}]');
+NOTICE:  x: &lt;NULL&gt;, y: &lt;NULL&gt;
+NOTICE:  x: 10, y: &lt;NULL&gt;
+NOTICE:  x: &lt;NULL&gt;, y: Hi
+NOTICE:  x: 1000, y: Hi
+</programlisting>
+    </para>
+
+    <para>
+     Assigning to PLpgSQL array variables is not supported.
+    </para>
+   </sect2>
+
    <sect2 id="plpgsql-error-trapping">
     <title>Trapping Errors</title>
 
diff --git a/src/backend/utils/adt/jsonb_util.c b/src/backend/utils/adt/jsonb_util.c
index 91fb9ea09bf..7513b1198dd 100644
--- a/src/backend/utils/adt/jsonb_util.c
+++ b/src/backend/utils/adt/jsonb_util.c
@@ -18,6 +18,7 @@
 #include "common/hashfn.h"
 #include "miscadmin.h"
 #include "port/pg_bitutils.h"
+#include "utils/builtins.h"
 #include "utils/date.h"
 #include "utils/datetime.h"
 #include "utils/datum.h"
diff --git a/src/pl/plpgsql/src/Makefile b/src/pl/plpgsql/src/Makefile
index 63cb96fae3e..5bd0cf31dfc 100644
--- a/src/pl/plpgsql/src/Makefile
+++ b/src/pl/plpgsql/src/Makefile
@@ -35,7 +35,7 @@ REGRESS_OPTS = --dbname=$(PL_TESTDB)
 REGRESS = plpgsql_array plpgsql_cache plpgsql_call plpgsql_control \
 	plpgsql_copy plpgsql_domain plpgsql_misc \
 	plpgsql_record plpgsql_simple plpgsql_transaction \
-	plpgsql_trap plpgsql_trigger plpgsql_varprops
+	plpgsql_trap plpgsql_trigger plpgsql_varprops plpgsql_foreach
 
 # where to find gen_keywordlist.pl and subsidiary files
 TOOLSDIR = $(top_srcdir)/src/tools
diff --git a/src/pl/plpgsql/src/expected/plpgsql_foreach.out b/src/pl/plpgsql/src/expected/plpgsql_foreach.out
new file mode 100644
index 00000000000..43ae84412f1
--- /dev/null
+++ b/src/pl/plpgsql/src/expected/plpgsql_foreach.out
@@ -0,0 +1,119 @@
+-- numeric to numeric
+do $$
+declare x numeric;
+begin
+  foreach x in json array '[10,20,30,3.14, null]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+NOTICE:  10
+NOTICE:  20
+NOTICE:  30
+NOTICE:  3.14
+NOTICE:  <NULL>
+-- numeric to int by cast
+do $$
+declare x int;
+begin
+  foreach x in json array '[10,20,30,3.14, null]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+NOTICE:  10
+NOTICE:  20
+NOTICE:  30
+NOTICE:  3
+NOTICE:  <NULL>
+-- conversion "3.14" to int should to fail due IO cast
+do $$
+declare x int;
+begin
+  foreach x in json array '["10",20,30,"3.14"]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+NOTICE:  10
+NOTICE:  20
+NOTICE:  30
+ERROR:  invalid input syntax for type integer: "3.14"
+CONTEXT:  PL/pgSQL function inline_code_block line 4 at FOREACH over json array
+-- jsonb to jsonb
+do $$
+declare x jsonb;
+begin
+  foreach x in json array '[10,20,30,3.14, null, "Hi"]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+NOTICE:  10
+NOTICE:  20
+NOTICE:  30
+NOTICE:  3.14
+NOTICE:  null
+NOTICE:  "Hi"
+-- jsonb to json
+do $$
+declare x json;
+begin
+  foreach x in json array '[10,20,30,3.14, null, "Hi"]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+NOTICE:  10
+NOTICE:  20
+NOTICE:  30
+NOTICE:  3.14
+NOTICE:  null
+NOTICE:  "Hi"
+-- iteration over composites
+do $$
+declare x int; y numeric; z varchar;
+begin
+  foreach x, y, z in json array '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]'
+  loop
+    raise notice 'x: %, y: %, z: %', x, y, z;
+  end loop;
+end;
+$$;
+NOTICE:  x: <NULL>, y: <NULL>, z: <NULL>
+NOTICE:  x: <NULL>, y: <NULL>, z: Hi
+NOTICE:  x: <NULL>, y: 3.14, z: <NULL>
+NOTICE:  x: 10, y: 3.14, z: Hi
+create type t3 as (x int, y numeric, z varchar);
+do $$
+declare c t3;
+begin
+  foreach c in json array '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]'
+  loop
+    raise notice 'x: %, y: %, z: %', c.x, c.y, c.z;
+  end loop;
+end;
+$$;
+NOTICE:  x: <NULL>, y: <NULL>, z: <NULL>
+NOTICE:  x: <NULL>, y: <NULL>, z: Hi
+NOTICE:  x: <NULL>, y: 3.14, z: <NULL>
+NOTICE:  x: 10, y: 3.14, z: Hi
+do $$
+declare c t3;
+begin
+  foreach c.x, c.y, c.z in json array '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]'
+  loop
+    raise notice 'x: %, y: %, z: %', c.x, c.y, c.z;
+  end loop;
+end;
+$$;
+NOTICE:  x: <NULL>, y: <NULL>, z: <NULL>
+NOTICE:  x: <NULL>, y: <NULL>, z: Hi
+NOTICE:  x: <NULL>, y: 3.14, z: <NULL>
+NOTICE:  x: 10, y: 3.14, z: Hi
+drop type t3;
diff --git a/src/pl/plpgsql/src/meson.build b/src/pl/plpgsql/src/meson.build
index 6ff27006cfc..609eed7a28d 100644
--- a/src/pl/plpgsql/src/meson.build
+++ b/src/pl/plpgsql/src/meson.build
@@ -88,6 +88,7 @@ tests += {
       'plpgsql_trap',
       'plpgsql_trigger',
       'plpgsql_varprops',
+      'plpgsql_foreach',
     ],
   },
 }
diff --git a/src/pl/plpgsql/src/pl_comp.c b/src/pl/plpgsql/src/pl_comp.c
index 5ecc7766757..8fa60976cfd 100644
--- a/src/pl/plpgsql/src/pl_comp.c
+++ b/src/pl/plpgsql/src/pl_comp.c
@@ -1253,6 +1253,7 @@ make_datum_param(PLpgSQL_expr *expr, int dno, int location)
 	PLpgSQL_datum *datum;
 	Param	   *param;
 	MemoryContext oldcontext;
+	char	   *refname;
 
 	/* see comment in resolve_column_ref */
 	estate = expr->func->cur_estate;
@@ -1273,7 +1274,8 @@ make_datum_param(PLpgSQL_expr *expr, int dno, int location)
 									 datum,
 									 &param->paramtype,
 									 &param->paramtypmod,
-									 &param->paramcollid);
+									 &param->paramcollid,
+									 &refname);
 	param->location = location;
 
 	return (Node *) param;
diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c
index 84552e32c87..3383b42c39a 100644
--- a/src/pl/plpgsql/src/pl_exec.c
+++ b/src/pl/plpgsql/src/pl_exec.c
@@ -41,6 +41,8 @@
 #include "utils/builtins.h"
 #include "utils/datum.h"
 #include "utils/fmgroids.h"
+#include "utils/jsonb.h"
+#include "utils/jsonfuncs.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
 #include "utils/rel.h"
@@ -305,6 +307,8 @@ static int	exec_stmt_forc(PLpgSQL_execstate *estate,
 						   PLpgSQL_stmt_forc *stmt);
 static int	exec_stmt_foreach_a(PLpgSQL_execstate *estate,
 								PLpgSQL_stmt_foreach_a *stmt);
+static int	exec_stmt_foreach_json_a(PLpgSQL_execstate *estate,
+									 PLpgSQL_stmt_foreach_json_a *stmt);
 static int	exec_stmt_open(PLpgSQL_execstate *estate,
 						   PLpgSQL_stmt_open *stmt);
 static int	exec_stmt_fetch(PLpgSQL_execstate *estate,
@@ -2075,6 +2079,10 @@ exec_stmts(PLpgSQL_execstate *estate, List *stmts)
 				rc = exec_stmt_foreach_a(estate, (PLpgSQL_stmt_foreach_a *) stmt);
 				break;
 
+			case PLPGSQL_STMT_FOREACH_JSON_A:
+				rc = exec_stmt_foreach_json_a(estate, (PLpgSQL_stmt_foreach_json_a *) stmt);
+				break;
+
 			case PLPGSQL_STMT_EXIT:
 				rc = exec_stmt_exit(estate, (PLpgSQL_stmt_exit *) stmt);
 				break;
@@ -2995,6 +3003,240 @@ exec_stmt_forc(PLpgSQL_execstate *estate, PLpgSQL_stmt_forc *stmt)
 }

+/*
+ * Convert JsonbValue to Datum that can be assigned to PLpgSQL_var.
+ */
+static Datum
+JsonbValueToDatum(JsonbValue *jbv,
+				  Oid *typid, int32 *typmod, bool *isnull,
+				  Oid expected_typid, int32 expected_typmod,
+				  void **cache, MemoryContext mcxt)
+{
+	if (expected_typid == JSONBOID)
+	{
+		*typid = JSONBOID;
+		*typmod = -1;
+		*isnull = false;
+
+		return PointerGetDatum(JsonbValueToJsonb(jbv));
+	}
+	else if (expected_typid == JSONOID)
+	{
+		Jsonb	   *jsonb;
+		char	   *str;
+
+		/* serialize JsonValue to JSON text */
+		jsonb = JsonbValueToJsonb(jbv);
+		str = JsonbToCString(NULL, &jsonb->root, VARSIZE(jsonb));
+
+		*typid = TEXTOID;
+		*typmod = -1;
+		*isnull = false;
+
+		return PointerGetDatum(cstring_to_text(str));
+	}
+	else if (jbv->type == jbvNull)
+	{
+		*typid = expected_typid;
+		*typmod = -1;
+		*isnull = true;
+
+		return (Datum) 0;
+	}
+	else if (jbv->type == jbvString)
+	{
+		*typid = TEXTOID;
+		*typmod = -1;
+		*isnull = false;
+
+		return PointerGetDatum(cstring_to_text_with_len(jbv->val.string.val, jbv->val.string.len));
+	}
+	else if (jbv->type == jbvNumeric)
+	{
+		*typid = NUMERICOID;
+		*typmod = -1;
+		*isnull = false;
+
+		return PointerGetDatum(jbv->val.numeric);
+	}
+	else if (jbv->type == jbvBool)
+	{
+		*typid = BOOLOID;
+		*typmod = -1;
+		*isnull = false;
+
+		return BoolGetDatum(jbv->val.boolean);
+	}
+	else
+	{
+		Jsonb	*jsonb;
+		Datum	result;
+
+		jsonb = JsonbValueToJsonb(jbv);
+		result = json_populate_type(PointerGetDatum(jsonb), JSONBOID,
+									expected_typid, expected_typmod,
+									cache, mcxt,
+									isnull, false, NULL);
+
+		*typid = expected_typid;
+		*typmod = expected_typmod;
+
+		return result;
+	}
+}
+
+/* ----------
+ * exec_stmt_foreach_json_a			Loop over elements in json array
+ *
+ * When target is a composite, then target is populated like json_to_populate_record.
+ * jsonb doesn't preserve attribute order, so position based mapping between
+ * target and source can be possibly dangerous (with unexpected behave).
+ * ----------
+ */
+static int
+exec_stmt_foreach_json_a(PLpgSQL_execstate *estate,
+						 PLpgSQL_stmt_foreach_json_a *stmt)
+{
+	Oid			exprtypeid;
+	int32		exprtypmod;
+	Datum		exprdatum;
+	PLpgSQL_datum *loop_var;
+	Oid			loop_var_typid;
+	int32		loop_var_typmod;
+	Oid			loop_var_collation;
+	char	   *loop_var_name;
+	Jsonb	   *jb;
+	JsonbIterator *it;
+	JsonbValue	jbv;
+	JsonbIteratorToken r;
+	MemoryContext stmt_mcontext;
+	MemoryContext oldcontext;
+	MemoryContext tmp_cxt;
+	bool		found = false;
+	bool		isnull;
+	bool		skipNested = false;
+	int			rc = PLPGSQL_RC_OK;
+	void	   *cache = NULL;
+
+	/* get the value of the expression */
+	exprdatum = exec_eval_expr(estate, stmt->expr, &isnull,
+							   &exprtypeid, &exprtypmod);
+	if (isnull)
+		ereport(ERROR,
+				(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
+				 errmsg("FOREACH expression must not be null")));
+
+	/*
+	 * Do as much as possible of the code below in stmt_mcontext, to avoid any
+	 * leaks from called subroutines.  We need a private stmt_mcontext since
+	 * we'll be calling arbitrary statement code.
+	 */
+	stmt_mcontext = get_stmt_mcontext(estate);
+	push_stmt_mcontext(estate);
+	oldcontext = MemoryContextSwitchTo(stmt_mcontext);
+
+	tmp_cxt = AllocSetContextCreate(CurrentMemoryContext,
+									"FOREACH IN JSON ARRAY temporary cxt",
+									ALLOCSET_DEFAULT_SIZES);
+
+	/* cast to jsonb */
+	exprdatum = exec_cast_value(estate, exprdatum, &isnull,
+								exprtypeid, exprtypmod,
+								JSONBOID, -1);
+
+	Assert(!isnull);
+
+	/*
+	 * We must copy the array into stmt_mcontext, else it will disappear in
+	 * exec_eval_cleanup.  This is annoying, but cleanup will certainly happen
+	 * while running the loop body, so we have little choice.
+	 */
+	jb = DatumGetJsonbPCopy(exprdatum);
+
+	/* Clean up any leftover temporary memory */
+	exec_eval_cleanup(estate);
+
+	/*
+	 * This is compatible with jsonb_array_element. SQL/JSON functions are not
+	 * too strict like PostgreSQL proprietary (old json) functions. In SQL/JSON
+	 * a scalar is equal to one element array. The basic question is if FOREACH
+	 * should be more restrictive like old JSON function, or less restrictive
+	 * like SQL/JSON functions.
+	 */
+	if (JB_ROOT_IS_SCALAR(jb))
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("cannot extract elements from a scalar")));
+	else if (!JB_ROOT_IS_ARRAY(jb))
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("cannot extract elements from an object")));
+
+	/* Set up the loop variable and see if it is of an array type */
+	loop_var = estate->datums[stmt->varno];
+
+	plpgsql_exec_get_datum_type_info(estate, loop_var,
+									 &loop_var_typid, &loop_var_typmod,
+									 &loop_var_collation, &loop_var_name);
+
+	it = JsonbIteratorInit(&jb->root);
+
+	while ((r = JsonbIteratorNext(&it, &jbv, skipNested)) != WJB_DONE)
+	{
+		skipNested = true;
+
+		if (r == WJB_ELEM)
+		{
+			Datum		val;
+			Oid			valtypid;
+			int32		valtypmod;
+			bool		valisnull;
+
+			MemoryContextSwitchTo(tmp_cxt);
+
+			val = JsonbValueToDatum(&jbv,
+									&valtypid, &valtypmod, &valisnull,
+									loop_var_typid, loop_var_typmod,
+									&cache, stmt_mcontext);
+
+			/* exec_assign_value and exec_stmts must run in the main context */
+			MemoryContextSwitchTo(oldcontext);
+
+			/* Assign current element/slice to the loop variable */
+			exec_assign_value(estate, loop_var, val,
+							  valisnull, valtypid, valtypmod);
+
+			MemoryContextReset(tmp_cxt);
+
+			/*
+			 * Execute the statements
+			 */
+			rc = exec_stmts(estate, stmt->body);
+
+			LOOP_RC_PROCESSING(stmt->label, break);
+
+			MemoryContextSwitchTo(stmt_mcontext);
+		}
+	}
+
+	/* Restore memory context state */
+	MemoryContextSwitchTo(oldcontext);
+	pop_stmt_mcontext(estate);
+
+	/* Release temporary memory, including the array value */
+	MemoryContextReset(stmt_mcontext);
+
+	/*
+	 * Set the FOUND variable to indicate the result of executing the loop
+	 * (namely, whether we looped one or more times). This must be set here so
+	 * that it does not interfere with the value of the FOUND variable inside
+	 * the loop processing itself.
+	 */
+	exec_set_found(estate, found);
+
+	return rc;
+}
+
 /* ----------
  * exec_stmt_foreach_a			Loop over elements or slices of an array
  *
@@ -5522,7 +5764,8 @@ plpgsql_exec_get_datum_type(PLpgSQL_execstate *estate,
 void
 plpgsql_exec_get_datum_type_info(PLpgSQL_execstate *estate,
 								 PLpgSQL_datum *datum,
-								 Oid *typeId, int32 *typMod, Oid *collation)
+								 Oid *typeId, int32 *typMod, Oid *collation,
+								 char **refname)
 {
 	switch (datum->dtype)
 	{
@@ -5534,6 +5777,54 @@ plpgsql_exec_get_datum_type_info(PLpgSQL_execstate *estate,
 				*typeId = var->datatype->typoid;
 				*typMod = var->datatype->atttypmod;
 				*collation = var->datatype->collation;
+				*refname = var->refname;
+				break;
+			}
+
+		case PLPGSQL_DTYPE_ROW:
+			{
+				PLpgSQL_row *row = (PLpgSQL_row *) datum;
+
+				if (!row->rowtupdesc)
+				{
+					int			i;
+
+					row->rowtupdesc = CreateTemplateTupleDesc(row->nfields);
+
+					for (i = 0; i < row->nfields; i++)
+					{
+						PLpgSQL_datum *var = estate->datums[row->varnos[i]];
+						Oid			vartypid;
+						int32		vartypmod;
+						Oid			varcollation;
+						char	   *varname;
+
+						/*
+						 * We cannot to use fieldnames for tupdescentry, because
+						 * these names can be suffixed by name of row variable.
+						 * Unfortunately, the PLpgSQL_recfield is not casted to
+						 * PLpgSQL_variable.
+						 */
+						plpgsql_exec_get_datum_type_info(estate, var,
+														 &vartypid, &vartypmod,
+														 &varcollation, &varname);
+
+						TupleDescInitEntry(row->rowtupdesc, i + 1,
+										   varname, vartypid, vartypmod,
+										   0);
+						TupleDescInitEntryCollation(row->rowtupdesc, i + 1,
+													varcollation);
+					}
+
+					/* Make sure we have a valid type/typmod setting */
+					BlessTupleDesc(row->rowtupdesc);
+				}
+
+				*typeId = row->rowtupdesc->tdtypeid;
+				*typMod = row->rowtupdesc->tdtypmod;
+				/* composite types are never collatable */
+				*collation = InvalidOid;
+				*refname = row->refname;
 				break;
 			}
 
