Track collation versions for indexes.

Record the current version of dependent collations in pg_depend when creating or rebuilding an index. When accessing the index later, warn that the index may be corrupted if the current version doesn't match. Thanks to Douglas Doole, Peter Eisentraut, Christoph Berg, Laurenz Albe, Michael Paquier, Robert Haas, Tom Lane and others for very helpful discussion. Author: Thomas Munro <thomas.munro@gmail.com> Author: Julien Rouhaud <rjuju123@gmail.com> Reviewed-by: Peter Eisentraut <peter.eisentraut@2ndquadrant.com> (earlier versions) Discussion: https://postgr.es/m/CAEepm%3D0uEQCpfq_%2BLYFBdArCe4Ot98t1aR4eYiYTe%3DyavQygiQ%40mail.gmail.com
2020-11-02 19:50:45 +13:00 · 2020-11-02 19:50:45 +13:00 · 257836a755
parent cd6f479e79
commit 257836a755
43 changed files with 1287 additions and 94 deletions
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@ -3308,7 +3308,8 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
       <structfield>refobjversion</structfield> <type>text</type>
       </para>
       <para>
-        An optional version for the referenced object.
+        An optional version for the referenced object.  Currently used for
+        indexes' collations (see <xref linkend="collation-versions"/>).
       </para>
      </entry>
     </row>
--- a/doc/src/sgml/charset.sgml
+++ b/doc/src/sgml/charset.sgml
@ -948,6 +948,44 @@ CREATE COLLATION ignore_accents (provider = icu, locale = 'und-u-ks-level1-kc-tr
    </tip>
   </sect3>
  </sect2>
+
+  <sect2 id="collation-versions">
+   <title>Collation Versions</title>
+
+   <para>
+    The sort order defined by a collation is not necessarily fixed over time.
+    <productname>PostgreSQL</productname> relies on external libraries that
+    are subject to operating system upgrades, and can also differ between
+    servers involved in binary replication and file-system-level migration.
+    Persistent data structures such as B-trees that depend on sort order might
+    be corrupted by any resulting change.
+    <productname>PostgreSQL</productname> defends against this by recording the
+    current version of each referenced collation for any index that depends on
+    it in the
+    <link linkend="catalog-pg-depend"><structname>pg_depend</structname></link>
+    catalog, if the collation provider makes that information available.  If the
+    provider later begins to report a different version, a warning will be
+    issued when the index is accessed, until either the
+    <xref linkend="sql-reindex"/> command or the
+    <xref linkend="sql-alterindex"/> command is used to update the version.
+   </para>
+   <para>
+    Version information is available from the
+    <literal>icu</literal> provider on all operating systems.  For the
+    <literal>libc</literal> provider, versions are currently only available
+    on systems using the GNU C library (most Linux systems) and Windows.
+   </para>
+
+   <note>
+    <para>
+     When using the GNU C library for collations, the C library's version
+     is used as a proxy for the collation version.  Many Linux distributions
+     change collation definitions only when upgrading the C library, but this
+     approach is imperfect as maintainers are free to back-port newer
+     collation definitions to older C library releases.
+    </para>
+   </note>
+  </sect2>
 </sect1>

 <sect1 id="multibyte">
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@ -25444,7 +25444,9 @@ postgres=# SELECT * FROM pg_walfile_name_offset(pg_stop_backup());
       </para>
       <para>
        Returns the actual version of the collation object as it is currently
-        installed in the operating system.
+        installed in the operating system.  <literal>null</literal> is returned
+        on operating systems where <productname>PostgreSQL</productname>
+        doesn't have support for versions.
       </para></entry>
      </row>

--- a/doc/src/sgml/ref/alter_index.sgml
+++ b/doc/src/sgml/ref/alter_index.sgml
@ -25,6 +25,7 @@ ALTER INDEX [ IF EXISTS ] <replaceable class="parameter">name</replaceable> RENA
 ALTER INDEX [ IF EXISTS ] <replaceable class="parameter">name</replaceable> SET TABLESPACE <replaceable class="parameter">tablespace_name</replaceable>
 ALTER INDEX <replaceable class="parameter">name</replaceable> ATTACH PARTITION <replaceable class="parameter">index_name</replaceable>
 ALTER INDEX <replaceable class="parameter">name</replaceable> DEPENDS ON EXTENSION <replaceable class="parameter">extension_name</replaceable>
+ALTER INDEX <replaceable class="parameter">name</replaceable> ALTER COLLATION <replaceable class="parameter">collation_name</replaceable> REFRESH VERSION
 ALTER INDEX [ IF EXISTS ] <replaceable class="parameter">name</replaceable> SET ( <replaceable class="parameter">storage_parameter</replaceable> [= <replaceable class="parameter">value</replaceable>] [, ... ] )
 ALTER INDEX [ IF EXISTS ] <replaceable class="parameter">name</replaceable> RESET ( <replaceable class="parameter">storage_parameter</replaceable> [, ... ] )
 ALTER INDEX [ IF EXISTS ] <replaceable class="parameter">name</replaceable> ALTER [ COLUMN ] <replaceable class="parameter">column_number</replaceable>
@ -112,6 +113,20 @@ ALTER INDEX ALL IN TABLESPACE <replaceable class="parameter">name</replaceable>
    </listitem>
   </varlistentry>

+   <varlistentry>
+    <term><literal>ALTER COLLATION <replaceable class="parameter">collation_name</replaceable> REFRESH VERSION</literal></term>
+    <listitem>
+     <para>
+      Silences warnings about mismatched collation versions, by declaring
+      that the index is compatible with the current collation definition.
+      Be aware that incorrect use of this command can hide index corruption.
+      If you don't know whether a collation's definition has changed
+      incompatibly, <xref linkend="sql-reindex"/> is a safe alternative.
+      See <xref linkend="collation-versions"/> for more information.
+     </para>
+    </listitem>
+   </varlistentry>
+
   <varlistentry>
    <term><literal>SET ( <replaceable class="parameter">storage_parameter</replaceable> [= <replaceable class="parameter">value</replaceable>] [, ... ] )</literal></term>
    <listitem>
--- a/doc/src/sgml/ref/pgupgrade.sgml
+++ b/doc/src/sgml/ref/pgupgrade.sgml
@ -215,6 +215,21 @@ PostgreSQL documentation
      </listitem>
     </varlistentry>

+     <varlistentry>
+      <term><option>--index-collation-versions-unknown</option></term>
+      <listitem>
+       <para>
+        When upgrading indexes from releases before 14 that didn't track
+        collation versions, <application>pg_upgrade</application>
+        assumes by default that the upgraded indexes are compatible with the
+        currently installed versions of relevant collations (see
+        <xref linkend="collation-versions"/>).  Specify
+        <option>--index-collation-versions-unknown</option> to mark
+        them as needing to be rebuilt instead.
+       </para>
+      </listitem>
+     </varlistentry>
+
     <varlistentry>
      <term><option>-?</option></term>
      <term><option>--help</option></term>
--- a/doc/src/sgml/ref/reindex.sgml
+++ b/doc/src/sgml/ref/reindex.sgml
@ -38,6 +38,15 @@ REINDEX [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] { IN
   several scenarios in which to use <command>REINDEX</command>:

   <itemizedlist>
+    <listitem>
+     <para>
+      The index depends on the sort order of a collation, and the definition
+      of the collation has changed.  This can cause index scans to fail to
+      find keys that are present.  See <xref linkend="collation-versions"/> for
+      more information.
+     </para>
+    </listitem>
+
    <listitem>
     <para>
      An index has become corrupted, and no longer contains valid
--- a/src/backend/catalog/dependency.c
+++ b/src/backend/catalog/dependency.c
@ -76,6 +76,7 @@
 #include "rewrite/rewriteRemove.h"
 #include "storage/lmgr.h"
 #include "utils/acl.h"
+#include "utils/builtins.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
 #include "utils/lsyscache.h"
@ -434,6 +435,84 @@ performMultipleDeletions(const ObjectAddresses *objects,
 	table_close(depRel, RowExclusiveLock);
 }

+/*
+ * Call a function for all objects that 'object' depend on.  If the function
+ * returns true, refobjversion will be updated in the catalog.
+ */
+void
+visitDependenciesOf(const ObjectAddress *object,
+					VisitDependenciesOfCB callback,
+					void *userdata)
+{
+	Relation	depRel;
+	ScanKeyData key[3];
+	SysScanDesc scan;
+	HeapTuple	tup;
+	ObjectAddress otherObject;
+
+	ScanKeyInit(&key[0],
+				Anum_pg_depend_classid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(object->classId));
+	ScanKeyInit(&key[1],
+				Anum_pg_depend_objid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(object->objectId));
+	ScanKeyInit(&key[2],
+				Anum_pg_depend_objsubid,
+				BTEqualStrategyNumber, F_INT4EQ,
+				Int32GetDatum(object->objectSubId));
+
+	depRel = table_open(DependRelationId, RowExclusiveLock);
+	scan = systable_beginscan(depRel, DependDependerIndexId, true,
+							  NULL, 3, key);
+
+	while (HeapTupleIsValid(tup = systable_getnext(scan)))
+	{
+		Form_pg_depend foundDep = (Form_pg_depend) GETSTRUCT(tup);
+		char	   *new_version;
+		Datum		depversion;
+		bool		isnull;
+
+		otherObject.classId = foundDep->refclassid;
+		otherObject.objectId = foundDep->refobjid;
+		otherObject.objectSubId = foundDep->refobjsubid;
+
+		depversion = heap_getattr(tup, Anum_pg_depend_refobjversion,
+								  RelationGetDescr(depRel), &isnull);
+
+		/* Does the callback want to update the version? */
+		if (callback(&otherObject,
+					 isnull ? NULL : TextDatumGetCString(depversion),
+					 &new_version,
+					 userdata))
+		{
+			Datum		values[Natts_pg_depend];
+			bool		nulls[Natts_pg_depend];
+			bool		replaces[Natts_pg_depend];
+
+			memset(values, 0, sizeof(values));
+			memset(nulls, false, sizeof(nulls));
+			memset(replaces, false, sizeof(replaces));
+
+			if (new_version)
+				values[Anum_pg_depend_refobjversion - 1] =
+					CStringGetTextDatum(new_version);
+			else
+				nulls[Anum_pg_depend_refobjversion - 1] = true;
+			replaces[Anum_pg_depend_refobjversion - 1] = true;
+
+			tup = heap_modify_tuple(tup, RelationGetDescr(depRel), values,
+									nulls, replaces);
+			CatalogTupleUpdate(depRel, &tup->t_self, tup);
+
+			heap_freetuple(tup);
+		}
+	}
+	systable_endscan(scan);
+	table_close(depRel, RowExclusiveLock);
+}
+
 /*
 * findDependentObjects - find all objects that depend on 'object'
 *
@ -1566,6 +1645,38 @@ ReleaseDeletionLock(const ObjectAddress *object)
 							 AccessExclusiveLock);
 }

+/*
+ * Record dependencies on a list of collations, optionally with their current
+ * version.
+ */
+void
+recordDependencyOnCollations(ObjectAddress *myself,
+							 List *collations,
+							 bool record_version)
+{
+	ObjectAddresses *addrs;
+	ListCell   *lc;
+
+	if (list_length(collations) == 0)
+		return;
+
+	addrs = new_object_addresses();
+	foreach(lc, collations)
+	{
+		ObjectAddress referenced;
+
+		ObjectAddressSet(referenced, CollationRelationId, lfirst_oid(lc));
+
+		add_exact_object_address(&referenced, addrs);
+	}
+
+	eliminate_duplicate_dependencies(addrs);
+	recordMultipleDependencies(myself, addrs->refs, addrs->numrefs,
+							   DEPENDENCY_NORMAL, record_version);
+
+	free_object_addresses(addrs);
+}
+
 /*
 * recordDependencyOnExpr - find expression dependencies
 *
@ -1602,8 +1713,8 @@ recordDependencyOnExpr(const ObjectAddress *depender,
 	recordMultipleDependencies(depender,
 							   context.addrs->refs,
 							   context.addrs->numrefs,
-							   NULL,
-							   behavior);
+							   behavior,
+							   false);

 	free_object_addresses(context.addrs);
 }
@ -1630,7 +1741,8 @@ recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 								Node *expr, Oid relId,
 								DependencyType behavior,
 								DependencyType self_behavior,
-								bool reverse_self)
+								bool reverse_self,
+								bool record_version)
 {
 	find_expr_references_context context;
 	RangeTblEntry rte;
@ -1691,8 +1803,8 @@ recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 			recordMultipleDependencies(depender,
 									   self_addrs->refs,
 									   self_addrs->numrefs,
-									   NULL,
-									   self_behavior);
+									   self_behavior,
+									   record_version);
 		else
 		{
 			/* Can't use recordMultipleDependencies, so do it the hard way */
@ -1713,8 +1825,8 @@ recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 	recordMultipleDependencies(depender,
 							   context.addrs->refs,
 							   context.addrs->numrefs,
-							   NULL,
-							   behavior);
+							   behavior,
+							   record_version);

 	free_object_addresses(context.addrs);
 }
@ -1770,6 +1882,29 @@ find_expr_references_walker(Node *node,
 			/* If it's a plain relation, reference this column */
 			add_object_address(OCLASS_CLASS, rte->relid, var->varattno,
 							   context->addrs);
+
+			/* Top-level collation if valid */
+			if (OidIsValid(var->varcollid))
+				add_object_address(OCLASS_COLLATION, var->varcollid, 0,
+								   context->addrs);
+			/* Otherwise, it may be a type with internal collations */
+			else if (var->vartype >= FirstNormalObjectId)
+			{
+				List	   *collations;
+				ListCell   *lc;
+
+				collations = GetTypeCollations(var->vartype);
+
+				foreach(lc, collations)
+				{
+					Oid			coll = lfirst_oid(lc);
+
+					if (OidIsValid(coll))
+						add_object_address(OCLASS_COLLATION,
+										   lfirst_oid(lc), 0,
+										   context->addrs);
+				}
+			}
 		}

