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[PATCH v17 4/7] Track collation versions for indexes.
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* [PATCH v17 4/7] Track collation versions for indexes.
@ 2019-05-28 18:16  Thomas Munro <[email protected]>
  0 siblings, 0 replies; 96+ messages in thread

From: Thomas Munro @ 2019-05-28 18:16 UTC (permalink / raw)

Record the current version of dependent collations in pg_depend when creating
or rebuilding an index.  The version is checked against the current version
whenever we call get_relation_info for an index or open the parent table
during non-full VACUUM or ANALYZE.  Warn that the index may be corrupted if
the versions don't match.

A new flag is added in RelationData to specify that the check has already been
done to avoid repetition.

Thanks to Doug Doole, Peter Eisentraut, Christoph Berg, Laurenz Albe,
Michael Paquier, Robert Haas, Tom Lane and others for design discussion.

Author: Thomas Munro and Julien Rouhaud
Reviewed-by: Peter Eisentraut, Laurenz Albe
Discussion: https://postgr.es/m/CAEepm%3D0uEQCpfq_%2BLYFBdArCe4Ot98t1aR4eYiYTe%3DyavQygiQ%40mail.gmail.com
---
 doc/src/sgml/func.sgml                        |   2 +-
 doc/src/sgml/ref/reindex.sgml                 |   6 +
 src/backend/catalog/dependency.c              | 188 +++++++++++++++--
 src/backend/catalog/heap.c                    |   7 +-
 src/backend/catalog/index.c                   | 194 +++++++++++++++++-
 src/backend/catalog/pg_constraint.c           |   2 +-
 src/backend/catalog/pg_depend.c               | 132 +++++++++++-
 src/backend/catalog/pg_type.c                 |  69 +++++++
 src/backend/commands/collationcmds.c          |  22 +-
 src/backend/commands/indexcmds.c              |  11 +
 src/backend/commands/vacuum.c                 |  32 +++
 src/backend/optimizer/util/plancat.c          |   9 +
 src/backend/utils/adt/pg_locale.c             |  52 ++++-
 src/backend/utils/cache/relcache.c            |   2 +
 src/include/catalog/dependency.h              |  19 +-
 src/include/catalog/index.h                   |   4 +
 src/include/catalog/pg_type.h                 |   2 +
 src/include/utils/pg_locale.h                 |   2 +-
 src/include/utils/rel.h                       |   1 +
 src/test/Makefile                             |   5 +-
 src/test/locale/.gitignore                    |   1 +
 src/test/locale/Makefile                      |   7 +
 src/test/locale/t/001_index.pl                |  76 +++++++
 .../regress/expected/collate.icu.utf8.out     | 157 ++++++++++++++
 src/test/regress/expected/create_index.out    |   8 +-
 src/test/regress/sql/collate.icu.utf8.sql     | 106 ++++++++++
 26 files changed, 1048 insertions(+), 68 deletions(-)
 create mode 100644 src/test/locale/t/001_index.pl

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index b84502295e..f919561923 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21123,7 +21123,7 @@ postgres=# SELECT * FROM pg_walfile_name_offset(pg_stop_backup());
    <para>
     <function>pg_collation_actual_version</function> returns the actual
     version of the collation object as it is currently installed in the
-    operating system.
+    operating system.  An empty string is returned if the version is unknown.
    </para>
 
    <para>
diff --git a/doc/src/sgml/ref/reindex.sgml b/doc/src/sgml/ref/reindex.sgml
index c54a7c420d..7209a606fa 100644
--- a/doc/src/sgml/ref/reindex.sgml
+++ b/doc/src/sgml/ref/reindex.sgml
@@ -39,6 +39,12 @@ REINDEX [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] { IN
 
    <itemizedlist>
     <listitem>
+     <para>
+      The index depends on the sort order of a collation, and the definition
+      of the collation has changed.  This can cause an index to fail to
+      find a key that is present in the index.  On some systems, collation
+      versions are tracked in order to generate warnings when this happens.
+     </para>
      <para>
       An index has become corrupted, and no longer contains valid
       data. Although in theory this should never happen, in
diff --git a/src/backend/catalog/dependency.c b/src/backend/catalog/dependency.c
index 281f5b7c28..ddcfb7a856 100644
--- a/src/backend/catalog/dependency.c
+++ b/src/backend/catalog/dependency.c
@@ -78,6 +78,7 @@
 #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"
@@ -138,6 +139,9 @@ typedef struct
 {
 	ObjectAddresses *addrs;		/* addresses being accumulated */
 	List	   *rtables;		/* list of rangetables to resolve Vars */
+	bool		track_version;	/* whether caller asked to track dependency
+								 * versions */
+	NodeTag		type;			/* nodetag of the current node */
 } find_expr_references_context;
 
 /*
@@ -438,6 +442,81 @@ performMultipleDeletions(const ObjectAddresses *objects,
 	table_close(depRel, RowExclusiveLock);
 }
 