@@ -5556,6 +5847,7 @@ plpgsql_exec_get_datum_type_info(PLpgSQL_execstate *estate,
 				}
 				/* composite types are never collatable */
 				*collation = InvalidOid;
+				*refname = rec->refname;
 				break;
 			}
 
@@ -5593,6 +5885,7 @@ plpgsql_exec_get_datum_type_info(PLpgSQL_execstate *estate,
 				*typeId = recfield->finfo.ftypeid;
 				*typMod = recfield->finfo.ftypmod;
 				*collation = recfield->finfo.fcollation;
+				*refname = recfield->fieldname;
 				break;
 			}
 
@@ -5601,6 +5894,7 @@ plpgsql_exec_get_datum_type_info(PLpgSQL_execstate *estate,
 			*typeId = InvalidOid;	/* keep compiler quiet */
 			*typMod = -1;
 			*collation = InvalidOid;
+			*refname = NULL;
 			break;
 	}
 }
diff --git a/src/pl/plpgsql/src/pl_funcs.c b/src/pl/plpgsql/src/pl_funcs.c
index 92cd9116c0e..7511fab7e68 100644
--- a/src/pl/plpgsql/src/pl_funcs.c
+++ b/src/pl/plpgsql/src/pl_funcs.c
@@ -253,6 +253,8 @@ plpgsql_stmt_typename(PLpgSQL_stmt *stmt)
 			return _("FOR over cursor");
 		case PLPGSQL_STMT_FOREACH_A:
 			return _("FOREACH over array");
+		case PLPGSQL_STMT_FOREACH_JSON_A:
+			return _("FOREACH over json array");
 		case PLPGSQL_STMT_EXIT:
 			return ((PLpgSQL_stmt_exit *) stmt)->is_exit ? "EXIT" : "CONTINUE";
 		case PLPGSQL_STMT_RETURN:
@@ -467,6 +469,14 @@ plpgsql_statement_tree_walker_impl(PLpgSQL_stmt *stmt,
 			{
 				PLpgSQL_stmt_foreach_a *fstmt = (PLpgSQL_stmt_foreach_a *) stmt;
 
+				E_WALK(fstmt->expr);
+				S_LIST_WALK(fstmt->body);
+				break;
+			}
+		case PLPGSQL_STMT_FOREACH_JSON_A:
+			{
+				PLpgSQL_stmt_foreach_json_a *fstmt = (PLpgSQL_stmt_foreach_json_a *) stmt;
+
 				E_WALK(fstmt->expr);
 				S_LIST_WALK(fstmt->body);
 				break;
@@ -795,6 +805,7 @@ static void dump_fori(PLpgSQL_stmt_fori *stmt);
 static void dump_fors(PLpgSQL_stmt_fors *stmt);
 static void dump_forc(PLpgSQL_stmt_forc *stmt);
 static void dump_foreach_a(PLpgSQL_stmt_foreach_a *stmt);
+static void dump_foreach_json_a(PLpgSQL_stmt_foreach_json_a *stmt);
 static void dump_exit(PLpgSQL_stmt_exit *stmt);
 static void dump_return(PLpgSQL_stmt_return *stmt);
 static void dump_return_next(PLpgSQL_stmt_return_next *stmt);
@@ -861,6 +872,9 @@ dump_stmt(PLpgSQL_stmt *stmt)
 		case PLPGSQL_STMT_FOREACH_A:
 			dump_foreach_a((PLpgSQL_stmt_foreach_a *) stmt);
 			break;
+		case PLPGSQL_STMT_FOREACH_JSON_A:
+			dump_foreach_json_a((PLpgSQL_stmt_foreach_json_a *) stmt);
+			break;
 		case PLPGSQL_STMT_EXIT:
 			dump_exit((PLpgSQL_stmt_exit *) stmt);
 			break;
@@ -1157,6 +1171,21 @@ dump_foreach_a(PLpgSQL_stmt_foreach_a *stmt)
 	printf("    ENDFOREACHA");
 }
 
+static void
+dump_foreach_json_a(PLpgSQL_stmt_foreach_json_a *stmt)
+{
+	dump_ind();
+	printf("FOREACHA var %d ", stmt->varno);
+	printf("IN JSON ARRAY ");
+	dump_expr(stmt->expr);
+	printf("\n");
+
+	dump_stmts(stmt->body);
+
+	dump_ind();
+	printf("    ENDFOREACHA");
+}
+
 static void
 dump_open(PLpgSQL_stmt_open *stmt)
 {
diff --git a/src/pl/plpgsql/src/pl_gram.y b/src/pl/plpgsql/src/pl_gram.y
index 5009e59a78f..23b465b10d5 100644
--- a/src/pl/plpgsql/src/pl_gram.y
+++ b/src/pl/plpgsql/src/pl_gram.y
@@ -178,6 +178,7 @@ static	void			check_raise_parameters(PLpgSQL_stmt_raise *stmt);
 	PLpgSQL_diag_item *diagitem;
 	PLpgSQL_stmt_fetch *fetch;
 	PLpgSQL_case_when *casewhen;
+	PLpgSQL_stmt_foreach *foreach;
 }
 
 %type <declhdr> decl_sect
@@ -220,6 +221,7 @@ static	void			check_raise_parameters(PLpgSQL_stmt_raise *stmt);
 
 %type <casewhen>	case_when
 %type <list>	case_when_list opt_case_else
+%type <foreach>	foreach_type
 
 %type <boolean>	getdiag_area_opt
 %type <list>	getdiag_list
@@ -341,6 +343,7 @@ static	void			check_raise_parameters(PLpgSQL_stmt_raise *stmt);
 %token <keyword>	K_PRINT_STRICT_PARAMS
 %token <keyword>	K_PRIOR
 %token <keyword>	K_QUERY
+%token <keyword>	K_JSON
 %token <keyword>	K_RAISE
 %token <keyword>	K_RELATIVE
 %token <keyword>	K_RETURN
@@ -1671,16 +1674,29 @@ for_variable	: T_DATUM
 					}
 				;
 
-stmt_foreach_a	: opt_loop_label K_FOREACH for_variable foreach_slice K_IN K_ARRAY expr_until_loop loop_body
+stmt_foreach_a	: opt_loop_label K_FOREACH for_variable foreach_slice K_IN foreach_type expr_until_loop loop_body
 					{
-						PLpgSQL_stmt_foreach_a *new;
+						PLpgSQL_stmt_foreach *new;
 
-						new = palloc0_object(PLpgSQL_stmt_foreach_a);
-						new->cmd_type = PLPGSQL_STMT_FOREACH_A;
+						new = $6;
 						new->lineno = plpgsql_location_to_lineno(@2, yyscanner);
 						new->stmtid = ++plpgsql_curr_compile->nstatements;
 						new->label = $1;
-						new->slice = $4;
+
+						if ($4 > 0)
+						{
+							/* slicing is supported only by FOREACH IN ARRAY */
+							if (new->cmd_type == PLPGSQL_STMT_FOREACH_A)
+							{
+								((PLpgSQL_stmt_foreach_a *) new)->slice = $4;
+							}
+							else
+								ereport(ERROR,
+										(errcode(ERRCODE_SYNTAX_ERROR),
+										 errmsg("not zero slice is allowed only for arrays"),
+												 parser_errposition(@4)));
+						}
+
 						new->expr = $7;
 						new->body = $8.stmts;
 
@@ -1719,6 +1735,19 @@ foreach_slice	:
 					}
 				;
 
+foreach_type	:
+				  K_ARRAY
+					{
+						$$ = (PLpgSQL_stmt_foreach *) palloc0_object(PLpgSQL_stmt_foreach_a);
+						$$->cmd_type = PLPGSQL_STMT_FOREACH_A;
+					}
+				| K_JSON K_ARRAY
+					{
+						$$ = (PLpgSQL_stmt_foreach *) palloc0_object(PLpgSQL_stmt_foreach_json_a);
+						$$->cmd_type = PLPGSQL_STMT_FOREACH_JSON_A;
+					}
+				;
+
 stmt_exit		: exit_type opt_label opt_exitcond
 					{
 						PLpgSQL_stmt_exit *new;
diff --git a/src/pl/plpgsql/src/pl_unreserved_kwlist.h b/src/pl/plpgsql/src/pl_unreserved_kwlist.h
index 6379e86c8cb..d7588d3b4ad 100644
--- a/src/pl/plpgsql/src/pl_unreserved_kwlist.h
+++ b/src/pl/plpgsql/src/pl_unreserved_kwlist.h
@@ -69,6 +69,7 @@ PG_KEYWORD("import", K_IMPORT)
 PG_KEYWORD("info", K_INFO)
 PG_KEYWORD("insert", K_INSERT)
 PG_KEYWORD("is", K_IS)
+PG_KEYWORD("json", K_JSON)
 PG_KEYWORD("last", K_LAST)
 PG_KEYWORD("log", K_LOG)
 PG_KEYWORD("merge", K_MERGE)
diff --git a/src/pl/plpgsql/src/plpgsql.h b/src/pl/plpgsql/src/plpgsql.h
index addb14a9959..4a1e9ba65bc 100644
--- a/src/pl/plpgsql/src/plpgsql.h
+++ b/src/pl/plpgsql/src/plpgsql.h
@@ -112,6 +112,7 @@ typedef enum PLpgSQL_stmt_type
 	PLPGSQL_STMT_FORS,
 	PLPGSQL_STMT_FORC,
 	PLPGSQL_STMT_FOREACH_A,
+	PLPGSQL_STMT_FOREACH_JSON_A,
 	PLPGSQL_STMT_EXIT,
 	PLPGSQL_STMT_RETURN,
 	PLPGSQL_STMT_RETURN_NEXT,
@@ -766,6 +767,20 @@ typedef struct PLpgSQL_stmt_dynfors
 	List	   *params;			/* USING expressions */
 } PLpgSQL_stmt_dynfors;
 
+/*
+ * FOREACH loop (ancestor IN ARRAY and IN JSON ARRAY loop)
+ */
+typedef struct PLpgSQL_stmt_foreach
+{
+	PLpgSQL_stmt_type cmd_type;
+	int			lineno;
+	unsigned int stmtid;
+	char	   *label;
+	int			varno;			/* loop target variable */
+	PLpgSQL_expr *expr;			/* set expression */
+	List	   *body;			/* List of statements */
+} PLpgSQL_stmt_foreach;
+
 /*
  * FOREACH item in array loop
  */
@@ -776,11 +791,27 @@ typedef struct PLpgSQL_stmt_foreach_a
 	unsigned int stmtid;
 	char	   *label;
 	int			varno;			/* loop target variable */
-	int			slice;			/* slice dimension, or 0 */
 	PLpgSQL_expr *expr;			/* array expression */
 	List	   *body;			/* List of statements */
+	/* end of fields that must match PLpgSQL_stmt_foreach */
+	int			slice;			/* slice dimension, or 0 */
 } PLpgSQL_stmt_foreach_a;
 
+/*
+ * FOREACH item in array loop
+ */
+typedef struct PLpgSQL_stmt_foreach_json_a
+{
+	PLpgSQL_stmt_type cmd_type;
+	int			lineno;
+	unsigned int stmtid;
+	char	   *label;
+	int			varno;			/* loop target variable */
+	PLpgSQL_expr *expr;			/* array expression */
+	List	   *body;			/* List of statements */
+	/* end of fields that must match PLpgSQL_stmt_foreach */
+} PLpgSQL_stmt_foreach_json_a;
+
 /*
  * OPEN a curvar
  */
@@ -1274,7 +1305,7 @@ extern PGDLLEXPORT Oid plpgsql_exec_get_datum_type(PLpgSQL_execstate *estate,
 extern void plpgsql_exec_get_datum_type_info(PLpgSQL_execstate *estate,
 											 PLpgSQL_datum *datum,
 											 Oid *typeId, int32 *typMod,
-											 Oid *collation);
+											 Oid *collation, char **refname);
 
