v6-0003-Add-EXCEPT-support-to-ALTER-PUBLICATION-SET-TABLE.patch

application/octet-stream

Filename: v6-0003-Add-EXCEPT-support-to-ALTER-PUBLICATION-SET-TABLE.patch
Type: application/octet-stream
Part: 2
Message: Re: Support EXCEPT for TABLES IN SCHEMA publications
From d7088cb54fa57c9000e57054f6db16721bbf0013 Mon Sep 17 00:00:00 2001
From: Nisha Moond <nisha.moond412@gmail.com>
Date: Tue, 19 May 2026 13:44:35 +0530
Subject: [PATCH v6 3/3] Add EXCEPT support to ALTER PUBLICATION SET TABLES IN
 SCHEMA

Extend AlterPublicationExceptTables() with the AP_SetObjects case,
which redefine the publication and replaces the entire EXCEPT list.

Syntax:
ALTER PUBLICATION pub SET TABLES IN SCHEMA s EXCEPT (TABLE t1);

This patch also cleans up EXCEPT entries when a schema is dropped
from the publication.
---
 doc/src/sgml/ref/alter_publication.sgml   |  36 ++++--
 src/backend/commands/publicationcmds.c    | 145 ++++++++++++++++++++--
 src/bin/psql/tab-complete.in.c            |  17 +++
 src/test/regress/expected/publication.out |  20 +++
 src/test/regress/sql/publication.sql      |  10 ++
 src/test/subscription/t/037_except.pl     |  90 ++++++++++++++
 6 files changed, 293 insertions(+), 25 deletions(-)

diff --git a/doc/src/sgml/ref/alter_publication.sgml b/doc/src/sgml/ref/alter_publication.sgml
index 8aedfd951a5..1b73b34e43a 100644
--- a/doc/src/sgml/ref/alter_publication.sgml
+++ b/doc/src/sgml/ref/alter_publication.sgml
@@ -54,10 +54,6 @@ ALTER PUBLICATION <replaceable class="parameter">name</replaceable> RENAME TO <r
 <phrase>and <replaceable class="parameter">table_object</replaceable> is:</phrase>
 
    [ ONLY ] <replaceable class="parameter">table_name</replaceable> [ * ]
-
-<phrase>and <replaceable class="parameter">except_table_object</replaceable> is:</phrase>
-
-   [ ONLY ] <replaceable class="parameter">table_name</replaceable> [ * ]
 </synopsis>
  </refsynopsisdiv>
 
@@ -97,7 +93,11 @@ ALTER PUBLICATION <replaceable class="parameter">name</replaceable> RENAME TO <r
    used with a publication defined with <literal>FOR TABLE</literal> or
    <literal>FOR TABLES IN SCHEMA</literal>, replaces the list of tables/schemas
    in the publication with the specified list; the existing tables or schemas
-   that were present in the publication will be removed.
+   that were present in the publication will be removed.  When
+   <literal>SET TABLES IN SCHEMA</literal> is used with an
+   <literal>EXCEPT</literal> clause, the excluded tables for each schema are
+   replaced with the specified list; if <literal>EXCEPT</literal> is omitted
+   for a schema, any existing exclusions for that schema are cleared.
   </para>
 
   <para>
@@ -116,7 +116,8 @@ ALTER PUBLICATION <replaceable class="parameter">name</replaceable> RENAME TO <r
 