 		/*
@ -1794,11 +1929,9 @@ find_expr_references_walker(Node *node,
 		/*
 		 * We must also depend on the constant's collation: it could be
 		 * different from the datatype's, if a CollateExpr was const-folded to
-		 * a simple constant.  However we can save work in the most common
-		 * case where the collation is "default", since we know that's pinned.
+		 * a simple constant.
 		 */
-		if (OidIsValid(con->constcollid) &&
-			con->constcollid != DEFAULT_COLLATION_OID)
+		if (OidIsValid(con->constcollid))
 			add_object_address(OCLASS_COLLATION, con->constcollid, 0,
 							   context->addrs);

@ -1887,8 +2020,7 @@ find_expr_references_walker(Node *node,
 		add_object_address(OCLASS_TYPE, param->paramtype, 0,
 						   context->addrs);
 		/* and its collation, just as for Consts */
-		if (OidIsValid(param->paramcollid) &&
-			param->paramcollid != DEFAULT_COLLATION_OID)
+		if (OidIsValid(param->paramcollid))
 			add_object_address(OCLASS_COLLATION, param->paramcollid, 0,
 							   context->addrs);
 	}
@ -1975,8 +2107,7 @@ find_expr_references_walker(Node *node,
 			add_object_address(OCLASS_TYPE, fselect->resulttype, 0,
 							   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
-		if (OidIsValid(fselect->resultcollid) &&
-			fselect->resultcollid != DEFAULT_COLLATION_OID)
+		if (OidIsValid(fselect->resultcollid))
 			add_object_address(OCLASS_COLLATION, fselect->resultcollid, 0,
 							   context->addrs);
 	}
@ -2006,8 +2137,7 @@ find_expr_references_walker(Node *node,
 		add_object_address(OCLASS_TYPE, relab->resulttype, 0,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
-		if (OidIsValid(relab->resultcollid) &&
-			relab->resultcollid != DEFAULT_COLLATION_OID)
+		if (OidIsValid(relab->resultcollid))
 			add_object_address(OCLASS_COLLATION, relab->resultcollid, 0,
 							   context->addrs);
 	}
@ -2019,8 +2149,7 @@ find_expr_references_walker(Node *node,
 		add_object_address(OCLASS_TYPE, iocoerce->resulttype, 0,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
-		if (OidIsValid(iocoerce->resultcollid) &&
-			iocoerce->resultcollid != DEFAULT_COLLATION_OID)
+		if (OidIsValid(iocoerce->resultcollid))
 			add_object_address(OCLASS_COLLATION, iocoerce->resultcollid, 0,
 							   context->addrs);
 	}
@ -2032,8 +2161,7 @@ find_expr_references_walker(Node *node,
 		add_object_address(OCLASS_TYPE, acoerce->resulttype, 0,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
-		if (OidIsValid(acoerce->resultcollid) &&
-			acoerce->resultcollid != DEFAULT_COLLATION_OID)
+		if (OidIsValid(acoerce->resultcollid))
 			add_object_address(OCLASS_COLLATION, acoerce->resultcollid, 0,
 							   context->addrs);
 		/* fall through to examine arguments */
@ -2121,8 +2249,7 @@ find_expr_references_walker(Node *node,
 		if (OidIsValid(wc->endInRangeFunc))
 			add_object_address(OCLASS_PROC, wc->endInRangeFunc, 0,
 							   context->addrs);
-		if (OidIsValid(wc->inRangeColl) &&
-			wc->inRangeColl != DEFAULT_COLLATION_OID)
+		if (OidIsValid(wc->inRangeColl))
 			add_object_address(OCLASS_COLLATION, wc->inRangeColl, 0,
 							   context->addrs);
 		/* fall through to examine substructure */
@ -2267,7 +2394,7 @@ find_expr_references_walker(Node *node,
 		{
 			Oid			collid = lfirst_oid(ct);

-			if (OidIsValid(collid) && collid != DEFAULT_COLLATION_OID)
+			if (OidIsValid(collid))
 				add_object_address(OCLASS_COLLATION, collid, 0,
 								   context->addrs);
 		}
@ -2289,7 +2416,7 @@ find_expr_references_walker(Node *node,
 		{
 			Oid			collid = lfirst_oid(ct);

-			if (OidIsValid(collid) && collid != DEFAULT_COLLATION_OID)
+			if (OidIsValid(collid))
 				add_object_address(OCLASS_COLLATION, collid, 0,
 								   context->addrs);
 		}
@ -2685,8 +2812,9 @@ record_object_address_dependencies(const ObjectAddress *depender,
 {
 	eliminate_duplicate_dependencies(referenced);
 	recordMultipleDependencies(depender,
-							   referenced->refs, referenced->numrefs, NULL,
-							   behavior);
+							   referenced->refs, referenced->numrefs,
+							   behavior,
+							   false);
 }

 /*
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@ -2336,7 +2336,7 @@ StoreAttrDefault(Relation rel, AttrNumber attnum,
 		 */
 		recordDependencyOnSingleRelExpr(&colobject, expr, RelationGetRelid(rel),
 										DEPENDENCY_AUTO,
-										DEPENDENCY_AUTO, false);
+										DEPENDENCY_AUTO, false, false);
 	}
 	else
 	{
@ -2346,7 +2346,7 @@ StoreAttrDefault(Relation rel, AttrNumber attnum,
 		 */
 		recordDependencyOnSingleRelExpr(&defobject, expr, RelationGetRelid(rel),
 										DEPENDENCY_NORMAL,
-										DEPENDENCY_NORMAL, false);
+										DEPENDENCY_NORMAL, false, false);
 	}

 	/*
@ -3706,7 +3706,8 @@ StorePartitionKey(Relation rel,
 										RelationGetRelid(rel),
 										DEPENDENCY_NORMAL,
 										DEPENDENCY_INTERNAL,
-										true /* reverse the self-deps */ );
+										true /* reverse the self-deps */ ,
+										false /* don't track versions */ );

 	/*
 	 * We must invalidate the relcache so that the next
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@ -53,6 +53,7 @@
 #include "catalog/pg_trigger.h"
 #include "catalog/pg_type.h"
 #include "catalog/storage.h"
+#include "commands/defrem.h"
 #include "commands/event_trigger.h"
 #include "commands/progress.h"
 #include "commands/tablecmds.h"
@ -75,6 +76,7 @@
 #include "utils/guc.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
+#include "utils/pg_locale.h"
 #include "utils/memutils.h"
 #include "utils/pg_rusage.h"
 #include "utils/rel.h"
@ -1020,6 +1022,8 @@ index_create(Relation heapRelation,
 		ObjectAddress myself,
 					referenced;
 		ObjectAddresses *addrs;
+		List	   *colls = NIL,
+				   *colls_no_version = NIL;

 		ObjectAddressSet(myself, RelationRelationId, indexRelationId);

@ -1103,30 +1107,65 @@ index_create(Relation heapRelation,
 			recordDependencyOn(&myself, &referenced, DEPENDENCY_PARTITION_SEC);
 		}

-		/* placeholder for normal dependencies */
-		addrs = new_object_addresses();
-
-		/* Store dependency on collations */
-
-		/* The default collation is pinned, so don't bother recording it */
+		/* Get dependencies on collations for all index keys. */
 		for (i = 0; i < indexInfo->ii_NumIndexKeyAttrs; i++)
 		{
-			if (OidIsValid(collationObjectId[i]) &&
-				collationObjectId[i] != DEFAULT_COLLATION_OID)
+			Oid			colloid = collationObjectId[i];
+
+			if (OidIsValid(colloid))
 			{
-				ObjectAddressSet(referenced, CollationRelationId,
-								 collationObjectId[i]);
-				add_exact_object_address(&referenced, addrs);
+				Oid			opclass = classObjectId[i];
+
+				/*
+				 * The *_pattern_ops opclasses are special: they explicitly do
+				 * not depend on collation order so we can save some effort.
+				 *
+				 * XXX With more analysis, we could also skip version tracking
+				 * for some cases like hash indexes with deterministic
+				 * collations, because they will never need to order strings.
+				 */
+				if (opclass == TEXT_BTREE_PATTERN_OPS_OID ||
+					opclass == VARCHAR_BTREE_PATTERN_OPS_OID ||
+					opclass == BPCHAR_BTREE_PATTERN_OPS_OID)
+					colls_no_version = lappend_oid(colls_no_version, colloid);
+				else
+					colls = lappend_oid(colls, colloid);
+			}
+			else
+			{
+				Form_pg_attribute att = TupleDescAttr(indexTupDesc, i);
+
+				Assert(i < indexTupDesc->natts);
+
+				/*
+				 * Even though there is no top-level collation, there may be
+				 * collations affecting ordering inside types, so look there
+				 * too.
+				 */
+				colls = list_concat(colls, GetTypeCollations(att->atttypid));
 			}
 		}

+		/*
+		 * If we have anything in both lists, keep just the versioned one to
+		 * avoid some duplication.
+		 */
+		if (colls_no_version != NIL && colls != NIL)
+			colls_no_version = list_difference_oid(colls_no_version, colls);
+
+		/* Store the versioned and unversioned collation dependencies. */
+		if (colls_no_version != NIL)
+			recordDependencyOnCollations(&myself, colls_no_version, false);
+		if (colls != NIL)
+			recordDependencyOnCollations(&myself, colls, true);
+
 		/* Store dependency on operator classes */
+		addrs = new_object_addresses();
 		for (i = 0; i < indexInfo->ii_NumIndexKeyAttrs; i++)
 		{
 			ObjectAddressSet(referenced, OperatorClassRelationId, classObjectId[i]);
 			add_exact_object_address(&referenced, addrs);
 		}
-
 		record_object_address_dependencies(&myself, addrs, DEPENDENCY_NORMAL);
 		free_object_addresses(addrs);

@ -1137,7 +1176,7 @@ index_create(Relation heapRelation,
 											(Node *) indexInfo->ii_Expressions,
 											heapRelationId,
 											DEPENDENCY_NORMAL,
-											DEPENDENCY_AUTO, false);
+											DEPENDENCY_AUTO, false, true);
 		}

 		/* Store dependencies on anything mentioned in predicate */
@ -1147,7 +1186,7 @@ index_create(Relation heapRelation,
 											(Node *) indexInfo->ii_Predicate,
 											heapRelationId,
 											DEPENDENCY_NORMAL,
-											DEPENDENCY_AUTO, false);
+											DEPENDENCY_AUTO, false, true);
 		}
 	}
 	else
@ -1226,6 +1265,129 @@ index_create(Relation heapRelation,
 	return indexRelationId;
 }

