Subject: [PATCH] pg_get_domain_ddl: DDL reconstruction function for CREATE DOMAIN statement

From: Tim Waizenegger <[email-masked]>
Date: Thu, 16 Oct 2025 11:16:54 +0200

Hi all,

Following the recent "Retail DDL" discussion [1], we're submitting another
implementation: pg_get_domain_ddl().

This function reconstructs CREATE DOMAIN statements for existing domains,
following what seems to be the agreed pg_get_{objecttype}_ddl naming convention.

## Function

pg_get_domain_ddl(regtype) returns text

Returns a complete CREATE DOMAIN statement including base type, default values,
and all constraints. Uses get_typdefault() for proper expression handling and
supports schema-qualified domains.

## Example

```
CREATE DOMAIN regress_us_postal_code AS TEXT
    DEFAULT '00000'
    CONSTRAINT regress_us_postal_code_check
        CHECK (
            VALUE ~ '^\d{5}$'
    OR VALUE ~ '^\d{5}-\d{4}$'
    );
SELECT pg_get_domain_ddl('regress_us_postal_code');

           pg_get_domain_ddl
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 CREATE DOMAIN public.regress_us_postal_code AS text DEFAULT
'00000'::text CONSTRAINT regress_us_postal_code_check CHECK (VALUE ~
'^\d{5}$'::text OR VALUE ~ '^\d{5}-\d{4}$'::text);
(1 row)
```

## Implementation

- New "Get Object DDL Functions" documentation section
- Comprehensive regression tests in a separate file where we will add
  tests for the other objects functions.

We're unsure about the place where to add the trigger to the `object_ddl` test.
We added it now in `src/test/regress/parallel_schedule`, please let us know
if there is a better place.

This is part of a coordinated effort where we've divided the DDL functions
among different contributors. Additional patches for other object types
(tables, indexes, etc.) will follow from other team members.
Already submitted are: CREATE TRIGGER [2] and CREATE POLICY [3].

Patch attached. Feedback welcome.

[1] https://www.postgresql.org/message-id/flat/945db7c5-be75-45bf-b55b-cb1e56f2e3e9%40dunslane.net
[2] https://www.postgresql.org/message-id/flat/CAPXBC8K5awmtMoq66DGHe%2BnD7hUf6HPRVHLeGNBRpCDpzusOXQ%40mail.gmail.com
[3] https://www.postgresql.org/message-id/flat/CANxoLDdJsRJqnjMXV3yjsk07Z5iRWxG-c2hZJC7bAKqf8ZXj_A%40mail.gmail.com

---
Best regards,
Florin Irion
Tim Waizenegger

EDB (EnterpriseDB)

---

From: jian he <[email-masked]>
Date: Thu, 16 Oct 2025 19:04:22 +0800

> supports schema-qualified domains.

        <indexterm>
+         <primary>pg_get_domain_ddl</primary>
+        </indexterm>
+        <function>pg_get_domain_ddl</function> (
<parameter>domain</parameter> <type>text</type> )
+        <returnvalue>text</returnvalue>
+       </para>
+       <para>
+        Reconstructs the creating command for a domain.
+        The result is a complete <command>CREATE DOMAIN</command> statement.
+       </para></entry>

<type>text</type>

should be
<type>regtype</type>

+ Oid domain_oid = PG_GETARG_OID(0);
+ HeapTuple typeTuple;
,....
+
+ /* Look up the domain in pg_type */
+ typeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(domain_oid));
+

select pg_get_domain_ddl(-1);
will cause segfault.
see https://www.postgresql.org/message-id/3759807.1711658868%40sss.pgh.pa.us
and pg_get_trigger_ddl thread.

NOT VALID check constraint handling is tricky currently.
create domain x as int;
alter domain x add constraint cc check(value > 2) not valid;

select pg_get_domain_ddl('x'::regtype);
CREATE DOMAIN public.x AS integer CONSTRAINT cc CHECK (VALUE > 2) NOT VALID;
but putting the above to psql would result in syntax error.

https://www.postgresql.org/docs/current/sql-createdomain.html
[ COLLATE collation ]
part not handled?

create domain d0 as text collate "C";
select pg_get_domain_ddl('d0'::regtype);
        pg_get_domain_ddl
----------------------------------
 CREATE DOMAIN public.d0 AS text;
(1 row)

we should expect
CREATE DOMAIN public.d0 AS text COLLATE "C";

---

From: Tim Waizenegger <[email-masked]>
Date: Wed, 22 Oct 2025 11:32:25 +0200

> select pg_get_domain_ddl('d0'::regtype);

Thanks for the feedback! We addressed the issues mentioned above and
also added more extensive test cases:

postgres=# select pg_get_domain_ddl(-1);
 pg_get_domain_ddl
-------------------

(1 row)

postgres=# create domain d0 as text collate "C";
CREATE DOMAIN
postgres=# select pg_get_domain_ddl('d0'::regtype);
              pg_get_domain_ddl
----------------------------------------------
 CREATE DOMAIN public.d0 AS text COLLATE "C";
(1 row)

postgres=# create domain x as int;
CREATE DOMAIN
postgres=# alter domain x add constraint cc check(value > 2) not valid;
ALTER DOMAIN
postgres=# select pg_get_domain_ddl('x'::regtype);
                          pg_get_domain_ddl
----------------------------------------------------------------------
 CREATE DOMAIN public.x AS integer;                                  +
 ALTER DOMAIN public.x ADD CONSTRAINT cc CHECK (VALUE > 2) NOT VALID;
(1 row)

updated patch is attached

---
Best regards,
Florin Irion
Tim Waizenegger

EDB (EnterpriseDB)

---

From: Chao Li <[email-masked]>
Date: Wed, 22 Oct 2025 18:26:44 +0800

Hi Tim,

Thanks for working on this. I haven’t finished reviewing the entire patch. But I got a quick question:

> On Oct 22, 2025, at 17:32, Tim Waizenegger <[email-masked]> wrote:
> 
> <v1-0001-Add-pg_get_domain_ddl-function-to-reconstruct-CRE.patch>

```
+/*
+ * pg_get_domain_ddl - Get CREATE DOMAIN statement for a domain
+ */
+Datum
+pg_get_domain_ddl(PG_FUNCTION_ARGS)
+{
+	StringInfoData buf;
+	Oid			domain_oid = PG_GETARG_OID(0);
+	HeapTuple	typeTuple;
+	Form_pg_type typForm;
+	Node	   *defaultExpr;
```

While reviewing a similar patch of pg_get_policy_ddl(), it take the last parameter as a pretty flag. I wonder why pg_get_domain_ddl() doesn’t support an argument for pretty? 

See the code snippet from the other patch:

```
+/*
+ * pg_get_policy_ddl
+ *
+ * Generate a CREATE POLICY statement for the specified policy.
+ *
+ * tableID - Table ID of the policy.
+ * policyName - Name of the policy for which to generate the DDL.
+ * pretty - If true, format the DDL with indentation and line breaks.
+ */
+Datum
+pg_get_policy_ddl(PG_FUNCTION_ARGS)
+{
+	Oid			tableID = PG_GETARG_OID(0);
+	Name		policyName = PG_GETARG_NAME(1);
+	bool		pretty = PG_GETARG_BOOL(2);  # <====== This is the pretty arg
+	bool		attrIsNull;
```

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

---

From: Tim Waizenegger <[email-masked]>
Date: Wed, 22 Oct 2025 14:00:21 +0200

> While reviewing a similar patch of pg_get_policy_ddl(), it take the last parameter as a pretty flag. I wonder why pg_get_domain_ddl() doesn’t support an argument for pretty?

That's a good point; we'll add pretty printing support for consistency
with the other functions. I'll send a new patch in the coming days.

Best regards,
Florin Irion
Tim Waizenegger
EDB (EnterpriseDB)

---

From: jian he <[email-masked]>
Date: Thu, 23 Oct 2025 12:21:34 +0800

> updated patch is attached

I’ve done some refactoring, hope it’s now more intuitive to you.
Since a domain’s base type can itself be another domain, it’s better to use

    appendStringInfo(&buf, "CREATE DOMAIN %s AS %s",
                     generate_qualified_type_name(domain_oid),
                     generate_qualified_type_name(typForm->typbasetype));

then the domain's base type is also fully qualified.

I also refactored the logic for printing domain constraints, which should reduce
syscache lookups or table scans compared to your version.

please check the attached.

---

From: Akshay Joshi <[email-masked]>
Date: Thu, 23 Oct 2025 14:49:48 +0530

On Wed, 22 Oct, 2025, 17:30 Tim Waizenegger, <
[email-masked]> wrote:

> > While reviewing a similar patch of pg_get_policy_ddl(), it take the last
> parameter as a pretty flag. I wonder why pg_get_domain_ddl() doesn’t
> support an argument for pretty?
> >
> >
>

I've already implemented a generic function for pretty-formatted DDL in the
ruleutils.c file as part of my pg_get_policy_ddl patch. I suggest reusing
it once my patch is accepted and committed by the community.

---

From: Tim Waizenegger <[email-masked]>
Date: Mon, 10 Nov 2025 13:44:36 +0100

>> > While reviewing a similar patch of pg_get_policy_ddl(), it take the last parameter as a pretty flag. I wonder why pg_get_domain_ddl() doesn’t support an argument for pretty?

We have now added pretty printing support in the latest version; see
attached patch. FYI, we tried to stay consistent in the implementation
with pg_get_policy_ddl from
https://www.postgresql.org/message-id/flat/CANxoLDdJsRJqnjMXV3yjsk07Z5iRWxG-c2hZJC7bAKqf8ZXj_A%40mail.gmail.com
or

On Thu, Oct 23, 2025 at 11:20 AM Akshay Joshi
<[email-masked]> wrote:
>
>> I've already implemented a generic function for pretty-formatted DDL in the ruleutils.c file as part of my pg_get_policy_ddl patch. I suggest reusing it once my patch is accepted and committed by the community.

Thanks Akshay, we adopted your "get_formatted_string()" function into
our path and tried to follow similar implementation patterns as well.

> then the domain's base type is also fully qualified.

Thanks for the feedback and refactoring Jian! We adopted the
"generate_qualified_type_name" into our patch; this is much better.

> syscache lookups or table scans compared to your version.

we did a lot of refactoring as well while integrating the
pretty-printing support and aligning with e.g. the pg_get_policy_ddl
command. Some of this refactoring follows your suggestiong.
There is one change we decided not to adopt: constructing the
ddl-strings _while_ scanning for constraints in order to optimize the
syscache lookups. The reason is this:

the optimization will save one "SearchSysCache1" per constraint in the
domain. But we still call "pg_get_constraintdef_worker" for each
constraint which does a full table scan.
So in that context, saving the cache lookup seems like a minor
improvement. To us it seemed more desirable to leave the code
unoptimized in this location so that constraint scan and constraint
processing can be decoupled into individual single-purpose
functions/blocks.
Let us know what you think.

Best regards,
Florin Irion
Tim Waizenegger
EDB (EnterpriseDB)

---

From: Florin Irion <[email-masked]>
Date: Tue, 11 Nov 2025 17:14:42 +0100

Hello, Cirrus-CI was complaining because we don't sort the constraints 
and thus
they were making the test fail because of the random order.
Made it sort with `list_sort`and `list_oid_cmp`not sure if that's the best
thing to sort them.
Check v4 attached.
Cheers,
Florin Irion
Tim Waizenegger
EDB (EnterpriseDB)
From 2aeca53cbaec510ee54145039742e5d484940895 Mon Sep 17 00:00:00 2001
From: Florin Irion <[email-masked]>
Date: Thu, 18 Sep 2025 18:52:43 +0200
Subject: [PATCH v4] Add pg_get_domain_ddl() function to reconstruct CREATE
 DOMAIN statements
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

This patch introduces a new system function pg_get_domain_ddl() that
reconstructs the CREATE DOMAIN statement for a given domain. The function
takes a regtype parameter and returns the complete DDL statement including
the domain name, base type, default value, and all associated constraints.

The function follows the same pattern as other DDL reconstruction functions
like pg_get_functiondef() and pg_get_constraintdef(), providing a
decompiled reconstruction rather than the original command text.