   <para>
    The <literal>EXCEPT</literal> clause can be used with
-   <literal>ADD TABLES IN SCHEMA</literal> to exclude specific tables from a
+   <literal>ADD TABLES IN SCHEMA</literal> and
+   <literal>SET TABLES IN SCHEMA</literal> to exclude specific tables from a
    schema-level publication. <literal>EXCEPT</literal> is not supported with
    <literal>DROP TABLES IN SCHEMA</literal>; instead, dropping a schema from
    the publication automatically removes all of its associated
@@ -217,12 +218,12 @@ ALTER PUBLICATION <replaceable class="parameter">name</replaceable> RENAME TO <r
      <para>
       Specifies tables to be excluded from a schema-level publication entry.
       This clause may be used with <literal>ADD TABLES IN SCHEMA</literal>
-      and not with <literal>DROP TABLES IN SCHEMA</literal>.  Each named
-      table must belong to the schema specified in the same
-      <literal>TABLES IN SCHEMA</literal> clause.  Table names may be
-      schema-qualified or unqualified; unqualified names are implicitly
-      qualified with the schema named in the same clause.  See
-      <xref linkend="sql-createpublication"/> for further details on the
+      and <literal>SET TABLES IN SCHEMA</literal>, and not with
+      <literal>DROP TABLES IN SCHEMA</literal>.  Each named table must belong
+      to the schema specified in the same <literal>TABLES IN SCHEMA</literal>
+      clause.  Table names may be schema-qualified or unqualified; unqualified
+      names are implicitly qualified with the schema named in the same clause.
+      See <xref linkend="sql-createpublication"/> for further details on the
       semantics of <literal>EXCEPT</literal>.
      </para>
     </listitem>
@@ -328,6 +329,17 @@ ALTER PUBLICATION sales_publication ADD TABLES IN SCHEMA sales EXCEPT (TABLE sal
 </programlisting>
   </para>
 
+  <para>
+   Replace the schema list of <structname>sales_publication</structname> with
+   <structname>sales</structname>, excluding only
+   <structname>sales.drafts</structname> (any previously excluded tables for
+   that schema are replaced, and schemas previously in the publication are
+   removed):
+<programlisting>
+ALTER PUBLICATION sales_publication SET TABLES IN SCHEMA sales EXCEPT (TABLE sales.drafts);
+</programlisting>
+  </para>
+
   <para>
    Add tables <structname>users</structname>,
    <structname>departments</structname> and schema
diff --git a/src/backend/commands/publicationcmds.c b/src/backend/commands/publicationcmds.c
index ea689e5da7c..5118881ff6c 100644
--- a/src/backend/commands/publicationcmds.c
+++ b/src/backend/commands/publicationcmds.c
@@ -1581,9 +1581,11 @@ AlterPublicationExceptTables(AlterPublicationStmt *stmt,
 	Oid			pubid = pubform->oid;
 
 	/*
-	 * Nothing to do if no EXCEPT entries.
+	 * Nothing to do if no EXCEPT entries, except in SET: for that it is quite
+	 * possible that the user has removed all exceptions, in which case we
+	 * need to drop any existing ones.
 	 */
-	if (!exceptrelations)
+	if (!exceptrelations && stmt->action != AP_SetObjects)
 		return;
 
 	/*
@@ -1605,17 +1607,6 @@ AlterPublicationExceptTables(AlterPublicationStmt *stmt,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("EXCEPT clause is not supported with DROP in ALTER PUBLICATION")));
 
-	/*
-	 * EXCEPT with SET is not supported: SET replaces the schema list but does
-	 * not have a well-defined semantics for merging or replacing existing
-	 * except entries.  Users should DROP and re-ADD the schema with the
-	 * desired EXCEPT list instead.
-	 */
-	if (stmt->action == AP_SetObjects)
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("EXCEPT clause is not supported with SET in ALTER PUBLICATION")));
-
 	if (stmt->action == AP_AddObjects)
 	{
 		List	   *rels;
@@ -1647,6 +1638,95 @@ AlterPublicationExceptTables(AlterPublicationStmt *stmt,
 
 		PublicationAddTables(pubid, rels, false, stmt);
 