+/*
+ * Call a function for all objects that depend on 'object'.  If the function
+ * returns a non-NULL pointer to a new version string, update the version.
+ */
+void
+visitDependentObjects(const ObjectAddress *object,
+					  VisitDependentObjectsFun 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	   *cur_version,
+				   *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);
+
+		cur_version = isnull ? NULL : TextDatumGetCString(depversion);
+
+		new_version = callback(&otherObject, cur_version, userdata);
+		if (new_version)
+		{
+			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));
+
+			values[Anum_pg_depend_refobjversion - 1] =
+				CStringGetTextDatum(new_version);
+			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'
  *
@@ -1591,6 +1670,10 @@ recordDependencyOnExpr(const ObjectAddress *depender,
 	find_expr_references_context context;
 
 	context.addrs = new_object_addresses();
+	if (expr)
+		context.type = expr->type;
+	else
+		context.type = T_Invalid;
 
 	/* Set up interpretation for Vars at varlevelsup = 0 */
 	context.rtables = list_make1(rtable);
@@ -1605,8 +1688,8 @@ recordDependencyOnExpr(const ObjectAddress *depender,
 	recordMultipleDependencies(depender,
 							   context.addrs->refs,
 							   context.addrs->numrefs,
-							   NULL,
-							   behavior);
+							   behavior,
+							   false);
 
 	free_object_addresses(context.addrs);
 }
@@ -1633,12 +1716,18 @@ recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 								Node *expr, Oid relId,
 								DependencyType behavior,
 								DependencyType self_behavior,
-								bool reverse_self)
+								bool reverse_self,
+								bool track_version)
 {
 	find_expr_references_context context;
 	RangeTblEntry rte;
 
 	context.addrs = new_object_addresses();
+	context.track_version = track_version;
+	if (expr)
+		context.type = expr->type;
+	else
+		context.type = T_Invalid;
 
 	/* We gin up a rather bogus rangetable list to handle Vars */
 	MemSet(&rte, 0, sizeof(rte));
@@ -1694,8 +1783,8 @@ recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 			recordMultipleDependencies(depender,
 									   self_addrs->refs,
 									   self_addrs->numrefs,
-									   NULL,
-									   self_behavior);
+									   self_behavior,
+									   track_version);
 		else
 		{
 			/* Can't use recordMultipleDependencies, so do it the hard way */
@@ -1716,8 +1805,8 @@ recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 	recordMultipleDependencies(depender,
 							   context.addrs->refs,
 							   context.addrs->numrefs,
-							   NULL,
-							   behavior);
+							   behavior,
+							   track_version);
 
 	free_object_addresses(context.addrs);
 }
@@ -1739,8 +1828,13 @@ static bool
 find_expr_references_walker(Node *node,
 							find_expr_references_context *context)
 {
+	NodeTag		parent_type = context->type;
+
 	if (node == NULL)
 		return false;
+
+	context->type = node->type;
+
 	if (IsA(node, Var))
 	{
 		Var		   *var = (Var *) node;
@@ -1773,6 +1867,49 @@ 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);
+
+			/*
+			 * Record collations from the type itself, or underlying in case
+			 * of complex type.  Note that if the direct parent is a
+			 * CollateExpr node, there's no need to record the type underlying
+			 * collation if any.  A dependency already exists for the owning
+			 * relation, and a change in the collation sort order wouldn't
+			 * cause any harm as the collation isn't used at all in such case.
+			 */
+			if (parent_type != T_CollateExpr)
+			{
+				/* type's collation if valid */
+				if (OidIsValid(var->varcollid))
+				{
+					add_object_address(OCLASS_COLLATION, var->varcollid, 0,
+									   context->addrs);
+				}
+
+				/*
+				 * otherwise, it may be a composite type having underlying
+				 * collations
+				 */
+				else if (var->vartype >= FirstNormalObjectId)
+				{
+					List	   *collations = NIL;
+					ListCell   *lc;
+
+					collations = GetTypeCollations(var->vartype, false);
+
+					foreach(lc, collations)
+					{
+						Oid			coll = lfirst_oid(lc);
+
+						if (OidIsValid(coll) &&
+							(coll != DEFAULT_COLLATION_OID ||
+							 context->track_version)
+							)
+							add_object_address(OCLASS_COLLATION,
+											   lfirst_oid(lc), 0,
+											   context->addrs);
+					}
+				}
+			}
 		}
 
 		/*
@@ -1798,10 +1935,12 @@ 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.
+		 * case where the collation is "default", since we know that's pinned,
+		 * if the caller didn't ask to track dependency versions.
 		 */
 		if (OidIsValid(con->constcollid) &&
-			con->constcollid != DEFAULT_COLLATION_OID)
+			(con->constcollid != DEFAULT_COLLATION_OID ||
+			 context->track_version))
 			add_object_address(OCLASS_COLLATION, con->constcollid, 0,
 							   context->addrs);
 