 /*
  * Functions for namespace handling in pl_funcs.c
diff --git a/src/pl/plpgsql/src/sql/plpgsql_foreach.sql b/src/pl/plpgsql/src/sql/plpgsql_foreach.sql
new file mode 100644
index 00000000000..7e7abfe2568
--- /dev/null
+++ b/src/pl/plpgsql/src/sql/plpgsql_foreach.sql
@@ -0,0 +1,89 @@
+-- numeric to numeric
+do $$
+declare x numeric;
+begin
+  foreach x in json array '[10,20,30,3.14, null]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+-- numeric to int by cast
+do $$
+declare x int;
+begin
+  foreach x in json array '[10,20,30,3.14, null]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+-- conversion "3.14" to int should to fail due IO cast
+do $$
+declare x int;
+begin
+  foreach x in json array '["10",20,30,"3.14"]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+-- jsonb to jsonb
+do $$
+declare x jsonb;
+begin
+  foreach x in json array '[10,20,30,3.14, null, "Hi"]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+-- jsonb to json
+do $$
+declare x json;
+begin
+  foreach x in json array '[10,20,30,3.14, null, "Hi"]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+-- iteration over composites
+do $$
+declare x int; y numeric; z varchar;
+begin
+  foreach x, y, z in json array '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]'
+  loop
+    raise notice 'x: %, y: %, z: %', x, y, z;
+  end loop;
+end;
+$$;
+
+create type t3 as (x int, y numeric, z varchar);
+
+do $$
+declare c t3;
+begin
+  foreach c in json array '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]'
+  loop
+    raise notice 'x: %, y: %, z: %', c.x, c.y, c.z;
+  end loop;
+end;
+$$;
+
+do $$
+declare c t3;
+begin
+  foreach c.x, c.y, c.z in json array '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]'
+  loop
+    raise notice 'x: %, y: %, z: %', c.x, c.y, c.z;
+  end loop;
+end;
+$$;
+
+drop type t3;
-- 
2.53.0

---

From: Pavel Stehule <[email-masked]>
Date: Sun, 1 Mar 2026 20:40:24 +0100

ne 1. 3. 2026 v 6:44 odesílatel Pavel Stehule <[email-masked]>
napsal:

> Hi
>
> small update
>
> Now assignment to plpgsql array variable and json array works. Some minor
> code cleaning + more regress tests.
>

fix uninitialized argument of  json_populate_type function

regards

Pavel

> Pavel
From 00267f26fe213d2459672fd16acbea73cc91641c Mon Sep 17 00:00:00 2001
From: "[email-masked]" <[email-masked]>
Date: Mon, 23 Feb 2026 12:53:44 +0100
Subject: [PATCH] FOREACH scalar IN JSON ARRAY

DECLARE t int;
BEGIN

The performance (best case for iteration over 1000 fields array) is about
4x better than when FOR IN SELECT jsonb_array_elements is used.
---
 doc/src/sgml/plpgsql.sgml                     |  59 ++++
 src/pl/plpgsql/src/Makefile                   |   2 +-
 .../plpgsql/src/expected/plpgsql_foreach.out  | 192 ++++++++++++
 src/pl/plpgsql/src/meson.build                |   1 +
 src/pl/plpgsql/src/pl_exec.c                  | 290 ++++++++++++++++++
 src/pl/plpgsql/src/pl_funcs.c                 |  29 ++
 src/pl/plpgsql/src/pl_gram.y                  |  39 ++-
 src/pl/plpgsql/src/pl_unreserved_kwlist.h     |   1 +
 src/pl/plpgsql/src/plpgsql.h                  |  36 ++-
 src/pl/plpgsql/src/sql/plpgsql_foreach.sql    | 159 ++++++++++
 10 files changed, 800 insertions(+), 8 deletions(-)
 create mode 100644 src/pl/plpgsql/src/expected/plpgsql_foreach.out
 create mode 100644 src/pl/plpgsql/src/sql/plpgsql_foreach.sql

diff --git a/doc/src/sgml/plpgsql.sgml b/doc/src/sgml/plpgsql.sgml
index 561f6e50d63..034fbd8bd45 100644
--- a/doc/src/sgml/plpgsql.sgml
+++ b/doc/src/sgml/plpgsql.sgml
@@ -2780,6 +2780,65 @@ NOTICE:  row = {10,11,12}
     </para>
    </sect2>

 
 # where to find gen_keywordlist.pl and subsidiary files
 TOOLSDIR = $(top_srcdir)/src/tools
diff --git a/src/pl/plpgsql/src/expected/plpgsql_foreach.out b/src/pl/plpgsql/src/expected/plpgsql_foreach.out
new file mode 100644
index 00000000000..bc366e78df3
--- /dev/null
+++ b/src/pl/plpgsql/src/expected/plpgsql_foreach.out
@@ -0,0 +1,192 @@
+-- numeric to numeric
+do $$
+declare x numeric;
+begin
+  foreach x in json array '[10,20,30,3.14, null]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+NOTICE:  10
+NOTICE:  20
+NOTICE:  30
+NOTICE:  3.14
+NOTICE:  <NULL>
+-- numeric to int by cast
+do $$
+declare x int;
+begin
+  foreach x in json array '[10,20,30,3.14, null]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+NOTICE:  10
+NOTICE:  20
+NOTICE:  30
+NOTICE:  3
+NOTICE:  <NULL>
+-- conversion "3.14" to int should to fail due IO cast
+do $$
+declare x int;
+begin
+  foreach x in json array '["10",20,30,"3.14"]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+NOTICE:  10
+NOTICE:  20
+NOTICE:  30
+ERROR:  invalid input syntax for type integer: "3.14"
+CONTEXT:  PL/pgSQL function inline_code_block line 4 at FOREACH over json array
+do $$
+declare x boolean;
+begin
+  foreach x in json array '[true, false]'
+  loop
+  if x then
+    raise notice 'true';
+  else
+    raise notice 'false';
+  end if;
+  end loop;
+end;
+$$;
+NOTICE:  true
+NOTICE:  false
+-- jsonb to jsonb
+do $$
+declare x jsonb;
+begin
+  foreach x in json array '[10,20,30,3.14, null, "Hi"]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+NOTICE:  10
+NOTICE:  20
+NOTICE:  30
+NOTICE:  3.14
+NOTICE:  null
+NOTICE:  "Hi"
+-- jsonb to json
+do $$
+declare x json;
+begin
+  foreach x in json array '[10,20,30,3.14, null, "Hi"]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+NOTICE:  10
+NOTICE:  20
+NOTICE:  30
+NOTICE:  3.14
+NOTICE:  null
+NOTICE:  "Hi"
+-- iteration over composites
+do $$
+declare x int; y numeric; z varchar;
+begin
+  foreach x, y, z in json array '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]'
+  loop
+    raise notice 'x: %, y: %, z: %', x, y, z;
+  end loop;
+end;
+$$;
+NOTICE:  x: <NULL>, y: <NULL>, z: <NULL>
+NOTICE:  x: <NULL>, y: <NULL>, z: Hi
+NOTICE:  x: <NULL>, y: 3.14, z: <NULL>
+NOTICE:  x: 10, y: 3.14, z: Hi
+create type t3 as (x int, y numeric, z varchar);
+do $$
+declare c t3;
+begin
+  foreach c in json array '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]'
+  loop
+    raise notice 'x: %, y: %, z: %', c.x, c.y, c.z;
+  end loop;
+end;
+$$;
+NOTICE:  x: <NULL>, y: <NULL>, z: <NULL>
+NOTICE:  x: <NULL>, y: <NULL>, z: Hi
+NOTICE:  x: <NULL>, y: 3.14, z: <NULL>
+NOTICE:  x: 10, y: 3.14, z: Hi
+do $$
+declare c t3;
+begin
+  foreach c.x, c.y, c.z in json array '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]'
+  loop
+    raise notice 'x: %, y: %, z: %', c.x, c.y, c.z;
+  end loop;
+end;
+$$;
+NOTICE:  x: <NULL>, y: <NULL>, z: <NULL>
+NOTICE:  x: <NULL>, y: <NULL>, z: Hi
+NOTICE:  x: <NULL>, y: 3.14, z: <NULL>
+NOTICE:  x: 10, y: 3.14, z: Hi
+drop type t3;
+-- target can be a array
+do $$
+declare x int[];
+begin
+  foreach x in json array '[[1,2,3],[4,5,6]]'
+  loop
+    raise notice '% % %', x[1], x[2], x[3];
+  end loop;
+end;
+$$;
+NOTICE:  1 2 3
+NOTICE:  4 5 6
+do $$
+declare x varchar[];
+begin
+  foreach x in json array '[["Hi","Hello"],["Hello","Hi"]]'
+  loop
+    raise notice '% %', x[1], x[2];
+  end loop;
+end;
+$$;
+NOTICE:  Hi Hello
+NOTICE:  Hello Hi
+do $$
+declare x varchar[];
+begin
+  foreach x in json array '[["Hi","Hello"],["Hello","Hi"]]'
+  loop
+    raise notice '% %', x[1], x[2];
+  end loop;
+end;
+$$;
+NOTICE:  Hi Hello
+NOTICE:  Hello Hi
+do $$
+declare x int[]; y varchar;
+begin
+  foreach x, y in json array '[{"x":[1,2,3], "y":"Hi"}, {"x":[4,5,6], "y":"Hi"}]'
+  loop
+    raise notice '% % %, y: %', x[1], x[2], x[3], y;
+  end loop;
+end;
+$$;
+NOTICE:  1 2 3, y: Hi
+NOTICE:  4 5 6, y: Hi
+create type t2 as (x int[], y varchar);
+do $$
+declare c t2;
+begin
+  foreach c in json array '[{"x":[1,2,3], "y":"Hi"}, {"x":[4,5,6], "y":"Hi"}]'
+  loop
+    raise notice '% % %, y: %', c.x[1], c.x[2], c.x[3], c.y;
+  end loop;
+end;
+$$;
+NOTICE:  1 2 3, y: Hi
+NOTICE:  4 5 6, y: Hi
+drop type t2;
diff --git a/src/pl/plpgsql/src/meson.build b/src/pl/plpgsql/src/meson.build
index 6ff27006cfc..609eed7a28d 100644
--- a/src/pl/plpgsql/src/meson.build
+++ b/src/pl/plpgsql/src/meson.build
@@ -88,6 +88,7 @@ tests += {
       'plpgsql_trap',
       'plpgsql_trigger',
       'plpgsql_varprops',
+      'plpgsql_foreach',
     ],
   },
 }
diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c
index 84552e32c87..267bbabee6a 100644
--- a/src/pl/plpgsql/src/pl_exec.c
+++ b/src/pl/plpgsql/src/pl_exec.c
@@ -41,6 +41,8 @@
 #include "utils/builtins.h"
 #include "utils/datum.h"
 #include "utils/fmgroids.h"
+#include "utils/jsonb.h"
+#include "utils/jsonfuncs.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
 #include "utils/rel.h"
@@ -305,6 +307,8 @@ static int	exec_stmt_forc(PLpgSQL_execstate *estate,
 						   PLpgSQL_stmt_forc *stmt);
 static int	exec_stmt_foreach_a(PLpgSQL_execstate *estate,
 								PLpgSQL_stmt_foreach_a *stmt);
+static int	exec_stmt_foreach_json_a(PLpgSQL_execstate *estate,
+									 PLpgSQL_stmt_foreach_json_a *stmt);
 static int	exec_stmt_open(PLpgSQL_execstate *estate,
 						   PLpgSQL_stmt_open *stmt);
 static int	exec_stmt_fetch(PLpgSQL_execstate *estate,
@@ -2075,6 +2079,10 @@ exec_stmts(PLpgSQL_execstate *estate, List *stmts)
 				rc = exec_stmt_foreach_a(estate, (PLpgSQL_stmt_foreach_a *) stmt);
 				break;
 
+			case PLPGSQL_STMT_FOREACH_JSON_A:
+				rc = exec_stmt_foreach_json_a(estate, (PLpgSQL_stmt_foreach_json_a *) stmt);
+				break;
+
 			case PLPGSQL_STMT_EXIT:
 				rc = exec_stmt_exit(estate, (PLpgSQL_stmt_exit *) stmt);
 				break;
@@ -2995,6 +3003,243 @@ exec_stmt_forc(PLpgSQL_execstate *estate, PLpgSQL_stmt_forc *stmt)
 }

+/*
+		return PointerGetDatum(cstring_to_text_with_len(jbv->val.string.val,
+														jbv->val.string.len));
+		/* isnull in json_populate_type is inout argument */
+									 &loop_var_collation);
@@ -5537,6 +5782,51 @@ plpgsql_exec_get_datum_type_info(PLpgSQL_execstate *estate,
 				break;
 			}
 
+														 &varcollation);
+										   var->refname, vartypid, vartypmod,
 		case PLPGSQL_DTYPE_REC:
 				PLpgSQL_rec *rec = (PLpgSQL_rec *) datum;
 
+				E_WALK(fstmt->expr);
 
+static void

 

 
 
+foreach_type	:
+				  K_ARRAY
+					{
index addb14a9959..c57b1da9b95 100644
@@ -299,6 +300,7 @@ typedef struct PLpgSQL_datum
 {
 	PLpgSQL_datum_type dtype;
 	int			dno;
+	char	   *refname;
 } PLpgSQL_datum;
 
 /*
@@ -444,9 +446,9 @@ typedef struct PLpgSQL_recfield
 {
 	PLpgSQL_datum_type dtype;
 	int			dno;
+	char	   *fieldname;		/* name of field */
 	/* end of PLpgSQL_datum fields */
 
-	char	   *fieldname;		/* name of field */
 	int			recparentno;	/* dno of parent record */
 	int			nextfield;		/* dno of next child, or -1 if none */
 	uint64		rectupledescid; /* record's tupledesc ID as of last lookup */
@@ -766,6 +768,20 @@ typedef struct PLpgSQL_stmt_dynfors
 	List	   *params;			/* USING expressions */
 } PLpgSQL_stmt_dynfors;
 