+		CloseTableList(rels);
+	}
+	else						/* AP_SetObjects */
+	{
+		List	   *oldexceptrelids = NIL;
+		List	   *newexceptrelids = NIL;
+		List	   *delrelids = NIL;
+		List	   *rels;
+		List	   *explicitrelids;
+		ListCell   *lc;
+
+		rels = OpenTableList(exceptrelations);
+
+		/* Collect OIDs of the desired new except list. */
+		foreach(lc, rels)
+		{
+			PublicationRelInfo *pri = (PublicationRelInfo *) lfirst(lc);
+
+			newexceptrelids = lappend_oid(newexceptrelids,
+										  RelationGetRelid(pri->relation));
+		}
+
+		explicitrelids = GetIncludedPublicationRelations(pubid,
+														 PUBLICATION_PART_ROOT);
+
+		/*
+		 * Validate that each excluded table is not also in the explicit table
+		 * list (which would be contradictory).
+		 */
+		foreach(lc, rels)
+		{
+			PublicationRelInfo *pri = (PublicationRelInfo *) lfirst(lc);
+			Oid			relid = RelationGetRelid(pri->relation);
+			Oid			relns = RelationGetNamespace(pri->relation);
+
+			if (list_member_oid(explicitrelids, relid))
+				ereport(ERROR,
+						errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+						errmsg("table \"%s.%s\" cannot appear in both the table list and the EXCEPT clause",
+							   get_namespace_name(relns),
+							   RelationGetRelationName(pri->relation)));
+		}
+
+		/*
+		 * Get the current set of except entries.  Only FOR ALL TABLES and
+		 * schema-level publications can have except entries; for any other
+		 * publication type oldexceptrelids stays NIL.
+		 *
+		 * Note: we check is_schema_publication() against the current catalog
+		 * state (before AlterPublicationSchemas has run), so if the caller is
+		 * doing SET TABLE t1 to convert a schema publication into a plain
+		 * table publication, is_schema_publication() still returns true here.
+		 * That is intentional: it lets us discover and clean up any stale
+		 * except entries that belong to the old schema definition.
+		 */
+		if (GetPublication(pubid)->alltables || is_schema_publication(pubid))
+			oldexceptrelids = GetExcludedPublicationTables(pubid,
+														   PUBLICATION_PART_ROOT);
+
+		/* Build a list of old except entries not present in the new list. */
+		foreach(lc, oldexceptrelids)
+		{
+			Oid			oldrelid = lfirst_oid(lc);
+
+			if (!list_member_oid(newexceptrelids, oldrelid))
+				delrelids = lappend_oid(delrelids, oldrelid);
+		}
+
+		/* Drop old except entries not present in the new list. */
+		foreach(lc, delrelids)
+		{
+			Oid			relid = lfirst_oid(lc);
+			Oid			proid;
+			ObjectAddress obj;
+
+			proid = GetSysCacheOid2(PUBLICATIONRELMAP,
+									Anum_pg_publication_rel_oid,
+									ObjectIdGetDatum(relid),
+									ObjectIdGetDatum(pubid));
+			if (!OidIsValid(proid))
+				continue;		/* already gone */
+
+			ObjectAddressSet(obj, PublicationRelRelationId, proid);
+			performDeletion(&obj, DROP_CASCADE, 0);
+		}
+
+		/* Add new except entries, skipping any already present. */
+		PublicationAddTables(pubid, rels, true, stmt);
+
 		CloseTableList(rels);
 	}
 }
@@ -2301,6 +2381,8 @@ PublicationDropSchemas(Oid pubid, List *schemas, bool missing_ok)
 	foreach(lc, schemas)
 	{
 		Oid			schemaid = lfirst_oid(lc);
+		List	   *exceptoids;
+		ListCell   *elc;
 
 		psid = GetSysCacheOid2(PUBLICATIONNAMESPACEMAP,
 							   Anum_pg_publication_namespace_oid,
@@ -2317,8 +2399,45 @@ PublicationDropSchemas(Oid pubid, List *schemas, bool missing_ok)
 							get_namespace_name(schemaid))));
 		}
 
+		/*
+		 * Collect prexcept rows for tables belonging to this schema before
+		 * removing the schema entry.  GetExcludedPublicationTables relies on
+		 * is_schema_publication(), which scans pg_publication_namespace; if
+		 * this is the last schema in the publication, performDeletion() below
+		 * would remove that row and make is_schema_publication() return
+		 * false, tripping the assertion.
+		 */
+		exceptoids = GetExcludedPublicationTables(pubid, PUBLICATION_PART_ROOT);
+
 		ObjectAddressSet(obj, PublicationNamespaceRelationId, psid);
 		performDeletion(&obj, DROP_CASCADE, 0);
+
+		/*
+		 * Drop any prexcept rows for tables belonging to this schema. These
+		 * rows have no pg_depend entry pointing at the
+		 * pg_publication_namespace row, so they are not cascaded by the
+		 * performDeletion() call above and must be cleaned up explicitly.
+		 */
+		foreach(elc, exceptoids)
+		{
+			Oid			relid = lfirst_oid(elc);
+			Oid			proid;
+
+			if (get_rel_namespace(relid) != schemaid)
+				continue;
+
+			proid = GetSysCacheOid2(PUBLICATIONRELMAP,
+									Anum_pg_publication_rel_oid,
+									ObjectIdGetDatum(relid),
+									ObjectIdGetDatum(pubid));
+			if (!OidIsValid(proid))
+				continue;		/* already gone */
+
+			ObjectAddressSet(obj, PublicationRelRelationId, proid);
+			performDeletion(&obj, DROP_CASCADE, 0);
+		}
+
+		list_free(exceptoids);
 	}
 }
 