@@ -1891,7 +2030,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* and its collation, just as for Consts */
 		if (OidIsValid(param->paramcollid) &&
-			param->paramcollid != DEFAULT_COLLATION_OID)
+			(param->paramcollid != DEFAULT_COLLATION_OID ||
+			 context->track_version))
 			add_object_address(OCLASS_COLLATION, param->paramcollid, 0,
 							   context->addrs);
 	}
@@ -1979,7 +2119,8 @@ find_expr_references_walker(Node *node,
 							   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(fselect->resultcollid) &&
-			fselect->resultcollid != DEFAULT_COLLATION_OID)
+			(fselect->resultcollid != DEFAULT_COLLATION_OID ||
+			 context->track_version))
 			add_object_address(OCLASS_COLLATION, fselect->resultcollid, 0,
 							   context->addrs);
 	}
@@ -2010,7 +2151,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(relab->resultcollid) &&
-			relab->resultcollid != DEFAULT_COLLATION_OID)
+			(relab->resultcollid != DEFAULT_COLLATION_OID ||
+			 context->track_version))
 			add_object_address(OCLASS_COLLATION, relab->resultcollid, 0,
 							   context->addrs);
 	}
@@ -2023,7 +2165,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(iocoerce->resultcollid) &&
-			iocoerce->resultcollid != DEFAULT_COLLATION_OID)
+			(iocoerce->resultcollid != DEFAULT_COLLATION_OID ||
+			 context->track_version))
 			add_object_address(OCLASS_COLLATION, iocoerce->resultcollid, 0,
 							   context->addrs);
 	}
@@ -2036,7 +2179,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(acoerce->resultcollid) &&
-			acoerce->resultcollid != DEFAULT_COLLATION_OID)
+			(acoerce->resultcollid != DEFAULT_COLLATION_OID ||
+			 context->track_version))
 			add_object_address(OCLASS_COLLATION, acoerce->resultcollid, 0,
 							   context->addrs);
 		/* fall through to examine arguments */
@@ -2125,7 +2269,8 @@ find_expr_references_walker(Node *node,
 			add_object_address(OCLASS_PROC, wc->endInRangeFunc, 0,
 							   context->addrs);
 		if (OidIsValid(wc->inRangeColl) &&
-			wc->inRangeColl != DEFAULT_COLLATION_OID)
+			(wc->inRangeColl != DEFAULT_COLLATION_OID ||
+			 context->track_version))
 			add_object_address(OCLASS_COLLATION, wc->inRangeColl, 0,
 							   context->addrs);
 		/* fall through to examine substructure */
@@ -2270,7 +2415,9 @@ find_expr_references_walker(Node *node,
 		{
 			Oid			collid = lfirst_oid(ct);
 
-			if (OidIsValid(collid) && collid != DEFAULT_COLLATION_OID)
+			if (OidIsValid(collid) &&
+				(collid != DEFAULT_COLLATION_OID ||
+				 context->track_version))
 				add_object_address(OCLASS_COLLATION, collid, 0,
 								   context->addrs);
 		}
@@ -2292,7 +2439,9 @@ find_expr_references_walker(Node *node,
 		{
 			Oid			collid = lfirst_oid(ct);
 
-			if (OidIsValid(collid) && collid != DEFAULT_COLLATION_OID)
+			if (OidIsValid(collid) &&
+				(collid != DEFAULT_COLLATION_OID ||
+				 context->track_version))
 				add_object_address(OCLASS_COLLATION, collid, 0,
 								   context->addrs);
 		}
@@ -2688,8 +2837,9 @@ 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);
 }
 
 /*
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 9d9e915979..b756af35d0 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -2304,7 +2304,7 @@ StoreAttrDefault(Relation rel, AttrNumber attnum,
 		 */
 		recordDependencyOnSingleRelExpr(&colobject, expr, RelationGetRelid(rel),
 										DEPENDENCY_AUTO,
-										DEPENDENCY_AUTO, false);
+										DEPENDENCY_AUTO, false, false);
 	}
 	else
 	{
@@ -2314,7 +2314,7 @@ StoreAttrDefault(Relation rel, AttrNumber attnum,
 		 */
 		recordDependencyOnSingleRelExpr(&defobject, expr, RelationGetRelid(rel),
 										DEPENDENCY_NORMAL,
-										DEPENDENCY_NORMAL, false);
+										DEPENDENCY_NORMAL, false, false);
 	}
 