+typedef struct do_collation_version_check_context
+{
+	Oid			relid;
+	List	   *warned_colls;
+} do_collation_version_check_context;
+
+/*
+ * Raise a warning if the recorded and current collation version don't match.
+ * This is a callback for visitDependenciesOf().
+ */
+static bool
+do_collation_version_check(const ObjectAddress *otherObject,
+						   const char *version,
+						   char **new_version,
+						   void *data)
+{
+	do_collation_version_check_context *context = data;
+	char	   *current_version;
+
+	/* We only care about dependencies on collations with a version. */
+	if (!version || otherObject->classId != CollationRelationId)
+		return false;
+
+	/* Ask the provider for the current version.  Give up if unsupported. */
+	current_version = get_collation_version_for_oid(otherObject->objectId);
+	if (!current_version)
+		return false;
+
+	/*
+	 * We don't expect too many duplicates, but it's possible, and we don't
+	 * want to generate duplicate warnings.
+	 */
+	if (list_member_oid(context->warned_colls, otherObject->objectId))
+		return false;
+
+	/* Do they match? */
+	if (strcmp(current_version, version) != 0)
+	{
+		/*
+		 * The version has changed, probably due to an OS/library upgrade or
+		 * streaming replication between different OS/library versions.
+		 */
+		ereport(WARNING,
+				(errmsg("index \"%s\" depends on collation \"%s\" version \"%s\", but the current version is \"%s\"",
+						get_rel_name(context->relid),
+						get_collation_name(otherObject->objectId),
+						version,
+						current_version),
+				 errdetail("The index may be corrupted due to changes in sort order."),
+				 errhint("REINDEX to avoid the risk of corruption.")));
+
+		/* Remember not to complain about this collation again. */
+		context->warned_colls = lappend_oid(context->warned_colls,
+											otherObject->objectId);
+	}
+
+	return false;
+}
+
+/* index_check_collation_versions
+ *		Check the collation version for all dependencies on the given index.
+ */
+void
+index_check_collation_versions(Oid relid)
+{
+	do_collation_version_check_context context;
+	ObjectAddress object;
+
+	/*
+	 * The callback needs the relid for error messages, and some scratch space
+	 * to avoid duplicate warnings.
+	 */
+	context.relid = relid;
+	context.warned_colls = NIL;
+
+	object.classId = RelationRelationId;
+	object.objectId = relid;
+	object.objectSubId = 0;
+
+	visitDependenciesOf(&object, &do_collation_version_check, &context);
+
+	list_free(context.warned_colls);
+}
+
+/*
+ * Update the version for collations.  A callback for visitDependenciesOf().
+ */
+static bool
+do_collation_version_update(const ObjectAddress *otherObject,
+							const char *version,
+							char **new_version,
+							void *data)
+{
+	Oid		   *coll = data;
+
+	/* We only care about dependencies on collations with versions. */
+	if (!version || otherObject->classId != CollationRelationId)
+		return false;
+
+	/* If we're only trying to update one collation, skip others. */
+	if (OidIsValid(*coll) && otherObject->objectId != *coll)
+		return false;
+
+	*new_version = get_collation_version_for_oid(otherObject->objectId);
+
+	return true;
+}
+
+/*
+ * Record the current versions of one or all collations that an index depends
+ * on.  InvalidOid means all.
+ */
+void
+index_update_collation_versions(Oid relid, Oid coll)
+{
+	ObjectAddress object;
+
+	object.classId = RelationRelationId;
+	object.objectId = relid;
+	object.objectSubId = 0;
+	visitDependenciesOf(&object, &do_collation_version_update, &coll);
+}
+
 /*
 * index_concurrently_create_copy
 *
@ -1686,6 +1848,10 @@ index_concurrently_swap(Oid newIndexId, Oid oldIndexId, const char *oldName)
 	changeDependenciesOf(RelationRelationId, oldIndexId, newIndexId);
 	changeDependenciesOn(RelationRelationId, oldIndexId, newIndexId);

+	/* Now we have the old index's collation versions, so fix that. */
+	CommandCounterIncrement();
+	index_update_collation_versions(newIndexId, InvalidOid);
+
 	/*
 	 * Copy over statistics from old to new index
 	 */
@ -3638,6 +3804,9 @@ reindex_index(Oid indexId, bool skip_constraint_checks, char persistence,
 	/* Close rels, but keep locks */
 	index_close(iRel, NoLock);
 	table_close(heapRelation, NoLock);
+
+	/* Record the current versions of all depended-on collations. */
+	index_update_collation_versions(indexId, InvalidOid);
 }

 /*
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@ -362,7 +362,7 @@ CreateConstraintEntry(const char *constraintName,
 		 */
 		recordDependencyOnSingleRelExpr(&conobject, conExpr, relId,
 										DEPENDENCY_NORMAL,
-										DEPENDENCY_NORMAL, false);
+										DEPENDENCY_NORMAL, false, true);
 	}

 	/* Post creation hook for new constraint */
--- a/src/backend/catalog/pg_depend.c
+++ b/src/backend/catalog/pg_depend.c
@ -19,6 +19,7 @@
 #include "access/table.h"
 #include "catalog/dependency.h"
 #include "catalog/indexing.h"
+#include "catalog/pg_collation.h"
 #include "catalog/pg_constraint.h"
 #include "catalog/pg_depend.h"
 #include "catalog/pg_extension.h"
@ -27,6 +28,7 @@
 #include "utils/builtins.h"
 #include "utils/fmgroids.h"
 #include "utils/lsyscache.h"
+#include "utils/pg_locale.h"
 #include "utils/rel.h"


@ -45,19 +47,24 @@ recordDependencyOn(const ObjectAddress *depender,
 				   const ObjectAddress *referenced,
 				   DependencyType behavior)
 {
-	recordMultipleDependencies(depender, referenced, 1, NULL, behavior);
+	recordMultipleDependencies(depender, referenced, 1, behavior, false);
 }

 /*
 * Record multiple dependencies (of the same kind) for a single dependent
 * object.  This has a little less overhead than recording each separately.
+ *
+ * If record_version is true, then a record is added even if the referenced
+ * object is pinned, and the dependency version will be retrieved according to
+ * the referenced object kind.  For now, only collation version is
+ * supported.
 */
 void
 recordMultipleDependencies(const ObjectAddress *depender,
 						   const ObjectAddress *referenced,
 						   int nreferenced,
-						   const char *version,
-						   DependencyType behavior)
+						   DependencyType behavior,
+						   bool record_version)
 {
 	Relation	dependDesc;
 	CatalogIndexState indstate;
@ -66,6 +73,7 @@ recordMultipleDependencies(const ObjectAddress *depender,
 				max_slots,
 				slot_init_count,
 				slot_stored_count;
+	char	   *version = NULL;

 	if (nreferenced <= 0)
 		return;					/* nothing to do */
@ -96,12 +104,38 @@ recordMultipleDependencies(const ObjectAddress *depender,
 	slot_init_count = 0;
 	for (i = 0; i < nreferenced; i++, referenced++)
 	{
+		bool		ignore_systempin = false;
+
+		if (record_version)
+		{
+			/* For now we only know how to deal with collations. */
+			if (referenced->classId == CollationRelationId)
+			{
+				/* C and POSIX don't need version tracking. */
+				if (referenced->objectId == C_COLLATION_OID ||
+					referenced->objectId == POSIX_COLLATION_OID)
+					continue;
+
+				version = get_collation_version_for_oid(referenced->objectId);
+
+				/*
+				 * Default collation is pinned, so we need to force recording
+				 * the dependency to store the version.
+				 */
+				if (referenced->objectId == DEFAULT_COLLATION_OID)
+					ignore_systempin = true;
+			}
+		}
+		else
+			Assert(!version);
+
 		/*
 		 * If the referenced object is pinned by the system, there's no real
-		 * need to record dependencies on it.  This saves lots of space in
-		 * pg_depend, so it's worth the time taken to check.
+		 * need to record dependencies on it, unless we need to record a
+		 * version.  This saves lots of space in pg_depend, so it's worth the
+		 * time taken to check.
 		 */
-		if (isObjectPinned(referenced, dependDesc))
+		if (!ignore_systempin && isObjectPinned(referenced, dependDesc))
 			continue;

 		if (slot_init_count < max_slots)
--- a/src/backend/catalog/pg_type.c
+++ b/src/backend/catalog/pg_type.c
@ -15,6 +15,7 @@
 #include "postgres.h"

 #include "access/htup_details.h"
+#include "access/relation.h"
 #include "access/table.h"
 #include "access/xact.h"
 #include "catalog/binary_upgrade.h"
@ -512,6 +513,65 @@ TypeCreate(Oid newTypeOid,
 	return address;
 }

+/*
+ * Get a list of all distinct collations that the given type depends on.
+ */
+List *
+GetTypeCollations(Oid typeoid)
+{
+	List	   *result = NIL;
+	HeapTuple	tuple;
+	Form_pg_type typeTup;
+
+	tuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typeoid));
+	if (!HeapTupleIsValid(tuple))
+		elog(ERROR, "cache lookup failed for type %u", typeoid);
+	typeTup = (Form_pg_type) GETSTRUCT(tuple);
+
+	if (OidIsValid(typeTup->typcollation))
+		result = list_append_unique_oid(result, typeTup->typcollation);
+	else if (typeTup->typtype == TYPTYPE_COMPOSITE)
+	{
+		Relation	rel = relation_open(typeTup->typrelid, AccessShareLock);
+		TupleDesc	desc = RelationGetDescr(rel);
+
+		for (int i = 0; i < RelationGetNumberOfAttributes(rel); i++)
+		{
+			Form_pg_attribute att = TupleDescAttr(desc, i);
+
+			if (OidIsValid(att->attcollation))
+				result = list_append_unique_oid(result, att->attcollation);
+			else
+				result = list_concat_unique_oid(result,
+												GetTypeCollations(att->atttypid));
+		}
+
+		relation_close(rel, NoLock);
+	}
+	else if (typeTup->typtype == TYPTYPE_DOMAIN)
+	{
+		Assert(OidIsValid(typeTup->typbasetype));
+
+		result = list_concat_unique_oid(result,
+										GetTypeCollations(typeTup->typbasetype));
+	}
+	else if (typeTup->typtype == TYPTYPE_RANGE)
+	{
+		Oid			rangeid = get_range_subtype(typeTup->oid);
+
+		Assert(OidIsValid(rangeid));
+
+		result = list_concat_unique_oid(result, GetTypeCollations(rangeid));
+	}
+	else if (OidIsValid(typeTup->typelem))
+		result = list_concat_unique_oid(result,
+										GetTypeCollations(typeTup->typelem));
+
+	ReleaseSysCache(tuple);
+
+	return result;
+}
+
 /*
 * GenerateTypeDependencies: build the dependencies needed for a type
 *
--- a/src/backend/commands/collationcmds.c
+++ b/src/backend/commands/collationcmds.c
@ -270,23 +270,9 @@ Datum
 pg_collation_actual_version(PG_FUNCTION_ARGS)
 {
 	Oid			collid = PG_GETARG_OID(0);
-	HeapTuple	tp;
-	char	   *collcollate;
-	char		collprovider;
 	char	   *version;

-	tp = SearchSysCache1(COLLOID, ObjectIdGetDatum(collid));
-	if (!HeapTupleIsValid(tp))
-		ereport(ERROR,
-				(errcode(ERRCODE_UNDEFINED_OBJECT),
-				 errmsg("collation with OID %u does not exist", collid)));
-
-	collcollate = pstrdup(NameStr(((Form_pg_collation) GETSTRUCT(tp))->collcollate));
-	collprovider = ((Form_pg_collation) GETSTRUCT(tp))->collprovider;
-
-	ReleaseSysCache(tp);
-
-	version = get_collation_actual_version(collprovider, collcollate);
+	version = get_collation_version_for_oid(collid);

 	if (version)
 		PG_RETURN_TEXT_P(cstring_to_text(version));
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@ -93,6 +93,7 @@
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
 #include "utils/partcache.h"
+#include "utils/pg_locale.h"
 #include "utils/relcache.h"
 #include "utils/ruleutils.h"
 #include "utils/snapmgr.h"
@ -559,6 +560,7 @@ static void refuseDupeIndexAttach(Relation parentIdx, Relation partIdx,
 								  Relation partitionTbl);
 static List *GetParentedForeignKeyRefs(Relation partition);
 static void ATDetachCheckNoForeignKeyRefs(Relation partition);
+static void ATExecAlterCollationRefreshVersion(Relation rel, List *coll);


 /* ----------------------------------------------------------------
@ -3986,6 +3988,10 @@ AlterTableGetLockLevel(List *cmds)
 				cmd_lockmode = AccessShareLock;
 				break;

+			case AT_AlterCollationRefreshVersion:
+				cmd_lockmode = AccessExclusiveLock;
+				break;
+
 			default:			/* oops */
 				elog(ERROR, "unrecognized alter table type: %d",
 					 (int) cmd->subtype);
@ -4160,6 +4166,12 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 			/* This command never recurses */
 			pass = AT_PASS_MISC;
 			break;
+		case AT_AlterCollationRefreshVersion:	/* ALTER COLLATION ... REFRESH
+												 * VERSION */
+			ATSimplePermissions(rel, ATT_INDEX);
+			/* This command never recurses */
+			pass = AT_PASS_MISC;
+			break;
 		case AT_SetStorage:		/* ALTER COLUMN SET STORAGE */
 			ATSimplePermissions(rel, ATT_TABLE | ATT_MATVIEW | ATT_FOREIGN_TABLE);
 			ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode, context);
@ -4738,6 +4750,11 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			Assert(rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE);
 			ATExecDetachPartition(rel, ((PartitionCmd *) cmd->def)->name);
 			break;
+		case AT_AlterCollationRefreshVersion:
+			/* ATPrepCmd ensured it must be an index */
+			Assert(rel->rd_rel->relkind == RELKIND_INDEX);
+			ATExecAlterCollationRefreshVersion(rel, cmd->object);
+			break;
 		default:				/* oops */
 			elog(ERROR, "unrecognized alter table type: %d",
 				 (int) cmd->subtype);
@ -17582,3 +17599,17 @@ ATDetachCheckNoForeignKeyRefs(Relation partition)
 		table_close(rel, NoLock);
 	}
 }
+
+/*
+ * ALTER INDEX ... ALTER COLLATION ... REFRESH VERSION
+ *
+ * Update refobjversion to the current collation version by force.  This clears
+ * warnings about version mismatches without the need to run REINDEX,
+ * potentially hiding corruption due to ordering changes.
+ */
+static void
+ATExecAlterCollationRefreshVersion(Relation rel, List *coll)
+{
+	index_update_collation_versions(rel->rd_id, get_collation_oid(coll, false));
+	CacheInvalidateRelcache(rel);
+}
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@ -3215,6 +3215,7 @@ _copyAlterTableCmd(const AlterTableCmd *from)