Key features:
* Supports domains with default values
* Includes all domain constraints (CHECK, NOT NULL)
* NOT VALID constraint are handled with an extra ALTER command.
* Properly quotes identifiers and schema names
* Handles complex constraint expressions
* pretty printing support

A new documentation section "Get Object DDL Functions" has been created
to group DDL reconstruction functions, starting with pg_get_domain_ddl().
This provides a foundation for future DDL functions for other object types.

Comprehensive regression tests are included covering various domain
configurations.

Reference: PG-151
Author: Florin Irion <[email-masked]>
Author: Tim Waizenegger <[email-masked]>
Reviewed-by: Álvaro Herrera [email-masked]
Reviewed-by: jian he <[email-masked]>
Reviewed-by: Chao Li <[email-masked]>
---
 doc/src/sgml/func/func-info.sgml         |  45 ++++
 src/backend/catalog/system_functions.sql |   6 +
 src/backend/utils/adt/ruleutils.c        | 233 ++++++++++++++++
 src/include/catalog/pg_proc.dat          |   3 +
 src/test/regress/expected/object_ddl.out | 328 +++++++++++++++++++++++
 src/test/regress/parallel_schedule       |   2 +-
 src/test/regress/sql/object_ddl.sql      | 135 ++++++++++
 7 files changed, 751 insertions(+), 1 deletion(-)
 create mode 100644 src/test/regress/expected/object_ddl.out
 create mode 100644 src/test/regress/sql/object_ddl.sql

diff --git a/doc/src/sgml/func/func-info.sgml b/doc/src/sgml/func/func-info.sgml
index d4508114a48..55527f468ae 100644
--- a/doc/src/sgml/func/func-info.sgml
+++ b/doc/src/sgml/func/func-info.sgml
@@ -3797,4 +3797,49 @@ acl      | {postgres=arwdDxtm/postgres,foo=r/postgres}
 
   </sect2>
 
+  <sect2 id="functions-get-object-ddl">
+   <title>Get Object DDL Functions</title>
+
+   <para>
+    The functions shown in <xref linkend="functions-get-object-ddl-table"/>
+    print the DDL statements for various database objects.
+    (This is a decompiled reconstruction, not the original text
+    of the command.)
+   </para>
+
+   <table id="functions-get-object-ddl-table">
+    <title>Get Object DDL Functions</title>
+    <tgroup cols="1">
+     <thead>
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        Function
+       </para>
+       <para>
+        Description
+       </para></entry>
+      </row>
+     </thead>
+
+     <tbody>
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <indexterm>
+         <primary>pg_get_domain_ddl</primary>
+        </indexterm>
+        <function>pg_get_domain_ddl</function> ( <parameter>domain</parameter> <type>regtype</type>
+         <optional> <parameter>pretty</parameter> <type>boolean</type> </optional>)
+        <returnvalue>text</returnvalue>
+       </para>
+       <para>
+        Reconstructs the creating command for a domain.
+        The result is a complete <command>CREATE DOMAIN</command> statement.
+       </para></entry>
+      </row>
+     </tbody>
+    </tgroup>
+   </table>
+
+  </sect2>
+
   </sect1>
diff --git a/src/backend/catalog/system_functions.sql b/src/backend/catalog/system_functions.sql
index 2d946d6d9e9..5a96ff1efcb 100644
--- a/src/backend/catalog/system_functions.sql
+++ b/src/backend/catalog/system_functions.sql
@@ -657,6 +657,12 @@ LANGUAGE INTERNAL
 STRICT VOLATILE PARALLEL UNSAFE
 AS 'pg_replication_origin_session_setup';
 
+CREATE OR REPLACE FUNCTION
+ pg_get_domain_ddl(domain_name regtype, pretty bool DEFAULT false)
+ RETURNS text
+ LANGUAGE internal
+AS 'pg_get_domain_ddl_ext';
+
 --
 -- The default permissions for functions mean that anyone can execute them.
 -- A number of functions shouldn't be executable by just anyone, but rather
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index 556ab057e5a..34d63f2f502 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -546,6 +546,11 @@ static void get_json_table_nested_columns(TableFunc *tf, JsonTablePlan *plan,
 										  deparse_context *context,
 										  bool showimplicit,
 										  bool needcomma);
+static void get_formatted_string(StringInfo buf,
+								 int prettyFlags,
+								 int noOfTabChars,
+								 const char *fmt,...) pg_attribute_printf(4, 5);
+static char *pg_get_domain_ddl_worker(Oid domain_oid, int prettyFlags);
 
 #define only_marker(rte)  ((rte)->inh ? "" : "ONLY ")
 
@@ -13743,3 +13748,231 @@ get_range_partbound_string(List *bound_datums)
 