 	/*
@@ -3638,7 +3638,8 @@ 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
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 76fd938ce3..11a998d3d4 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -52,6 +52,7 @@
 #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"
@@ -74,6 +75,7 @@
 #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/snapmgr.h"
@@ -117,6 +119,7 @@ static void UpdateIndexRelation(Oid indexoid, Oid heapoid,
 								bool immediate,
 								bool isvalid,
 								bool isready);
+static bool index_depends_stable_coll_order(Oid amoid);
 static void index_update_stats(Relation rel,
 							   bool hasindex,
 							   double reltuples);
@@ -1025,6 +1028,10 @@ index_create(Relation heapRelation,
 	{
 		ObjectAddress myself,
 					referenced;
+		ListCell   *lc;
+		List	   *colls = NIL,
+				   *determ_colls = NIL,
+				   *nondeterm_colls = NIL;
 
 		myself.classId = RelationRelationId;
 		myself.objectId = indexRelationId;
@@ -1115,21 +1122,77 @@ index_create(Relation heapRelation,
 			recordDependencyOn(&myself, &referenced, DEPENDENCY_PARTITION_SEC);
 		}
 
-		/* Store dependency on collations */
-		/* The default collation is pinned, so don't bother recording it */
+		/* First, get all 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))
+				colls = lappend_oid(colls, colloid);
+			else
 			{
-				referenced.classId = CollationRelationId;
-				referenced.objectId = collationObjectId[i];
-				referenced.objectSubId = 0;
+				Form_pg_attribute att = TupleDescAttr(indexTupDesc, i);
 
-				recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
+				Assert(i < indexTupDesc->natts);
+
+				colls = list_concat(colls,
+									GetTypeCollations(att->atttypid, false));
 			}
 		}
 
+		/*
+		 * Then split the dependencies on whether they're deterministic or
+		 * not, removing any duplicates.
+		 */
+		foreach(lc, colls)
+		{
+			Oid			c = lfirst_oid(lc);
+
+			if (!OidIsValid(c))
+				continue;
+
+			if (get_collation_isdeterministic(c))
+				determ_colls = list_append_unique_oid(determ_colls, c);
+			else
+				nondeterm_colls = list_append_unique_oid(nondeterm_colls, c);
+		}
+
+		/*
+		 * For deterministic transaction, only track the version if the AM
+		 * relies on a stable ordering.
+		 */
+		if (determ_colls)
+		{
+			bool		track_version;
+
+			track_version = index_depends_stable_coll_order(indexInfo->ii_Am);
+
+			recordDependencyOnCollations(&myself, determ_colls, track_version);
+
+			/*
+			 * Advance the command counter so that later calls to
+			 * recordMultipleDependencies calls can see the newly-entered
+			 * pg_depend catalog tuples for the index.
+			 */
+			CommandCounterIncrement();
+		}
+
+		/*
+		 * We always record the version for dependency on non-deterministic
+		 * collations.
+		 */
+		if (nondeterm_colls)
+		{
+			recordDependencyOnCollations(&myself, nondeterm_colls, true);
+
+			/*
+			 * Advance the command counter so that later calls to
+			 * recordMultipleDependencies calls can see the newly-entered
+			 * pg_depend catalog tuples for the index.
+			 */
+			CommandCounterIncrement();
+		}
+
 		/* Store dependency on operator classes */
 		for (i = 0; i < indexInfo->ii_NumIndexKeyAttrs; i++)
 		{
@@ -1143,21 +1206,30 @@ index_create(Relation heapRelation,
 		/* Store dependencies on anything mentioned in index expressions */
 		if (indexInfo->ii_Expressions)
 		{
+			/* recordDependencyOnSingleRelExpr get rid of duplicated entries */
 			recordDependencyOnSingleRelExpr(&myself,
 											(Node *) indexInfo->ii_Expressions,
 											heapRelationId,
 											DEPENDENCY_NORMAL,
-											DEPENDENCY_AUTO, false);
+											DEPENDENCY_AUTO, false, true);
+
+			/*
+			 * Advance the command counter so that later
+			 * recordMultipleDependencies calls can see the newly-entered
+			 * pg_depend catalog tuples for the index.
+			 */
+			CommandCounterIncrement();
 		}
 
 		/* Store dependencies on anything mentioned in predicate */
 		if (indexInfo->ii_Predicate)
 		{
+			/* recordDependencyOnSingleRelExpr get rid of duplicated entries */
 			recordDependencyOnSingleRelExpr(&myself,
 											(Node *) indexInfo->ii_Predicate,
 											heapRelationId,
 											DEPENDENCY_NORMAL,
-											DEPENDENCY_AUTO, false);
+											DEPENDENCY_AUTO, false, true);
 		}
 	}
 	else
@@ -1229,6 +1301,94 @@ index_create(Relation heapRelation,
 	return indexRelationId;
 }
 