 	COPY_SCALAR_FIELD(subtype);
 	COPY_STRING_FIELD(name);
+	COPY_NODE_FIELD(object);
 	COPY_SCALAR_FIELD(num);
 	COPY_NODE_FIELD(newowner);
 	COPY_NODE_FIELD(def);
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@ -28,6 +28,7 @@
 #include "catalog/catalog.h"
 #include "catalog/dependency.h"
 #include "catalog/heap.h"
+#include "catalog/index.h"
 #include "catalog/pg_am.h"
 #include "catalog/pg_proc.h"
 #include "catalog/pg_statistic_ext.h"
@ -198,6 +199,14 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
 			indexRelation = index_open(indexoid, lmode);
 			index = indexRelation->rd_index;

+			/* Warn if any dependent collations' versions have moved. */
+			if (!IsSystemRelation(relation) &&
+				!indexRelation->rd_version_checked)
+			{
+				index_check_collation_versions(indexoid);
+				indexRelation->rd_version_checked = true;
+			}
+
 			/*
 			 * Ignore invalid indexes, since they can't safely be used for
 			 * queries.  Note that this is OK because the data structure we
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@ -2591,6 +2591,14 @@ alter_table_cmd:
 					n->subtype = AT_NoForceRowSecurity;
 					$$ = (Node *)n;
 				}
+			/* ALTER INDEX <name> ALTER COLLATION ... REFRESH VERSION */
+			| ALTER COLLATION any_name REFRESH VERSION_P
+				{
+					AlterTableCmd *n = makeNode(AlterTableCmd);
+					n->subtype = AT_AlterCollationRefreshVersion;
+					n->object = $3;
+					$$ = (Node *)n;
+				}
 			| alter_generic_options
 				{
 					AlterTableCmd *n = makeNode(AlterTableCmd);
--- a/src/backend/utils/adt/pg_locale.c
+++ b/src/backend/utils/adt/pg_locale.c
@ -57,7 +57,9 @@
 #include "access/htup_details.h"
 #include "catalog/pg_collation.h"
 #include "catalog/pg_control.h"
+#include "catalog/pg_database.h"
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
 #include "utils/builtins.h"
 #include "utils/formatting.h"
 #include "utils/hsearch.h"
@ -139,6 +141,9 @@ static char *IsoLocaleName(const char *);	/* MSVC specific */
 static void icu_set_collation_attributes(UCollator *collator, const char *loc);
 #endif

+static char *get_collation_actual_version(char collprovider,
+										  const char *collcollate);
+
 /*
 * pg_perm_setlocale
 *
@ -1630,7 +1635,7 @@ pg_newlocale_from_collation(Oid collid)
 * Get provider-specific collation version string for the given collation from
 * the operating system/library.
 */
-char *
+static char *
 get_collation_actual_version(char collprovider, const char *collcollate)
 {
 	char	   *collversion = NULL;
@ -1712,6 +1717,45 @@ get_collation_actual_version(char collprovider, const char *collcollate)
 	return collversion;
 }

+/*
+ * Get provider-specific collation version string for a given collation OID.
+ * Return NULL if the provider doesn't support versions.
+ */
+char *
+get_collation_version_for_oid(Oid oid)
+{
+	HeapTuple	tp;
+	char	   *version = NULL;
+
+	Assert(oid != C_COLLATION_OID && oid != POSIX_COLLATION_OID);
+
+	if (oid == DEFAULT_COLLATION_OID)
+	{
+		Form_pg_database dbform;
+
+		tp = SearchSysCache1(DATABASEOID, ObjectIdGetDatum(MyDatabaseId));
+		if (!HeapTupleIsValid(tp))
+			elog(ERROR, "cache lookup failed for database %u", MyDatabaseId);
+		dbform = (Form_pg_database) GETSTRUCT(tp);
+		version = get_collation_actual_version(COLLPROVIDER_LIBC,
+											   NameStr(dbform->datcollate));
+	}
+	else
+	{
+		Form_pg_collation collform;
+
+		tp = SearchSysCache1(COLLOID, ObjectIdGetDatum(oid));
+		if (!HeapTupleIsValid(tp))
+			elog(ERROR, "cache lookup failed for collation %u", oid);
+		collform = (Form_pg_collation) GETSTRUCT(tp);
+		version = get_collation_actual_version(collform->collprovider,
+											   NameStr(collform->collcollate));
+	}
+
+	ReleaseSysCache(tp);
+
+	return version;
+}

 #ifdef USE_ICU
 /*
--- a/src/backend/utils/adt/pg_upgrade_support.c
+++ b/src/backend/utils/adt/pg_upgrade_support.c
@ -13,6 +13,7 @@

 #include "catalog/binary_upgrade.h"
 #include "catalog/heap.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_type.h"
 #include "commands/extension.h"
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@ -42,6 +42,7 @@
 #include "access/xact.h"
 #include "access/xlog.h"
 #include "catalog/catalog.h"
+#include "catalog/index.h"
 #include "catalog/indexing.h"
 #include "catalog/namespace.h"
 #include "catalog/partition.h"
@ -5934,6 +5935,7 @@ load_relcache_init_file(bool shared)
 		rel->rd_idattr = NULL;
 		rel->rd_pubactions = NULL;
 		rel->rd_statvalid = false;
+		rel->rd_version_checked = false;
 		rel->rd_statlist = NIL;
 		rel->rd_fkeyvalid = false;
 		rel->rd_fkeylist = NIL;
--- a/src/bin/pg_dump/pg_backup.h
+++ b/src/bin/pg_dump/pg_backup.h
@ -179,6 +179,7 @@ typedef struct _dumpOptions

 	int			sequence_data;	/* dump sequence data even in schema-only mode */
 	int			do_nothing;
+	int			coll_unknown;
 } DumpOptions;

 /*
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@ -46,6 +46,7 @@
 #include "catalog/pg_attribute_d.h"
 #include "catalog/pg_cast_d.h"
 #include "catalog/pg_class_d.h"
+#include "catalog/pg_collation_d.h"
 #include "catalog/pg_default_acl_d.h"
 #include "catalog/pg_largeobject_d.h"
 #include "catalog/pg_largeobject_metadata_d.h"
@ -285,6 +286,9 @@ static void binary_upgrade_extension_member(PQExpBuffer upgrade_buffer,
 static const char *getAttrName(int attrnum, TableInfo *tblInfo);
 static const char *fmtCopyColumnList(const TableInfo *ti, PQExpBuffer buffer);
 static bool nonemptyReloptions(const char *reloptions);
+static void appendIndexCollationVersion(PQExpBuffer buffer, IndxInfo *indxinfo,
+										int enc, bool coll_unknown,
+										Archive *fount);
 static void appendReloptionsArrayAH(PQExpBuffer buffer, const char *reloptions,
 									const char *prefix, Archive *fout);
 static char *get_synchronized_snapshot(Archive *fout);
@ -385,6 +389,7 @@ main(int argc, char **argv)
 		{"on-conflict-do-nothing", no_argument, &dopt.do_nothing, 1},
 		{"rows-per-insert", required_argument, NULL, 10},
 		{"include-foreign-data", required_argument, NULL, 11},
+		{"index-collation-versions-unknown", no_argument, &dopt.coll_unknown, 1},

 		{NULL, 0, NULL, 0}
 	};
@ -712,6 +717,10 @@ main(int argc, char **argv)
 	if (archiveFormat != archDirectory && numWorkers > 1)
 		fatal("parallel backup only supported by the directory format");

+	/* Unknown collation versions only relevant in binary upgrade mode */
+	if (dopt.coll_unknown && !dopt.binary_upgrade)
+		fatal("option --index-collation-versions-unknown only works in binary upgrade mode");
+
 	/* Open the output file */
 	fout = CreateArchive(filename, archiveFormat, compressLevel, dosync,
 						 archiveMode, setupDumpWorker);
@ -7031,7 +7040,9 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 				i_tablespace,
 				i_indreloptions,
 				i_indstatcols,
-				i_indstatvals;
+				i_indstatvals,
+				i_inddependcollnames,
+				i_inddependcollversions;
 	int			ntups;

 	for (i = 0; i < numTables; i++)
@ -7067,7 +7078,7 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 		 * is not.
 		 */
 		resetPQExpBuffer(query);
-		if (fout->remoteVersion >= 110000)
+		if (fout->remoteVersion >= 140000)
 		{
 			appendPQExpBuffer(query,
 							  "SELECT t.tableoid, t.oid, "
@ -7092,7 +7103,66 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 							  "(SELECT pg_catalog.array_agg(attstattarget ORDER BY attnum) "
 							  "  FROM pg_catalog.pg_attribute "
 							  "  WHERE attrelid = i.indexrelid AND "
-							  "    attstattarget >= 0) AS indstatvals "
+							  "    attstattarget >= 0) AS indstatvals, "
+							  "(SELECT pg_catalog.array_agg(quote_ident(ns.nspname) || '.' || quote_ident(c.collname) ORDER BY refobjid) "
+							  "  FROM pg_catalog.pg_depend d "
+							  "  JOIN pg_catalog.pg_collation c ON (c.oid = d.refobjid) "
+							  "  JOIN pg_catalog.pg_namespace ns ON (c.collnamespace = ns.oid) "
+							  "  WHERE d.classid = 'pg_catalog.pg_class'::regclass AND "
+							  "    d.objid = i.indexrelid AND "
+							  "    d.objsubid = 0 AND "
+							  "    d.refclassid = 'pg_catalog.pg_collation'::regclass AND "
+							  "    d.refobjversion IS NOT NULL) AS inddependcollnames, "
+							  "(SELECT pg_catalog.array_agg(quote_literal(refobjversion) ORDER BY refobjid) "
+							  "  FROM pg_catalog.pg_depend "
+							  "  WHERE classid = 'pg_catalog.pg_class'::regclass AND "
+							  "    objid = i.indexrelid AND "
+							  "    objsubid = 0 AND "
+							  "    refclassid = 'pg_catalog.pg_collation'::regclass AND "
+							  "    refobjversion IS NOT NULL) AS inddependcollversions "
+							  "FROM pg_catalog.pg_index i "
+							  "JOIN pg_catalog.pg_class t ON (t.oid = i.indexrelid) "
+							  "JOIN pg_catalog.pg_class t2 ON (t2.oid = i.indrelid) "
+							  "LEFT JOIN pg_catalog.pg_constraint c "
+							  "ON (i.indrelid = c.conrelid AND "
+							  "i.indexrelid = c.conindid AND "
+							  "c.contype IN ('p','u','x')) "
+							  "LEFT JOIN pg_catalog.pg_inherits inh "
+							  "ON (inh.inhrelid = indexrelid) "
+							  "WHERE i.indrelid = '%u'::pg_catalog.oid "
+							  "AND (i.indisvalid OR t2.relkind = 'p') "
+							  "AND i.indisready "
+							  "ORDER BY indexname",
+							  tbinfo->dobj.catId.oid);
+		}
+		else if (fout->remoteVersion >= 110000)
+		{
+			appendPQExpBuffer(query,
+							  "SELECT t.tableoid, t.oid, "
+							  "t.relname AS indexname, "
+							  "inh.inhparent AS parentidx, "
+							  "pg_catalog.pg_get_indexdef(i.indexrelid) AS indexdef, "
+							  "i.indnkeyatts AS indnkeyatts, "
+							  "i.indnatts AS indnatts, "
+							  "i.indkey, i.indisclustered, "
+							  "i.indisreplident, "
+							  "c.contype, c.conname, "
+							  "c.condeferrable, c.condeferred, "
+							  "c.tableoid AS contableoid, "
+							  "c.oid AS conoid, "
+							  "pg_catalog.pg_get_constraintdef(c.oid, false) AS condef, "
+							  "(SELECT spcname FROM pg_catalog.pg_tablespace s WHERE s.oid = t.reltablespace) AS tablespace, "
+							  "t.reloptions AS indreloptions, "
+							  "(SELECT pg_catalog.array_agg(attnum ORDER BY attnum) "
+							  "  FROM pg_catalog.pg_attribute "
+							  "  WHERE attrelid = i.indexrelid AND "
+							  "    attstattarget >= 0) AS indstatcols,"
+							  "(SELECT pg_catalog.array_agg(attstattarget ORDER BY attnum) "
+							  "  FROM pg_catalog.pg_attribute "
+							  "  WHERE attrelid = i.indexrelid AND "
+							  "    attstattarget >= 0) AS indstatvals, "
+							  "'{}' AS inddependcollnames, "
+							  "'{}' AS inddependcollversions "
 							  "FROM pg_catalog.pg_index i "
 							  "JOIN pg_catalog.pg_class t ON (t.oid = i.indexrelid) "
 							  "JOIN pg_catalog.pg_class t2 ON (t2.oid = i.indrelid) "
@ -7131,7 +7201,9 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 							  "(SELECT spcname FROM pg_catalog.pg_tablespace s WHERE s.oid = t.reltablespace) AS tablespace, "
 							  "t.reloptions AS indreloptions, "
 							  "'' AS indstatcols, "
-							  "'' AS indstatvals "
+							  "'' AS indstatvals, "
+							  "'{}' AS inddependcollnames, "
+							  "'{}' AS inddependcollversions "
 							  "FROM pg_catalog.pg_index i "
 							  "JOIN pg_catalog.pg_class t ON (t.oid = i.indexrelid) "
 							  "LEFT JOIN pg_catalog.pg_constraint c "
@ -7166,7 +7238,9 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 							  "(SELECT spcname FROM pg_catalog.pg_tablespace s WHERE s.oid = t.reltablespace) AS tablespace, "
 							  "t.reloptions AS indreloptions, "
 							  "'' AS indstatcols, "
-							  "'' AS indstatvals "
+							  "'' AS indstatvals, "
+							  "'{}' AS inddependcollnames, "
+							  "'{}' AS inddependcollversions "
 							  "FROM pg_catalog.pg_index i "
 							  "JOIN pg_catalog.pg_class t ON (t.oid = i.indexrelid) "
 							  "LEFT JOIN pg_catalog.pg_constraint c "
@ -7197,7 +7271,9 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 							  "(SELECT spcname FROM pg_catalog.pg_tablespace s WHERE s.oid = t.reltablespace) AS tablespace, "
 							  "t.reloptions AS indreloptions, "
 							  "'' AS indstatcols, "
-							  "'' AS indstatvals "
+							  "'' AS indstatvals, "
+							  "'{}' AS inddependcollnames, "
+							  "'{}' AS inddependcollversions "
 							  "FROM pg_catalog.pg_index i "
 							  "JOIN pg_catalog.pg_class t ON (t.oid = i.indexrelid) "
 							  "LEFT JOIN pg_catalog.pg_depend d "
@ -7231,7 +7307,9 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 							  "(SELECT spcname FROM pg_catalog.pg_tablespace s WHERE s.oid = t.reltablespace) AS tablespace, "
 							  "null AS indreloptions, "
 							  "'' AS indstatcols, "
-							  "'' AS indstatvals "
+							  "'' AS indstatvals, "
+							  "'{}' AS inddependcollnames, "
+							  "'{}' AS inddependcollversions "
 							  "FROM pg_catalog.pg_index i "
 							  "JOIN pg_catalog.pg_class t ON (t.oid = i.indexrelid) "
 							  "LEFT JOIN pg_catalog.pg_depend d "
@ -7271,6 +7349,8 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 		i_indreloptions = PQfnumber(res, "indreloptions");
 		i_indstatcols = PQfnumber(res, "indstatcols");
 		i_indstatvals = PQfnumber(res, "indstatvals");
+		i_inddependcollnames = PQfnumber(res, "inddependcollnames");
+		i_inddependcollversions = PQfnumber(res, "inddependcollversions");