 	return buf.data;
 }
+
+/*
+ * get_formatted_string
+ *
+ * Return a formatted version of the string.
+ *
+ * pretty - If pretty is true, the output includes tabs (\t) and newlines (\n).
+ * noOfTabChars - indent with specified no of tabs.
+ * fmt - printf-style format string used by appendStringInfoVA.
+ */
+static void
+get_formatted_string(StringInfo buf, int prettyFlags, int noOfTabChars, const char *fmt,...)
+{
+	va_list		args;
+
+	if (prettyFlags & PRETTYFLAG_INDENT)
+	{
+		appendStringInfoChar(buf, '\n');
+		/* Indent with tabs */
+		for (int i = 0; i < noOfTabChars; i++)
+		{
+			appendStringInfoChar(buf, '\t');
+		}
+	}
+	else
+		appendStringInfoChar(buf, ' ');
+
+	va_start(args, fmt);
+	appendStringInfoVA(buf, fmt, args);
+	va_end(args);
+}
+
+
+/*
+ * Helper function to scan domain constraints
+ */
+static void
+scan_domain_constraints(Oid domain_oid, List **validcons, List **invalidcons)
+{
+	Relation	constraintRel;
+	SysScanDesc sscan;
+	ScanKeyData skey;
+	HeapTuple	constraintTup;
+
+	*validcons = NIL;
+	*invalidcons = NIL;
+
+	constraintRel = table_open(ConstraintRelationId, AccessShareLock);
+
+	ScanKeyInit(&skey,
+				Anum_pg_constraint_contypid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(domain_oid));
+
+	sscan = systable_beginscan(constraintRel,
+							   ConstraintTypidIndexId,
+							   true,
+							   NULL,
+							   1,
+							   &skey);
+
+	while (HeapTupleIsValid(constraintTup = systable_getnext(sscan)))
+	{
+		Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(constraintTup);
+
+		if (con->convalidated)
+			*validcons = lappend_oid(*validcons, con->oid);
+		else
+			*invalidcons = lappend_oid(*invalidcons, con->oid);
+	}
+
+	systable_endscan(sscan);
+	table_close(constraintRel, AccessShareLock);
+
+	/* Sort constraints by OID for stable output */
+	if (list_length(*validcons) > 1)
+		list_sort(*validcons, list_oid_cmp);
+	if (list_length(*invalidcons) > 1)
+		list_sort(*invalidcons, list_oid_cmp);
+}
+
+/*
+ * Helper function to build CREATE DOMAIN statement
+ */
+static void
+build_create_domain_statement(StringInfo buf, Form_pg_type typForm,
+							  Node *defaultExpr, List *validConstraints, int prettyFlags)
+{
+	HeapTuple	baseTypeTuple;
+	Form_pg_type baseTypeForm;
+	Oid			baseCollation = InvalidOid;
+	ListCell   *lc;
+
+	appendStringInfo(buf, "CREATE DOMAIN %s AS %s",
+					 generate_qualified_type_name(typForm->oid),
+					 generate_qualified_type_name(typForm->typbasetype));
+
+	/* Add collation if it differs from base type's collation */
+	if (OidIsValid(typForm->typcollation))
+	{
+		/* Get base type's collation for comparison */
+		baseTypeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typForm->typbasetype));
+		if (HeapTupleIsValid(baseTypeTuple))
+		{
+			baseTypeForm = (Form_pg_type) GETSTRUCT(baseTypeTuple);
+			baseCollation = baseTypeForm->typcollation;
+			ReleaseSysCache(baseTypeTuple);
+		}
+
+		/* Only add COLLATE if domain's collation differs from base type's */
+		if (typForm->typcollation != baseCollation)
+		{
+			get_formatted_string(buf, prettyFlags, 1, "COLLATE %s",
+								 generate_collation_name(typForm->typcollation));
+		}
+	}
+
+	/* Add default value if present */
+	if (defaultExpr != NULL)
+	{
+		char	   *defaultValue = deparse_expression_pretty(defaultExpr, NIL, false, false, prettyFlags, 0);
+
+		get_formatted_string(buf, prettyFlags, 1, "DEFAULT %s", defaultValue);
+	}
+
+	/* Add valid constraints */
+	foreach(lc, validConstraints)
+	{
+		Oid			constraintOid = lfirst_oid(lc);
+		HeapTuple	constraintTup;
+		Form_pg_constraint con;
+		char	   *constraintDef;
+
+		/* Look up the constraint info */
+		constraintTup = SearchSysCache1(CONSTROID, ObjectIdGetDatum(constraintOid));
+		if (!HeapTupleIsValid(constraintTup))
+			continue;			/* constraint was dropped concurrently */
+
+		con = (Form_pg_constraint) GETSTRUCT(constraintTup);
+		constraintDef = pg_get_constraintdef_worker(constraintOid, false, prettyFlags, true);
+
+		get_formatted_string(buf, prettyFlags, 1, "CONSTRAINT %s",
+							 quote_identifier(NameStr(con->conname)));
+		get_formatted_string(buf, prettyFlags, 2, "%s", constraintDef);
+
+		ReleaseSysCache(constraintTup);
+	}
+
+	appendStringInfoChar(buf, ';');
+}
+
+/*
+ * Helper function to add ALTER DOMAIN statements for invalid constraints
+ */
+static void
+add_alter_domain_statements(StringInfo buf, List *invalidConstraints, int prettyFlags)
+{
+	ListCell   *lc;
+
+	foreach(lc, invalidConstraints)
+	{
+		Oid			constraintOid = lfirst_oid(lc);
+		char	   *alterStmt = pg_get_constraintdef_worker(constraintOid, true, prettyFlags, true);
+
+		if (alterStmt)
+			appendStringInfo(buf, "\n%s;", alterStmt);
+	}
+}
+
+/*
+ * pg_get_domain_ddl_ext - Get CREATE DOMAIN statement for a domain with pretty-print option
+ */
+Datum
+pg_get_domain_ddl_ext(PG_FUNCTION_ARGS)
+{
+	Oid			domain_oid = PG_GETARG_OID(0);
+	bool		pretty = PG_GETARG_BOOL(1);
+	char	   *res;
+	int			prettyFlags;
+
+	prettyFlags = pretty ? GET_PRETTY_FLAGS(pretty) : 0;
+
+	res = pg_get_domain_ddl_worker(domain_oid, prettyFlags);
+	if (res == NULL)
+		PG_RETURN_NULL();
+	PG_RETURN_TEXT_P(string_to_text(res));
+}
+
+
+
+static char *
+pg_get_domain_ddl_worker(Oid domain_oid, int prettyFlags)
+{
+	StringInfoData buf;
+	HeapTuple	typeTuple;
+	Form_pg_type typForm;
+	Node	   *defaultExpr;
+	List	   *validConstraints;
+	List	   *invalidConstraints;
+
+	/* Look up the domain in pg_type */
+	typeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(domain_oid));
+	if (!HeapTupleIsValid(typeTuple))
+		return NULL;
+
+	typForm = (Form_pg_type) GETSTRUCT(typeTuple);
+
+	/* Get default expression */
+	defaultExpr = get_typdefault(domain_oid);
+
+	/* Scan for valid and invalid constraints */
+	scan_domain_constraints(domain_oid, &validConstraints, &invalidConstraints);
+
+	/* Build the DDL statement */
+	initStringInfo(&buf);
+	build_create_domain_statement(&buf, typForm, defaultExpr, validConstraints, prettyFlags);
+
+	/* Add ALTER DOMAIN statements for invalid constraints */
+	if (list_length(invalidConstraints) > 0)
+		add_alter_domain_statements(&buf, invalidConstraints, prettyFlags);
+
+	/* Cleanup */
+	list_free(validConstraints);
+	list_free(invalidConstraints);
+	ReleaseSysCache(typeTuple);
+
+	return buf.data;
+}
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 5cf9e12fcb9..476874d0063 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -8515,6 +8515,9 @@
 { oid => '2508', descr => 'constraint description with pretty-print option',
   proname => 'pg_get_constraintdef', provolatile => 's', prorettype => 'text',
   proargtypes => 'oid bool', prosrc => 'pg_get_constraintdef_ext' },
+{ oid => '8024', descr => 'get CREATE statement for DOMAIN with pretty option',
+  proname => 'pg_get_domain_ddl', prorettype => 'text',
+  proargtypes => 'regtype bool', prosrc => 'pg_get_domain_ddl_ext' },
 { oid => '2509',
   descr => 'deparse an encoded expression with pretty-print option',
   proname => 'pg_get_expr', provolatile => 's', prorettype => 'text',
diff --git a/src/test/regress/expected/object_ddl.out b/src/test/regress/expected/object_ddl.out
new file mode 100644
index 00000000000..9aad54347da
--- /dev/null
+++ b/src/test/regress/expected/object_ddl.out
@@ -0,0 +1,328 @@
+--
+-- Test for the following functions to get object DDL:
+-- - pg_get_domain_ddl
+--
+CREATE DOMAIN regress_us_postal_code AS TEXT
+    DEFAULT '00000'
+    CONSTRAINT regress_us_postal_code_check
+        CHECK (
+            VALUE ~ '^\d{5}$'
+    OR VALUE ~ '^\d{5}-\d{4}$'
+    );
+SELECT pg_get_domain_ddl('regress_us_postal_code');
+                                                                                          pg_get_domain_ddl                                                                                           
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_us_postal_code AS pg_catalog.text DEFAULT '00000'::text CONSTRAINT regress_us_postal_code_check CHECK (((VALUE ~ '^\d{5}$'::text) OR (VALUE ~ '^\d{5}-\d{4}$'::text)));
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_us_postal_code', pretty => false);
+                                                                                          pg_get_domain_ddl                                                                                           
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_us_postal_code AS pg_catalog.text DEFAULT '00000'::text CONSTRAINT regress_us_postal_code_check CHECK (((VALUE ~ '^\d{5}$'::text) OR (VALUE ~ '^\d{5}-\d{4}$'::text)));
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_us_postal_code', false);
+                                                                                          pg_get_domain_ddl                                                                                           
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_us_postal_code AS pg_catalog.text DEFAULT '00000'::text CONSTRAINT regress_us_postal_code_check CHECK (((VALUE ~ '^\d{5}$'::text) OR (VALUE ~ '^\d{5}-\d{4}$'::text)));
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_us_postal_code', pretty => true);
+                                 pg_get_domain_ddl                                 
+-----------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_us_postal_code AS pg_catalog.text                   +
+         DEFAULT '00000'::text                                                    +
+         CONSTRAINT regress_us_postal_code_check                                  +
+                 CHECK (VALUE ~ '^\d{5}$'::text OR VALUE ~ '^\d{5}-\d{4}$'::text);
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_us_postal_code', true);
+                                 pg_get_domain_ddl                                 
+-----------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_us_postal_code AS pg_catalog.text                   +
+         DEFAULT '00000'::text                                                    +
+         CONSTRAINT regress_us_postal_code_check                                  +
+                 CHECK (VALUE ~ '^\d{5}$'::text OR VALUE ~ '^\d{5}-\d{4}$'::text);
+(1 row)
+
+CREATE DOMAIN regress_domain_not_null AS INT NOT NULL;
+SELECT pg_get_domain_ddl('regress_domain_not_null');
+                                                   pg_get_domain_ddl                                                   
+-----------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_domain_not_null AS pg_catalog.int4 CONSTRAINT regress_domain_not_null_not_null NOT NULL;
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_domain_not_null', pretty => true);
+                        pg_get_domain_ddl                        
+-----------------------------------------------------------------
+ CREATE DOMAIN public.regress_domain_not_null AS pg_catalog.int4+
+         CONSTRAINT regress_domain_not_null_not_null            +
+                 NOT NULL;
+(1 row)
+
+CREATE DOMAIN regress_domain_check AS INT
+    CONSTRAINT regress_a CHECK (VALUE < 100)
+    CONSTRAINT regress_b CHECK (VALUE > 10);
+SELECT pg_get_domain_ddl('regress_domain_check');
+                                                                 pg_get_domain_ddl                                                                  
+----------------------------------------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_domain_check AS pg_catalog.int4 CONSTRAINT regress_a CHECK ((VALUE < 100)) CONSTRAINT regress_b CHECK ((VALUE > 10));
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_domain_check', pretty => true);
+                      pg_get_domain_ddl                       
+--------------------------------------------------------------
+ CREATE DOMAIN public.regress_domain_check AS pg_catalog.int4+
+         CONSTRAINT regress_a                                +
+                 CHECK (VALUE < 100)                         +
+         CONSTRAINT regress_b                                +
+                 CHECK (VALUE > 10);
+(1 row)
+
+CREATE DOMAIN "regress_domain with space" AS INT
+    CONSTRAINT regress_a CHECK (VALUE < 100)
+    CONSTRAINT "regress_Constraint B" CHECK (VALUE > 10)
+    CONSTRAINT "regress_ConstraintC" CHECK (VALUE != 55);
+SELECT pg_get_domain_ddl('"regress_domain with space"');
+                                                                                                       pg_get_domain_ddl                                                                                                       
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public."regress_domain with space" AS pg_catalog.int4 CONSTRAINT regress_a CHECK ((VALUE < 100)) CONSTRAINT "regress_Constraint B" CHECK ((VALUE > 10)) CONSTRAINT "regress_ConstraintC" CHECK ((VALUE <> 55));
+(1 row)
+
+SELECT pg_get_domain_ddl('"regress_domain with space"', pretty => true);
+                          pg_get_domain_ddl                          
+---------------------------------------------------------------------
+ CREATE DOMAIN public."regress_domain with space" AS pg_catalog.int4+
+         CONSTRAINT regress_a                                       +
+                 CHECK (VALUE < 100)                                +
+         CONSTRAINT "regress_Constraint B"                          +
+                 CHECK (VALUE > 10)                                 +
+         CONSTRAINT "regress_ConstraintC"                           +
+                 CHECK (VALUE <> 55);
+(1 row)
+
+-- Test error cases
+SELECT pg_get_domain_ddl('regress_nonexistent_domain'::regtype);  -- should fail
+ERROR:  type "regress_nonexistent_domain" does not exist
+LINE 1: SELECT pg_get_domain_ddl('regress_nonexistent_domain'::regty...
+                                 ^
+SELECT pg_get_domain_ddl(NULL);  -- should return NULL
+ pg_get_domain_ddl 
+-------------------
+ 
+(1 row)
+
+SELECT pg_get_domain_ddl(NULL, pretty => true);  -- should return NULL
+ pg_get_domain_ddl 
+-------------------
+ 
+(1 row)
+
+-- Test domains with no constraints
+CREATE DOMAIN regress_simple_domain AS text;
+SELECT pg_get_domain_ddl('regress_simple_domain');
+                       pg_get_domain_ddl                        
+----------------------------------------------------------------
+ CREATE DOMAIN public.regress_simple_domain AS pg_catalog.text;
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_simple_domain', pretty => true);
+                       pg_get_domain_ddl                        
+----------------------------------------------------------------
+ CREATE DOMAIN public.regress_simple_domain AS pg_catalog.text;
+(1 row)
+
+-- Test domain over another domain
+CREATE DOMAIN regress_base_domain AS varchar(10);
+CREATE DOMAIN regress_derived_domain AS regress_base_domain CHECK (LENGTH(VALUE) > 3);
+SELECT pg_get_domain_ddl('regress_derived_domain');
+                                                                   pg_get_domain_ddl                                                                    
+--------------------------------------------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_derived_domain AS public.regress_base_domain CONSTRAINT regress_derived_domain_check CHECK ((length((VALUE)::text) > 3));
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_derived_domain', pretty => true);
+                             pg_get_domain_ddl                             
+---------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_derived_domain AS public.regress_base_domain+
+         CONSTRAINT regress_derived_domain_check                          +
+                 CHECK (length(VALUE::text) > 3);
+(1 row)
+
+-- Test domain with complex default expressions
+CREATE SEQUENCE regress_test_seq;
+CREATE DOMAIN regress_seq_domain AS int DEFAULT nextval('regress_test_seq');
+SELECT pg_get_domain_ddl('regress_seq_domain');
+                                             pg_get_domain_ddl                                             
+-----------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_seq_domain AS pg_catalog.int4 DEFAULT nextval('regress_test_seq'::regclass);
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_seq_domain', pretty => true);
+                     pg_get_domain_ddl                      
+------------------------------------------------------------
+ CREATE DOMAIN public.regress_seq_domain AS pg_catalog.int4+
+         DEFAULT nextval('regress_test_seq'::regclass);
+(1 row)
+
+-- Test domain with a renamed sequence as default expression
+ALTER SEQUENCE regress_test_seq RENAME TO regress_test_seq_renamed;
+SELECT pg_get_domain_ddl('regress_seq_domain');
+                                                 pg_get_domain_ddl                                                 
+-------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_seq_domain AS pg_catalog.int4 DEFAULT nextval('regress_test_seq_renamed'::regclass);
+(1 row)
+
+-- Test domain with type modifiers
+CREATE DOMAIN regress_precise_numeric AS numeric(10,2) DEFAULT 0.00;
+SELECT pg_get_domain_ddl('regress_precise_numeric');
+                                 pg_get_domain_ddl                                  
+------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_precise_numeric AS pg_catalog."numeric" DEFAULT 0.00;
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_precise_numeric', pretty => true);
+                          pg_get_domain_ddl                           
+----------------------------------------------------------------------
+ CREATE DOMAIN public.regress_precise_numeric AS pg_catalog."numeric"+
+         DEFAULT 0.00;
+(1 row)
+
+-- Test domain over array type
+CREATE DOMAIN regress_int_array_domain AS int[] CHECK (array_length(VALUE, 1) <= 5);
+SELECT pg_get_domain_ddl('regress_int_array_domain');
+                                                                 pg_get_domain_ddl                                                                  
+----------------------------------------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_int_array_domain AS pg_catalog._int4 CONSTRAINT regress_int_array_domain_check CHECK ((array_length(VALUE, 1) <= 5));
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_int_array_domain', pretty => true);
+                         pg_get_domain_ddl                         
+-------------------------------------------------------------------
+ CREATE DOMAIN public.regress_int_array_domain AS pg_catalog._int4+
+         CONSTRAINT regress_int_array_domain_check                +
+                 CHECK (array_length(VALUE, 1) <= 5);
+(1 row)
+
+-- Test domain in non-public schema
+CREATE SCHEMA regress_test_schema;
+CREATE DOMAIN regress_test_schema.regress_schema_domain AS text DEFAULT 'test';
+SELECT pg_get_domain_ddl('regress_test_schema.regress_schema_domain');
+                                        pg_get_domain_ddl                                         
+--------------------------------------------------------------------------------------------------
+ CREATE DOMAIN regress_test_schema.regress_schema_domain AS pg_catalog.text DEFAULT 'test'::text;
+(1 row)
+
+-- Test domain with multiple constraint types combined
+CREATE DOMAIN regress_comprehensive_domain AS varchar(50)
+    NOT NULL
+    DEFAULT 'default_value'
+    CHECK (LENGTH(VALUE) >= 5)
+    CHECK (VALUE !~ '^\s*$');  -- not just whitespace
+SELECT pg_get_domain_ddl('regress_comprehensive_domain');
+                                                                                                                                                                     pg_get_domain_ddl                                                                                                                                                                      
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_comprehensive_domain AS pg_catalog."varchar" DEFAULT 'default_value'::character varying CONSTRAINT regress_comprehensive_domain_not_null NOT NULL CONSTRAINT regress_comprehensive_domain_check CHECK ((length((VALUE)::text) >= 5)) CONSTRAINT regress_comprehensive_domain_check1 CHECK (((VALUE)::text !~ '^\s*$'::text));
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_comprehensive_domain', pretty => true);
+                             pg_get_domain_ddl                             
+---------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_comprehensive_domain AS pg_catalog."varchar"+
+         DEFAULT 'default_value'::character varying                       +
+         CONSTRAINT regress_comprehensive_domain_not_null                 +
+                 NOT NULL                                                 +
+         CONSTRAINT regress_comprehensive_domain_check                    +
+                 CHECK (length(VALUE::text) >= 5)                         +
+         CONSTRAINT regress_comprehensive_domain_check1                   +
+                 CHECK (VALUE::text !~ '^\s*$'::text);
+(1 row)
+
+-- Test domain over composite type
+CREATE TYPE regress_address_type AS (street text, city text, zipcode text);
+CREATE DOMAIN regress_address_domain AS regress_address_type CHECK ((VALUE).zipcode ~ '^\d{5}$');
+SELECT pg_get_domain_ddl('regress_address_domain');
+                                                                        pg_get_domain_ddl                                                                        
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_address_domain AS public.regress_address_type CONSTRAINT regress_address_domain_check CHECK (((VALUE).zipcode ~ '^\d{5}$'::text));
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_address_domain', pretty => true);
+                             pg_get_domain_ddl                              
+----------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_address_domain AS public.regress_address_type+
+         CONSTRAINT regress_address_domain_check                           +
+                 CHECK ((VALUE).zipcode ~ '^\d{5}$'::text);
+(1 row)
+
+-- Test domain with NOT VALID constraint
+CREATE DOMAIN regress_domain_not_valid AS int;
+ALTER DOMAIN regress_domain_not_valid ADD CONSTRAINT check_positive CHECK (VALUE > 0) NOT VALID;
+SELECT pg_get_domain_ddl('regress_domain_not_valid');
+                                             pg_get_domain_ddl                                             
+-----------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_domain_not_valid AS pg_catalog.int4;                                        +
+ ALTER DOMAIN public.regress_domain_not_valid ADD CONSTRAINT check_positive CHECK ((VALUE > 0)) NOT VALID;
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_domain_not_valid', pretty => true);
+                                            pg_get_domain_ddl                                            
+---------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_domain_not_valid AS pg_catalog.int4;                                      +
+ ALTER DOMAIN public.regress_domain_not_valid ADD CONSTRAINT check_positive CHECK (VALUE > 0) NOT VALID;
+(1 row)
+
+-- Test domain with mix of valid and not valid constraints
+CREATE DOMAIN regress_domain_mixed AS int CHECK (VALUE != 0);
+ALTER DOMAIN regress_domain_mixed ADD CONSTRAINT check_range CHECK (VALUE BETWEEN 1 AND 100) NOT VALID;
+SELECT pg_get_domain_ddl('regress_domain_mixed');
+                                                    pg_get_domain_ddl                                                     
+--------------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_domain_mixed AS pg_catalog.int4 CONSTRAINT regress_domain_mixed_check CHECK ((VALUE <> 0));+
+ ALTER DOMAIN public.regress_domain_mixed ADD CONSTRAINT check_range CHECK (((VALUE >= 1) AND (VALUE <= 100))) NOT VALID;
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_domain_mixed', pretty => true);
+                                                 pg_get_domain_ddl                                                  
+--------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_domain_mixed AS pg_catalog.int4                                                      +
+         CONSTRAINT regress_domain_mixed_check                                                                     +
+                 CHECK (VALUE <> 0);                                                                               +
+ ALTER DOMAIN public.regress_domain_mixed ADD CONSTRAINT check_range CHECK (VALUE >= 1 AND VALUE <= 100) NOT VALID;
+(1 row)
+
+-- Test domain with collation
+CREATE DOMAIN regress_domain_with_collate AS text COLLATE "C";
+SELECT pg_get_domain_ddl('regress_domain_with_collate');
+                                pg_get_domain_ddl                                 
+----------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_domain_with_collate AS pg_catalog.text COLLATE "C";
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_domain_with_collate', pretty => true);
+                          pg_get_domain_ddl                          
+---------------------------------------------------------------------
+ CREATE DOMAIN public.regress_domain_with_collate AS pg_catalog.text+
+         COLLATE "C";
+(1 row)
+
+-- Cleanup
+DROP DOMAIN regress_us_postal_code;
+DROP DOMAIN regress_domain_not_null;
+DROP DOMAIN regress_domain_check;
+DROP DOMAIN "regress_domain with space";
+DROP DOMAIN regress_comprehensive_domain;
+DROP DOMAIN regress_test_schema.regress_schema_domain;
+DROP SCHEMA regress_test_schema;
+DROP DOMAIN regress_address_domain;
+DROP TYPE regress_address_type;
+DROP DOMAIN regress_int_array_domain;
+DROP DOMAIN regress_precise_numeric;
+DROP DOMAIN regress_seq_domain;
+DROP SEQUENCE regress_test_seq_renamed;
+DROP DOMAIN regress_derived_domain;
+DROP DOMAIN regress_base_domain;
+DROP DOMAIN regress_simple_domain;
+DROP DOMAIN regress_domain_not_valid;
+DROP DOMAIN regress_domain_mixed;
+DROP DOMAIN regress_domain_with_collate;
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index f56482fb9f1..8b6881c397f 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -28,7 +28,7 @@ test: strings md5 numerology point lseg line box path polygon circle date time t
 # geometry depends on point, lseg, line, box, path, polygon, circle
 # horology depends on date, time, timetz, timestamp, timestamptz, interval
 # ----------
-test: geometry horology tstypes regex type_sanity opr_sanity misc_sanity comments expressions unicode xid mvcc database stats_import
+test: geometry horology tstypes regex type_sanity opr_sanity misc_sanity comments expressions unicode xid mvcc database stats_import object_ddl
 