+/*
@@ -776,11 +792,27 @@ typedef struct PLpgSQL_stmt_foreach_a
 
+/*
+ * FOREACH item in array loop
+ */
+typedef struct PLpgSQL_stmt_foreach_json_a
+{
+	PLpgSQL_stmt_type cmd_type;
+	int			lineno;
+	unsigned int stmtid;
+	char	   *label;
+	int			varno;			/* loop target variable */
+	PLpgSQL_expr *expr;			/* array expression */
+	List	   *body;			/* List of statements */
+	/* end of fields that must match PLpgSQL_stmt_foreach */
+} PLpgSQL_stmt_foreach_json_a;
+
 /*
  * OPEN a curvar
  */
diff --git a/src/pl/plpgsql/src/sql/plpgsql_foreach.sql b/src/pl/plpgsql/src/sql/plpgsql_foreach.sql
new file mode 100644
index 00000000000..33acb8f924c
--- /dev/null
+++ b/src/pl/plpgsql/src/sql/plpgsql_foreach.sql
@@ -0,0 +1,159 @@
+-- numeric to numeric
+do $$
+declare x numeric;
+begin
+  foreach x in json array '[10,20,30,3.14, null]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+-- numeric to int by cast
+do $$
+declare x int;
+begin
+  foreach x in json array '[10,20,30,3.14, null]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+-- conversion "3.14" to int should to fail due IO cast
+do $$
+declare x int;
+begin
+  foreach x in json array '["10",20,30,"3.14"]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+do $$
+declare x boolean;
+begin
+  foreach x in json array '[true, false]'
+  loop
+  if x then
+    raise notice 'true';
+  else
+    raise notice 'false';
+  end if;
+  end loop;
+end;
+$$;
+
+-- jsonb to jsonb
+do $$
+declare x jsonb;
+begin
+  foreach x in json array '[10,20,30,3.14, null, "Hi"]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+-- jsonb to json
+do $$
+declare x json;
+begin
+  foreach x in json array '[10,20,30,3.14, null, "Hi"]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+-- iteration over composites
+do $$
+declare x int; y numeric; z varchar;
+begin
+  foreach x, y, z in json array '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]'
+  loop
+    raise notice 'x: %, y: %, z: %', x, y, z;
+  end loop;
+end;
+$$;
+
+create type t3 as (x int, y numeric, z varchar);
+
+do $$
+declare c t3;
+begin
+  foreach c in json array '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]'
+  loop
+    raise notice 'x: %, y: %, z: %', c.x, c.y, c.z;
+  end loop;
+end;
+$$;
+
+do $$
+declare c t3;
+begin
+  foreach c.x, c.y, c.z in json array '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]'
+  loop
+    raise notice 'x: %, y: %, z: %', c.x, c.y, c.z;
+  end loop;
+end;
+$$;
+
+drop type t3;
+
+-- target can be a array
+do $$
+declare x int[];
+begin
+  foreach x in json array '[[1,2,3],[4,5,6]]'
+  loop
+    raise notice '% % %', x[1], x[2], x[3];
+  end loop;
+end;
+$$;
+
+do $$
+declare x varchar[];
+begin
+  foreach x in json array '[["Hi","Hello"],["Hello","Hi"]]'
+  loop
+    raise notice '% %', x[1], x[2];
+  end loop;
+end;
+$$;
+
+do $$
+declare x varchar[];
+begin
+  foreach x in json array '[["Hi","Hello"],["Hello","Hi"]]'
+  loop
+    raise notice '% %', x[1], x[2];
+  end loop;
+end;
+$$;
+
+
+do $$
+declare x int[]; y varchar;
+begin
+  foreach x, y in json array '[{"x":[1,2,3], "y":"Hi"}, {"x":[4,5,6], "y":"Hi"}]'
+  loop
+    raise notice '% % %, y: %', x[1], x[2], x[3], y;
+  end loop;
+end;
+$$;
+
+create type t2 as (x int[], y varchar);
+
+do $$
+declare c t2;
+begin
+  foreach c in json array '[{"x":[1,2,3], "y":"Hi"}, {"x":[4,5,6], "y":"Hi"}]'
+  loop
+    raise notice '% % %, y: %', c.x[1], c.x[2], c.x[3], c.y;
+  end loop;
+end;
+$$;
+
+drop type t2;
-- 
2.53.0

---

From: Jim Jones <[email-masked]>
Date: Tue, 3 Mar 2026 08:42:59 +0100

Hi Pavel,

I quickly tested the patch, and I also could observe a ~3x performance
improvement!

A few first impressions:

## in exec_stmt_foreach_json_a the boolean variable found is declared as
false, bit its value is never set to true until exec_set_found() is called:

/*
 * Set the FOUND variable to indicate the result of executing the loop
 * (namely, whether we looped one or more times). This must be set here so
 * that it does not interfere with the value of the FOUND variable inside
 * the loop processing itself.
 */
exec_set_found(estate, found);

Test:

DO $$
DECLARE
  x int;
BEGIN
  FOREACH x IN JSON ARRAY '[1,2,3]'
  LOOP
    RAISE NOTICE 'x: %', x;
  END LOOP;

  IF FOUND THEN
    RAISE NOTICE 'FOUND is true';
  ELSE
    RAISE NOTICE 'FOUND is false';
  END IF;
END;
$$;
NOTICE:  x: 1
NOTICE:  x: 2
NOTICE:  x: 3
NOTICE:  FOUND is false

## Suggestion in the plpgsql.sgml

The <literal>FOREACH</literal> loop is much like a
<literal>FOREACH</literal> loop,

to

"much like a regular <literal>FOREACH</literal> loop over arrays"

## Typo in comment

/*
 * We cannot to use fieldnames for tupdescentry, because
 * these names can be suffixed by name of row variable.
...

We cannot to use > We cannot use

## Nit pick

These error messages are not wrong, but IMO a errhint/errdetail could
add some value here:

ereport(ERROR,
    (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
     errmsg("cannot extract elements from a scalar")));

ereport(ERROR,
    (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
    errmsg("cannot extract elements from an object")));

Something like this perhaps?

ereport(ERROR,
    (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
     errmsg("cannot extract elements from a scalar"),
     errhint("FOREACH IN JSON ARRAY requires an array value.")));

ereport(ERROR,
    (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
     errmsg("FOREACH expression must evaluate to a JSON array"),
     errdetail("Cannot iterate over a scalar value.")));

Thanks for the patch!

Best, Jim

---

From: Pavel Stehule <[email-masked]>
Date: Tue, 3 Mar 2026 14:45:07 +0100

Hi

>     RAISE NOTICE 'FOUND is false';
fixed + regress tests

> "much like a regular <literal>FOREACH</literal> loop over arrays"

done

> We cannot to use > We cannot use

fixed

>      errdetail("Cannot iterate over a scalar value.")));
I rewrote it to

    if (JB_ROOT_IS_SCALAR(jb))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("FOREACH expression must evaluate to a JSON array"),
                 errhint("Cannot iterate over a scalar value.")));
    else if (JB_ROOT_IS_OBJECT(jb))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("FOREACH expression must evaluate to a JSON array"),
                 errdetail("Cannot iterate over a object value.")));

    Assert(JB_ROOT_IS_ARRAY(jb));

+ regress tests

> Thanks for the patch!

Thank you for check

Regards

Pavel

> Best, Jim
From 899ee1689d9dc537c57a8e74e04088d638cc3ccc Mon Sep 17 00:00:00 2001
From: "[email-masked]" <[email-masked]>
Date: Mon, 23 Feb 2026 12:53:44 +0100
Subject: [PATCH] FOREACH scalar IN JSON ARRAY

DECLARE t int;
BEGIN

The performance (best case for iteration over 1000 fields array) is about
4x better than when FOR IN SELECT jsonb_array_elements is used.
---
 doc/src/sgml/plpgsql.sgml                     |  60 ++++
 src/pl/plpgsql/src/Makefile                   |   2 +-
 .../plpgsql/src/expected/plpgsql_foreach.out  | 253 +++++++++++++++
 src/pl/plpgsql/src/meson.build                |   1 +
 src/pl/plpgsql/src/pl_exec.c                  | 296 ++++++++++++++++++
 src/pl/plpgsql/src/pl_funcs.c                 |  29 ++
 src/pl/plpgsql/src/pl_gram.y                  |  39 ++-
 src/pl/plpgsql/src/pl_unreserved_kwlist.h     |   1 +
 src/pl/plpgsql/src/plpgsql.h                  |  36 ++-
 src/pl/plpgsql/src/sql/plpgsql_foreach.sql    | 214 +++++++++++++
 10 files changed, 923 insertions(+), 8 deletions(-)
 create mode 100644 src/pl/plpgsql/src/expected/plpgsql_foreach.out
 create mode 100644 src/pl/plpgsql/src/sql/plpgsql_foreach.sql

diff --git a/doc/src/sgml/plpgsql.sgml b/doc/src/sgml/plpgsql.sgml
index 561f6e50d63..ad12d2191aa 100644
--- a/doc/src/sgml/plpgsql.sgml
+++ b/doc/src/sgml/plpgsql.sgml
@@ -2780,6 +2780,66 @@ NOTICE:  row = {10,11,12}
     </para>
    </sect2>
 
+     The <literal>FOREACH</literal> loop is much like a regular
+     <literal>FOREACH</literal> loop over arrays,

index 00000000000..b24e73277f1
@@ -0,0 +1,253 @@
+-- input must be a JSON array
+  foreach x in json array NULL -- fail
+ERROR:  FOREACH expression must not be null
+  foreach x in json array '10' -- fail
+ERROR:  FOREACH expression must evaluate to a JSON array
+HINT:  Cannot iterate over a scalar value.
+  foreach x in json array '{}' -- fail
+ERROR:  FOREACH expression must evaluate to a JSON array
+DETAIL:  Cannot iterate over a object value.
+-- test of FOUND variable
+  foreach x in json array '[10]'
+  raise notice 'FOUND: %', found;
+NOTICE:  FOUND: t
+-- test of FOUND variable
+  foreach x in json array '[]'
+  raise notice 'FOUND: %', found;
+NOTICE:  FOUND: f
index 84552e32c87..036390f07a4 100644
 
+			case PLPGSQL_STMT_FOREACH_JSON_A:
+				rc = exec_stmt_foreach_json_a(estate, (PLpgSQL_stmt_foreach_json_a *) stmt);
+				break;
+
 			case PLPGSQL_STMT_EXIT:
 				rc = exec_stmt_exit(estate, (PLpgSQL_stmt_exit *) stmt);
 				break;
@@ -2995,6 +3003,249 @@ exec_stmt_forc(PLpgSQL_execstate *estate, PLpgSQL_stmt_forc *stmt)
 }

+/*
+				 errmsg("FOREACH expression must evaluate to a JSON array"),
+				 errhint("Cannot iterate over a scalar value.")));
+	else if (JB_ROOT_IS_OBJECT(jb))
+				 errmsg("FOREACH expression must evaluate to a JSON array"),
+				 errdetail("Cannot iterate over a object value.")));
+	Assert(JB_ROOT_IS_ARRAY(jb));
+			found = true;			/* looped at least once */
@@ -5537,6 +5788,51 @@ plpgsql_exec_get_datum_type_info(PLpgSQL_execstate *estate,
 				break;
 			}
 
+						 * We cannot use fieldnames for tupdescentry, because
 
+				E_WALK(fstmt->expr);
 
+static void

 

 
 
+foreach_type	:
+				  K_ARRAY
+					{
 
 /*

+/*
 
+/*
+ * FOREACH item in array loop
+ */
+typedef struct PLpgSQL_stmt_foreach_json_a
+{
+	PLpgSQL_stmt_type cmd_type;
+	int			lineno;
+	unsigned int stmtid;
+	char	   *label;
+	int			varno;			/* loop target variable */
+	PLpgSQL_expr *expr;			/* array expression */
+	List	   *body;			/* List of statements */
+	/* end of fields that must match PLpgSQL_stmt_foreach */
+} PLpgSQL_stmt_foreach_json_a;
+
 /*
  * OPEN a curvar
  */
diff --git a/src/pl/plpgsql/src/sql/plpgsql_foreach.sql b/src/pl/plpgsql/src/sql/plpgsql_foreach.sql
new file mode 100644
index 00000000000..0e5c7106d1e
--- /dev/null
+++ b/src/pl/plpgsql/src/sql/plpgsql_foreach.sql
@@ -0,0 +1,214 @@
+-- input must be a JSON array
+do $$
+declare x numeric;
+begin
+  foreach x in json array NULL -- fail
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+do $$
+declare x numeric;
+begin
+  foreach x in json array '10' -- fail
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+do $$
+declare x numeric;
+begin
+  foreach x in json array '{}' -- fail
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+-- numeric to numeric
+do $$
+declare x numeric;
+begin
+  foreach x in json array '[10,20,30,3.14, null]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+-- numeric to int by cast
+do $$
+declare x int;
+begin
+  foreach x in json array '[10,20,30,3.14, null]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+-- test of FOUND variable
+do $$
+declare x int;
+begin
+  foreach x in json array '[10]'
+  loop
+    raise notice '%', x;
+  end loop;
+  raise notice 'FOUND: %', found;
+end;
+$$;
+
+-- test of FOUND variable
+do $$
+declare x int;
+begin
+  foreach x in json array '[]'
+  loop
+    raise notice '%', x;
+  end loop;
+  raise notice 'FOUND: %', found;
+end;
+$$;
+
+-- conversion "3.14" to int should to fail due IO cast
+do $$
+declare x int;
+begin
+  foreach x in json array '["10",20,30,"3.14"]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+do $$
+declare x boolean;
+begin
+  foreach x in json array '[true, false]'
+  loop
+  if x then
+    raise notice 'true';
+  else
+    raise notice 'false';
+  end if;
+  end loop;
+end;
+$$;
+
+-- jsonb to jsonb
+do $$
+declare x jsonb;
+begin
+  foreach x in json array '[10,20,30,3.14, null, "Hi"]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+-- jsonb to json
+do $$
+declare x json;
+begin
+  foreach x in json array '[10,20,30,3.14, null, "Hi"]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+-- iteration over composites
+do $$
+declare x int; y numeric; z varchar;
+begin
+  foreach x, y, z in json array '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]'
+  loop
+    raise notice 'x: %, y: %, z: %', x, y, z;
+  end loop;
+end;
+$$;
+
+create type t3 as (x int, y numeric, z varchar);
+
+do $$
+declare c t3;
+begin
+  foreach c in json array '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]'
+  loop
+    raise notice 'x: %, y: %, z: %', c.x, c.y, c.z;
+  end loop;
+end;
+$$;
+
+do $$
+declare c t3;
+begin
+  foreach c.x, c.y, c.z in json array '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]'
+  loop
+    raise notice 'x: %, y: %, z: %', c.x, c.y, c.z;
+  end loop;
+end;
+$$;
+
+drop type t3;
+
+-- target can be a array
+do $$
+declare x int[];
+begin
+  foreach x in json array '[[1,2,3],[4,5,6]]'
+  loop
+    raise notice '% % %', x[1], x[2], x[3];
+  end loop;
+end;
+$$;
+
+do $$
+declare x varchar[];
+begin
+  foreach x in json array '[["Hi","Hello"],["Hello","Hi"]]'
+  loop
+    raise notice '% %', x[1], x[2];
+  end loop;
+end;
+$$;
+
+do $$
+declare x varchar[];
+begin
+  foreach x in json array '[["Hi","Hello"],["Hello","Hi"]]'
+  loop
+    raise notice '% %', x[1], x[2];
+  end loop;
+end;
+$$;
+
+
+do $$
+declare x int[]; y varchar;
+begin
+  foreach x, y in json array '[{"x":[1,2,3], "y":"Hi"}, {"x":[4,5,6], "y":"Hi"}]'
+  loop
+    raise notice '% % %, y: %', x[1], x[2], x[3], y;
+  end loop;
+end;
+$$;
+
+create type t2 as (x int[], y varchar);
+
+do $$
+declare c t2;
+begin
+  foreach c in json array '[{"x":[1,2,3], "y":"Hi"}, {"x":[4,5,6], "y":"Hi"}]'
+  loop
+    raise notice '% % %, y: %', c.x[1], c.x[2], c.x[3], c.y;
+  end loop;
+end;
+$$;
+
+drop type t2;
-- 
2.53.0

---

From: Jim Jones <[email-masked]>
Date: Wed, 4 Mar 2026 12:35:17 +0100

I reviewed the code I have nothing to add at this point. LGTM!