+static char *
+index_check_collation_version(const ObjectAddress *otherObject,
+							  const char *version,
+							  void *userdata)
+{
+	Oid			relid = *(Oid *) userdata;
+	char	   *current_version;
+
+	/* We only care about dependencies on collations. */
+	if (otherObject->classId != CollationRelationId)
+		return NULL;
+
+	/* Compare with the current version. */
+	current_version = get_collation_version_for_oid(otherObject->objectId);
+
+	/* XXX should we warn about "disappearing" versions? */
+	if (current_version)
+	{
+		/*
+		 * We now support versioning for the underlying collation library on
+		 * this system, or previous version is unknown.
+		 */
+		if (!version || (strcmp(version, "") == 0 && strcmp(current_version,
+															"") != 0))
+		{
+			ereport(WARNING,
+					(errmsg("index \"%s\" depends on collation \"%s\" with an unknown version, and the current version is \"%s\"",
+							get_rel_name(relid),
+							get_collation_name(otherObject->objectId),
+							current_version),
+					 errdetail("The index may be corrupted due to changes in sort order."),
+					 errhint("REINDEX to avoid the risk of corruption.")));
+		}
+		else if (strcmp(current_version, version) != 0)
+		{
+			ereport(WARNING,
+					(errmsg("index \"%s\" depends on collation \"%s\" version \"%s\", but the current version is \"%s\"",
+							get_rel_name(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.")));
+		}
+	}
+
+	return NULL;
+}
+
+void
+index_check_collation_versions(Oid relid)
+{
+	ObjectAddress object;
+
+	object.classId = RelationRelationId;
+	object.objectId = relid;
+	object.objectSubId = 0;
+	visitDependentObjects(&object, &index_check_collation_version, &relid);
+}
+
+static char *
+index_update_collation_version(const ObjectAddress *otherObject,
+							   const char *version,
+							   void *userdata)
+{
+	char	   *current_version = (char *) userdata;
+
+	/* We only care about dependencies on collations. */
+	if (otherObject->classId != CollationRelationId)
+		return NULL;
+
+	current_version = get_collation_version_for_oid(otherObject->objectId);
+	return current_version;
+}
+
+void
+index_update_collation_versions(Oid relid)
+{
+	ObjectAddress object;
+	NameData	current_version;
+
+	object.classId = RelationRelationId;
+	object.objectId = relid;
+	object.objectSubId = 0;
+	visitDependentObjects(&object, &index_update_collation_version,
+						  &current_version);
+}
+
 /*
  * index_concurrently_create_copy
  *
@@ -2635,6 +2795,17 @@ FormIndexDatum(IndexInfo *indexInfo,
 		elog(ERROR, "wrong number of index expressions");
 }
 
+/*
+ * Returns whether the given index access method depend on a stable collation
+ * order.
+ */
+static bool
+index_depends_stable_coll_order(Oid amoid)
+{
+	return (amoid != HASH_AM_OID &&
+			strcmp(get_am_name(amoid), "bloom") != 0);
+}
+
 
 /*
  * index_update_stats --- update pg_class entry after CREATE INDEX or REINDEX
@@ -3623,6 +3794,9 @@ 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);
 }
 
 /*
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index 90932be831..3cc0f6651c 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -360,7 +360,7 @@ CreateConstraintEntry(const char *constraintName,
 		 */
 		recordDependencyOnSingleRelExpr(&conobject, conExpr, relId,
 										DEPENDENCY_NORMAL,
-										DEPENDENCY_NORMAL, false);
+										DEPENDENCY_NORMAL, false, true);
 	}
 
 	/* Post creation hook for new constraint */
diff --git a/src/backend/catalog/pg_depend.c b/src/backend/catalog/pg_depend.c
index 84a0b99311..a17bbe4442 100644
--- 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"
@@ -27,9 +28,12 @@
 #include "utils/builtins.h"
 #include "utils/fmgroids.h"
 #include "utils/lsyscache.h"
+#include "utils/pg_locale.h"
 #include "utils/rel.h"
 
 
+static bool dependencyExists(const ObjectAddress *depender,
+							 const ObjectAddress *referenced);
 static bool isObjectPinned(const ObjectAddress *object, Relation rel);
 
 
@@ -45,19 +49,48 @@ recordDependencyOn(const ObjectAddress *depender,
 				   const ObjectAddress *referenced,
 				   DependencyType behavior)
 {
-	recordMultipleDependencies(depender, referenced, 1, NULL, behavior);
+	recordMultipleDependencies(depender, referenced, 1, behavior, false);
+}
+
+/*
+ * Given a list of collations, record a dependency on its underlying collation
+ * version.
+ */
+void
+recordDependencyOnCollations(ObjectAddress *myself,
+							 List *collations,
+							 bool record_version)
+{
+	ListCell   *lc;
+
+	foreach(lc, collations)
+	{
+		ObjectAddress referenced;
+
+		referenced.classId = CollationRelationId;
+		referenced.objectId = lfirst_oid(lc);
+		referenced.objectSubId = 0;
+
+		recordMultipleDependencies(myself, &referenced, 1,
+								   DEPENDENCY_NORMAL, record_version);
+	}
 }
 