 # ----------
 # Load huge amounts of data
diff --git a/src/test/regress/sql/object_ddl.sql b/src/test/regress/sql/object_ddl.sql
new file mode 100644
index 00000000000..98fb20017ea
--- /dev/null
+++ b/src/test/regress/sql/object_ddl.sql
@@ -0,0 +1,135 @@
+--
+-- Test for the following functions to get object DDL:
+-- - pg_get_domain_ddl
+--
+
+CREATE DOMAIN regress_us_postal_code AS TEXT
+    DEFAULT '00000'
+    CONSTRAINT regress_us_postal_code_check
+        CHECK (
+            VALUE ~ '^\d{5}$'
+    OR VALUE ~ '^\d{5}-\d{4}$'
+    );
+
+SELECT pg_get_domain_ddl('regress_us_postal_code');
+SELECT pg_get_domain_ddl('regress_us_postal_code', pretty => false);
+SELECT pg_get_domain_ddl('regress_us_postal_code', false);
+SELECT pg_get_domain_ddl('regress_us_postal_code', pretty => true);
+SELECT pg_get_domain_ddl('regress_us_postal_code', true);
+
+
+CREATE DOMAIN regress_domain_not_null AS INT NOT NULL;
+
+SELECT pg_get_domain_ddl('regress_domain_not_null');
+SELECT pg_get_domain_ddl('regress_domain_not_null', pretty => true);
+
+
+CREATE DOMAIN regress_domain_check AS INT
+    CONSTRAINT regress_a CHECK (VALUE < 100)
+    CONSTRAINT regress_b CHECK (VALUE > 10);
+
+SELECT pg_get_domain_ddl('regress_domain_check');
+SELECT pg_get_domain_ddl('regress_domain_check', pretty => true);
+
+
+CREATE DOMAIN "regress_domain with space" AS INT
+    CONSTRAINT regress_a CHECK (VALUE < 100)
+    CONSTRAINT "regress_Constraint B" CHECK (VALUE > 10)
+    CONSTRAINT "regress_ConstraintC" CHECK (VALUE != 55);
+
+SELECT pg_get_domain_ddl('"regress_domain with space"');
+SELECT pg_get_domain_ddl('"regress_domain with space"', pretty => true);
+
+-- Test error cases
+SELECT pg_get_domain_ddl('regress_nonexistent_domain'::regtype);  -- should fail
+SELECT pg_get_domain_ddl(NULL);  -- should return NULL
+SELECT pg_get_domain_ddl(NULL, pretty => true);  -- should return NULL
+
+-- Test domains with no constraints
+CREATE DOMAIN regress_simple_domain AS text;
+SELECT pg_get_domain_ddl('regress_simple_domain');
+SELECT pg_get_domain_ddl('regress_simple_domain', pretty => true);
+
+-- Test domain over another domain
+CREATE DOMAIN regress_base_domain AS varchar(10);
+CREATE DOMAIN regress_derived_domain AS regress_base_domain CHECK (LENGTH(VALUE) > 3);
+SELECT pg_get_domain_ddl('regress_derived_domain');
+SELECT pg_get_domain_ddl('regress_derived_domain', pretty => true);
+
+-- Test domain with complex default expressions
+CREATE SEQUENCE regress_test_seq;
+CREATE DOMAIN regress_seq_domain AS int DEFAULT nextval('regress_test_seq');
+SELECT pg_get_domain_ddl('regress_seq_domain');
+SELECT pg_get_domain_ddl('regress_seq_domain', pretty => true);
+
+-- Test domain with a renamed sequence as default expression
+ALTER SEQUENCE regress_test_seq RENAME TO regress_test_seq_renamed;
+SELECT pg_get_domain_ddl('regress_seq_domain');
+
+-- Test domain with type modifiers
+CREATE DOMAIN regress_precise_numeric AS numeric(10,2) DEFAULT 0.00;
+SELECT pg_get_domain_ddl('regress_precise_numeric');
+SELECT pg_get_domain_ddl('regress_precise_numeric', pretty => true);
+
+-- Test domain over array type
+CREATE DOMAIN regress_int_array_domain AS int[] CHECK (array_length(VALUE, 1) <= 5);
+SELECT pg_get_domain_ddl('regress_int_array_domain');
+SELECT pg_get_domain_ddl('regress_int_array_domain', pretty => true);
+
+-- Test domain in non-public schema
+CREATE SCHEMA regress_test_schema;
+CREATE DOMAIN regress_test_schema.regress_schema_domain AS text DEFAULT 'test';
+SELECT pg_get_domain_ddl('regress_test_schema.regress_schema_domain');
+
+-- Test domain with multiple constraint types combined
+CREATE DOMAIN regress_comprehensive_domain AS varchar(50)
+    NOT NULL
+    DEFAULT 'default_value'
+    CHECK (LENGTH(VALUE) >= 5)
+    CHECK (VALUE !~ '^\s*$');  -- not just whitespace
+SELECT pg_get_domain_ddl('regress_comprehensive_domain');
+SELECT pg_get_domain_ddl('regress_comprehensive_domain', pretty => true);
+
+-- Test domain over composite type
+CREATE TYPE regress_address_type AS (street text, city text, zipcode text);
+CREATE DOMAIN regress_address_domain AS regress_address_type CHECK ((VALUE).zipcode ~ '^\d{5}$');
+SELECT pg_get_domain_ddl('regress_address_domain');
+SELECT pg_get_domain_ddl('regress_address_domain', pretty => true);
+
+-- Test domain with NOT VALID constraint
+CREATE DOMAIN regress_domain_not_valid AS int;
+ALTER DOMAIN regress_domain_not_valid ADD CONSTRAINT check_positive CHECK (VALUE > 0) NOT VALID;
+SELECT pg_get_domain_ddl('regress_domain_not_valid');
+SELECT pg_get_domain_ddl('regress_domain_not_valid', pretty => true);
+
+-- Test domain with mix of valid and not valid constraints
+CREATE DOMAIN regress_domain_mixed AS int CHECK (VALUE != 0);
+ALTER DOMAIN regress_domain_mixed ADD CONSTRAINT check_range CHECK (VALUE BETWEEN 1 AND 100) NOT VALID;
+SELECT pg_get_domain_ddl('regress_domain_mixed');
+SELECT pg_get_domain_ddl('regress_domain_mixed', pretty => true);
+
+-- Test domain with collation
+CREATE DOMAIN regress_domain_with_collate AS text COLLATE "C";
+SELECT pg_get_domain_ddl('regress_domain_with_collate');
+SELECT pg_get_domain_ddl('regress_domain_with_collate', pretty => true);
+
+-- Cleanup
+DROP DOMAIN regress_us_postal_code;
+DROP DOMAIN regress_domain_not_null;
+DROP DOMAIN regress_domain_check;
+DROP DOMAIN "regress_domain with space";
+DROP DOMAIN regress_comprehensive_domain;
+DROP DOMAIN regress_test_schema.regress_schema_domain;
+DROP SCHEMA regress_test_schema;
+DROP DOMAIN regress_address_domain;
+DROP TYPE regress_address_type;
+DROP DOMAIN regress_int_array_domain;
+DROP DOMAIN regress_precise_numeric;
+DROP DOMAIN regress_seq_domain;
+DROP SEQUENCE regress_test_seq_renamed;
+DROP DOMAIN regress_derived_domain;
+DROP DOMAIN regress_base_domain;
+DROP DOMAIN regress_simple_domain;
+DROP DOMAIN regress_domain_not_valid;
+DROP DOMAIN regress_domain_mixed;
+DROP DOMAIN regress_domain_with_collate;
-- 
2.45.1

---

From: Man Zeng <[email-masked]>
Date: Thu, 20 Nov 2025 06:55:03 +0000

Quick correction with an apology: I accidentally created a new thread (https://www.postgresql.org/message-id/tencent_64301BB7627E58CD256CE15F%40qq.com) and submitted the patch there—my apologies for the mix-up! Let’s just continue the discussion here as planned.