diff --git a/src/bin/psql/tab-complete.in.c b/src/bin/psql/tab-complete.in.c
index 6ea92444105..8dce408143f 100644
--- a/src/bin/psql/tab-complete.in.c
+++ b/src/bin/psql/tab-complete.in.c
@@ -2381,6 +2381,23 @@ match_previous_words(int pattern_id,
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_tables);
 	else if (Matches("ALTER", "PUBLICATION", MatchAny, "ADD", "TABLES", "IN", "SCHEMA", MatchAny, "EXCEPT", "(", "TABLE", MatchAnyN) && !ends_with(prev_wd, ','))
 		COMPLETE_WITH(")");
+	/* After a single schema name in SET context, offer EXCEPT ( TABLE */
+	else if (Matches("ALTER", "PUBLICATION", MatchAny, "SET", "TABLES", "IN", "SCHEMA", MatchAny) &&
+			 !ends_with(prev_wd, ','))
+		COMPLETE_WITH("EXCEPT ( TABLE");
+	else if (Matches("ALTER", "PUBLICATION", MatchAny, "SET", "TABLES", "IN", "SCHEMA", MatchAny, "EXCEPT"))
+		COMPLETE_WITH("( TABLE");
+	else if (Matches("ALTER", "PUBLICATION", MatchAny, "SET", "TABLES", "IN", "SCHEMA", MatchAny, "EXCEPT", "("))
+		COMPLETE_WITH("TABLE");
+	else if (Matches("ALTER", "PUBLICATION", MatchAny, "SET", "TABLES", "IN", "SCHEMA", MatchAny, "EXCEPT", "(", "TABLE"))
+	{
+		set_completion_reference(prev4_wd);
+		COMPLETE_WITH_QUERY_VERBATIM(Query_for_list_of_tables_in_schema);
+	}
+	else if (Matches("ALTER", "PUBLICATION", MatchAny, "SET", "TABLES", "IN", "SCHEMA", MatchAny, "EXCEPT", "(", "TABLE", MatchAnyN) && ends_with(prev_wd, ','))
+		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_tables);
+	else if (Matches("ALTER", "PUBLICATION", MatchAny, "SET", "TABLES", "IN", "SCHEMA", MatchAny, "EXCEPT", "(", "TABLE", MatchAnyN) && !ends_with(prev_wd, ','))
+		COMPLETE_WITH(")");
 	/* ALTER PUBLICATION <name> SET ( */
 	else if (Matches("ALTER", "PUBLICATION", MatchAny, MatchAnyN, "SET", "("))
 		COMPLETE_WITH("publish", "publish_generated_columns", "publish_via_partition_root");
diff --git a/src/test/regress/expected/publication.out b/src/test/regress/expected/publication.out
index a9d5e7a49db..c93d1c96276 100644
--- a/src/test/regress/expected/publication.out
+++ b/src/test/regress/expected/publication.out
@@ -580,6 +580,26 @@ Tables from schemas:
 Except tables:
     "pub_test.testpub_tbl_s1"
 