 /*
  * Record multiple dependencies (of the same kind) for a single dependent
  * object.  This has a little less overhead than recording each separately.
+ *
+ * If track_version is true, then a record could be added even if the referenced
+ * dependency 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 track_version)
 {
 	Relation	dependDesc;
 	CatalogIndexState indstate;
@@ -65,6 +98,7 @@ recordMultipleDependencies(const ObjectAddress *depender,
 	int			i;
 	bool		nulls[Natts_pg_depend];
 	Datum		values[Natts_pg_depend];
+	char	   *version = NULL;
 
 	if (nreferenced <= 0)
 		return;					/* nothing to do */
@@ -83,12 +117,49 @@ recordMultipleDependencies(const ObjectAddress *depender,
 
 	for (i = 0; i < nreferenced; i++, referenced++)
 	{
+		bool		ignore_systempin = false;
+
+		if (track_version)
+		{
+			/* Only dependency on a collation is supported. */
+			if (referenced->classId == CollationRelationId)
+			{
+				/* C and POSIX collations don't require tracking the version */
+				if (referenced->objectId == C_COLLATION_OID ||
+					referenced->objectId == POSIX_COLLATION_OID)
+					continue;
+
+				/*
+				 * We don't want to record redundant depedencies that are used
+				 * to track versions to avoid redundant warnings in case of
+				 * non-matching versions when those are checked.  Note that
+				 * callers have to take care of removing duplicated entries
+				 * and calling CommandCounterIncrement() if the dependencies
+				 * are registered in multiple calls.
+				 */
+				if (dependencyExists(depender, referenced))
+					continue;
+
+				/*
+				 * 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;
+				version = get_collation_version_for_oid(referenced->objectId);
+				Assert(version);
+			}
+		}
+		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))
 		{
 			/*
 			 * Record the Dependency.  Note we don't bother to check for
@@ -545,6 +616,55 @@ changeDependenciesOn(Oid refClassId, Oid oldRefObjectId,
 	return count;
 }
 
+/* dependencyExists()
+ *
+ * Test if a record exists for the given depender and referenced addresses.
+ */
+static bool
+dependencyExists(const ObjectAddress *depender,
+				 const ObjectAddress *referenced)
+{
+	Relation	depRel;
+	ScanKeyData key[3];
+	SysScanDesc scan;
+	HeapTuple	tup;
+	bool		ret = false;
+
+	ScanKeyInit(&key[0],
+				Anum_pg_depend_classid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(depender->classId));
+	ScanKeyInit(&key[1],
+				Anum_pg_depend_objid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(depender->objectId));
+	ScanKeyInit(&key[2],
+				Anum_pg_depend_objsubid,
+				BTEqualStrategyNumber, F_INT4EQ,
+				Int32GetDatum(depender->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);
+
+		if (foundDep->refclassid == referenced->classId &&
+			foundDep->refobjid == referenced->objectId &&
+			foundDep->refobjsubid == referenced->objectSubId)
+		{
+			ret = true;
+			break;
+		}
+	}
+	systable_endscan(scan);
+	table_close(depRel, RowExclusiveLock);
+
+	return ret;
+}
+
 /*
  * isObjectPinned()
  *
diff --git a/src/backend/catalog/pg_type.c b/src/backend/catalog/pg_type.c
index cd56714968..2b62e6f47c 100644
--- 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 +513,74 @@ TypeCreate(Oid newTypeOid,
 	return address;
 }
 
+/* Get a list of all distinct collations oid that the given type depends on. */
+List *
+GetTypeCollations(Oid typeoid, bool non_deterministic_only)
+{
+	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))
+	{
+		if (!non_deterministic_only ||
+			!get_collation_isdeterministic(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))
+			{
+				if (!non_deterministic_only ||
+					!get_collation_isdeterministic(att->attcollation))
+					result = list_append_unique_oid(result, att->attcollation);
+			}
+			else
+				result = list_concat_unique_oid(result,
+												GetTypeCollations(att->atttypid,
+																  non_deterministic_only));
+		}
+
+		relation_close(rel, NoLock);
+	}
+	else if (typeTup->typtype == TYPTYPE_DOMAIN)
+	{
+		Assert(OidIsValid(typeTup->typbasetype));
+
+		result = list_concat_unique_oid(result,
+										GetTypeCollations(typeTup->typbasetype,
+														  non_deterministic_only));
+	}
+	else if (typeTup->typtype == TYPTYPE_RANGE)
+	{
+		Oid			rangeid = get_range_subtype(typeTup->oid);
+
+		Assert(OidIsValid(rangeid));
+
+		result = list_concat_unique_oid(result,
+										GetTypeCollations(rangeid, non_deterministic_only));
+	}
+	else if (OidIsValid(typeTup->typelem))
+		result = list_concat_unique_oid(result,
+										GetTypeCollations(typeTup->typelem, non_deterministic_only));
+
+	ReleaseSysCache(tuple);
+
+	return result;
+}
+
 /*
  * GenerateTypeDependencies: build the dependencies needed for a type
  *
diff --git a/src/backend/commands/collationcmds.c b/src/backend/commands/collationcmds.c
index 78eceda848..d4eccf163f 100644
--- a/src/backend/commands/collationcmds.c
+++ b/src/backend/commands/collationcmds.c
@@ -273,28 +273,12 @@ 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);
+	Assert(version);
 