The tests touch a lot of different scenarios, but for the sake of
completeness I'd like to suggest adding these three cases:

-- EXIT and CONTINUE can be triggered by LOOP_RC_PROCESSING
DO $$
DECLARE x int;
BEGIN
  FOREACH x IN JSON ARRAY '[1,2,3,4,5]'
  LOOP
    EXIT WHEN x = 3;
    RAISE NOTICE '%', x;
  END LOOP;
END;
$$;

DO $$
DECLARE x int;
BEGIN
  FOREACH x IN JSON ARRAY '[1,2,3,4,5]'
  LOOP
    CONTINUE WHEN x % 2 = 0;
    RAISE NOTICE '%', x;
  END LOOP;
END;
$$;

-- Variable instead of string
DO $$
DECLARE x int; arr jsonb;
BEGIN
  SELECT jsonb_agg(i) INTO arr
  FROM generate_series(1,3) i;

  FOREACH x IN JSON ARRAY arr
  LOOP
    RAISE NOTICE '%', x;
  END LOOP;
END;
$$;

Thanks!

Best, Jim

---

From: Pavel Stehule <[email-masked]>
Date: Wed, 4 Mar 2026 19:50:34 +0100

Hi

>   FOREACH x IN JSON ARRAY arr
I merged these examples to tests

Thank you for review

Regards

Pavel

> Best, Jim
From b4fb57ca7e20ddef5454f1742bb14670f4ab495c Mon Sep 17 00:00:00 2001
From: "[email-masked]" <[email-masked]>
Date: Mon, 23 Feb 2026 12:53:44 +0100
Subject: [PATCH] FOREACH scalar IN JSON ARRAY

DECLARE t int;
BEGIN

The performance (best case for iteration over 1000 fields array) is about
4x better than when FOR IN SELECT jsonb_array_elements is used.
---
 doc/src/sgml/plpgsql.sgml                     |  60 ++++
 src/pl/plpgsql/src/Makefile                   |   2 +-
 .../plpgsql/src/expected/plpgsql_foreach.out  | 297 ++++++++++++++++++
 src/pl/plpgsql/src/meson.build                |   1 +
 src/pl/plpgsql/src/pl_exec.c                  | 296 +++++++++++++++++
 src/pl/plpgsql/src/pl_funcs.c                 |  29 ++
 src/pl/plpgsql/src/pl_gram.y                  |  39 ++-
 src/pl/plpgsql/src/pl_unreserved_kwlist.h     |   1 +
 src/pl/plpgsql/src/plpgsql.h                  |  36 ++-
 src/pl/plpgsql/src/sql/plpgsql_foreach.sql    | 253 +++++++++++++++
 10 files changed, 1006 insertions(+), 8 deletions(-)
 create mode 100644 src/pl/plpgsql/src/expected/plpgsql_foreach.out
 create mode 100644 src/pl/plpgsql/src/sql/plpgsql_foreach.sql

index 561f6e50d63..761b3cd9d35 100644
 
+   <sect2 id="plpgsql-foreach-json-array">
+    <title>Looping through JSON arrays</title>
+
+    <para>
+     The <literal>FOREACH</literal> loop is much like a regular
+     <literal>FOREACH</literal> loop over arrays,
+     but instead of iterating through elements of the array,
+     it iterates through the elements of a JSON array value
+     (expression is internally casted to jsonb type).
+
+<synopsis>
+<optional> &lt;&lt;<replaceable>label</replaceable>&gt;&gt; </optional>
+FOREACH <replaceable>target</replaceable> IN JSON ARRAY <replaceable>expression</replaceable> LOOP
+    <replaceable>statements</replaceable>
+END LOOP <optional> <replaceable>label</replaceable> </optional>;
+</synopsis>
+    </para>
+
+    <para>
+     The target can be a scalar variable, a composite variable, or a list
+     of scalar variables. When variable is not scalar, then assigned value
+     should be a JSON object and the JSON attributes are assigned by names.
+
+<programlisting>
+CREATE FUNCTION print_elements(jsonb) RETURNS void AS $$
+DECLARE
+  x int;
+BEGIN
+  FOREACH x IN JSON ARRAY $1
+  LOOP
+    RAISE NOTICE 'row = %', x;
+  END LOOP;
+END;
+$$ LANGUAGE plpgsql;
+
+SELECT print_elements('[1,2,3]');
+NOTICE:  row = 1
+NOTICE:  row = 2
+NOTICE:  row = 3
+
+CREATE FUNCTION print_fields(jsonb) RETURNS void AS $$
+DECLARE
+  x int; y varchar;
+BEGIN
+  FOREACH x, y IN JSON ARRAY $1
+  LOOP
+    RAISE NOTICE 'x: %, y: %', x, y;
+  END LOOP;
+END;
+$$ LANGUAGE plpgsql;
+
+SELECT print_fields('[{},{"x":10},{"y":"Hi"},{"y":"Hi", "x":1000}]');
+NOTICE:  x: &lt;NULL&gt;, y: &lt;NULL&gt;
+NOTICE:  x: 10, y: &lt;NULL&gt;
+NOTICE:  x: &lt;NULL&gt;, y: Hi
+NOTICE:  x: 1000, y: Hi
+</programlisting>
+    </para>
+   </sect2>
+
    <sect2 id="plpgsql-error-trapping">
     <title>Trapping Errors</title>

index 00000000000..6d39560bade
@@ -0,0 +1,297 @@
+-- EXIT and CONTINUE can be triggered by LOOP_RC_PROCESSING
+  foreach x in json array '[1,2,3,4,5]'
+    exit when x = 3;
+NOTICE:  1
+NOTICE:  2
+  foreach x in json array '[1,2,3,4,5]'
+    continue when x % 2 = 0;
+NOTICE:  1
+NOTICE:  5
+-- Variable instead of string
+DO $$
+declare
+  arr jsonb;
+  select jsonb_agg(i) into arr
+    from generate_series(1,3) g(i);
+  foreach x in json array arr
+NOTICE:  1
+NOTICE:  2

+/*

+				E_WALK(fstmt->expr);
 
+static void

 

 
 
+foreach_type	:
+				  K_ARRAY
+					{
 
 /*

+/*
 
+/*
index 00000000000..0dde8d6fba4
+-- EXIT and CONTINUE can be triggered by LOOP_RC_PROCESSING
+do $$
+declare x int;
+begin
+  foreach x in json array '[1,2,3,4,5]'
+  loop
+    exit when x = 3;
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+do $$
+declare x int;
+begin
+  foreach x in json array '[1,2,3,4,5]'
+  loop
+    continue when x % 2 = 0;
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+-- Variable instead of string
+DO $$
+declare
+  x int;
+  arr jsonb;
+begin
+  select jsonb_agg(i) into arr
+    from generate_series(1,3) g(i);
+
+  foreach x in json array arr
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
-- 
2.53.0

---

From: Pavel Stehule <[email-masked]>
Date: Mon, 9 Mar 2026 07:44:03 +0100

po 9. 3. 2026 v 7:12 odesílatel Shreeya Sharma <[email-masked]>
napsal:

> The following review has been posted through the commitfest application:
> make installcheck-world:  tested, passed
> Implements feature:       tested, passed
> Spec compliant:           tested, passed
> Documentation:            tested, passed
>
> The changes are good
>
> The new status of this patch is: Ready for Committer
>

Thank you very much

Regards

Pavel

---

From: Peter Eisentraut <[email-masked]>
Date: Wed, 11 Mar 2026 21:57:58 +0100

> I wrote PoC for previously proposed plpgsql statement FOREACH IN JSON ARRAY

Maybe this could be written in such a way that it doesn't hardcode JSON 
arrays specifically, but a type could have an iteration helper function 
that would feed this feature?

---

From: Chao Li <[email-masked]>
Date: Thu, 12 Mar 2026 11:54:52 +0800

> On Mar 5, 2026, at 02:50, Pavel Stehule <[email-masked]> wrote:
> 
> Hi
> 
> st 4. 3. 2026 v 12:35 odesílatel Jim Jones <[email-masked]> napsal:
> <v20260304-5-0001-FOREACH-scalar-IN-JSON-ARRAY.patch>

I just reviewed and tested the patch. Here comes my comments:

1 - pl_gram.y
```
+								ereport(ERROR,
```

* () around errcode and errmsg are no longer needed. This comment is general, and I saw other ereport() also use () in this patch.
* parser_errposition should have the same indention as errmsg.

2 - pl_exec.c
```
```

Typo: a -> an

3 - pl_exec.c
```
```

Do we need to destroy tmp_cxt after the loop?

4 Looks like record type of loop var is not supported:
```
evantest=# do $$
declare
  r record;
begin
  foreach r in json array '[{"x":1,"y":"hi"},{"x":2,"y":"hello"}]’
  loop
    raise notice 'x: %, y: %', r.x, r.y; 
  end loop;
end;
$$;
ERROR:  record type has not been registered
CONTEXT:  PL/pgSQL function inline_code_block line 5 at FOREACH over json array
```

So, I want to check if you intentionally don’t want to support that or just missed that? If it’s not supported, then maybe document that.

5 I tried that composite type of loop var is supported, maybe add a test case for that. What I tested:
```
create type t_foreach_json_row as (
  x int,
  y text,
  z numeric
);

do $$
declare
  r t_foreach_json_row;
begin
  foreach r in json array
    '[{"x":1,"y":"one","z":1.5},
      {"x":2,"y":"two"},
      {"y":"three","z":3.14},
      {}]'
  loop
    raise notice 'x=%, y=%, z=%', r.x, r.y, r.z;
  end loop;
end;
$$;

drop type t_foreach_json_row;
```

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/

---

From: Pavel Stehule <[email-masked]>
Date: Thu, 12 Mar 2026 08:00:19 +0100

Hi

čt 12. 3. 2026 v 5:30 odesílatel Tom Lane <[email-masked]> napsal:

> Peter Eisentraut <[email-masked]> writes:
> +1.  ISTM that this feature would make sense for subscriptable types,
> so one way to shoehorn it into the system without a lot of new overhead
> could be to extend struct SubscriptRoutines to offer optional support
> function(s) for iterating through all the elements of a subscriptable
> object.
>

I'll try to write second patch in this way

Regards

Pavel

>                         regards, tom lane

---

From: Pavel Stehule <[email-masked]>
Date: Thu, 12 Mar 2026 11:38:11 +0100

Hi

čt 12. 3. 2026 v 4:55 odesílatel Chao Li <[email-masked]> napsal:

>      (errcode(ERRCODE_SYNTAX_ERROR),
> +
>       errmsg("not zero slice is allowed only for arrays"),
> +
>                       parser_errposition(@4)));
> ```
>
> * () around errcode and errmsg are no longer needed. This comment is
> general, and I saw other ereport() also use () in this patch.

fixed

fixed

>  "FOREACH IN JSON ARRAY temporary cxt",
> +
>  ALLOCSET_DEFAULT_SIZES);
> ```
>

no - it is cleaned by MemoryContextReset(stmt_mcontext);

> So, I want to check if you intentionally don’t want to support that or
> just missed that? If it’s not supported, then maybe document that.
>

It is intentional at this moment (and I think so it will be in future too).
For reading fields from a json object I use the json_populate_type
function, and this function needs a known tupdesc. Generally JSON objects
have no fixed structure, and when a record's variable has no assigned type,
then we have to create new tupdesc for each value. This can be possibly
slow and memory expensive. Probably - I never tested this case. It is valid
use case, but it can be solved in later - and the support will be more
invasive - requires support in json_populate_type

I enhanced doc

    <para>
     The target variable can be of type RECORD, but the real structure has
to be
     assigned before usage in FOREACH statement.
    </para>

> drop type t_foreach_json_row;

it is there already

create type t3 as (x int, y numeric, z varchar);

do $$
declare c t3;
begin
  foreach c in json array '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10,
"y":3.14}]'
  loop
    raise notice 'x: %, y: %, z: %', c.x, c.y, c.z;
  end loop;
end;
$$;

assigned updated version -

I'll try to modify this patch like Tom proposed in the next version. But
the fundament behavior should be same

Thank you for check and testing

Regards

Pavel

> Best regards,
From 0798d478ddbfa1676ace2dafe8bd8441423a56a4 Mon Sep 17 00:00:00 2001
From: "[email-masked]" <[email-masked]>
Date: Mon, 23 Feb 2026 12:53:44 +0100
Subject: [PATCH] FOREACH scalar IN JSON ARRAY

DECLARE t int;
BEGIN

 doc/src/sgml/plpgsql.sgml                     |  65 ++++
 10 files changed, 1011 insertions(+), 8 deletions(-)

diff --git a/doc/src/sgml/plpgsql.sgml b/doc/src/sgml/plpgsql.sgml
index 561f6e50d63..4a27e013f2a 100644
--- a/doc/src/sgml/plpgsql.sgml
+++ b/doc/src/sgml/plpgsql.sgml
@@ -2780,6 +2780,71 @@ NOTICE:  row = {10,11,12}
     </para>
    </sect2>
 
+     The target variable can be of type <literal>RECORD</literal>, but the real structure has to be
+     assigned before usage in the <literal>FOREACH</literal> statement.

index 00000000000..090da983848
+DETAIL:  Cannot iterate over an object value.
index 84552e32c87..2e108d7e918 100644

+/*
+				 errdetail("Cannot iterate over an object value.")));

+				E_WALK(fstmt->expr);
 
+static void
index 5009e59a78f..c760e04d66b 100644

 

 
 
+foreach_type	:
+				  K_ARRAY
+					{
 
 /*

+/*
 
+/*

---

From: Pavel Stehule <[email-masked]>
Date: Tue, 17 Mar 2026 07:58:20 +0100

Hi

>> function(s) for iterating through all the elements of a subscriptable
attached patch do this - new interface has two
methods: CreateForeachAIterator and iterate

diff --git a/src/include/nodes/subscripting.h
b/src/include/nodes/subscripting.h
index 301f21dac2f..08bfe59ede4 100644
--- a/src/include/nodes/subscripting.h
+++ b/src/include/nodes/subscripting.h
@@ -154,6 +154,32 @@ typedef void (*SubscriptExecSetup) (const
SubscriptingRef *sbsref,
                                    SubscriptingRefState *sbsrefstate,
                                    SubscriptExecSteps *methods);

+typedef struct _ForeachAIterator ForeachAIterator;
+
+/*
+ * ForeachAIiterator is used by PLpgSQL FOREACH IN ARRAY statement.
+ * Input value should not be null, and inside CreateForeachAIterator
+ * routine must be copied to current (statement) context. "iterate"
+ * routine is called under short life memory context, that is resetted
+ * after any call.
+ */
+struct _ForeachAIterator
+{
+   bool        (*iterate) (ForeachAIterator *self,
+                           Datum *value,
+                           bool *isnull,
+                           Oid *typid,
+                           int32 *typmod);
+   /* Private fields might appear beyond this point... */
+};
+
+typedef ForeachAIterator * (*CreateForeachAIterator) (Datum value,
+                                                     Oid typid,
+                                                     int32 typmod,
+                                                     int slice,
+                                                     Oid target_typid,
+                                                     int32 target_typmod);
+
 /* Struct returned by the SQL-visible subscript handler function */
 typedef struct SubscriptRoutines
 {
@@ -163,6 +189,9 @@ typedef struct SubscriptRoutines
    bool        fetch_leakproof;    /* is fetch SubscriptingRef leakproof?
*/
    bool        store_leakproof;    /* is assignment SubscriptingRef
                                     * leakproof? */
+
+   /* returns iterator used by PL/pgSQL FOREACH statement */
+   CreateForeachAIterator create_foreach_a_iterator;
 } SubscriptRoutines;

 #endif                         /* SUBSCRIPTING_H */

Regards

Pavel

>>                         regards, tom lane
From b7b6509381a7d6b4629b3b25ebb4a189b1eb34be Mon Sep 17 00:00:00 2001
From: "[email-masked]" <[email-masked]>
Date: Mon, 23 Feb 2026 12:53:44 +0100
Subject: [PATCH] FOREACH scalar IN ARRAY jsonb_expr

this patch introduce support FOREACH scalar_var IN ARRAY expr, when the
result of the expression can be Jsonb. The design is based
on behave of jsonb_array_elements functions. In this case, FOREACH enforce
casting to target type (because we know target type) and try to reduce
IO casting. Attention: IO casting can be more strict, then casting based
on cast functions.