-- 
Regrads,
Man Zeng

---

From: Chao Li <[email-masked]>
Date: Thu, 20 Nov 2025 16:47:19 +0800

> On Nov 12, 2025, at 00:14, Florin Irion <[email-masked]> wrote:
> 
> Hello, Cirrus-CI was complaining because we don't sort the constraints and thus
> <v4-0001-Add-pg_get_domain_ddl-function-to-reconstruct-CRE.patch>

I just tested v4, and see two problems:

```
evantest=# CREATE DOMAIN public.int AS pg_catalog.int4;
CREATE DOMAIN
evantest=# SELECT pg_get_domain_ddl('int');
ERROR:  cache lookup failed for type 0
evantest=#
evantest=#
evantest=# SELECT pg_get_domain_ddl('pg_class');
ERROR:  cache lookup failed for type 0
evantest=#
evantest=#
evantest=# SELECT pg_get_domain_ddl('public.int');
               pg_get_domain_ddl
------------------------------------------------
 CREATE DOMAIN public."int" AS pg_catalog.int4;
(1 row)

evantest=# show search_path;
   search_path
-----------------
 "$user", public
(1 row)
```

1. The error message "cache lookup failed for type 0” looks not good. At lease saying something like “domain ‘int’ does not exist”.

2. I created a domain “int” in “public”, as you see, “public” is in the search_path, but SELECT pg_get_domain_ddl('int’); failed.

Best regards,

---

From: Neil Chen <[email-masked]>
Date: Thu, 20 Nov 2025 17:44:07 +0800

Hi Florin,

> + prettyFlags = pretty ? GET_PRETTY_FLAGS(pretty) : 0;

Seems like we should directly use GET_PRETTY_FLAGS here, as it already
checks the value of "pretty". For a "display-oriented" result, using
PRETTYFLAG_INDENT looks more appropriate.

> + generate_qualified_type_name(typForm->typbasetype));

It might be good to first call get_typtype to check if it is TYPTYPE_DOMAIN.

---

From: Florin Irion <[email-masked]>
Date: Tue, 2 Dec 2025 22:11:39 +0100

Hello,

> 2. I created a domain “int” in “public”, as you see, “public” is in the search_path, but SELECT pg_get_domain_ddl('int’); failed.

Thank you both Man Zeng and Chao Li for checking this. Changes added in v5.
I don't think there is a way to make the path issue work, so we just 
give more info
to the caller. We exit with error when a built-in name is used and we 
throw also a
hint saying that schema-qualified domain name should be used to be sure 
it's not
conflicting with a built in  name.

> PRETTYFLAG_INDENT looks more appropriate.

Well, actually no,
GET_PRETTY_FLAGS(false) returns PRETTYFLAG_INDENT
But we actually want 0 when pretty is false (no indentation, just spaces)

> It might be good to first call get_typtype to check if it is 

I added this in `pg_get_domain_ddl_worker`, as we need to make this 
check ASAP.

Cheers,
Florin Irion
Tim Waizenegger
EDB (EnterpriseDB)

From 30738bef278cd0140e9b3030dde62b5f048a0dfc Mon Sep 17 00:00:00 2001
From: Florin Irion <[email-masked]>
Date: Thu, 18 Sep 2025 18:52:43 +0200
Subject: [PATCH v5] Add pg_get_domain_ddl() function to reconstruct CREATE
 DOMAIN statements
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Key features:
* warn against conflicting built-in names

Reference: PG-151
Author: Florin Irion <[email-masked]>
Author: Tim Waizenegger <[email-masked]>
Reviewed-by: Álvaro Herrera [email-masked]
Reviewed-by: jian he <[email-masked]>
Reviewed-by: Chao Li <[email-masked]>
Reviewed-by: Neil Chen <[email-masked]>
Reviewed-by: Man Zeng <[email-masked]>
---
 doc/src/sgml/func/func-info.sgml         |  53 ++++
 src/backend/catalog/system_functions.sql |   6 +
 src/backend/utils/adt/ruleutils.c        | 240 ++++++++++++++++
 src/include/catalog/pg_proc.dat          |   3 +
 src/test/regress/expected/object_ddl.out | 348 +++++++++++++++++++++++
 src/test/regress/parallel_schedule       |   2 +-
 src/test/regress/sql/object_ddl.sql      | 145 ++++++++++
 7 files changed, 796 insertions(+), 1 deletion(-)
 create mode 100644 src/test/regress/expected/object_ddl.out
 create mode 100644 src/test/regress/sql/object_ddl.sql

diff --git a/doc/src/sgml/func/func-info.sgml b/doc/src/sgml/func/func-info.sgml
index d4508114a48..4bba7551c21 100644
--- a/doc/src/sgml/func/func-info.sgml
+++ b/doc/src/sgml/func/func-info.sgml
@@ -3797,4 +3797,57 @@ acl      | {postgres=arwdDxtm/postgres,foo=r/postgres}
 
   </sect2>
 
+  <sect2 id="functions-get-object-ddl">
+   <title>Get Object DDL Functions</title>
+
+   <para>
+    The functions shown in <xref linkend="functions-get-object-ddl-table"/>
+    print the DDL statements for various database objects.
+    (This is a decompiled reconstruction, not the original text
+    of the command.)
+   </para>
+
+   <table id="functions-get-object-ddl-table">
+    <title>Get Object DDL Functions</title>
+    <tgroup cols="1">
+     <thead>
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        Function
+       </para>
+       <para>
+        Description
+       </para></entry>
+      </row>
+     </thead>
+
+     <tbody>
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <indexterm>
+         <primary>pg_get_domain_ddl</primary>
+        </indexterm>
+        <function>pg_get_domain_ddl</function> ( <parameter>domain</parameter> <type>regtype</type>
+         <optional> <parameter>pretty</parameter> <type>boolean</type> </optional>)
+        <returnvalue>text</returnvalue>
+       </para>
+       <para>
+        Reconstructs the creating command for a domain.
+        The result is a complete <command>CREATE DOMAIN</command> statement.
+       </para>
+       <para>
+        The <parameter>domain</parameter> parameter uses type <type>regtype</type>,
+        which follows the standard <varname>search_path</varname> for type name
+        resolution. If a domain name conflicts with a built-in type name
+        (for example, a domain named <literal>int</literal>), you must use a
+        schema-qualified name (for example, <literal>'public.int'::regtype</literal>)
+        to reference the domain.
+       </para></entry>
+      </row>
+     </tbody>
+    </tgroup>
+   </table>
+
+  </sect2>
+
   </sect1>
diff --git a/src/backend/catalog/system_functions.sql b/src/backend/catalog/system_functions.sql
index 2d946d6d9e9..5a96ff1efcb 100644
--- a/src/backend/catalog/system_functions.sql
+++ b/src/backend/catalog/system_functions.sql
@@ -657,6 +657,12 @@ LANGUAGE INTERNAL
 STRICT VOLATILE PARALLEL UNSAFE
 AS 'pg_replication_origin_session_setup';
 
index 6cf90be40bb..ae676557210 100644

@@ -13743,3 +13748,238 @@ get_range_partbound_string(List *bound_datums)
 
 	return buf.data;
 }
+
+/*
+ * get_formatted_string
+ *
+	/* Check that this is actually a domain */
+	if (typForm->typtype != TYPTYPE_DOMAIN)
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("\"%s\" is not a domain", format_type_be(domain_oid)),
+				 errhint("Use a schema-qualified name if the domain name conflicts with a built-in name.")));
index 66af2d96d67..2f7869103f3 100644
index 00000000000..1241b89a770
@@ -0,0 +1,348 @@
+SELECT pg_get_domain_ddl('pg_class');  -- should fail - not a domain
+ERROR:  "pg_class" is not a domain
+HINT:  Use a schema-qualified name if the domain name conflicts with a built-in name.
+SELECT pg_get_domain_ddl('integer');  -- should fail - not a domain
+ERROR:  "integer" is not a domain
+HINT:  Use a schema-qualified name if the domain name conflicts with a built-in name.
+-- Test domain that shadows a built-in type name (must use schema-qualified name)
+CREATE DOMAIN public.int AS pg_catalog.int4;
+-- This should fail because 'int' resolves to pg_catalog.int4, not public.int
+SELECT pg_get_domain_ddl('int');  -- should fail
+ERROR:  "integer" is not a domain
+HINT:  Use a schema-qualified name if the domain name conflicts with a built-in name.
+-- This should work with schema-qualified name
+SELECT pg_get_domain_ddl('public.int');
+------------------------------------------------
+ CREATE DOMAIN public."int" AS pg_catalog.int4;
+DROP DOMAIN public.int;
index cc6d799bcea..5a615806dcf 100644
-test: geometry horology tstypes regex type_sanity opr_sanity misc_sanity comments expressions unicode xid mvcc database stats_import pg_ndistinct pg_dependencies
+test: geometry horology tstypes regex type_sanity opr_sanity misc_sanity comments expressions unicode xid mvcc database stats_import pg_ndistinct pg_dependencies object_ddl
 
 # ----------
index 00000000000..4eb0e5b86d6
@@ -0,0 +1,145 @@
+SELECT pg_get_domain_ddl('pg_class');  -- should fail - not a domain
+SELECT pg_get_domain_ddl('integer');  -- should fail - not a domain
+-- Test domain that shadows a built-in type name (must use schema-qualified name)
+CREATE DOMAIN public.int AS pg_catalog.int4;
+-- This should fail because 'int' resolves to pg_catalog.int4, not public.int
+SELECT pg_get_domain_ddl('int');  -- should fail
+-- This should work with schema-qualified name
+SELECT pg_get_domain_ddl('public.int');
+DROP DOMAIN public.int;
-- 
2.45.1

---

From: Florin Irion <[email-masked]>
Date: Mon, 2 Mar 2026 17:41:41 +0100

Hi Haritabh, Tom,

Thanks for the thorough review. v8 fixes all reported bugs and adds
round-trip tests to address the forcing-function concern.

Haritabh's bugs — all fixed in attached v8.

On 19/02/26 01:10, Tom Lane wrote:

> This report crystallized something that's been bothering me
> about not only pg_get_domain_ddl() but all the similar patches
> that are in the queue.  They are adding a large amount of new
> code that will have to be kept in sync with behavior elsewhere
> and there is basically zero forcing function to ensure that
> that happens.  Even the rather-overly-voluminous test cases
> proposed for the functions cannot catch errors of omission,
> especially not future errors of omission.

v8 adds a PL/pgSQL round-trip harness that captures DDL, drops
the domain, re-executes the DDL, and ASSERTs the regenerated DDL
is identical, any suggestions on how to improve it are welcomed.
This function can be re-used also with other get_<object>_ddl
as it accepts a parameter for the <object_type>, this way we can
use some common code.