-	if (version)
-		PG_RETURN_TEXT_P(cstring_to_text(version));
-	else
-		PG_RETURN_NULL();
+	PG_RETURN_TEXT_P(cstring_to_text(version));
 }
 
 
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 4e8263af4b..8f42da2444 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -3323,6 +3323,17 @@ ReindexRelationConcurrently(Oid relationOid, int options)
 	/* Start a new transaction to finish process properly */
 	StartTransactionCommand();
 
+	/*
+	 * Record the current versions of all depended-on collations, for all new
+	 * indexes.
+	 */
+	foreach(lc, newIndexIds)
+	{
+		Oid			indOid = lfirst_oid(lc);
+
+		index_update_collation_versions(indOid);
+	}
+
 	/* Log what we did */
 	if (options & REINDEXOPT_VERBOSE)
 	{
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index d625d17bf4..8f92601865 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -31,6 +31,8 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/catalog.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -634,6 +636,36 @@ vacuum_open_relation(Oid relid, RangeVar *relation, int options,
 		rel_lock = false;
 	}
 
+	/*
+	 * Perform version sanity checks on the relation underlying indexes if
+	 * it's not a VACUUM FULL, as VACUUM FULL will recreate the index and
+	 * update the recorded collation version.
+	 */
+	if (!(options & VACOPT_FULL) && onerel && !IsSystemRelation(onerel) &&
+		onerel->rd_rel->relhasindex)
+	{
+		List	   *indexoidlist;
+		ListCell   *l;
+
+		indexoidlist = RelationGetIndexList(onerel);
+		foreach(l, indexoidlist)
+		{
+			Oid			indexoid = lfirst_oid(l);
+			Relation	indexRelation;
+
+			indexRelation = index_open(indexoid, AccessShareLock);
+
+			/* Warn if any dependent collations' versions have moved. */
+			if (!indexRelation->rd_version_checked)
+			{
+				index_check_collation_versions(indexoid);
+				indexRelation->rd_version_checked = true;
+			}
+
+			index_close(indexRelation, NoLock);
+		}
+	}
+
 	/* if relation is opened, leave */
 	if (onerel)
 		return onerel;
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index d82fc5ab8b..28ef63d6ab 100644
--- 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
diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index 60dab33fcb..fc3a41221f 100644
--- 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"
@@ -148,6 +150,9 @@ 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
  *
@@ -1473,7 +1478,7 @@ pg_newlocale_from_collation(Oid collid)
  * NULL (if it doesn't support versions).  It must not return NULL for some
  * collcollate and not NULL for others.
  */
-char *
+static char *
 get_collation_actual_version(char collprovider, const char *collcollate)
 {
 	char	   *collversion = NULL;
@@ -1511,6 +1516,51 @@ get_collation_actual_version(char collprovider, const char *collcollate)
 	return collversion;
 }
 
+/*
+ * Get provider-specific collation version string given a collation OID.
+ *
+ * As this version is used in index dependency tracking, an empty string is
+ * returned when the version is unknown, to distinguish from dependencies where
+ * the version should not be tracked, represented by a NULL version.
+ */
+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);
+
+	if (!version)
+		return "";
+	else
+		return version;
+}
 
 #ifdef USE_ICU
 /*
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index ff70326474..bdf50ffe89 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -41,6 +41,7 @@
 #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/pg_am.h"
@@ -5623,6 +5624,7 @@ 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;
diff --git a/src/include/catalog/dependency.h b/src/include/catalog/dependency.h
index 62e86a19b6..e39e362524 100644
--- a/src/include/catalog/dependency.h
+++ b/src/include/catalog/dependency.h
@@ -156,7 +156,8 @@ extern void recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 											Node *expr, Oid relId,
 											DependencyType behavior,
 											DependencyType self_behavior,
-											bool reverse_self);
+											bool reverse_self,
+											bool track_version);
 
 extern ObjectClass getObjectClass(const ObjectAddress *object);
 
@@ -176,17 +177,29 @@ extern void sort_object_addresses(ObjectAddresses *addrs);
 
 extern void free_object_addresses(ObjectAddresses *addrs);
 