 		tbinfo->indexes = indxinfo =
 			(IndxInfo *) pg_malloc(ntups * sizeof(IndxInfo));
@ -7296,6 +7376,8 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 			indxinfo[j].indreloptions = pg_strdup(PQgetvalue(res, j, i_indreloptions));
 			indxinfo[j].indstatcols = pg_strdup(PQgetvalue(res, j, i_indstatcols));
 			indxinfo[j].indstatvals = pg_strdup(PQgetvalue(res, j, i_indstatvals));
+			indxinfo[j].inddependcollnames = pg_strdup(PQgetvalue(res, j, i_inddependcollnames));
+			indxinfo[j].inddependcollversions = pg_strdup(PQgetvalue(res, j, i_inddependcollversions));
 			indxinfo[j].indkeys = (Oid *) pg_malloc(indxinfo[j].indnattrs * sizeof(Oid));
 			parseOidArray(PQgetvalue(res, j, i_indkey),
 						  indxinfo[j].indkeys, indxinfo[j].indnattrs);
@ -16362,7 +16444,8 @@ dumpIndex(Archive *fout, IndxInfo *indxinfo)

 	/*
 	 * If there's an associated constraint, don't dump the index per se, but
-	 * do dump any comment for it.  (This is safe because dependency ordering
+	 * do dump any comment, or in binary upgrade mode dependency on a
+	 * collation version for it.  (This is safe because dependency ordering
 	 * will have ensured the constraint is emitted first.)	Note that the
 	 * emitted comment has to be shown as depending on the constraint, not the
 	 * index, in such cases.
@ -16429,6 +16512,10 @@ dumpIndex(Archive *fout, IndxInfo *indxinfo)
 									"pg_catalog.pg_class",
 									"INDEX", qqindxname);

+		if (dopt->binary_upgrade)
+			appendIndexCollationVersion(q, indxinfo, fout->encoding,
+										dopt->coll_unknown, fout);
+
 		/* If the index defines identity, we need to record that. */
 		if (indxinfo->indisreplident)
 		{
@ -16457,6 +16544,21 @@ dumpIndex(Archive *fout, IndxInfo *indxinfo)
 		if (indstatvalsarray)
 			free(indstatvalsarray);
 	}
+	else if (dopt->binary_upgrade)
+	{
+		appendIndexCollationVersion(q, indxinfo, fout->encoding,
+									dopt->coll_unknown, fout);
+
+		if (indxinfo->dobj.dump & DUMP_COMPONENT_DEFINITION)
+			ArchiveEntry(fout, indxinfo->dobj.catId, indxinfo->dobj.dumpId,
+						 ARCHIVE_OPTS(.tag = indxinfo->dobj.name,
+									  .namespace = tbinfo->dobj.namespace->dobj.name,
+									  .tablespace = indxinfo->tablespace,
+									  .owner = tbinfo->rolname,
+									  .description = "INDEX",
+									  .section = SECTION_POST_DATA,
+									  .createStmt = q->data));
+	}

 	/* Dump Index Comments */
 	if (indxinfo->dobj.dump & DUMP_COMPONENT_COMMENT)
@ -18441,6 +18543,70 @@ nonemptyReloptions(const char *reloptions)
 	return (reloptions != NULL && strlen(reloptions) > 2);
 }

+/*
+ * Generate UPDATE statements to import the collation versions into the new
+ * cluster, during a binary upgrade.
+ */
+static void
+appendIndexCollationVersion(PQExpBuffer buffer, IndxInfo *indxinfo, int enc,
+							bool coll_unknown, Archive *fout)
+{
+	char	   *inddependcollnames = indxinfo->inddependcollnames;
+	char	   *inddependcollversions = indxinfo->inddependcollversions;
+	char	  **inddependcollnamesarray;
+	char	  **inddependcollversionsarray;
+	int			ninddependcollnames;
+	int			ninddependcollversions;
+
+	/*
+	 * By default, the new cluster's index will have pg_depends rows with
+	 * current collation versions, meaning that we assume the index isn't
+	 * corrupted if importing from a release that didn't record versions.
+	 * However, if --index-collation-versions-unknown was passed in, then we
+	 * assume such indexes might be corrupted, and clobber versions with
+	 * 'unknown' to trigger version warnings.
+	 */
+	if (coll_unknown)
+	{
+		appendPQExpBuffer(buffer,
+						  "\n-- For binary upgrade, clobber new index's collation versions\n");
+		appendPQExpBuffer(buffer,
+						  "UPDATE pg_catalog.pg_depend SET refobjversion = 'unknown' WHERE objid = '%u'::pg_catalog.oid AND refclassid = 'pg_catalog.pg_collation'::regclass AND refobjversion IS NOT NULL;\n",
+						  indxinfo->dobj.catId.oid);
+	}
+
+	/* Restore the versions that were recorded by the old cluster (if any). */
+	parsePGArray(inddependcollnames,
+				 &inddependcollnamesarray,
+				 &ninddependcollnames);
+	parsePGArray(inddependcollversions,
+				 &inddependcollversionsarray,
+				 &ninddependcollversions);
+	Assert(ninddependcollnames == ninddependcollversions);
+
+	if (ninddependcollnames > 0)
+		appendPQExpBufferStr(buffer,
+							 "\n-- For binary upgrade, restore old index's collation versions\n");
+	for (int i = 0; i < ninddependcollnames; i++)
+	{
+		/*
+		 * Import refobjversion from the old cluster, being careful to resolve
+		 * the collation OID by name in the new cluster.
+		 */
+		appendPQExpBuffer(buffer,
+						  "UPDATE pg_catalog.pg_depend SET refobjversion = %s WHERE objid = '%u'::pg_catalog.oid AND refclassid = 'pg_catalog.pg_collation'::regclass AND refobjversion IS NOT NULL AND refobjid = ",
+						  inddependcollversionsarray[i],
+						  indxinfo->dobj.catId.oid);
+		appendStringLiteralAH(buffer,inddependcollnamesarray[i], fout);
+		appendPQExpBuffer(buffer, "::regcollation;\n");
+	}
+
+	if (inddependcollnamesarray)
+		free(inddependcollnamesarray);
+	if (inddependcollversionsarray)
+		free(inddependcollversionsarray);
+}
+
 /*
 * Format a reloptions array and append it to the given buffer.
 *
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@ -366,6 +366,8 @@ typedef struct _indxInfo
 	int			indnattrs;		/* total number of index attributes */
 	Oid		   *indkeys;		/* In spite of the name 'indkeys' this field
 								 * contains both key and nonkey attributes */
+	char	   *inddependcollnames;	/* FQ names of depended-on collations */
+	char	   *inddependcollversions;	/* versions of the above */
 	bool		indisclustered;
 	bool		indisreplident;
 	Oid			parentidx;		/* if a partition, parent index OID */
--- a/src/bin/pg_upgrade/dump.c
+++ b/src/bin/pg_upgrade/dump.c
@ -52,9 +52,11 @@ generate_old_dump(void)

 		parallel_exec_prog(log_file_name, NULL,
 						   "\"%s/pg_dump\" %s --schema-only --quote-all-identifiers "
-						   "--binary-upgrade --format=custom %s --file=\"%s\" %s",
+						   "--binary-upgrade --format=custom %s %s --file=\"%s\" %s",
 						   new_cluster.bindir, cluster_conn_opts(&old_cluster),
 						   log_opts.verbose ? "--verbose" : "",
+						   user_opts.ind_coll_unknown ?
+						   "--index-collation-versions-unknown" : "",
 						   sql_file_name, escaped_connstr.data);

 		termPQExpBuffer(&escaped_connstr);
--- a/src/bin/pg_upgrade/option.c
+++ b/src/bin/pg_upgrade/option.c
@ -56,6 +56,7 @@ parseCommandLine(int argc, char *argv[])
 		{"socketdir", required_argument, NULL, 's'},
 		{"verbose", no_argument, NULL, 'v'},
 		{"clone", no_argument, NULL, 1},
+		{"index-collation-versions-unknown", no_argument, NULL, 2},

 		{NULL, 0, NULL, 0}
 	};
@ -203,6 +204,10 @@ parseCommandLine(int argc, char *argv[])
 				user_opts.transfer_mode = TRANSFER_MODE_CLONE;
 				break;

+			case 2:
+				user_opts.ind_coll_unknown = true;
+				break;
+
 			default:
 				fprintf(stderr, _("Try \"%s --help\" for more information.\n"),
 						os_info.progname);
@ -307,6 +312,8 @@ usage(void)
 	printf(_("  -v, --verbose                 enable verbose internal logging\n"));
 	printf(_("  -V, --version                 display version information, then exit\n"));
 	printf(_("  --clone                       clone instead of copying files to new cluster\n"));
+	printf(_("  --index-collation-versions-unknown\n"));
+	printf(_("                                mark text indexes as needing to be rebuilt\n"));
 	printf(_("  -?, --help                    show this help, then exit\n"));
 	printf(_("\n"
 			 "Before running pg_upgrade you must:\n"
--- a/src/bin/pg_upgrade/pg_upgrade.h
+++ b/src/bin/pg_upgrade/pg_upgrade.h
@ -292,6 +292,7 @@ typedef struct
 	transferMode transfer_mode; /* copy files or link them? */
 	int			jobs;			/* number of processes/threads to use */
 	char	   *socketdir;		/* directory to use for Unix sockets */
+	bool		ind_coll_unknown;	/* mark unknown index collation versions */
 } UserOpts;

 typedef struct
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@ -45,6 +45,7 @@