+-- SET: replace the except list (keep same schema, different except table)
+ALTER PUBLICATION testpub_alter_except SET TABLES IN SCHEMA pub_test EXCEPT (TABLE pub_test.testpub_tbl_s2);
+\dRp+ testpub_alter_except
+                                                       Publication testpub_alter_except
+          Owner           | All tables | All sequences | Inserts | Updates | Deletes | Truncates | Generated columns | Via root | Description 
+--------------------------+------------+---------------+---------+---------+---------+-----------+-------------------+----------+-------------
+ regress_publication_user | f          | f             | t       | t       | t       | t         | none              | f        | 
+Tables from schemas:
+    "pub_test"
+Except tables:
+    "pub_test.testpub_tbl_s2"
+
+-- error: EXCEPT is not allowed with DROP
+ALTER PUBLICATION testpub_alter_except DROP TABLES IN SCHEMA pub_test EXCEPT (TABLE pub_test.testpub_tbl_s2);
+ERROR:  EXCEPT clause is not supported with DROP in ALTER PUBLICATION
+-- error: except table's schema (public) not in the publication's schema list (pub_test)
+ALTER PUBLICATION testpub_alter_except SET TABLES IN SCHEMA pub_test EXCEPT (TABLE public.testpub_tbl1);
+ERROR:  table "public.testpub_tbl1" in EXCEPT clause does not belong to schema "pub_test"
+LINE 1: ...xcept SET TABLES IN SCHEMA pub_test EXCEPT (TABLE public.tes...
+                                                             ^
 RESET client_min_messages;
 DROP TABLE pub_test.testpub_tbl_s1, pub_test.testpub_tbl_s2;
 DROP TABLE pub_test.testpub_parted_s CASCADE;
diff --git a/src/test/regress/sql/publication.sql b/src/test/regress/sql/publication.sql
index 6b9eb26a2af..496c039ca25 100644
--- a/src/test/regress/sql/publication.sql
+++ b/src/test/regress/sql/publication.sql
@@ -287,6 +287,16 @@ CREATE PUBLICATION testpub_alter_except;
 ALTER PUBLICATION testpub_alter_except ADD TABLES IN SCHEMA pub_test EXCEPT (TABLE pub_test.testpub_tbl_s1);
 \dRp+ testpub_alter_except
 
+-- SET: replace the except list (keep same schema, different except table)
+ALTER PUBLICATION testpub_alter_except SET TABLES IN SCHEMA pub_test EXCEPT (TABLE pub_test.testpub_tbl_s2);
+\dRp+ testpub_alter_except
+
+-- error: EXCEPT is not allowed with DROP
+ALTER PUBLICATION testpub_alter_except DROP TABLES IN SCHEMA pub_test EXCEPT (TABLE pub_test.testpub_tbl_s2);
+
+-- error: except table's schema (public) not in the publication's schema list (pub_test)
+ALTER PUBLICATION testpub_alter_except SET TABLES IN SCHEMA pub_test EXCEPT (TABLE public.testpub_tbl1);
+
 RESET client_min_messages;
 DROP TABLE pub_test.testpub_tbl_s1, pub_test.testpub_tbl_s2;
 DROP TABLE pub_test.testpub_parted_s CASCADE;
diff --git a/src/test/subscription/t/037_except.pl b/src/test/subscription/t/037_except.pl
index 0ba6d6f8bb2..a32b2d7861a 100644
--- a/src/test/subscription/t/037_except.pl
+++ b/src/test/subscription/t/037_except.pl
@@ -376,6 +376,66 @@ $result =
 is($result, qq(0),
 	'ALTER ... ADD TABLES IN SCHEMA EXCEPT: excluded table not synced');
 