> I don't really know what to do about this, but I don't like the
> implementation approach that's being proposed.  I think it's
> loading too much development effort and future maintenance effort
> onto us in comparison to the expected benefit of having these
> functions.

I understand your point that there are multiple implementations
and each have its own way of doing it. I think we should start
somewhere and eventually ask further implementations to adapt to
use common code or make it work with all existing (at that point)
implementations, one at a time.
pg_get_domain_ddl implementation uses mainly common code in ruleutils.c
plus some glue code. We could maybe also create a new separate
module and put all the code for all these features there.

What do you think?

Cheers,
Florin

-- 
*Florin Irion*
www.enterprisedb.com <https://www.enterprisedb.com>
From 8e3683a199595ac6100eabd459ab9cbcc858f0ab Mon Sep 17 00:00:00 2001
From: Florin Irion <[email-masked]>
Date: Thu, 18 Sep 2025 18:52:43 +0200
Subject: [PATCH v8] Add pg_get_domain_ddl() function to reconstruct CREATE
 DOMAIN statements
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Key features:
* Uses GET_DDL_PRETTY_FLAGS macro for consistent pretty-printing behavior

Comprehensive regression tests are included covering various domain
configurations. In a separate file sql/object_ddl.sql where more
"get_object_ddl" functions can be tested in the future.
Round-trip regression tests that drop and recreate every test domain
from its own DDL output, asserting the regenerated DDL is identical.
The reusable harness (regress_verify_ddl_roundtrip) is parameterized
by object type, so future pg_get_*_ddl() functions can reuse it.

Reference: PG-151
Author: Florin Irion <[email-masked]>
Author: Tim Waizenegger <[email-masked]>
Reviewed-by: Álvaro Herrera [email-masked]
Reviewed-by: jian he <[email-masked]>
Reviewed-by: Chao Li <[email-masked]>
Reviewed-by: Neil Chen <[email-masked]>
Reviewed-by: Man Zeng <[email-masked]>
Reviewed-by: Haritabh <Gupta [email-masked]>
---
 doc/src/sgml/func/func-info.sgml         |  53 +++
 src/backend/catalog/system_functions.sql |   7 +
 src/backend/utils/adt/ruleutils.c        | 260 +++++++++++++
 src/include/catalog/pg_proc.dat          |   3 +
 src/test/regress/expected/object_ddl.out | 461 +++++++++++++++++++++++
 src/test/regress/parallel_schedule       |   2 +-
 src/test/regress/sql/object_ddl.sql      | 180 +++++++++
 7 files changed, 965 insertions(+), 1 deletion(-)
 create mode 100644 src/test/regress/expected/object_ddl.out
 create mode 100644 src/test/regress/sql/object_ddl.sql

diff --git a/doc/src/sgml/func/func-info.sgml b/doc/src/sgml/func/func-info.sgml
index 294f45e82a3..eb128fede09 100644
--- a/doc/src/sgml/func/func-info.sgml
+++ b/doc/src/sgml/func/func-info.sgml
@@ -3845,4 +3845,57 @@ acl      | {postgres=arwdDxtm/postgres,foo=r/postgres}
 
   </sect2>
 
+         <optional>, <parameter>pretty</parameter> <type>boolean</type> </optional>)
index 69699f8830a..f4829cc7765 100644
@@ -378,6 +378,13 @@ BEGIN ATOMIC
 END;

+ STABLE PARALLEL SAFE
index f16f1535785..45e04bcf15b 100644
@@ -94,6 +94,11 @@
 	((pretty) ? (PRETTYFLAG_PAREN | PRETTYFLAG_INDENT | PRETTYFLAG_SCHEMA) \
 	 : PRETTYFLAG_INDENT)
 
+/* Conversion of "bool pretty" option for DDL statements (0 when false) */
+#define GET_DDL_PRETTY_FLAGS(pretty) \
+	((pretty) ? (PRETTYFLAG_PAREN | PRETTYFLAG_INDENT | PRETTYFLAG_SCHEMA) \
+	 : 0)
+
 /* Default line length for pretty-print wrapping: 0 means wrap always */
 #define WRAP_COLUMN_DEFAULT		0
 
@@ -547,6 +552,11 @@ static void get_json_table_nested_columns(TableFunc *tf, JsonTablePlan *plan,

@@ -13760,3 +13770,253 @@ get_range_partbound_string(List *bound_datums)
 