 #include "catalog/pg_am_d.h"
 #include "catalog/pg_class_d.h"
+#include "catalog/pg_collation_d.h"
 #include "common.h"
 #include "libpq-fe.h"
 #include "pqexpbuffer.h"
@ -820,6 +821,20 @@ static const SchemaQuery Query_for_list_of_statistics = {
 "       (SELECT tgrelid FROM pg_catalog.pg_trigger "\
 "         WHERE pg_catalog.quote_ident(tgname)='%s')"

+/* the silly-looking length condition is just to eat up the current word */
+#define Query_for_list_of_colls_for_one_index \
+" SELECT DISTINCT pg_catalog.quote_ident(coll.collname) " \
+"   FROM pg_catalog.pg_depend d, pg_catalog.pg_collation coll, " \
+"     pg_catalog.pg_class c" \
+" WHERE (%d = pg_catalog.length('%s'))" \
+"   AND d.refclassid = " CppAsString2(CollationRelationId) \
+"   AND d.refobjid = coll.oid " \
+"   AND d.classid = " CppAsString2(RelationRelationId) \
+"   AND d.objid = c.oid " \
+"   AND c.relkind = " CppAsString2(RELKIND_INDEX) \
+"   AND pg_catalog.pg_table_is_visible(c.oid) " \
+"   AND c.relname = '%s'"
+
 #define Query_for_list_of_ts_configurations \
 "SELECT pg_catalog.quote_ident(cfgname) FROM pg_catalog.pg_ts_config "\
 " WHERE substring(pg_catalog.quote_ident(cfgname),1,%d)='%s'"
@ -1715,14 +1730,15 @@ psql_completion(const char *text, int start, int end)
 	/* ALTER INDEX <name> */
 	else if (Matches("ALTER", "INDEX", MatchAny))
 		COMPLETE_WITH("ALTER COLUMN", "OWNER TO", "RENAME TO", "SET",
-					  "RESET", "ATTACH PARTITION", "DEPENDS", "NO DEPENDS");
+					  "RESET", "ATTACH PARTITION", "DEPENDS", "NO DEPENDS",
+					  "ALTER COLLATION");
 	else if (Matches("ALTER", "INDEX", MatchAny, "ATTACH"))
 		COMPLETE_WITH("PARTITION");
 	else if (Matches("ALTER", "INDEX", MatchAny, "ATTACH", "PARTITION"))
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_indexes, NULL);
 	/* ALTER INDEX <name> ALTER */
 	else if (Matches("ALTER", "INDEX", MatchAny, "ALTER"))
-		COMPLETE_WITH("COLUMN");
+		COMPLETE_WITH("COLLATION", "COLUMN");
 	/* ALTER INDEX <name> ALTER COLUMN */
 	else if (Matches("ALTER", "INDEX", MatchAny, "ALTER", "COLUMN"))
 	{
@ -1765,6 +1781,15 @@ psql_completion(const char *text, int start, int end)
 		COMPLETE_WITH("ON EXTENSION");
 	else if (Matches("ALTER", "INDEX", MatchAny, "DEPENDS"))
 		COMPLETE_WITH("ON EXTENSION");
+	/* ALTER INDEX <name> ALTER COLLATION */
+	else if (Matches("ALTER", "INDEX", MatchAny, "ALTER", "COLLATION"))
+	{
+		completion_info_charp = prev3_wd;
+		COMPLETE_WITH_QUERY(Query_for_list_of_colls_for_one_index);
+	}
+	/* ALTER INDEX <name> ALTER COLLATION <name> */
+	else if (Matches("ALTER", "INDEX", MatchAny, "ALTER", "COLLATION", MatchAny))
+		COMPLETE_WITH("REFRESH VERSION");

 	/* ALTER LANGUAGE <name> */
 	else if (Matches("ALTER", "LANGUAGE", MatchAny))
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@ -53,6 +53,6 @@
 */

 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	202011012
+#define CATALOG_VERSION_NO	202011013

 #endif
--- a/src/include/catalog/dependency.h
+++ b/src/include/catalog/dependency.h
@ -160,7 +160,8 @@ extern void recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 											Node *expr, Oid relId,
 											DependencyType behavior,
 											DependencyType self_behavior,
-											bool reverse_self);
+											bool reverse_self,
+											bool record_version);

 extern ObjectClass getObjectClass(const ObjectAddress *object);

@ -180,17 +181,30 @@ extern void sort_object_addresses(ObjectAddresses *addrs);

 extern void free_object_addresses(ObjectAddresses *addrs);

+typedef bool(*VisitDependenciesOfCB) (const ObjectAddress *otherObject,
+									  const char *version,
+									  char **new_version,
+									  void *data);
+
+extern void visitDependenciesOf(const ObjectAddress *object,
+								VisitDependenciesOfCB callback,
+								void *data);
+
 /* in pg_depend.c */

 extern void recordDependencyOn(const ObjectAddress *depender,
 							   const ObjectAddress *referenced,
 							   DependencyType behavior);

+extern void recordDependencyOnCollations(ObjectAddress *myself,
+										 List *collations,
+										 bool record_version);
+
 extern void recordMultipleDependencies(const ObjectAddress *depender,
 									   const ObjectAddress *referenced,
 									   int nreferenced,
-									   const char *version,
-									   DependencyType behavior);
+									   DependencyType behavior,
+									   bool record_version);

 extern void recordDependencyOnCurrentExtension(const ObjectAddress *object,
 											   bool isReplace);
@ -209,10 +223,9 @@ extern long changeDependencyFor(Oid classId, Oid objectId,
 								Oid refClassId, Oid oldRefObjectId,
 								Oid newRefObjectId);

-extern long changeDependenciesOf(Oid classId, Oid oldObjectId,
+long changeDependenciesOf(Oid classId, Oid oldObjectId,
 								 Oid newObjectId);
-
-extern long changeDependenciesOn(Oid refClassId, Oid oldRefObjectId,
+long changeDependenciesOn(Oid refClassId, Oid oldRefObjectId,
 								 Oid newRefObjectId);

 extern Oid	getExtensionOfObject(Oid classId, Oid objectId);
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@ -121,6 +121,9 @@ extern void FormIndexDatum(IndexInfo *indexInfo,
 						   Datum *values,
 						   bool *isnull);

+extern void index_check_collation_versions(Oid relid);
+extern void index_update_collation_versions(Oid relid, Oid coll);
+
 extern void index_build(Relation heapRelation,
 						Relation indexRelation,
 						IndexInfo *indexInfo,
--- a/src/include/catalog/pg_depend.h
+++ b/src/include/catalog/pg_depend.h
@ -62,8 +62,7 @@ CATALOG(pg_depend,2608,DependRelationId)
 	 */
 	char		deptype;		/* see codes in dependency.h */
 #ifdef CATALOG_VARLEN
-	text		refobjversion;	/* version tracking, NULL if not used or
-								 * unknown */
+	text		refobjversion;	/* version of referenced object */
 #endif
 } FormData_pg_depend;

--- a/src/include/catalog/pg_type.h
+++ b/src/include/catalog/pg_type.h
@ -368,6 +368,8 @@ extern void GenerateTypeDependencies(HeapTuple typeTuple,
 									 bool isDependentType,
 									 bool rebuild);

+extern List *GetTypeCollations(Oid typeObjectid);
+
 extern void RenameTypeInternal(Oid typeOid, const char *newTypeName,
 							   Oid typeNamespace);

--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@ -1853,7 +1853,8 @@ typedef enum AlterTableType
 	AT_DetachPartition,			/* DETACH PARTITION */
 	AT_AddIdentity,				/* ADD IDENTITY */
 	AT_SetIdentity,				/* SET identity column options */
-	AT_DropIdentity				/* DROP IDENTITY */
+	AT_DropIdentity,			/* DROP IDENTITY */
+	AT_AlterCollationRefreshVersion	/* ALTER COLLATION ... REFRESH VERSION */
 } AlterTableType;

 typedef struct ReplicaIdentityStmt
@ -1869,6 +1870,7 @@ typedef struct AlterTableCmd	/* one subcommand of an ALTER TABLE */
 	AlterTableType subtype;		/* Type of table alteration to apply */
 	char	   *name;			/* column, constraint, or trigger to act on,
 								 * or tablespace */
+	List	   *object;			/* collation to act on if it's a collation */
 	int16		num;			/* attribute number for columns referenced by
 								 * number */
 	RoleSpec   *newowner;
--- a/src/include/utils/pg_locale.h
+++ b/src/include/utils/pg_locale.h
@ -103,7 +103,7 @@ typedef struct pg_locale_struct *pg_locale_t;

 extern pg_locale_t pg_newlocale_from_collation(Oid collid);

-extern char *get_collation_actual_version(char collprovider, const char *collcollate);
+extern char *get_collation_version_for_oid(Oid collid);

 #ifdef USE_ICU
 extern int32_t icu_to_uchar(UChar **buff_uchar, const char *buff, size_t nbytes);
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@ -63,6 +63,7 @@ typedef struct RelationData
 	bool		rd_indexvalid;	/* is rd_indexlist valid? (also rd_pkindex and
 								 * rd_replidindex) */
 	bool		rd_statvalid;	/* is rd_statlist valid? */
+	bool		rd_version_checked; /* has version check been done yet? */

 	/*----------
 	 * rd_createSubid is the ID of the highest subtransaction the rel has
--- a/src/test/Makefile
+++ b/src/test/Makefile
@ -12,7 +12,8 @@ subdir = src/test
 top_builddir = ../..
 include $(top_builddir)/src/Makefile.global

-SUBDIRS = perl regress isolation modules authentication recovery subscription
+SUBDIRS = perl regress isolation modules authentication recovery subscription \
+	  locale

 # Test suites that are not safe by default but can be run if selected
 # by the user via the whitespace-separated list in variable
--- a/src/test/locale/.gitignore
+++ b/src/test/locale/.gitignore
@ -1 +1,2 @@
 /test-ctype
+/tmp_check/
--- a/src/test/locale/Makefile
+++ b/src/test/locale/Makefile
@ -4,6 +4,7 @@ subdir = src/test/locale
 top_builddir = ../../..
 include $(top_builddir)/src/Makefile.global

+export with_icu

 PROGS = test-ctype
 DIRS = de_DE.ISO8859-1 gr_GR.ISO8859-7 koi8-r koi8-to-win1251
@ -19,3 +20,9 @@ clean distclean maintainer-clean:
 # These behave like installcheck targets.
 check-%: all
 	@$(MAKE) -C `echo $@ | sed 's/^check-//'` test
+
+check:
+	$(prove_check)
+
+installcheck:
+	$(prove_installcheck)
--- a/src/test/locale/t/001_index.pl
+++ b/src/test/locale/t/001_index.pl
@ -0,0 +1,67 @@
+use strict;
+use warnings;
+
+use Config;
+use PostgresNode;
+use TestLib;
+use Test::More;
+
+if ($ENV{with_icu} eq 'yes')
+{
+	plan tests => 10;
+}
+else
+{
+	plan skip_all => 'ICU not supported by this build';
+}
+
+#### Set up the server
+
+note "setting up data directory";
+my $node = get_new_node('main');
+$node->init(extra => [ '--encoding=UTF8' ]);
+
+$ENV{PGHOST} = $node->host;
+$ENV{PGPORT} = $node->port;
+$node->start;
+
+sub test_index
+{
+	my ($err_like, $err_comm) = @_;
+	my ($ret, $out, $err) = $node->psql('postgres', "SELECT * FROM icu1");
+	is($ret, 0, 'SELECT should succeed.');
+	like($err, $err_like, $err_comm);
+}
+
+$node->safe_psql('postgres', 'CREATE TABLE icu1(val text);');
+$node->safe_psql('postgres', 'CREATE INDEX icu1_fr ON icu1 (val COLLATE "fr-x-icu");');
+
+test_index(qr/^$/, 'No warning should be raised');
+
+# Simulate different collation version
+$node->safe_psql('postgres',
+	"UPDATE pg_depend SET refobjversion = 'not_a_version'"
+	. " WHERE refobjversion IS NOT NULL"
+	. " AND objid::regclass::text = 'icu1_fr';");
+
+test_index(qr/index "icu1_fr" depends on collation "fr-x-icu" version "not_a_version", but the current version is/,
+	'Different collation version warning should be raised.');
+
+$node->safe_psql('postgres', 'ALTER INDEX icu1_fr ALTER COLLATION "fr-x-icu" REFRESH VERSION;');
+
+test_index(qr/^$/, 'No warning should be raised');
+
+# Simulate different collation version
+$node->safe_psql('postgres',
+	"UPDATE pg_depend SET refobjversion = 'not_a_version'"
+	. " WHERE refobjversion IS NOT NULL"
+	. " AND objid::regclass::text = 'icu1_fr';");
+
+test_index(qr/index "icu1_fr" depends on collation "fr-x-icu" version "not_a_version", but the current version is/,
+	'Different collation version warning should be raised.');
+
+$node->safe_psql('postgres', 'REINDEX TABLE icu1;');
+
+test_index(qr/^$/, 'No warning should be raised');
+
+$node->stop;
--- a/src/test/regress/expected/collate.icu.utf8.out
+++ b/src/test/regress/expected/collate.icu.utf8.out
@ -1897,6 +1897,207 @@ SELECT (SELECT count(*) FROM test33_0) <> (SELECT count(*) FROM test33_1);
 t
 (1 row)