+# SET: replace the except list; tab_excluded is now included and tab_published is excluded.
+$node_publisher->safe_psql('postgres',
+	"ALTER PUBLICATION sch_pub SET TABLES IN SCHEMA sch1 EXCEPT (TABLE sch1.tab_published)"
+);
+$node_subscriber->safe_psql('postgres',
+	"ALTER SUBSCRIPTION sch_sub REFRESH PUBLICATION");
+$node_subscriber->wait_for_subscription_sync($node_publisher, 'sch_sub');
+
+$node_publisher->safe_psql(
+	'postgres', qq(
+	INSERT INTO sch1.tab_published VALUES (7);
+	INSERT INTO sch1.tab_excluded VALUES (7);
+));
+$node_publisher->wait_for_catchup('sch_sub');
+
+$result =
+  $node_subscriber->safe_psql('postgres',
+	"SELECT count(*) FROM sch1.tab_excluded");
+is($result, qq(7),
+	'ALTER ... SET TABLES IN SCHEMA EXCEPT: newly included table is replicated'
+);
+$result =
+  $node_subscriber->safe_psql('postgres',
+	"SELECT count(*) FROM sch1.tab_published");
+is($result, qq(6),
+	'ALTER ... SET TABLES IN SCHEMA EXCEPT: now-excluded table is not replicated'
+);
+
+# SET without EXCEPT: clears the except list; both tables are now published.
+# tab_published will be re-synced because REFRESH removed its entry when it was
+# excluded.  Truncate the subscriber copy beforehand so the re-sync produces
+# a predictable count: publisher has 7 rows (6 original + INSERT(7)), so the
+# subscriber ends up with 7 after re-sync, then 8 after INSERT(8).
+$node_subscriber->safe_psql('postgres', 'TRUNCATE sch1.tab_published');
+$node_publisher->safe_psql('postgres',
+	"ALTER PUBLICATION sch_pub SET TABLES IN SCHEMA sch1");
+$node_subscriber->safe_psql('postgres',
+	"ALTER SUBSCRIPTION sch_sub REFRESH PUBLICATION");
+$node_subscriber->wait_for_subscription_sync($node_publisher, 'sch_sub');
+
+$node_publisher->safe_psql(
+	'postgres', qq(
+	INSERT INTO sch1.tab_published VALUES (8);
+	INSERT INTO sch1.tab_excluded VALUES (8);
+));
+$node_publisher->wait_for_catchup('sch_sub');
+
+$result =
+  $node_subscriber->safe_psql('postgres',
+	"SELECT count(*) FROM sch1.tab_published");
+is($result, qq(8),
+	'ALTER ... SET TABLES IN SCHEMA (no EXCEPT): tab_published replicated after except list cleared'
+);
+$result =
+  $node_subscriber->safe_psql('postgres',
+	"SELECT count(*) FROM sch1.tab_excluded");
+is($result, qq(8),
+	'ALTER ... SET TABLES IN SCHEMA (no EXCEPT): tab_excluded replicated after except list cleared'
+);
+
 $node_subscriber->safe_psql('postgres', 'DROP SUBSCRIPTION sch_sub');
 $node_publisher->safe_psql('postgres', 'DROP PUBLICATION sch_pub');
 
@@ -443,6 +503,36 @@ $node_subscriber->safe_psql('postgres', 'DROP SUBSCRIPTION tap_sub');
 $node_publisher->safe_psql('postgres', 'DROP PUBLICATION tap_pub1');
 $node_publisher->safe_psql('postgres', 'DROP PUBLICATION tap_pub2');
 
+# OK when a table is excluded by a TABLES IN SCHEMA EXCEPT publication,
+# but is included by another publication.
+$node_publisher->safe_psql('postgres', 'TRUNCATE tab1');
+$node_subscriber->safe_psql('postgres', 'TRUNCATE tab1');
+
+$node_publisher->safe_psql(
+	'postgres', qq(
+	CREATE PUBLICATION tap_pub1 FOR TABLES IN SCHEMA public EXCEPT (TABLE public.tab1);
+	CREATE PUBLICATION tap_pub2 FOR TABLE tab1;
+	INSERT INTO tab1 VALUES(1);
+));
+$node_subscriber->psql('postgres',
+	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr' PUBLICATION tap_pub1, tap_pub2"
+);
+$node_subscriber->wait_for_subscription_sync($node_publisher, 'tap_sub');
+
+$node_publisher->safe_psql('postgres', qq(INSERT INTO tab1 VALUES(2)));
+$node_publisher->wait_for_catchup('tap_sub');
+
+$result =
+  $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1 ORDER BY a");
+is( $result, qq(1
+2),
+	"TABLES IN SCHEMA EXCEPT: table excluded in schema pub but included by another pub is replicated"
+);
+
+$node_subscriber->safe_psql('postgres', 'DROP SUBSCRIPTION tap_sub');
+$node_publisher->safe_psql('postgres', 'DROP PUBLICATION tap_pub1');
+$node_publisher->safe_psql('postgres', 'DROP PUBLICATION tap_pub2');
+
 $node_publisher->stop('fast');
 
 done_testing();
-- 
2.50.1 (Apple Git-155)