 	return buf.data;
 }
+
+/*
+ * get_formatted_string
+ *
+ * Return a formatted version of the string.
+ *
+ * prettyFlags - If pretty is true, the output includes tabs (\t) and newlines (\n).
+ * noOfTabChars - indent with specified no of tabs.
+ * fmt - printf-style format string used by appendStringInfoVA.
+ */
+static void
+get_formatted_string(StringInfo buf, int prettyFlags, int noOfTabChars, const char *fmt,...)
+{
+	int			save_errno = errno;
+
+	if (prettyFlags & PRETTYFLAG_INDENT)
+	{
+		appendStringInfoChar(buf, '\n');
+		/* Indent with tabs */
+		for (int i = 0; i < noOfTabChars; i++)
+		{
+			appendStringInfoChar(buf, '\t');
+		}
+	}
+	else
+		appendStringInfoChar(buf, ' ');
+
+	for (;;)
+	{
+		va_list		args;
+		int			needed;
+
+		errno = save_errno;
+		va_start(args, fmt);
+		needed = appendStringInfoVA(buf, fmt, args);
+		va_end(args);
+
+		if (needed == 0)
+			break;
+
+		enlargeStringInfo(buf, needed);
+	}
+}
+
+
+/*
+ * Helper function to scan domain constraints
+ */
+static void
+scan_domain_constraints(Oid domain_oid, List **validcons, List **invalidcons)
+{
+	Relation	constraintRel;
+	SysScanDesc sscan;
+	ScanKeyData skey;
+	HeapTuple	constraintTup;
+
+	*validcons = NIL;
+	*invalidcons = NIL;
+
+	constraintRel = table_open(ConstraintRelationId, AccessShareLock);
+
+	ScanKeyInit(&skey,
+				Anum_pg_constraint_contypid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(domain_oid));
+
+	sscan = systable_beginscan(constraintRel,
+							   ConstraintTypidIndexId,
+							   true,
+							   NULL,
+							   1,
+							   &skey);
+
+	while (HeapTupleIsValid(constraintTup = systable_getnext(sscan)))
+	{
+		Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(constraintTup);
+
+		if (con->convalidated)
+			*validcons = lappend_oid(*validcons, con->oid);
+		else
+			*invalidcons = lappend_oid(*invalidcons, con->oid);
+	}
+
+	systable_endscan(sscan);
+	table_close(constraintRel, AccessShareLock);
+
+	/* Sort constraints by OID for stable output */
+	if (list_length(*validcons) > 1)
+		list_sort(*validcons, list_oid_cmp);
+	if (list_length(*invalidcons) > 1)
+		list_sort(*invalidcons, list_oid_cmp);
+}
+
+/*
+ * Helper function to build CREATE DOMAIN statement
+ */
+static void
+build_create_domain_statement(StringInfo buf, Form_pg_type typForm,
+							  Node *defaultExpr, List *validConstraints, int prettyFlags)
+{
+	HeapTuple	baseTypeTuple;
+	Form_pg_type baseTypeForm;
+	Oid			baseCollation = InvalidOid;
+	ListCell   *lc;
+
+	appendStringInfo(buf, "CREATE DOMAIN %s AS %s",
+					 generate_qualified_type_name(typForm->oid),
+					 format_type_extended(typForm->typbasetype,
+										  typForm->typtypmod,
+										  FORMAT_TYPE_TYPEMOD_GIVEN |
+										  FORMAT_TYPE_FORCE_QUALIFY));
+
+	/* Add collation if it differs from base type's collation */
+	if (OidIsValid(typForm->typcollation))
+	{
+		/* Get base type's collation for comparison */
+		baseTypeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typForm->typbasetype));
+		if (HeapTupleIsValid(baseTypeTuple))
+		{
+			baseTypeForm = (Form_pg_type) GETSTRUCT(baseTypeTuple);
+			baseCollation = baseTypeForm->typcollation;
+			ReleaseSysCache(baseTypeTuple);
+		}
+
+		/* Only add COLLATE if domain's collation differs from base type's */
+		if (typForm->typcollation != baseCollation)
+		{
+			get_formatted_string(buf, prettyFlags, 1, "COLLATE %s",
+								 generate_collation_name(typForm->typcollation));
+		}
+	}
+
+	/* Add default value if present */
+	if (defaultExpr != NULL)
+	{
+		char	   *defaultValue = deparse_expression_pretty(defaultExpr, NIL, false, false, prettyFlags, 0);
+
+		get_formatted_string(buf, prettyFlags, 1, "DEFAULT %s", defaultValue);
+	}
+
+	/* Add valid constraints */
+	foreach(lc, validConstraints)
+	{
+		Oid			constraintOid = lfirst_oid(lc);
+		HeapTuple	constraintTup;
+		Form_pg_constraint con;
+		char	   *constraintDef;
+
+		/* Look up the constraint info */
+		constraintTup = SearchSysCache1(CONSTROID, ObjectIdGetDatum(constraintOid));
+		if (!HeapTupleIsValid(constraintTup))
+			continue;			/* constraint was dropped concurrently */
+
+		con = (Form_pg_constraint) GETSTRUCT(constraintTup);
+		constraintDef = pg_get_constraintdef_worker(constraintOid, false, prettyFlags, true);
+
+		get_formatted_string(buf, prettyFlags, 1, "CONSTRAINT %s",
+							 quote_identifier(NameStr(con->conname)));
+		get_formatted_string(buf, prettyFlags, 2, "%s", constraintDef);
+
+		ReleaseSysCache(constraintTup);
+	}
+
+	appendStringInfoChar(buf, ';');
+}
+
+/*
+ * Helper function to add ALTER DOMAIN statements for invalid constraints
+ */
+static void
+add_alter_domain_statements(StringInfo buf, List *invalidConstraints, int prettyFlags)
+{
+	ListCell   *lc;
+
+	foreach(lc, invalidConstraints)
+	{
+		Oid			constraintOid = lfirst_oid(lc);
+		char	   *alterStmt = pg_get_constraintdef_worker(constraintOid, true, prettyFlags, true);
+
+		if (alterStmt)
+			appendStringInfo(buf, "\n%s;", alterStmt);
+	}
+}
+
+/*
+ * pg_get_domain_ddl_ext - Get CREATE DOMAIN statement for a domain with pretty-print option
+ */
+Datum
+pg_get_domain_ddl_ext(PG_FUNCTION_ARGS)
+{
+	Oid			domain_oid = PG_GETARG_OID(0);
+	bool		pretty = PG_GETARG_BOOL(1);
+	char	   *res;
+	int			prettyFlags;
+
+	prettyFlags = GET_DDL_PRETTY_FLAGS(pretty);
+
+	res = pg_get_domain_ddl_worker(domain_oid, prettyFlags);
+	if (res == NULL)
+		PG_RETURN_NULL();
+	PG_RETURN_TEXT_P(string_to_text(res));
+}
+
+
+
+static char *
+pg_get_domain_ddl_worker(Oid domain_oid, int prettyFlags)
+{
+	StringInfoData buf;
+	HeapTuple	typeTuple;
+	Form_pg_type typForm;
+	Node	   *defaultExpr;
+	List	   *validConstraints;
+	List	   *invalidConstraints;
+
+	/* Look up the domain in pg_type */
+	typeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(domain_oid));
+	if (!HeapTupleIsValid(typeTuple))
+		return NULL;
+
+	typForm = (Form_pg_type) GETSTRUCT(typeTuple);
+
+	/* Check that this is actually a domain */
+	if (typForm->typtype != TYPTYPE_DOMAIN)
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("\"%s\" is not a domain", format_type_be(domain_oid)),
+				 errhint("Use a schema-qualified name if the domain name conflicts with a built-in name.")));
+
+	/* Get default expression */
+	defaultExpr = get_typdefault(domain_oid);
+
+	/* Scan for valid and invalid constraints */
+	scan_domain_constraints(domain_oid, &validConstraints, &invalidConstraints);
+
+	/* Build the DDL statement */
+	initStringInfo(&buf);
+	build_create_domain_statement(&buf, typForm, defaultExpr, validConstraints, prettyFlags);
+
+	/* Add ALTER DOMAIN statements for invalid constraints */
+	if (list_length(invalidConstraints) > 0)
+		add_alter_domain_statements(&buf, invalidConstraints, prettyFlags);
+
+	/* Cleanup */
+	list_free(validConstraints);
+	list_free(invalidConstraints);
+	ReleaseSysCache(typeTuple);
+
+	return buf.data;
+}
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index dac40992cbc..d1a4fbaf40a 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -8539,6 +8539,9 @@
 { oid => '2508', descr => 'constraint description with pretty-print option',
   proname => 'pg_get_constraintdef', provolatile => 's', prorettype => 'text',
   proargtypes => 'oid bool', prosrc => 'pg_get_constraintdef_ext' },
+{ oid => '8024', descr => 'get CREATE statement for DOMAIN with pretty option',
+  proname => 'pg_get_domain_ddl', provolatile => 's', prorettype => 'text',
+  proargtypes => 'regtype bool', prosrc => 'pg_get_domain_ddl_ext' },
 { oid => '2509',
   descr => 'deparse an encoded expression with pretty-print option',
   proname => 'pg_get_expr', provolatile => 's', prorettype => 'text',
diff --git a/src/test/regress/expected/object_ddl.out b/src/test/regress/expected/object_ddl.out
new file mode 100644
index 00000000000..f8dc8d12dd6
--- /dev/null
+++ b/src/test/regress/expected/object_ddl.out
@@ -0,0 +1,461 @@
+--
+-- Test for the following functions to get object DDL:
+-- - pg_get_domain_ddl
+--
+CREATE DOMAIN regress_us_postal_code AS TEXT
+    DEFAULT '00000'
+    CONSTRAINT regress_us_postal_code_check
+        CHECK (
+            VALUE ~ '^\d{5}$'
+    OR VALUE ~ '^\d{5}-\d{4}$'
+    );
+SELECT pg_get_domain_ddl('regress_us_postal_code');
+                                                                                          pg_get_domain_ddl                                                                                           
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_us_postal_code AS pg_catalog.text DEFAULT '00000'::text CONSTRAINT regress_us_postal_code_check CHECK (((VALUE ~ '^\d{5}$'::text) OR (VALUE ~ '^\d{5}-\d{4}$'::text)));
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_us_postal_code', pretty => false);
+                                                                                          pg_get_domain_ddl                                                                                           
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_us_postal_code AS pg_catalog.text DEFAULT '00000'::text CONSTRAINT regress_us_postal_code_check CHECK (((VALUE ~ '^\d{5}$'::text) OR (VALUE ~ '^\d{5}-\d{4}$'::text)));
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_us_postal_code', false);
+                                                                                          pg_get_domain_ddl                                                                                           
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_us_postal_code AS pg_catalog.text DEFAULT '00000'::text CONSTRAINT regress_us_postal_code_check CHECK (((VALUE ~ '^\d{5}$'::text) OR (VALUE ~ '^\d{5}-\d{4}$'::text)));
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_us_postal_code', pretty => true);
+                                 pg_get_domain_ddl                                 
+-----------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_us_postal_code AS pg_catalog.text                   +
+         DEFAULT '00000'::text                                                    +
+         CONSTRAINT regress_us_postal_code_check                                  +
+                 CHECK (VALUE ~ '^\d{5}$'::text OR VALUE ~ '^\d{5}-\d{4}$'::text);
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_us_postal_code', true);
+                                 pg_get_domain_ddl                                 
+-----------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_us_postal_code AS pg_catalog.text                   +
+         DEFAULT '00000'::text                                                    +
+         CONSTRAINT regress_us_postal_code_check                                  +
+                 CHECK (VALUE ~ '^\d{5}$'::text OR VALUE ~ '^\d{5}-\d{4}$'::text);
+(1 row)
+
+CREATE DOMAIN regress_domain_not_null AS INT NOT NULL;
+SELECT pg_get_domain_ddl('regress_domain_not_null');
+                                               pg_get_domain_ddl                                               
+---------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_domain_not_null AS integer CONSTRAINT regress_domain_not_null_not_null NOT NULL;
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_domain_not_null', pretty => true);
+                    pg_get_domain_ddl                    
+---------------------------------------------------------
+ CREATE DOMAIN public.regress_domain_not_null AS integer+
+         CONSTRAINT regress_domain_not_null_not_null    +
+                 NOT NULL;
+(1 row)
+
+CREATE DOMAIN regress_domain_check AS INT
+    CONSTRAINT regress_a CHECK (VALUE < 100)
+    CONSTRAINT regress_b CHECK (VALUE > 10);
+SELECT pg_get_domain_ddl('regress_domain_check');
+                                                             pg_get_domain_ddl                                                              
+--------------------------------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_domain_check AS integer CONSTRAINT regress_a CHECK ((VALUE < 100)) CONSTRAINT regress_b CHECK ((VALUE > 10));
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_domain_check', pretty => true);
+                  pg_get_domain_ddl                   
+------------------------------------------------------
+ CREATE DOMAIN public.regress_domain_check AS integer+
+         CONSTRAINT regress_a                        +
+                 CHECK (VALUE < 100)                 +
+         CONSTRAINT regress_b                        +
+                 CHECK (VALUE > 10);
+(1 row)
+
+CREATE DOMAIN "regress_domain with space" AS INT
+    CONSTRAINT regress_a CHECK (VALUE < 100)
+    CONSTRAINT "regress_Constraint B" CHECK (VALUE > 10)
+    CONSTRAINT "regress_ConstraintC" CHECK (VALUE != 55);
+SELECT pg_get_domain_ddl('"regress_domain with space"');
+                                                                                                   pg_get_domain_ddl                                                                                                   
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public."regress_domain with space" AS integer CONSTRAINT regress_a CHECK ((VALUE < 100)) CONSTRAINT "regress_Constraint B" CHECK ((VALUE > 10)) CONSTRAINT "regress_ConstraintC" CHECK ((VALUE <> 55));
+(1 row)
+
+SELECT pg_get_domain_ddl('"regress_domain with space"', pretty => true);
+                      pg_get_domain_ddl                      
+-------------------------------------------------------------
+ CREATE DOMAIN public."regress_domain with space" AS integer+
+         CONSTRAINT regress_a                               +
+                 CHECK (VALUE < 100)                        +
+         CONSTRAINT "regress_Constraint B"                  +
+                 CHECK (VALUE > 10)                         +
+         CONSTRAINT "regress_ConstraintC"                   +
+                 CHECK (VALUE <> 55);
+(1 row)
+
+-- Test error cases
+SELECT pg_get_domain_ddl('regress_nonexistent_domain'::regtype);  -- should fail
+ERROR:  type "regress_nonexistent_domain" does not exist
+LINE 1: SELECT pg_get_domain_ddl('regress_nonexistent_domain'::regty...
+                                 ^
+SELECT pg_get_domain_ddl(NULL);  -- should return NULL
+ pg_get_domain_ddl 
+-------------------
+ 
+(1 row)
+
+SELECT pg_get_domain_ddl(NULL, pretty => true);  -- should return NULL
+ pg_get_domain_ddl 
+-------------------
+ 
+(1 row)
+
+SELECT pg_get_domain_ddl('pg_class');  -- should fail - not a domain
+ERROR:  "pg_class" is not a domain
+HINT:  Use a schema-qualified name if the domain name conflicts with a built-in name.
+SELECT pg_get_domain_ddl('integer');  -- should fail - not a domain
+ERROR:  "integer" is not a domain
+HINT:  Use a schema-qualified name if the domain name conflicts with a built-in name.
+-- Test domains with no constraints
+CREATE DOMAIN regress_simple_domain AS text;
+SELECT pg_get_domain_ddl('regress_simple_domain');
+                       pg_get_domain_ddl                        
+----------------------------------------------------------------
+ CREATE DOMAIN public.regress_simple_domain AS pg_catalog.text;
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_simple_domain', pretty => true);
+                       pg_get_domain_ddl                        
+----------------------------------------------------------------
+ CREATE DOMAIN public.regress_simple_domain AS pg_catalog.text;
+(1 row)
+
+-- Test domain over another domain
+CREATE DOMAIN regress_base_domain AS varchar(10);
+CREATE DOMAIN regress_derived_domain AS regress_base_domain CHECK (LENGTH(VALUE) > 3);
+SELECT pg_get_domain_ddl('regress_derived_domain');
+                                                                   pg_get_domain_ddl                                                                    
+--------------------------------------------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_derived_domain AS public.regress_base_domain CONSTRAINT regress_derived_domain_check CHECK ((length((VALUE)::text) > 3));
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_derived_domain', pretty => true);
+                             pg_get_domain_ddl                             
+---------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_derived_domain AS public.regress_base_domain+
+         CONSTRAINT regress_derived_domain_check                          +
+                 CHECK (length(VALUE::text) > 3);
+(1 row)
+
+-- Test domain with complex default expressions
+CREATE SEQUENCE regress_test_seq;
+CREATE DOMAIN regress_seq_domain AS int DEFAULT nextval('regress_test_seq');
+SELECT pg_get_domain_ddl('regress_seq_domain');
+                                         pg_get_domain_ddl                                         
+---------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_seq_domain AS integer DEFAULT nextval('regress_test_seq'::regclass);
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_seq_domain', pretty => true);
+                   pg_get_domain_ddl                    
+--------------------------------------------------------
+ CREATE DOMAIN public.regress_seq_domain AS integer    +
+         DEFAULT nextval('regress_test_seq'::regclass);
+(1 row)
+
+-- Test domain with a renamed sequence as default expression
+ALTER SEQUENCE regress_test_seq RENAME TO regress_test_seq_renamed;
+SELECT pg_get_domain_ddl('regress_seq_domain');
+                                             pg_get_domain_ddl                                             
+-----------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_seq_domain AS integer DEFAULT nextval('regress_test_seq_renamed'::regclass);
+(1 row)
+
+-- Test domain with type modifiers
+CREATE DOMAIN regress_precise_numeric AS numeric(10,2) DEFAULT 0.00;
+SELECT pg_get_domain_ddl('regress_precise_numeric');
+                              pg_get_domain_ddl                              
+-----------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_precise_numeric AS numeric(10,2) DEFAULT 0.00;
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_precise_numeric', pretty => true);
+                       pg_get_domain_ddl                       
+---------------------------------------------------------------
+ CREATE DOMAIN public.regress_precise_numeric AS numeric(10,2)+
+         DEFAULT 0.00;
+(1 row)
+
+-- Test domain over array type
+CREATE DOMAIN regress_int_array_domain AS int[] CHECK (array_length(VALUE, 1) <= 5);
+SELECT pg_get_domain_ddl('regress_int_array_domain');
+                                                              pg_get_domain_ddl                                                              
+---------------------------------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_int_array_domain AS integer[] CONSTRAINT regress_int_array_domain_check CHECK ((array_length(VALUE, 1) <= 5));
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_int_array_domain', pretty => true);
+                     pg_get_domain_ddl                      
+------------------------------------------------------------
+ CREATE DOMAIN public.regress_int_array_domain AS integer[]+
+         CONSTRAINT regress_int_array_domain_check         +
+                 CHECK (array_length(VALUE, 1) <= 5);
+(1 row)
+
+-- Test domain in non-public schema
+CREATE SCHEMA regress_test_schema;
+CREATE DOMAIN regress_test_schema.regress_schema_domain AS text DEFAULT 'test';
+SELECT pg_get_domain_ddl('regress_test_schema.regress_schema_domain');
+                                        pg_get_domain_ddl                                         
+--------------------------------------------------------------------------------------------------
+ CREATE DOMAIN regress_test_schema.regress_schema_domain AS pg_catalog.text DEFAULT 'test'::text;
+(1 row)
+
+-- Test domain with multiple constraint types combined
+CREATE DOMAIN regress_comprehensive_domain AS varchar(50)
+    NOT NULL
+    DEFAULT 'default_value'
+    CHECK (LENGTH(VALUE) >= 5)
+    CHECK (VALUE !~ '^\s*$');  -- not just whitespace
+SELECT pg_get_domain_ddl('regress_comprehensive_domain');
+                                                                                                                                                                      pg_get_domain_ddl                                                                                                                                                                      
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_comprehensive_domain AS character varying(50) DEFAULT 'default_value'::character varying CONSTRAINT regress_comprehensive_domain_not_null NOT NULL CONSTRAINT regress_comprehensive_domain_check CHECK ((length((VALUE)::text) >= 5)) CONSTRAINT regress_comprehensive_domain_check1 CHECK (((VALUE)::text !~ '^\s*$'::text));
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_comprehensive_domain', pretty => true);
+                             pg_get_domain_ddl                              
+----------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_comprehensive_domain AS character varying(50)+
+         DEFAULT 'default_value'::character varying                        +
+         CONSTRAINT regress_comprehensive_domain_not_null                  +
+                 NOT NULL                                                  +
+         CONSTRAINT regress_comprehensive_domain_check                     +
+                 CHECK (length(VALUE::text) >= 5)                          +
+         CONSTRAINT regress_comprehensive_domain_check1                    +
+                 CHECK (VALUE::text !~ '^\s*$'::text);
+(1 row)
+
+-- Test domain over composite type
+CREATE TYPE regress_address_type AS (street text, city text, zipcode text);
+CREATE DOMAIN regress_address_domain AS regress_address_type CHECK ((VALUE).zipcode ~ '^\d{5}$');
+SELECT pg_get_domain_ddl('regress_address_domain');
+                                                                        pg_get_domain_ddl                                                                        
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_address_domain AS public.regress_address_type CONSTRAINT regress_address_domain_check CHECK (((VALUE).zipcode ~ '^\d{5}$'::text));
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_address_domain', pretty => true);
+                             pg_get_domain_ddl                              
+----------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_address_domain AS public.regress_address_type+
+         CONSTRAINT regress_address_domain_check                           +
+                 CHECK ((VALUE).zipcode ~ '^\d{5}$'::text);
+(1 row)
+
+-- Test domain with NOT VALID constraint
+CREATE DOMAIN regress_domain_not_valid AS int;
+ALTER DOMAIN regress_domain_not_valid ADD CONSTRAINT check_positive CHECK (VALUE > 0) NOT VALID;
+SELECT pg_get_domain_ddl('regress_domain_not_valid');
+                                             pg_get_domain_ddl                                             
+-----------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_domain_not_valid AS integer;                                                +
+ ALTER DOMAIN public.regress_domain_not_valid ADD CONSTRAINT check_positive CHECK ((VALUE > 0)) NOT VALID;
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_domain_not_valid', pretty => true);
+                                            pg_get_domain_ddl                                            
+---------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_domain_not_valid AS integer;                                              +
+ ALTER DOMAIN public.regress_domain_not_valid ADD CONSTRAINT check_positive CHECK (VALUE > 0) NOT VALID;
+(1 row)
+
+-- Test domain with mix of valid and not valid constraints
+CREATE DOMAIN regress_domain_mixed AS int CHECK (VALUE != 0);
+ALTER DOMAIN regress_domain_mixed ADD CONSTRAINT check_range CHECK (VALUE BETWEEN 1 AND 100) NOT VALID;
+SELECT pg_get_domain_ddl('regress_domain_mixed');
+                                                    pg_get_domain_ddl                                                     
+--------------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_domain_mixed AS integer CONSTRAINT regress_domain_mixed_check CHECK ((VALUE <> 0));        +
+ ALTER DOMAIN public.regress_domain_mixed ADD CONSTRAINT check_range CHECK (((VALUE >= 1) AND (VALUE <= 100))) NOT VALID;
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_domain_mixed', pretty => true);
+                                                 pg_get_domain_ddl                                                  
+--------------------------------------------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_domain_mixed AS integer                                                              +
+         CONSTRAINT regress_domain_mixed_check                                                                     +
+                 CHECK (VALUE <> 0);                                                                               +
+ ALTER DOMAIN public.regress_domain_mixed ADD CONSTRAINT check_range CHECK (VALUE >= 1 AND VALUE <= 100) NOT VALID;
+(1 row)
+
+-- Test domain with collation
+CREATE DOMAIN regress_domain_with_collate AS text COLLATE "C";
+SELECT pg_get_domain_ddl('regress_domain_with_collate');
+                                pg_get_domain_ddl                                 
+----------------------------------------------------------------------------------
+ CREATE DOMAIN public.regress_domain_with_collate AS pg_catalog.text COLLATE "C";
+(1 row)
+
+SELECT pg_get_domain_ddl('regress_domain_with_collate', pretty => true);
+                          pg_get_domain_ddl                          
+---------------------------------------------------------------------
+ CREATE DOMAIN public.regress_domain_with_collate AS pg_catalog.text+
+         COLLATE "C";
+(1 row)
+
+-- Test domain that shadows a built-in type name (must use schema-qualified name)
+CREATE DOMAIN public.int AS pg_catalog.int4;
+-- This should fail because 'int' resolves to pg_catalog.int4, not public.int
+SELECT pg_get_domain_ddl('int');  -- should fail
+ERROR:  "integer" is not a domain
+HINT:  Use a schema-qualified name if the domain name conflicts with a built-in name.
+-- This should work with schema-qualified name
+SELECT pg_get_domain_ddl('public.int');
+           pg_get_domain_ddl            
+----------------------------------------
+ CREATE DOMAIN public."int" AS integer;
+(1 row)
+
+-- Round-trip tests: verify DDL is syntactically valid and semantically correct
+CREATE FUNCTION regress_verify_ddl_roundtrip(object_type text, object_name text) RETURNS void
+LANGUAGE plpgsql AS $$
+DECLARE
+    original_ddl text;
+    recreated_ddl text;
+BEGIN
+    EXECUTE format('SELECT pg_get_%s_ddl(%L)', object_type, object_name) INTO original_ddl;
+    EXECUTE format('DROP %s %s', object_type, object_name);
+    EXECUTE original_ddl;
+    EXECUTE format('SELECT pg_get_%s_ddl(%L)', object_type, object_name) INTO recreated_ddl;
+    ASSERT original_ddl = recreated_ddl,
+        format(E'round-trip mismatch for %s %s:\n  original:  %s\n  recreated: %s',
+               object_type, object_name, original_ddl, recreated_ddl);
+END;
+$$;
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_us_postal_code');
+ regress_verify_ddl_roundtrip 
+------------------------------
+ 
+(1 row)
+
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_domain_not_null');
+ regress_verify_ddl_roundtrip 
+------------------------------
+ 
+(1 row)
+
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_domain_check');
+ regress_verify_ddl_roundtrip 
+------------------------------
+ 
+(1 row)
+
+SELECT regress_verify_ddl_roundtrip('domain', '"regress_domain with space"');
+ regress_verify_ddl_roundtrip 
+------------------------------
+ 
+(1 row)
+
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_simple_domain');
+ regress_verify_ddl_roundtrip 
+------------------------------
+ 
+(1 row)
+
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_derived_domain');
+ regress_verify_ddl_roundtrip 
+------------------------------
+ 
+(1 row)
+
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_seq_domain');
+ regress_verify_ddl_roundtrip 
+------------------------------
+ 
+(1 row)
+
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_precise_numeric');
+ regress_verify_ddl_roundtrip 
+------------------------------
+ 
+(1 row)
+
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_int_array_domain');
+ regress_verify_ddl_roundtrip 
+------------------------------
+ 
+(1 row)
+
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_test_schema.regress_schema_domain');
+ regress_verify_ddl_roundtrip 
+------------------------------
+ 
+(1 row)
+
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_comprehensive_domain');
+ regress_verify_ddl_roundtrip 
+------------------------------
+ 
+(1 row)
+
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_address_domain');
+ regress_verify_ddl_roundtrip 
+------------------------------
+ 
+(1 row)
+
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_domain_not_valid');
+ regress_verify_ddl_roundtrip 
+------------------------------
+ 
+(1 row)
+
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_domain_mixed');
+ regress_verify_ddl_roundtrip 
+------------------------------
+ 
+(1 row)
+
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_domain_with_collate');
+ regress_verify_ddl_roundtrip 
+------------------------------
+ 
+(1 row)
+
+SELECT regress_verify_ddl_roundtrip('domain', 'public."int"');
+ regress_verify_ddl_roundtrip 
+------------------------------
+ 
+(1 row)
+
+-- Cleanup
+DROP FUNCTION regress_verify_ddl_roundtrip;
+DROP DOMAIN regress_us_postal_code;
+DROP DOMAIN regress_domain_not_null;
+DROP DOMAIN regress_domain_check;
+DROP DOMAIN "regress_domain with space";
+DROP DOMAIN regress_comprehensive_domain;
+DROP DOMAIN regress_test_schema.regress_schema_domain;
+DROP SCHEMA regress_test_schema;
+DROP DOMAIN regress_address_domain;
+DROP TYPE regress_address_type;
+DROP DOMAIN regress_int_array_domain;
+DROP DOMAIN regress_precise_numeric;
+DROP DOMAIN regress_seq_domain;
+DROP SEQUENCE regress_test_seq_renamed;
+DROP DOMAIN regress_derived_domain;
+DROP DOMAIN regress_base_domain;
+DROP DOMAIN regress_simple_domain;
+DROP DOMAIN regress_domain_not_valid;
+DROP DOMAIN regress_domain_mixed;
+DROP DOMAIN regress_domain_with_collate;
+DROP DOMAIN public.int;
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 549e9b2d7be..52b24ab806e 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -28,7 +28,7 @@ test: strings md5 numerology point lseg line box path polygon circle date time t
 # geometry depends on point, lseg, line, box, path, polygon, circle
 # horology depends on date, time, timetz, timestamp, timestamptz, interval
 # ----------
-test: geometry horology tstypes regex type_sanity opr_sanity misc_sanity comments expressions unicode xid mvcc database stats_import pg_ndistinct pg_dependencies oid8 encoding euc_kr
+test: geometry horology tstypes regex type_sanity opr_sanity misc_sanity comments expressions unicode xid mvcc database stats_import pg_ndistinct pg_dependencies oid8 encoding euc_kr object_ddl
 