+-- collation versioning support
+CREATE TYPE t_en_fr AS (fr text COLLATE "fr-x-icu", en text COLLATE "en-x-icu");
+CREATE DOMAIN d_en_fr AS t_en_fr;
+CREATE DOMAIN d_es AS text COLLATE "es-x-icu";
+CREATE TYPE t_en_fr_ga AS (en_fr t_en_fr, ga text COLLATE "ga-x-icu");
+CREATE DOMAIN d_en_fr_ga AS t_en_fr_ga;
+CREATE TYPE t_custom AS (meh text, meh2 text);
+CREATE DOMAIN d_custom AS t_custom;
+CREATE COLLATION custom (
+    LOCALE = 'fr-x-icu', PROVIDER = 'icu'
+);
+CREATE TYPE myrange AS range (subtype = text);
+CREATE TYPE myrange_en_fr_ga AS range(subtype = t_en_fr_ga);
+CREATE TYPE mood AS ENUM ('sad', 'ok', 'happy');
+CREATE TABLE collate_test (
+    id integer,
+    val text COLLATE "fr-x-icu",
+    t_en_fr t_en_fr,
+    d_en_fr d_en_fr,
+    d_es d_es,
+    t_en_fr_ga t_en_fr_ga,
+    d_en_fr_ga d_en_fr_ga,
+    d_en_fr_ga_arr d_en_fr_ga[],
+    myrange myrange,
+    myrange_en_fr_ga myrange_en_fr_ga,
+    mood mood
+);
+CREATE INDEX icuidx00_val ON collate_test(val);
+-- shouldn't get duplicated dependencies
+CREATE INDEX icuidx00_val_val ON collate_test(val, val);
+-- shouldn't track version
+CREATE INDEX icuidx00_val_pattern ON collate_test(val text_pattern_ops);
+-- should have single dependency, no version
+CREATE INDEX icuidx00_val_pattern_val_pattern ON collate_test(val text_pattern_ops, val text_pattern_ops);
+-- should have single dependency, with version
+CREATE INDEX icuidx00_val_pattern_val ON collate_test(val text_pattern_ops, val);
+-- should have single dependency, with version
+CREATE INDEX icuidx00_val_val_pattern ON collate_test(val, val text_pattern_ops);
+-- two rows expected, only one a version, because we don't try to merge these yet
+CREATE INDEX icuidx00_val_pattern_where ON collate_test(val text_pattern_ops) WHERE val >= val;
+-- two rows expected with version, because we don't try to merge these yet
+CREATE INDEX icuidx00_val_where ON collate_test(val) WHERE val >= val;
+-- two rows expected with version (expression walker + attribute)
+CREATE INDEX icuidx00_val_pattern_expr ON collate_test(val varchar_pattern_ops, (val || val));
+-- two rows expected, one with a version (expression walker + attribute)
+CREATE INDEX icuidx00_val_pattern_expr_pattern ON collate_test(val varchar_pattern_ops, (val || val) text_pattern_ops);
+-- should have single dependency, with version tracked
+CREATE INDEX icuidx01_t_en_fr__d_es ON collate_test (t_en_fr, d_es);
+CREATE INDEX icuidx02_d_en_fr ON collate_test (d_en_fr);
+CREATE INDEX icuidx03_t_en_fr_ga ON collate_test (t_en_fr_ga);
+CREATE INDEX icuidx04_d_en_fr_ga ON collate_test (d_en_fr_ga);
+CREATE INDEX icuidx05_d_en_fr_ga_arr ON collate_test (d_en_fr_ga_arr);
+CREATE INDEX icuidx06_d_en_fr_ga ON collate_test(id) WHERE (d_en_fr_ga).en_fr.fr = 'foo';
+CREATE INDEX icuidx07_d_en_fr_ga ON collate_test(id) WHERE (d_en_fr_ga).ga = 'foo';
+CREATE INDEX icuidx08_d_en_fr_ga ON collate_test(id) WHERE (t_en_fr_ga) = ('foo', 'bar', 'baz');
+CREATE INDEX icuidx09_d_en_fr_ga ON collate_test(id) WHERE (d_en_fr_ga) = ('foo', 'bar', 'baz');
+CREATE INDEX icuidx10_d_en_fr_ga_es ON collate_test(id) WHERE (d_en_fr_ga) = ('foo', 'bar', 'baz' COLLATE "es-x-icu");
+CREATE INDEX icuidx11_d_es ON collate_test(id) WHERE (d_es) = ('foo');
+CREATE INDEX icuidx12_custom ON collate_test(id) WHERE ('foo', 'bar')::d_custom = ('foo', 'bar' COLLATE custom)::d_custom;
+CREATE INDEX icuidx13_custom ON collate_test(id) WHERE ('foo' COLLATE custom, 'bar')::d_custom = ('foo', 'bar')::d_custom;
+CREATE INDEX icuidx14_myrange ON collate_test(myrange);
+CREATE INDEX icuidx15_myrange_en_fr_ga ON collate_test USING gist (myrange_en_fr_ga);
+CREATE INDEX icuidx16_mood ON collate_test(id) WHERE mood > 'ok' COLLATE "fr-x-icu";
+CREATE TABLE collate_part(id integer, val text COLLATE "en-x-icu") PARTITION BY range(id);
+CREATE TABLE collate_part_0 PARTITION OF collate_part FOR VALUES FROM (0) TO (1);
+CREATE TABLE collate_part_1 PARTITION OF collate_part FOR VALUES FROM (1) TO (1000000);
+CREATE INDEX icuidx17_part ON collate_part_1 (val);
+SELECT objid::regclass::text collate "C", refobjid::regcollation::text collate "C",
+CASE
+WHEN refobjid = 'default'::regcollation THEN 'XXX' -- depends on libc version support
+WHEN refobjversion IS NULL THEN 'version not tracked'
+WHEN refobjversion = pg_collation_actual_version(refobjid) THEN 'up to date'
+ELSE 'out of date'
+END AS version
+FROM pg_depend d
+LEFT JOIN pg_class c ON c.oid = d.objid
+WHERE refclassid = 'pg_collation'::regclass
+AND coalesce(relkind, 'i') = 'i'
+AND relname LIKE 'icuidx%'
+ORDER BY 1, 2, 3;
+               objid               |  refobjid  |       version       
+-----------------------------------+------------+---------------------
+ icuidx00_val                      | "fr-x-icu" | up to date
+ icuidx00_val_pattern              | "fr-x-icu" | version not tracked
+ icuidx00_val_pattern_expr         | "fr-x-icu" | up to date
+ icuidx00_val_pattern_expr         | "fr-x-icu" | up to date
+ icuidx00_val_pattern_expr_pattern | "fr-x-icu" | up to date
+ icuidx00_val_pattern_expr_pattern | "fr-x-icu" | version not tracked
+ icuidx00_val_pattern_val          | "fr-x-icu" | up to date
+ icuidx00_val_pattern_val_pattern  | "fr-x-icu" | version not tracked
+ icuidx00_val_pattern_where        | "fr-x-icu" | up to date
+ icuidx00_val_pattern_where        | "fr-x-icu" | version not tracked
+ icuidx00_val_val                  | "fr-x-icu" | up to date
+ icuidx00_val_val_pattern          | "fr-x-icu" | up to date
+ icuidx00_val_where                | "fr-x-icu" | up to date
+ icuidx00_val_where                | "fr-x-icu" | up to date
+ icuidx01_t_en_fr__d_es            | "en-x-icu" | up to date
+ icuidx01_t_en_fr__d_es            | "es-x-icu" | up to date
+ icuidx01_t_en_fr__d_es            | "fr-x-icu" | up to date
+ icuidx02_d_en_fr                  | "en-x-icu" | up to date
+ icuidx02_d_en_fr                  | "fr-x-icu" | up to date
+ icuidx03_t_en_fr_ga               | "en-x-icu" | up to date
+ icuidx03_t_en_fr_ga               | "fr-x-icu" | up to date
+ icuidx03_t_en_fr_ga               | "ga-x-icu" | up to date
+ icuidx04_d_en_fr_ga               | "en-x-icu" | up to date
+ icuidx04_d_en_fr_ga               | "fr-x-icu" | up to date
+ icuidx04_d_en_fr_ga               | "ga-x-icu" | up to date
+ icuidx05_d_en_fr_ga_arr           | "en-x-icu" | up to date
+ icuidx05_d_en_fr_ga_arr           | "fr-x-icu" | up to date
+ icuidx05_d_en_fr_ga_arr           | "ga-x-icu" | up to date
+ icuidx06_d_en_fr_ga               | "default"  | XXX
+ icuidx06_d_en_fr_ga               | "en-x-icu" | up to date
+ icuidx06_d_en_fr_ga               | "fr-x-icu" | up to date
+ icuidx06_d_en_fr_ga               | "ga-x-icu" | up to date
+ icuidx07_d_en_fr_ga               | "default"  | XXX
+ icuidx07_d_en_fr_ga               | "en-x-icu" | up to date
+ icuidx07_d_en_fr_ga               | "fr-x-icu" | up to date
+ icuidx07_d_en_fr_ga               | "ga-x-icu" | up to date
+ icuidx08_d_en_fr_ga               | "en-x-icu" | up to date
+ icuidx08_d_en_fr_ga               | "fr-x-icu" | up to date
+ icuidx08_d_en_fr_ga               | "ga-x-icu" | up to date
+ icuidx09_d_en_fr_ga               | "en-x-icu" | up to date
+ icuidx09_d_en_fr_ga               | "fr-x-icu" | up to date
+ icuidx09_d_en_fr_ga               | "ga-x-icu" | up to date
+ icuidx10_d_en_fr_ga_es            | "en-x-icu" | up to date
+ icuidx10_d_en_fr_ga_es            | "es-x-icu" | up to date
+ icuidx10_d_en_fr_ga_es            | "fr-x-icu" | up to date
+ icuidx10_d_en_fr_ga_es            | "ga-x-icu" | up to date
+ icuidx11_d_es                     | "default"  | XXX
+ icuidx11_d_es                     | "es-x-icu" | up to date
+ icuidx12_custom                   | "default"  | XXX
+ icuidx12_custom                   | custom     | up to date
+ icuidx13_custom                   | "default"  | XXX
+ icuidx13_custom                   | custom     | up to date
+ icuidx14_myrange                  | "default"  | XXX
+ icuidx15_myrange_en_fr_ga         | "en-x-icu" | up to date
+ icuidx15_myrange_en_fr_ga         | "fr-x-icu" | up to date
+ icuidx15_myrange_en_fr_ga         | "ga-x-icu" | up to date
+ icuidx16_mood                     | "fr-x-icu" | up to date
+ icuidx17_part                     | "en-x-icu" | up to date
+(58 rows)
+
+-- Validate that REINDEX will update the stored version.
+UPDATE pg_depend SET refobjversion = 'not a version'
+WHERE refclassid = 'pg_collation'::regclass
+AND objid::regclass::text LIKE 'icuidx%'
+AND refobjversion IS NOT NULL;
+REINDEX TABLE collate_test;
+REINDEX TABLE collate_part_0;
+REINDEX TABLE collate_part_1;
+SELECT objid::regclass FROM pg_depend WHERE refobjversion = 'not a version';
+ objid 
+-------
+(0 rows)
+
+-- Validate that REINDEX CONCURRENTLY will update the stored version.
+UPDATE pg_depend SET refobjversion = 'not a version'
+WHERE refclassid = 'pg_collation'::regclass
+AND objid::regclass::text LIKE 'icuidx%'
+AND refobjversion IS NOT NULL;
+REINDEX TABLE CONCURRENTLY collate_test;
+REINDEX TABLE CONCURRENTLY collate_part_0;
+REINDEX INDEX CONCURRENTLY icuidx17_part;
+SELECT objid::regclass FROM pg_depend WHERE refobjversion = 'not a version';
+ objid 
+-------
+(0 rows)
+
+-- Validate that VACUUM FULL will update the stored version.
+UPDATE pg_depend SET refobjversion = 'not a version'
+WHERE refclassid = 'pg_collation'::regclass
+AND objid::regclass::text LIKE 'icuidx%'
+AND refobjversion IS NOT NULL;
+VACUUM FULL collate_test;
+VACUUM FULL collate_part_0;
+VACUUM FULL collate_part_1;
+SELECT objid::regclass FROM pg_depend WHERE refobjversion = 'not a version';
+ objid 
+-------
+(0 rows)
+
+-- Test ALTER INDEX name ALTER COLLATION name REFRESH VERSION
+UPDATE pg_depend SET refobjversion = 'not a version'
+WHERE refclassid = 'pg_collation'::regclass
+AND objid::regclass::text = 'icuidx17_part'
+AND refobjversion IS NOT NULL;
+SELECT objid::regclass FROM pg_depend WHERE refobjversion = 'not a version';
+     objid     
+---------------
+ icuidx17_part
+(1 row)
+
+ALTER INDEX icuidx17_part ALTER COLLATION "en-x-icu" REFRESH VERSION;
+SELECT objid::regclass, refobjversion = 'not a version' AS ver FROM pg_depend
+WHERE refclassid = 'pg_collation'::regclass
+AND objid::regclass::text = 'icuidx17_part';
+     objid     | ver 
+---------------+-----
+ icuidx17_part | f
+(1 row)
+
 -- cleanup
 RESET search_path;
 SET client_min_messages TO warning;
--- a/src/test/regress/expected/create_index.out
+++ b/src/test/regress/expected/create_index.out
@ -2065,14 +2065,16 @@ WHERE classid = 'pg_class'::regclass AND
                   obj                    |                           objref                           | deptype 
 ------------------------------------------+------------------------------------------------------------+---------
 index concur_reindex_ind1                | constraint concur_reindex_ind1 on table concur_reindex_tab | i
+ index concur_reindex_ind2                | collation "default"                                        | n
 index concur_reindex_ind2                | column c2 of table concur_reindex_tab                      | a
 index concur_reindex_ind3                | column c1 of table concur_reindex_tab                      | a
 index concur_reindex_ind3                | table concur_reindex_tab                                   | a
+ index concur_reindex_ind4                | collation "default"                                        | n
 index concur_reindex_ind4                | column c1 of table concur_reindex_tab                      | a
 index concur_reindex_ind4                | column c2 of table concur_reindex_tab                      | a
 materialized view concur_reindex_matview | schema public                                              | n
 table concur_reindex_tab                 | schema public                                              | n
-(8 rows)
+(10 rows)