DECLARE t int;
BEGIN
  -- this can work because we use cast numeric -> int
  FOREACH t IN ARRAY '[1,2,3.14]'::jsonb
  LOOP

  -- this fails, because IO cast is used, and integer input function
  -- allows only digits
  FOREAC t IN JSON ARRAY '[1,2,3,"3.14"]'::jsonb
  LOOP

  FOREACH t IN ARRAY '[1,2,3]' ERROR ON EMPTY ERROR ON ERROR
  LOOP
    ...

Because we use "old" syntax - FOREACH IN ARRAY, I prefer "old" behaviour,
that is more similar to iteration over an array.

The performance (best case for iteration over 1000 fields array) is about
4x better than when FOR IN SELECT jsonb_array_elements is used.
---
 doc/src/sgml/plpgsql.sgml                     |  62 +++-
 src/backend/utils/adt/arraysubs.c             |  97 +++++-
 src/backend/utils/adt/jsonbsubs.c             | 181 ++++++++++-
 src/include/nodes/subscripting.h              |  29 ++
 src/pl/plpgsql/src/Makefile                   |   2 +-
 .../plpgsql/src/expected/plpgsql_foreach.out  | 297 ++++++++++++++++++
 src/pl/plpgsql/src/meson.build                |   1 +
 src/pl/plpgsql/src/pl_exec.c                  | 189 +++++------
 src/pl/plpgsql/src/plpgsql.h                  |   3 +-
 src/pl/plpgsql/src/sql/plpgsql_foreach.sql    | 252 +++++++++++++++
 10 files changed, 1016 insertions(+), 97 deletions(-)
 create mode 100644 src/pl/plpgsql/src/expected/plpgsql_foreach.out
 create mode 100644 src/pl/plpgsql/src/sql/plpgsql_foreach.sql

diff --git a/doc/src/sgml/plpgsql.sgml b/doc/src/sgml/plpgsql.sgml
index 561f6e50d63..6bc9fb02e1e 100644
--- a/doc/src/sgml/plpgsql.sgml
+++ b/doc/src/sgml/plpgsql.sgml
@@ -2697,12 +2697,12 @@ END LOOP <optional> <replaceable>label</replaceable> </optional>;
    </sect2>
 
    <sect2 id="plpgsql-foreach-array">
-    <title>Looping through Arrays</title>
+    <title>Looping through Arrays or Jsonb arrays</title>
 
     <para>
      The <literal>FOREACH</literal> loop is much like a <literal>FOR</literal> loop,
      but instead of iterating through the rows returned by an SQL query,
-     it iterates through the elements of an array value.
+     it iterates through the elements of an array value or of jsonb array value.
      (In general, <literal>FOREACH</literal> is meant for looping through
      components of a composite-valued expression; variants for looping
      through composites besides arrays may be added in future.)
@@ -2778,6 +2778,64 @@ NOTICE:  row = {7,8,9}
 NOTICE:  row = {10,11,12}
 </programlisting>
     </para>
+
+    <para>
+     The <literal>SLICE</literal> higher than zero cannot be used when iterates
+     through jsonb arrays.
+    </para>
+
+    <para>
+     The <literal>FOREACH</literal> loop over jsonb arrays uses
+     same syntax like <literal>FOREACH</literal> loop over arrays,
+     but instead of iterating through elements of the array,
+     it iterates through the elements of a Jsonb array value.
+    </para>
+
+    <para>
+     The target can be a scalar variable, a composite variable, or a list
+     of scalar variables. When variable is not scalar, then assigned value
+     should be a JSON object and the JSON attributes are assigned by names.
+
+<programlisting>
+CREATE FUNCTION print_elements(jsonb) RETURNS void AS $$
+DECLARE
+  x int;
+BEGIN
+  FOREACH x IN ARRAY $1
+  LOOP
+    RAISE NOTICE 'row = %', x;
+  END LOOP;
+END;
+$$ LANGUAGE plpgsql;
+
+SELECT print_elements('[1,2,3]');
+NOTICE:  row = 1
+NOTICE:  row = 2
+NOTICE:  row = 3
+
+CREATE FUNCTION print_fields(jsonb) RETURNS void AS $$
+DECLARE
+  x int; y varchar;
+BEGIN
+  FOREACH x, y IN ARRAY $1
+  LOOP
+    RAISE NOTICE 'x: %, y: %', x, y;
+  END LOOP;
+END;
+$$ LANGUAGE plpgsql;
+
+SELECT print_fields('[{},{"x":10},{"y":"Hi"},{"y":"Hi", "x":1000}]');
+NOTICE:  x: &lt;NULL&gt;, y: &lt;NULL&gt;
+NOTICE:  x: 10, y: &lt;NULL&gt;
+NOTICE:  x: &lt;NULL&gt;, y: Hi
+NOTICE:  x: 1000, y: Hi
+</programlisting>
+    </para>
+
+    <para>
+     The target variable can be of type <literal>RECORD</literal>, but the real structure has to be
+     assigned before usage in the <literal>FOREACH</literal> statement.
+    </para>
    </sect2>
 
    <sect2 id="plpgsql-error-trapping">
diff --git a/src/backend/utils/adt/arraysubs.c b/src/backend/utils/adt/arraysubs.c
index 2bf9e9509fb..a42248ed633 100644
--- a/src/backend/utils/adt/arraysubs.c
+++ b/src/backend/utils/adt/arraysubs.c
@@ -23,6 +23,7 @@
 #include "parser/parse_coerce.h"
 #include "parser/parse_expr.h"
 #include "utils/array.h"
+#include "utils/builtins.h"
 #include "utils/fmgrprotos.h"
 #include "utils/lsyscache.h"
 
@@ -46,6 +47,96 @@ typedef struct ArraySubWorkspace
 	int			lowerindex[MAXDIM];
 } ArraySubWorkspace;
 
+typedef struct
+{
+	ForeachAIterator pub;
+	ArrayIterator it;
+	Oid			result_typid;
+	int32		result_typmod;
+} ForeachAArrayIterState;
+
+static bool
+foreach_a_array_iterate(ForeachAIterator *self,
+						Datum *value, bool *isnull,
+						Oid *typid, int32 *typmod)
+{
+	ForeachAArrayIterState *iter = (ForeachAArrayIterState *) self;
+
+	*typid = iter->result_typid;
+	*typmod = iter->result_typmod;
+
+	return array_iterate(iter->it, value, isnull);
+}
+
+/*
+ * Used by plpgsql FOREACH IN ARRAY when input expression is an array
+ */
+static ForeachAIterator *
+create_foreach_a_array_iterator(Datum value, Oid typid, int32 typmod,
+								int slice, Oid target_typid, int32 target_typmod)
+{
+	ForeachAArrayIterState *iter = palloc0(sizeof(ForeachAArrayIterState));
+	ArrayType  *arr;
+	Oid			target_elem_typid;
+
+	/* check the type of the expression - must be an array */
+	if (!OidIsValid(get_element_type(typid)))
+		ereport(ERROR,
+				(errcode(ERRCODE_DATATYPE_MISMATCH),
+				 errmsg("FOREACH expression must yield an array, not type %s",
+						format_type_be(typid))));
+
+	/*
+	 * We must copy the array into current context, because input expression
+	 * is evaluated in context cleaned by exec_eval_cleanup.
+	 */
+	arr = DatumGetArrayTypePCopy(value);
+
+	/* Slice dimension must be less than or equal to array dimension */
+	if (slice < 0 || slice > ARR_NDIM(arr))
+		ereport(ERROR,
+				(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
+				 errmsg("slice dimension (%d) is out of the valid range 0..%d",
+						slice, ARR_NDIM(arr))));
+
+	/*
+	 * Sanity-check the target type.  We don't try very hard here, and
+	 * should not be too picky since it's possible that exec_assign_value can
+	 * coerce values of different types.  But it seems worthwhile to complain
+	 * if the array-ness of the loop variable is not right.
+	 */
+	target_elem_typid = get_element_type(target_typid);
+
+	if (slice > 0 && target_elem_typid == InvalidOid)
+		ereport(ERROR,
+				(errcode(ERRCODE_DATATYPE_MISMATCH),
+				 errmsg("FOREACH ... SLICE loop variable must be of an array type")));
+	if (slice == 0 && target_elem_typid != InvalidOid)
+		ereport(ERROR,
+				(errcode(ERRCODE_DATATYPE_MISMATCH),
+				 errmsg("FOREACH loop variable must not be of an array type")));
+
+	/* Identify iterator result type */
+	if (slice > 0)
+	{
+		/* When slicing, nominal type of result is same as array type */
+		iter->result_typid = typid;
+		iter->result_typmod = typmod;
+	}
+	else
+	{
+		/* Without slicing, results are individual array elements */
+		iter->result_typid = ARR_ELEMTYPE(arr);
+		iter->result_typmod = typmod;
+	}
+
+	/* Create an iterator to step through the array */
+	iter->it = array_create_iterator(arr, slice, NULL);
+
+	iter->pub.iterate = foreach_a_array_iterate;
+
+	return (ForeachAIterator *) iter;
+}
 
 /*
  * Finish parse analysis of a SubscriptingRef expression for an array.
@@ -545,7 +636,8 @@ array_subscript_handler(PG_FUNCTION_ARGS)
 		.exec_setup = array_exec_setup,
 		.fetch_strict = true,	/* fetch returns NULL for NULL inputs */
 		.fetch_leakproof = true,	/* fetch returns NULL for bad subscript */
-		.store_leakproof = false	/* ... but assignment throws error */
+		.store_leakproof = false,	/* ... but assignment throws error */
+		.create_foreach_a_iterator = create_foreach_a_array_iterator
 	};
 
 	PG_RETURN_POINTER(&sbsroutines);
@@ -572,7 +664,8 @@ raw_array_subscript_handler(PG_FUNCTION_ARGS)
 		.exec_setup = array_exec_setup,
 		.fetch_strict = true,	/* fetch returns NULL for NULL inputs */
 		.fetch_leakproof = true,	/* fetch returns NULL for bad subscript */
-		.store_leakproof = false	/* ... but assignment throws error */
+		.store_leakproof = false,	/* ... but assignment throws error */
+		.create_foreach_a_iterator = create_foreach_a_array_iterator
 	};
 
 	PG_RETURN_POINTER(&sbsroutines);
diff --git a/src/backend/utils/adt/jsonbsubs.c b/src/backend/utils/adt/jsonbsubs.c
index f2745b29a3f..ad2edf525de 100644
--- a/src/backend/utils/adt/jsonbsubs.c
+++ b/src/backend/utils/adt/jsonbsubs.c
@@ -22,6 +22,7 @@
 #include "parser/parse_expr.h"
 #include "utils/builtins.h"
 #include "utils/jsonb.h"
+#include "utils/jsonfuncs.h"

 /* SubscriptingRefState.workspace for jsonb subscripting execution */
@@ -33,6 +34,17 @@ typedef struct JsonbSubWorkspace
 	Datum	   *index;			/* Subscript values in Datum format */
 } JsonbSubWorkspace;
 
+typedef struct
+{
+	ForeachAIterator pub;
+	JsonbIterator *it;
+	bool		skip_nested;
+	Oid			target_typid;
+	int32		target_typmod;
+
+	MemoryContext cache_mcxt;
+	void	   *cache;
+} ForeachAJsonbIterState;
 
 /*
  * Finish parse analysis of a SubscriptingRef expression for a jsonb.
@@ -394,6 +406,172 @@ jsonb_exec_setup(const SubscriptingRef *sbsref,
 	methods->sbs_fetch_old = jsonb_subscript_fetch_old;
 }
 
+/*
+ * Convert JsonbValue to Datum. This function is used in
+ * generic array iterator, that is used by FOREACH plpgsql
+ * statement. Against other cases, the result should not be
+ * necessary of expected_typid, because the value can be
+ * converted later when the value is assigned to PL/pgSQL
+ * variable. This can be more effective than generic IO
+ * cast used by json_populate_type.
+ */
+static Datum
+JsonbValueToDatum(JsonbValue *jbv,
+				  Oid *typid, int32 *typmod, bool *isnull,
+				  Oid expected_typid, int32 expected_typmod,
+				  void **cache, MemoryContext mcxt)
+{
+	Datum		result;
+
+	*isnull = false;
+	*typmod = -1;
+
+	/*
+	 * These types can holds JSON null, so must be processed
+	 * before processing jbvNull. We don't want to convert
+	 * JSON null, to SQL null, when targer is of JSON.
+	 */
+	if (expected_typid == JSONBOID || expected_typid == JSONOID)
+	{
+		Jsonb	   *jb = JsonbValueToJsonb(jbv);
+
+		if (expected_typid == JSONOID)
+		{
+			char	   *str;
+
+			str = JsonbToCString(NULL, &jb->root, VARSIZE(jb));
+			result = PointerGetDatum(cstring_to_text(str));
+		}
+		else
+			result = PointerGetDatum(jb);
+
+		*typid = expected_typid;
+	}
+
+	/*
+	 * For special cases we can skip conversion to Jsonb
+	 * and possibly IO cast.
+	 */
+	else if (jbv->type == jbvNull)
+	{
+		result = (Datum) 0;
+		*isnull = true;
+		*typid = expected_typid;
+	}
+	else if (jbv->type == jbvString)
+	{
+		text	   *txt = cstring_to_text_with_len(jbv->val.string.val,
+												   jbv->val.string.len);
+
+		result = PointerGetDatum(txt);
+		*typid = TEXTOID;
+	}
+	else if (jbv->type == jbvNumeric)
+	{
+		result = PointerGetDatum(jbv->val.numeric);
+		*typid = NUMERICOID;
+	}
+	else if (jbv->type == jbvBool)
+	{
+		result = BoolGetDatum(jbv->val.boolean);
+		*typid = BOOLOID;
+	}
+
+	/* generic conversion */
+	else
+	{
+		Jsonb	   *jb = JsonbValueToJsonb(jbv);
+
+		result = json_populate_type(PointerGetDatum(jb), JSONBOID,
+									expected_typid, expected_typmod,
+									cache, mcxt,
+									isnull, false, NULL);
+
+		*typid = expected_typid;
+		*typmod = expected_typmod;
+	}
+
+	return result;
+}
+
+static bool
+foreach_a_jsonb_iterate(ForeachAIterator *self,
+						Datum *value, bool *isnull,
+						Oid *typid, int32 *typmod)
+{
+	ForeachAJsonbIterState *iter = (ForeachAJsonbIterState *) self;
+	JsonbIteratorToken r;
+	JsonbValue	jbv;
+
+	while ((r = JsonbIteratorNext(&iter->it, &jbv, iter->skip_nested)) != WJB_DONE)
+	{
+		iter->skip_nested = true;
+
+		if (r == WJB_ELEM)
+		{
+			*value = JsonbValueToDatum(&jbv, typid, typmod, isnull,
+									   iter->target_typid, iter->target_typmod,
+									   &iter->cache, iter->cache_mcxt);
+
+			return true;
+		}
+	}
+
+	return false;
+}
+
+/*
+ * Create foreach array iterator for jsonb array
+ */
+static ForeachAIterator *
+create_foreach_a_jsonb_iterator(Datum value, Oid typid, int32 typmod,
+								int slice, Oid target_typid, int32 target_typmod)
+{
+	ForeachAJsonbIterState *iter = palloc0(sizeof(ForeachAJsonbIterState));
+	Jsonb	   *jb;
+
+	if (typid != JSONBOID)
+		elog(ERROR, "unexpected source type");
+
+	if (slice > 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("jsonb array iterator doesn't support slicing")));
+
+	/*
+	 * We must copy the JSON into current context, because input expression
+	 * is evaluated in context cleaned by exec_eval_cleanup.
+	 */
+	jb = DatumGetJsonbPCopy(value);
+
+	/*
+	 * Jsonb iterator is designed like jsonb_array_element. Input value
+	 * must be json array.
+	 */
+	if (JB_ROOT_IS_SCALAR(jb))
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("FOREACH expression must evaluate to a JSON array"),
+				 errhint("Cannot iterate over a scalar value.")));
+	else if (JB_ROOT_IS_OBJECT(jb))
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("FOREACH expression must evaluate to a JSON array"),
+				 errdetail("Cannot iterate over an object value.")));
+
+	Assert(JB_ROOT_IS_ARRAY(jb));
+
+	iter->it = JsonbIteratorInit(&jb->root);
+
+	iter->target_typid = target_typid;
+	iter->target_typmod = target_typmod;
+	iter->cache_mcxt = CurrentMemoryContext;
+
+	iter->pub.iterate = foreach_a_jsonb_iterate;
+
+	return (ForeachAIterator *) iter;
+}
+
 /*
  * jsonb_subscript_handler
  *		Subscripting handler for jsonb.
@@ -407,7 +585,8 @@ jsonb_subscript_handler(PG_FUNCTION_ARGS)
 		.exec_setup = jsonb_exec_setup,
 		.fetch_strict = true,	/* fetch returns NULL for NULL inputs */
 		.fetch_leakproof = true,	/* fetch returns NULL for bad subscript */
-		.store_leakproof = false	/* ... but assignment throws error */
+		.store_leakproof = false,	/* ... but assignment throws error */
+		.create_foreach_a_iterator = create_foreach_a_jsonb_iterator
 	};
 