 # ----------
index 00000000000..f214e3b4611
@@ -0,0 +1,180 @@
+-- Round-trip tests: verify DDL is syntactically valid and semantically correct
+CREATE FUNCTION regress_verify_ddl_roundtrip(object_type text, object_name text) RETURNS void
+LANGUAGE plpgsql AS $$
+DECLARE
+    original_ddl text;
+    recreated_ddl text;
+BEGIN
+    EXECUTE format('SELECT pg_get_%s_ddl(%L)', object_type, object_name) INTO original_ddl;
+    EXECUTE format('DROP %s %s', object_type, object_name);
+    EXECUTE original_ddl;
+    EXECUTE format('SELECT pg_get_%s_ddl(%L)', object_type, object_name) INTO recreated_ddl;
+    ASSERT original_ddl = recreated_ddl,
+        format(E'round-trip mismatch for %s %s:\n  original:  %s\n  recreated: %s',
+               object_type, object_name, original_ddl, recreated_ddl);
+END;
+$$;
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_us_postal_code');
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_domain_not_null');
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_domain_check');
+SELECT regress_verify_ddl_roundtrip('domain', '"regress_domain with space"');
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_simple_domain');
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_derived_domain');
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_seq_domain');
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_precise_numeric');
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_int_array_domain');
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_test_schema.regress_schema_domain');
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_comprehensive_domain');
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_address_domain');
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_domain_not_valid');
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_domain_mixed');
+SELECT regress_verify_ddl_roundtrip('domain', 'regress_domain_with_collate');
+SELECT regress_verify_ddl_roundtrip('domain', 'public."int"');
+DROP FUNCTION regress_verify_ddl_roundtrip;