 REINDEX INDEX CONCURRENTLY concur_reindex_ind1;
 REINDEX TABLE CONCURRENTLY concur_reindex_tab;
@ -2092,14 +2094,16 @@ WHERE classid = 'pg_class'::regclass AND
                   obj                    |                           objref                           | deptype 
 ------------------------------------------+------------------------------------------------------------+---------
 index concur_reindex_ind1                | constraint concur_reindex_ind1 on table concur_reindex_tab | i
+ index concur_reindex_ind2                | collation "default"                                        | n
 index concur_reindex_ind2                | column c2 of table concur_reindex_tab                      | a
 index concur_reindex_ind3                | column c1 of table concur_reindex_tab                      | a
 index concur_reindex_ind3                | table concur_reindex_tab                                   | a
+ index concur_reindex_ind4                | collation "default"                                        | n
 index concur_reindex_ind4                | column c1 of table concur_reindex_tab                      | a
 index concur_reindex_ind4                | column c2 of table concur_reindex_tab                      | a
 materialized view concur_reindex_matview | schema public                                              | n
 table concur_reindex_tab                 | schema public                                              | n
-(8 rows)
+(10 rows)

 -- Check that comments are preserved
 CREATE TABLE testcomment (i int);
--- a/src/test/regress/sql/collate.icu.utf8.sql
+++ b/src/test/regress/sql/collate.icu.utf8.sql
@ -716,6 +716,138 @@ INSERT INTO test33 VALUES (2, 'DEF');
 -- they end up in the same partition (but it's platform-dependent which one)
 SELECT (SELECT count(*) FROM test33_0) <> (SELECT count(*) FROM test33_1);

+-- collation versioning support
+CREATE TYPE t_en_fr AS (fr text COLLATE "fr-x-icu", en text COLLATE "en-x-icu");
+CREATE DOMAIN d_en_fr AS t_en_fr;
+CREATE DOMAIN d_es AS text COLLATE "es-x-icu";
+CREATE TYPE t_en_fr_ga AS (en_fr t_en_fr, ga text COLLATE "ga-x-icu");
+CREATE DOMAIN d_en_fr_ga AS t_en_fr_ga;
+CREATE TYPE t_custom AS (meh text, meh2 text);
+CREATE DOMAIN d_custom AS t_custom;
+
+CREATE COLLATION custom (
+    LOCALE = 'fr-x-icu', PROVIDER = 'icu'
+);
+
+CREATE TYPE myrange AS range (subtype = text);
+CREATE TYPE myrange_en_fr_ga AS range(subtype = t_en_fr_ga);
+
+CREATE TYPE mood AS ENUM ('sad', 'ok', 'happy');
+
+CREATE TABLE collate_test (
+    id integer,
+    val text COLLATE "fr-x-icu",
+    t_en_fr t_en_fr,
+    d_en_fr d_en_fr,
+    d_es d_es,
+    t_en_fr_ga t_en_fr_ga,
+    d_en_fr_ga d_en_fr_ga,
+    d_en_fr_ga_arr d_en_fr_ga[],
+    myrange myrange,
+    myrange_en_fr_ga myrange_en_fr_ga,
+    mood mood
+);
+
+CREATE INDEX icuidx00_val ON collate_test(val);
+-- shouldn't get duplicated dependencies
+CREATE INDEX icuidx00_val_val ON collate_test(val, val);
+-- shouldn't track version
+CREATE INDEX icuidx00_val_pattern ON collate_test(val text_pattern_ops);
+-- should have single dependency, no version
+CREATE INDEX icuidx00_val_pattern_val_pattern ON collate_test(val text_pattern_ops, val text_pattern_ops);
+-- should have single dependency, with version
+CREATE INDEX icuidx00_val_pattern_val ON collate_test(val text_pattern_ops, val);
+-- should have single dependency, with version
+CREATE INDEX icuidx00_val_val_pattern ON collate_test(val, val text_pattern_ops);
+-- two rows expected, only one a version, because we don't try to merge these yet
+CREATE INDEX icuidx00_val_pattern_where ON collate_test(val text_pattern_ops) WHERE val >= val;
+-- two rows expected with version, because we don't try to merge these yet
+CREATE INDEX icuidx00_val_where ON collate_test(val) WHERE val >= val;
+-- two rows expected with version (expression walker + attribute)
+CREATE INDEX icuidx00_val_pattern_expr ON collate_test(val varchar_pattern_ops, (val || val));
+-- two rows expected, one with a version (expression walker + attribute)
+CREATE INDEX icuidx00_val_pattern_expr_pattern ON collate_test(val varchar_pattern_ops, (val || val) text_pattern_ops);
+-- should have single dependency, with version tracked
+CREATE INDEX icuidx01_t_en_fr__d_es ON collate_test (t_en_fr, d_es);
+CREATE INDEX icuidx02_d_en_fr ON collate_test (d_en_fr);
+CREATE INDEX icuidx03_t_en_fr_ga ON collate_test (t_en_fr_ga);
+CREATE INDEX icuidx04_d_en_fr_ga ON collate_test (d_en_fr_ga);
+CREATE INDEX icuidx05_d_en_fr_ga_arr ON collate_test (d_en_fr_ga_arr);
+CREATE INDEX icuidx06_d_en_fr_ga ON collate_test(id) WHERE (d_en_fr_ga).en_fr.fr = 'foo';
+CREATE INDEX icuidx07_d_en_fr_ga ON collate_test(id) WHERE (d_en_fr_ga).ga = 'foo';
+CREATE INDEX icuidx08_d_en_fr_ga ON collate_test(id) WHERE (t_en_fr_ga) = ('foo', 'bar', 'baz');
+CREATE INDEX icuidx09_d_en_fr_ga ON collate_test(id) WHERE (d_en_fr_ga) = ('foo', 'bar', 'baz');
+CREATE INDEX icuidx10_d_en_fr_ga_es ON collate_test(id) WHERE (d_en_fr_ga) = ('foo', 'bar', 'baz' COLLATE "es-x-icu");
+CREATE INDEX icuidx11_d_es ON collate_test(id) WHERE (d_es) = ('foo');
+CREATE INDEX icuidx12_custom ON collate_test(id) WHERE ('foo', 'bar')::d_custom = ('foo', 'bar' COLLATE custom)::d_custom;
+CREATE INDEX icuidx13_custom ON collate_test(id) WHERE ('foo' COLLATE custom, 'bar')::d_custom = ('foo', 'bar')::d_custom;
+CREATE INDEX icuidx14_myrange ON collate_test(myrange);
+CREATE INDEX icuidx15_myrange_en_fr_ga ON collate_test USING gist (myrange_en_fr_ga);
+CREATE INDEX icuidx16_mood ON collate_test(id) WHERE mood > 'ok' COLLATE "fr-x-icu";
+
+CREATE TABLE collate_part(id integer, val text COLLATE "en-x-icu") PARTITION BY range(id);
+CREATE TABLE collate_part_0 PARTITION OF collate_part FOR VALUES FROM (0) TO (1);
+CREATE TABLE collate_part_1 PARTITION OF collate_part FOR VALUES FROM (1) TO (1000000);
+CREATE INDEX icuidx17_part ON collate_part_1 (val);
+
+SELECT objid::regclass::text collate "C", refobjid::regcollation::text collate "C",
+CASE
+WHEN refobjid = 'default'::regcollation THEN 'XXX' -- depends on libc version support
+WHEN refobjversion IS NULL THEN 'version not tracked'
+WHEN refobjversion = pg_collation_actual_version(refobjid) THEN 'up to date'
+ELSE 'out of date'
+END AS version
+FROM pg_depend d
+LEFT JOIN pg_class c ON c.oid = d.objid
+WHERE refclassid = 'pg_collation'::regclass
+AND coalesce(relkind, 'i') = 'i'
+AND relname LIKE 'icuidx%'
+ORDER BY 1, 2, 3;
+
+-- Validate that REINDEX will update the stored version.
+UPDATE pg_depend SET refobjversion = 'not a version'
+WHERE refclassid = 'pg_collation'::regclass
+AND objid::regclass::text LIKE 'icuidx%'
+AND refobjversion IS NOT NULL;
+
+REINDEX TABLE collate_test;
+REINDEX TABLE collate_part_0;
+REINDEX TABLE collate_part_1;
+
+SELECT objid::regclass FROM pg_depend WHERE refobjversion = 'not a version';
+
+-- Validate that REINDEX CONCURRENTLY will update the stored version.
+UPDATE pg_depend SET refobjversion = 'not a version'
+WHERE refclassid = 'pg_collation'::regclass
+AND objid::regclass::text LIKE 'icuidx%'
+AND refobjversion IS NOT NULL;
+REINDEX TABLE CONCURRENTLY collate_test;
+REINDEX TABLE CONCURRENTLY collate_part_0;
+REINDEX INDEX CONCURRENTLY icuidx17_part;
+
+SELECT objid::regclass FROM pg_depend WHERE refobjversion = 'not a version';
+
+-- Validate that VACUUM FULL will update the stored version.
+UPDATE pg_depend SET refobjversion = 'not a version'
+WHERE refclassid = 'pg_collation'::regclass
+AND objid::regclass::text LIKE 'icuidx%'
+AND refobjversion IS NOT NULL;
+VACUUM FULL collate_test;
+VACUUM FULL collate_part_0;
+VACUUM FULL collate_part_1;
+
+SELECT objid::regclass FROM pg_depend WHERE refobjversion = 'not a version';
+
+-- Test ALTER INDEX name ALTER COLLATION name REFRESH VERSION
+UPDATE pg_depend SET refobjversion = 'not a version'
+WHERE refclassid = 'pg_collation'::regclass
+AND objid::regclass::text = 'icuidx17_part'
+AND refobjversion IS NOT NULL;
+SELECT objid::regclass FROM pg_depend WHERE refobjversion = 'not a version';
+ALTER INDEX icuidx17_part ALTER COLLATION "en-x-icu" REFRESH VERSION;
+SELECT objid::regclass, refobjversion = 'not a version' AS ver FROM pg_depend
+WHERE refclassid = 'pg_collation'::regclass
+AND objid::regclass::text = 'icuidx17_part';

 -- cleanup
 RESET search_path;
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@ -2914,6 +2914,8 @@ dlist_head
 dlist_iter
 dlist_mutable_iter
 dlist_node
+do_collation_version_check_context
+do_collation_version_update_context
 ds_state
 dsa_area
 dsa_area_control