 	PG_RETURN_POINTER(&sbsroutines);
diff --git a/src/include/nodes/subscripting.h b/src/include/nodes/subscripting.h
index 301f21dac2f..08bfe59ede4 100644
--- a/src/include/nodes/subscripting.h
+++ b/src/include/nodes/subscripting.h
@@ -154,6 +154,32 @@ typedef void (*SubscriptExecSetup) (const SubscriptingRef *sbsref,
 									SubscriptingRefState *sbsrefstate,
 									SubscriptExecSteps *methods);
 
+typedef struct _ForeachAIterator ForeachAIterator;
+
+/*
+ * ForeachAIiterator is used by PLpgSQL FOREACH IN ARRAY statement.
+ * Input value should not be null, and inside CreateForeachAIterator
+ * routine must be copied to current (statement) context. "iterate"
+ * routine is called under short life memory context, that is resetted
+ * after any call.
+ */
+struct _ForeachAIterator
+{
+	bool		(*iterate) (ForeachAIterator *self,
+							Datum *value,
+							bool *isnull,
+							Oid *typid,
+							int32 *typmod);
+	/* Private fields might appear beyond this point... */
+};
+
+typedef ForeachAIterator * (*CreateForeachAIterator) (Datum value,
+													  Oid typid,
+													  int32 typmod,
+													  int slice,
+													  Oid target_typid,
+													  int32 target_typmod);
+
 /* Struct returned by the SQL-visible subscript handler function */
 typedef struct SubscriptRoutines
 {
@@ -163,6 +189,9 @@ typedef struct SubscriptRoutines
 	bool		fetch_leakproof;	/* is fetch SubscriptingRef leakproof? */
 	bool		store_leakproof;	/* is assignment SubscriptingRef
 									 * leakproof? */
+
+	/* returns iterator used by PL/pgSQL FOREACH statement */
+	CreateForeachAIterator create_foreach_a_iterator;
 } SubscriptRoutines;
 
 #endif							/* SUBSCRIPTING_H */
 
 # where to find gen_keywordlist.pl and subsidiary files
 TOOLSDIR = $(top_srcdir)/src/tools
diff --git a/src/pl/plpgsql/src/expected/plpgsql_foreach.out b/src/pl/plpgsql/src/expected/plpgsql_foreach.out
new file mode 100644
index 00000000000..ddc571f3c79
--- /dev/null
+++ b/src/pl/plpgsql/src/expected/plpgsql_foreach.out
@@ -0,0 +1,297 @@
+-- input must be a JSON array
+do $$
+declare x numeric;
+begin
+  foreach x in array NULL::jsonb -- fail
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+ERROR:  FOREACH expression must not be null
+CONTEXT:  PL/pgSQL function inline_code_block line 4 at FOREACH over array
+do $$
+declare x numeric;
+begin
+  foreach x in array jsonb '10' -- fail
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+ERROR:  FOREACH expression must evaluate to a JSON array
+HINT:  Cannot iterate over a scalar value.
+CONTEXT:  PL/pgSQL function inline_code_block line 4 at FOREACH over array
+do $$
+declare x numeric;
+begin
+  foreach x in array jsonb '{}' -- fail
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+ERROR:  FOREACH expression must evaluate to a JSON array
+DETAIL:  Cannot iterate over an object value.
+CONTEXT:  PL/pgSQL function inline_code_block line 4 at FOREACH over array
+-- numeric to numeric
+do $$
+declare x numeric;
+begin
+  foreach x in array jsonb '[10,20,30,3.14, null]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+NOTICE:  10
+NOTICE:  20
+NOTICE:  30
+NOTICE:  3.14
+NOTICE:  <NULL>
+-- numeric to int by cast
+do $$
+declare x int;
+begin
+  foreach x in array jsonb '[10,20,30,3.14, null]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+NOTICE:  10
+NOTICE:  20
+NOTICE:  30
+NOTICE:  3
+NOTICE:  <NULL>
+-- test of FOUND variable
+do $$
+declare x int;
+begin
+  foreach x in array jsonb '[10]'
+  loop
+    raise notice '%', x;
+  end loop;
+  raise notice 'FOUND: %', found;
+end;
+$$;
+NOTICE:  10
+NOTICE:  FOUND: t
+-- test of FOUND variable
+do $$
+declare x int;
+begin
+  foreach x in array jsonb '[]'
+  loop
+    raise notice '%', x;
+  end loop;
+  raise notice 'FOUND: %', found;
+end;
+$$;
+NOTICE:  FOUND: f
+-- conversion "3.14" to int should to fail due IO cast
+do $$
+declare x int;
+begin
+  foreach x in array jsonb '["10",20,30,"3.14"]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+NOTICE:  10
+NOTICE:  20
+NOTICE:  30
+ERROR:  invalid input syntax for type integer: "3.14"
+CONTEXT:  PL/pgSQL function inline_code_block line 4 at FOREACH over array
+do $$
+declare x boolean;
+begin
+  foreach x in array jsonb '[true, false]'
+  loop
+  if x then
+    raise notice 'true';
+  else
+    raise notice 'false';
+  end if;
+  end loop;
+end;
+$$;
+NOTICE:  true
+NOTICE:  false
+-- jsonb to jsonb
+do $$
+declare x jsonb;
+begin
+  foreach x in array jsonb '[10,20,30,3.14, null, "Hi"]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+NOTICE:  10
+NOTICE:  20
+NOTICE:  30
+NOTICE:  3.14
+NOTICE:  null
+NOTICE:  "Hi"
+-- jsonb to json
+do $$
+declare x json;
+begin
+  foreach x in array jsonb '[10,20,30,3.14, null, "Hi"]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+NOTICE:  10
+NOTICE:  20
+NOTICE:  30
+NOTICE:  3.14
+NOTICE:  null
+NOTICE:  "Hi"
+-- iteration over composites
+do $$
+declare x int; y numeric; z varchar;
+begin
+  foreach x, y, z in array jsonb '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]'
+  loop
+    raise notice 'x: %, y: %, z: %', x, y, z;
+  end loop;
+end;
+$$;
+NOTICE:  x: <NULL>, y: <NULL>, z: <NULL>
+NOTICE:  x: <NULL>, y: <NULL>, z: Hi
+NOTICE:  x: <NULL>, y: 3.14, z: <NULL>
+NOTICE:  x: 10, y: 3.14, z: Hi
+create type t3 as (x int, y numeric, z varchar);
+do $$
+declare c t3;
+begin
+  foreach c in array jsonb '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]'
+  loop
+    raise notice 'x: %, y: %, z: %', c.x, c.y, c.z;
+  end loop;
+end;
+$$;
+NOTICE:  x: <NULL>, y: <NULL>, z: <NULL>
+NOTICE:  x: <NULL>, y: <NULL>, z: Hi
+NOTICE:  x: <NULL>, y: 3.14, z: <NULL>
+NOTICE:  x: 10, y: 3.14, z: Hi
+do $$
+declare c t3;
+begin
+  foreach c.x, c.y, c.z in array jsonb '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]'
+  loop
+    raise notice 'x: %, y: %, z: %', c.x, c.y, c.z;
+  end loop;
+end;
+$$;
+NOTICE:  x: <NULL>, y: <NULL>, z: <NULL>
+NOTICE:  x: <NULL>, y: <NULL>, z: Hi
+NOTICE:  x: <NULL>, y: 3.14, z: <NULL>
+NOTICE:  x: 10, y: 3.14, z: Hi
+drop type t3;
+-- target can be a array
+do $$
+declare x int[];
+begin
+  foreach x in array jsonb '[[1,2,3],[4,5,6]]'
+  loop
+    raise notice '% % %', x[1], x[2], x[3];
+  end loop;
+end;
+$$;
+NOTICE:  1 2 3
+NOTICE:  4 5 6
+do $$
+declare x varchar[];
+begin
+  foreach x in array jsonb '[["Hi","Hello"],["Hello","Hi"]]'
+  loop
+    raise notice '% %', x[1], x[2];
+  end loop;
+end;
+$$;
+NOTICE:  Hi Hello
+NOTICE:  Hello Hi
+do $$
+declare x varchar[];
+begin
+  foreach x in array jsonb '[["Hi","Hello"],["Hello","Hi"]]'
+  loop
+    raise notice '% %', x[1], x[2];
+  end loop;
+end;
+$$;
+NOTICE:  Hi Hello
+NOTICE:  Hello Hi
+do $$
+declare x int[]; y varchar;
+begin
+  foreach x, y in array jsonb '[{"x":[1,2,3], "y":"Hi"}, {"x":[4,5,6], "y":"Hi"}]'
+  loop
+    raise notice '% % %, y: %', x[1], x[2], x[3], y;
+  end loop;
+end;
+$$;
+NOTICE:  1 2 3, y: Hi
+NOTICE:  4 5 6, y: Hi
+create type t2 as (x int[], y varchar);
+do $$
+declare c t2;
+begin
+  foreach c in array jsonb '[{"x":[1,2,3], "y":"Hi"}, {"x":[4,5,6], "y":"Hi"}]'
+  loop
+    raise notice '% % %, y: %', c.x[1], c.x[2], c.x[3], c.y;
+  end loop;
+end;
+$$;
+NOTICE:  1 2 3, y: Hi
+NOTICE:  4 5 6, y: Hi
+drop type t2;
+-- EXIT and CONTINUE can be triggered by LOOP_RC_PROCESSING
+do $$
+declare x int;
+begin
+  foreach x in array jsonb  '[1,2,3,4,5]'
+  loop
+    exit when x = 3;
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+NOTICE:  1
+NOTICE:  2
+do $$
+declare x int;
+begin
+  foreach x in array jsonb '[1,2,3,4,5]'
+  loop
+    continue when x % 2 = 0;
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+NOTICE:  1
+NOTICE:  3
+NOTICE:  5
+-- Variable instead of string
+DO $$
+declare
+  x int;
+  arr jsonb;
+begin
+  select jsonb_agg(i) into arr
+    from generate_series(1,3) g(i);
+
+  foreach x in array arr
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+NOTICE:  1
+NOTICE:  2
+NOTICE:  3
diff --git a/src/pl/plpgsql/src/meson.build b/src/pl/plpgsql/src/meson.build
index 6ff27006cfc..609eed7a28d 100644
--- a/src/pl/plpgsql/src/meson.build
+++ b/src/pl/plpgsql/src/meson.build
@@ -88,6 +88,7 @@ tests += {
       'plpgsql_trap',
       'plpgsql_trigger',
       'plpgsql_varprops',
+      'plpgsql_foreach',
     ],
   },
 }
diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c
index 84552e32c87..331d64119c1 100644
--- a/src/pl/plpgsql/src/pl_exec.c
+++ b/src/pl/plpgsql/src/pl_exec.c
@@ -29,6 +29,7 @@
 #include "mb/stringinfo_mb.h"
 #include "miscadmin.h"
 #include "nodes/nodeFuncs.h"
+#include "nodes/subscripting.h"
 #include "nodes/supportnodes.h"
 #include "optimizer/optimizer.h"
 #include "parser/parse_coerce.h"
@@ -2994,40 +2995,49 @@ exec_stmt_forc(PLpgSQL_execstate *estate, PLpgSQL_stmt_forc *stmt)
 	return rc;
 }
 
-
 /* ----------
- * exec_stmt_foreach_a			Loop over elements or slices of an array
- *
- * When looping over elements, the loop variable is the same type that the
- * array stores (eg: integer), when looping through slices, the loop variable
- * is an array of size and dimensions to match the size of the slice.
- * ----------
+ * exec_stmt_foreach_a			Loop over elements in an array or jsonb array
+  * ----------
  */
 static int
 exec_stmt_foreach_a(PLpgSQL_execstate *estate, PLpgSQL_stmt_foreach_a *stmt)
 {
-	ArrayType  *arr;
-	Oid			arrtype;
-	int32		arrtypmod;
-	PLpgSQL_datum *loop_var;
-	Oid			loop_var_elem_type;
-	bool		found = false;
+	Datum		expr;
+	Oid			expr_typid;
+	int32		expr_typmod;
+	bool		isnull;
+	PLpgSQL_datum *target_var;
+	Oid			target_typid;
+	int32		target_typmod;
+	Oid			target_collation;
+	Datum		value;
+	Oid			typid;
+	int32		typmod;
 	int			rc = PLPGSQL_RC_OK;
+	const struct SubscriptRoutines *sbroutines;
+	ForeachAIterator *iterator;
 	MemoryContext stmt_mcontext;
+	MemoryContext tmp_cxt;
 	MemoryContext oldcontext;
-	ArrayIterator array_iterator;
-	Oid			iterator_result_type;
-	int32		iterator_result_typmod;
-	Datum		value;
-	bool		isnull;
+	bool		found = false;
 
-	/* get the value of the array expression */
-	value = exec_eval_expr(estate, stmt->expr, &isnull, &arrtype, &arrtypmod);
+	/* get the value of the expression */
+	expr = exec_eval_expr(estate, stmt->expr, &isnull,
+						  &expr_typid, &expr_typmod);
 	if (isnull)
 		ereport(ERROR,
 				(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
 				 errmsg("FOREACH expression must not be null")));
 
+	sbroutines = getSubscriptingRoutines(expr_typid, NULL);
+	if (!sbroutines)
+		ereport(ERROR,
+				(errcode(ERRCODE_DATATYPE_MISMATCH),
+				 errmsg("cannot iterate over type %s because it does not support subscripting",
+						format_type_be(expr_typid))));
+
+	Assert(sbroutines->create_foreach_a_iterator);
+
 	/*
 	 * Do as much as possible of the code below in stmt_mcontext, to avoid any
 	 * leaks from called subroutines.  We need a private stmt_mcontext since
@@ -3037,79 +3047,34 @@ exec_stmt_foreach_a(PLpgSQL_execstate *estate, PLpgSQL_stmt_foreach_a *stmt)
 	push_stmt_mcontext(estate);
 	oldcontext = MemoryContextSwitchTo(stmt_mcontext);
 
-	/* check the type of the expression - must be an array */
-	if (!OidIsValid(get_element_type(arrtype)))
-		ereport(ERROR,
-				(errcode(ERRCODE_DATATYPE_MISMATCH),
-				 errmsg("FOREACH expression must yield an array, not type %s",
-						format_type_be(arrtype))));
+	/* Set up the target (loop) variable */
+	target_var = estate->datums[stmt->varno];
+
+	plpgsql_exec_get_datum_type_info(estate, target_var,
+									 &target_typid, &target_typmod,
+									 &target_collation);
 
 	/*
-	 * We must copy the array into stmt_mcontext, else it will disappear in
-	 * exec_eval_cleanup.  This is annoying, but cleanup will certainly happen
-	 * while running the loop body, so we have little choice.
+	 * inside iterator constroctor, the expr should be copied to
+	 * current memory context (stmt_mcontext). Without it, it will be released
+	 * by next exec_eval_cleanup. The iterator constructor should
+	 * be called under stmt memory context.
 	 */
-	arr = DatumGetArrayTypePCopy(value);
+	iterator = sbroutines->create_foreach_a_iterator(expr,
+													 expr_typid, expr_typmod,
+													 stmt->slice, target_typid,
+													 target_typmod);
 
 	/* Clean up any leftover temporary memory */
 	exec_eval_cleanup(estate);
 
-	/* Slice dimension must be less than or equal to array dimension */
-	if (stmt->slice < 0 || stmt->slice > ARR_NDIM(arr))
-		ereport(ERROR,
-				(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
-				 errmsg("slice dimension (%d) is out of the valid range 0..%d",
-						stmt->slice, ARR_NDIM(arr))));
-
-	/* Set up the loop variable and see if it is of an array type */
-	loop_var = estate->datums[stmt->varno];
-	if (loop_var->dtype == PLPGSQL_DTYPE_REC ||
-		loop_var->dtype == PLPGSQL_DTYPE_ROW)
-	{
-		/*
-		 * Record/row variable is certainly not of array type, and might not
-		 * be initialized at all yet, so don't try to get its type
-		 */
-		loop_var_elem_type = InvalidOid;
-	}
-	else
-		loop_var_elem_type = get_element_type(plpgsql_exec_get_datum_type(estate,
-																		  loop_var));
+	tmp_cxt = AllocSetContextCreate(stmt_mcontext,
+									"FOREACH IN ARRAY temporary cxt",
+									ALLOCSET_DEFAULT_SIZES);
 
-	/*
-	 * Sanity-check the loop variable type.  We don't try very hard here, and
-	 * should not be too picky since it's possible that exec_assign_value can
-	 * coerce values of different types.  But it seems worthwhile to complain
-	 * if the array-ness of the loop variable is not right.
-	 */
-	if (stmt->slice > 0 && loop_var_elem_type == InvalidOid)
-		ereport(ERROR,
-				(errcode(ERRCODE_DATATYPE_MISMATCH),
-				 errmsg("FOREACH ... SLICE loop variable must be of an array type")));
-	if (stmt->slice == 0 && loop_var_elem_type != InvalidOid)
-		ereport(ERROR,
-				(errcode(ERRCODE_DATATYPE_MISMATCH),
-				 errmsg("FOREACH loop variable must not be of an array type")));
+	MemoryContextSwitchTo(tmp_cxt);
 
-	/* Create an iterator to step through the array */
-	array_iterator = array_create_iterator(arr, stmt->slice, NULL);
-
-	/* Identify iterator result type */
-	if (stmt->slice > 0)
-	{
-		/* When slicing, nominal type of result is same as array type */
-		iterator_result_type = arrtype;
-		iterator_result_typmod = arrtypmod;
-	}
-	else
-	{
-		/* Without slicing, results are individual array elements */
-		iterator_result_type = ARR_ELEMTYPE(arr);
-		iterator_result_typmod = arrtypmod;
-	}
-
-	/* Iterate over the array elements or slices */
-	while (array_iterate(array_iterator, &value, &isnull))
+	while (iterator->iterate(iterator, &value, &isnull, &typid, &typmod))
 	{
 		found = true;			/* looped at least once */
 
@@ -3117,12 +3082,9 @@ exec_stmt_foreach_a(PLpgSQL_execstate *estate, PLpgSQL_stmt_foreach_a *stmt)
 		MemoryContextSwitchTo(oldcontext);
 
 		/* Assign current element/slice to the loop variable */
-		exec_assign_value(estate, loop_var, value, isnull,
-						  iterator_result_type, iterator_result_typmod);
+		exec_assign_value(estate, target_var, value, isnull, typid, typmod);
 
-		/* In slice case, value is temporary; must free it to avoid leakage */
-		if (stmt->slice > 0)
-			pfree(DatumGetPointer(value));
+		MemoryContextReset(tmp_cxt);
 
 		/*
 		 * Execute the statements
@@ -3131,7 +3093,7 @@ exec_stmt_foreach_a(PLpgSQL_execstate *estate, PLpgSQL_stmt_foreach_a *stmt)
 
 		LOOP_RC_PROCESSING(stmt->label, break);
 
-		MemoryContextSwitchTo(stmt_mcontext);
+		MemoryContextSwitchTo(tmp_cxt);
 	}
 
 	/* Restore memory context state */
@@ -5537,6 +5499,53 @@ plpgsql_exec_get_datum_type_info(PLpgSQL_execstate *estate,
 				break;
 			}
 
+					TupleDescFinalize(row->rowtupdesc);
index addb14a9959..5cbdb4ecd9d 100644
@@ -299,6 +299,7 @@ typedef struct PLpgSQL_datum
 
 /*
@@ -444,9 +445,9 @@ typedef struct PLpgSQL_recfield
 {
 	PLpgSQL_datum_type dtype;
 	int			dno;
+	char	   *fieldname;		/* name of field */
 	/* end of PLpgSQL_datum fields */
 
-	char	   *fieldname;		/* name of field */
 	int			recparentno;	/* dno of parent record */
 	int			nextfield;		/* dno of next child, or -1 if none */
 	uint64		rectupledescid; /* record's tupledesc ID as of last lookup */
diff --git a/src/pl/plpgsql/src/sql/plpgsql_foreach.sql b/src/pl/plpgsql/src/sql/plpgsql_foreach.sql
new file mode 100644
index 00000000000..a64004417af
--- /dev/null
+++ b/src/pl/plpgsql/src/sql/plpgsql_foreach.sql
@@ -0,0 +1,252 @@
+-- input must be a JSON array
+do $$
+declare x numeric;
+begin
+  foreach x in array NULL::jsonb -- fail
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+do $$
+declare x numeric;
+begin
+  foreach x in array jsonb '10' -- fail
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+do $$
+declare x numeric;
+begin
+  foreach x in array jsonb '{}' -- fail
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+-- numeric to numeric
+do $$
+declare x numeric;
+begin
+  foreach x in array jsonb '[10,20,30,3.14, null]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+-- numeric to int by cast
+do $$
+declare x int;
+begin
+  foreach x in array jsonb '[10,20,30,3.14, null]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+-- test of FOUND variable
+do $$
+declare x int;
+begin
+  foreach x in array jsonb '[10]'
+  loop
+    raise notice '%', x;
+  end loop;
+  raise notice 'FOUND: %', found;
+end;
+$$;
+
+-- test of FOUND variable
+do $$
+declare x int;
+begin
+  foreach x in array jsonb '[]'
+  loop
+    raise notice '%', x;
+  end loop;
+  raise notice 'FOUND: %', found;
+end;
+$$;
+
+-- conversion "3.14" to int should to fail due IO cast
+do $$
+declare x int;
+begin
+  foreach x in array jsonb '["10",20,30,"3.14"]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+do $$
+declare x boolean;
+begin
+  foreach x in array jsonb '[true, false]'
+  loop
+  if x then
+    raise notice 'true';
+  else
+    raise notice 'false';
+  end if;
+  end loop;
+end;
+$$;
+
+-- jsonb to jsonb
+do $$
+declare x jsonb;
+begin
+  foreach x in array jsonb '[10,20,30,3.14, null, "Hi"]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+-- jsonb to json
+do $$
+declare x json;
+begin
+  foreach x in array jsonb '[10,20,30,3.14, null, "Hi"]'
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+-- iteration over composites
+do $$
+declare x int; y numeric; z varchar;
+begin
+  foreach x, y, z in array jsonb '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]'
+  loop
+    raise notice 'x: %, y: %, z: %', x, y, z;
+  end loop;
+end;
+$$;
+
+create type t3 as (x int, y numeric, z varchar);
+
+do $$
+declare c t3;
+begin
+  foreach c in array jsonb '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]'
+  loop
+    raise notice 'x: %, y: %, z: %', c.x, c.y, c.z;
+  end loop;
+end;
+$$;
+
+do $$
+declare c t3;
+begin
+  foreach c.x, c.y, c.z in array jsonb '[{}, {"z":"Hi"}, {"y": 3.14}, {"z":"Hi", "x":10, "y":3.14}]'
+  loop
+    raise notice 'x: %, y: %, z: %', c.x, c.y, c.z;
+  end loop;
+end;
+$$;
+
+drop type t3;
+
+-- target can be a array
+do $$
+declare x int[];
+begin
+  foreach x in array jsonb '[[1,2,3],[4,5,6]]'
+  loop
+    raise notice '% % %', x[1], x[2], x[3];
+  end loop;
+end;
+$$;
+
+do $$
+declare x varchar[];
+begin
+  foreach x in array jsonb '[["Hi","Hello"],["Hello","Hi"]]'
+  loop
+    raise notice '% %', x[1], x[2];
+  end loop;
+end;
+$$;
+
+do $$
+declare x varchar[];
+begin
+  foreach x in array jsonb '[["Hi","Hello"],["Hello","Hi"]]'
+  loop
+    raise notice '% %', x[1], x[2];
+  end loop;
+end;
+$$;
+
+do $$
+declare x int[]; y varchar;
+begin
+  foreach x, y in array jsonb '[{"x":[1,2,3], "y":"Hi"}, {"x":[4,5,6], "y":"Hi"}]'
+  loop
+    raise notice '% % %, y: %', x[1], x[2], x[3], y;
+  end loop;
+end;
+$$;
+
+create type t2 as (x int[], y varchar);
+
+do $$
+declare c t2;
+begin
+  foreach c in array jsonb '[{"x":[1,2,3], "y":"Hi"}, {"x":[4,5,6], "y":"Hi"}]'
+  loop
+    raise notice '% % %, y: %', c.x[1], c.x[2], c.x[3], c.y;
+  end loop;
+end;
+$$;
+
+drop type t2;
+
+-- EXIT and CONTINUE can be triggered by LOOP_RC_PROCESSING
+do $$
+declare x int;
+begin
+  foreach x in array jsonb  '[1,2,3,4,5]'
+  loop
+    exit when x = 3;
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+do $$
+declare x int;
+begin
+  foreach x in array jsonb '[1,2,3,4,5]'
+  loop
+    continue when x % 2 = 0;
+    raise notice '%', x;
+  end loop;
+end;
+$$;
+
+-- Variable instead of string
+DO $$
+declare
+  x int;
+  arr jsonb;
+begin
+  select jsonb_agg(i) into arr
+    from generate_series(1,3) g(i);
+
+  foreach x in array arr
+  loop
+    raise notice '%', x;
+  end loop;
+end;
+$$;
-- 
2.53.0

---

From: Pavel Stehule <[email-masked]>
Date: Sat, 21 Mar 2026 19:40:06 +0100

Hi

only rebase

Regards

Pavel
From a08a1205caaf0b546b7f21a1a6251551db2a0196 Mon Sep 17 00:00:00 2001
From: "[email-masked]" <[email-masked]>
Date: Mon, 23 Feb 2026 12:53:44 +0100
Subject: [PATCH] FOREACH scalar IN ARRAY jsonb_expr

DECLARE t int;
BEGIN

 
 
     <para>

 
+typedef struct
+{
+	ForeachAIterator pub;
+	ArrayIterator it;
+	Oid			result_typid;
+	int32		result_typmod;
 
 /*

 
+typedef struct
+{
+	ForeachAIterator pub;
+	JsonbIterator *it;
+	bool		skip_nested;
+	Oid			target_typid;
+	int32		target_typmod;
+
 
 /*
 
+/*

 
 
index 45d667428f4..9ed346f13ab 100644
@@ -3026,40 +3027,49 @@ exec_stmt_forc(PLpgSQL_execstate *estate, PLpgSQL_stmt_forc *stmt)
 	return rc;
 }
 
-
 /* ----------

@@ -3069,79 +3079,34 @@ exec_stmt_foreach_a(PLpgSQL_execstate *estate, PLpgSQL_stmt_foreach_a *stmt)

 	/*

 
-	/*

@@ -3149,12 +3114,9 @@ exec_stmt_foreach_a(PLpgSQL_execstate *estate, PLpgSQL_stmt_foreach_a *stmt)
 		MemoryContextSwitchTo(oldcontext);

 
 		/*
 		 * Execute the statements
@@ -3163,7 +3125,7 @@ exec_stmt_foreach_a(PLpgSQL_execstate *estate, PLpgSQL_stmt_foreach_a *stmt)

 
 	/* Restore memory context state */
@@ -5637,6 +5599,53 @@ plpgsql_exec_get_datum_type_info(PLpgSQL_execstate *estate,
 				break;
 			}

 /*

---

From: Pavel Stehule <[email-masked]>
Date: Tue, 26 May 2026 08:51:41 +0200

Hi

fresh rebase

Regards

Pavel
From 78a4eb85d8a4cf9b2aaa6082bcbadc46a7472e60 Mon Sep 17 00:00:00 2001
From: "[email-masked]" <[email-masked]>
Date: Mon, 23 Feb 2026 12:53:44 +0100
Subject: [PATCH] FOREACH scalar IN ARRAY jsonb_expr

DECLARE t int;
BEGIN

 
 
     <para>

 
+typedef struct
+{
+	ForeachAIterator pub;
+	ArrayIterator it;
+	Oid			result_typid;
+	int32		result_typmod;
 
 /*

 
+typedef struct
+{
+	ForeachAIterator pub;
+	JsonbIterator *it;
+	bool		skip_nested;
+	Oid			target_typid;
+	int32		target_typmod;
+
 
 /*
 
+/*

 
 
index 65b0fd0790f..1c1d98157df 100644
 
-
 /* ----------

 
 
 	/*

 
-	/*

 

 		/*
 		 * Execute the statements

 
 	/* Restore memory context state */
@@ -5639,6 +5601,53 @@ plpgsql_exec_get_datum_type_info(PLpgSQL_execstate *estate,
 				break;
 			}

 /*
 
2.54.0