+typedef char *(*VisitDependentObjectsFun) (const ObjectAddress *otherObject,
+										   const char *version,
+										   void *userdata);
+
+extern void visitDependentObjects(const ObjectAddress *object,
+								  VisitDependentObjectsFun callback,
+								  void *userdata);
+
 /* 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 track_version);
 
 extern void recordDependencyOnCurrentExtension(const ObjectAddress *object,
 											   bool isReplace);
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index a2890c1314..0899a203c0 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -121,6 +121,8 @@ extern void FormIndexDatum(IndexInfo *indexInfo,
 						   Datum *values,
 						   bool *isnull);
 
+extern void index_check_collation_versions(Oid relid);
+
 extern void index_build(Relation heapRelation,
 						Relation indexRelation,
 						IndexInfo *indexInfo,
@@ -131,6 +133,8 @@ extern void validate_index(Oid heapId, Oid indexId, Snapshot snapshot);
 
 extern void index_set_state_flags(Oid indexId, IndexStateFlagsAction action);
 
+void index_update_collation_versions(Oid relid);
+
 extern void reindex_index(Oid indexId, bool skip_constraint_checks,
 						  char relpersistence, int options);
 
diff --git a/src/include/catalog/pg_type.h b/src/include/catalog/pg_type.h
index 97890946c5..3eb5ec4fcd 100644
--- a/src/include/catalog/pg_type.h
+++ b/src/include/catalog/pg_type.h
@@ -350,6 +350,8 @@ extern void GenerateTypeDependencies(HeapTuple typeTuple,
 									 bool isDependentType,
 									 bool rebuild);
 
+extern List *GetTypeCollations(Oid typeObjectid, bool non_deterministic_only);
+
 extern void RenameTypeInternal(Oid typeOid, const char *newTypeName,
 							   Oid typeNamespace);
 
diff --git a/src/include/utils/pg_locale.h b/src/include/utils/pg_locale.h
index 9cb7d91ddf..96da132c03 100644
--- 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);
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 44ed04dd3f..82005e9eba 100644
--- 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 being done yet? */
 
 	/*
 	 * rd_createSubid is the ID of the highest subtransaction the rel has
diff --git a/src/test/Makefile b/src/test/Makefile
index efb206aa75..4ef0d11702 100644
--- 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
@@ -37,7 +38,7 @@ endif
 # clean" etc to recurse into them.  (We must filter out those that we
 # have conditionally included into SUBDIRS above, else there will be
 # make confusion.)
-ALWAYS_SUBDIRS = $(filter-out $(SUBDIRS),examples kerberos ldap locale thread ssl)
+ALWAYS_SUBDIRS = $(filter-out $(SUBDIRS),examples kerberos ldap thread ssl)
 
 # We want to recurse to all subdirs for all standard targets, except that
 # installcheck and install should not recurse into the subdirectory "modules".
diff --git a/src/test/locale/.gitignore b/src/test/locale/.gitignore
index 620d3df425..64e1bf2a80 100644
--- a/src/test/locale/.gitignore
+++ b/src/test/locale/.gitignore
@@ -1 +1,2 @@
 /test-ctype
+/tmp_check/
diff --git a/src/test/locale/Makefile b/src/test/locale/Makefile
index 22a45b65f2..73495cf16b 100644
--- 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:
+	$(prove_installcheck)
diff --git a/src/test/locale/t/001_index.pl b/src/test/locale/t/001_index.pl
new file mode 100644
index 0000000000..468fbb63b6
--- /dev/null
+++ b/src/test/locale/t/001_index.pl
@@ -0,0 +1,76 @@
+use strict;
+use warnings;
+
+use Config;
+use PostgresNode;
+use TestLib;
+use Test::More;
+
+if ($ENV{with_icu} eq 'yes')
+{
+	plan tests => 12;
+}
+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;
+
+$ENV{PGHOST} = $node->host;
+$ENV{PGPORT} = $node->port;
+$node->start;
+
+sub test_index
+{
+	my ($err_like, $err_comm) = @_;
+
+	my ($ret, $out, $err) = $node->psql('postgres',
+		'SET enable_seqscan = 0;'
+		. "EXPLAIN SELECT val FROM icu1 WHERE val = '0'");
+
+	is($ret, 0, 'EXPLAIN should succeed.');
+	like($out, qr/icu1_fr/, 'Index icu1_fr should be used.');
+	like($err, $err_like, $err_comm);
+}
+
+$node->safe_psql('postgres',
+	'CREATE TABLE icu1(val text);'
+	. 'INSERT INTO icu1 SELECT i::text FROM generate_series(1, 10000) i;'
+	. 'CREATE INDEX icu1_fr ON icu1 (val COLLATE "fr-x-icu");');
+$node->safe_psql('postgres', 'VACUUM ANALYZE icu1;');
+
+test_index(qr/^$/, 'No warning should be raised');
+
+# Simulate different collation version
+$node->safe_psql('postgres',
+	"UPDATE pg_depend SET refobjversion = 'not_a_version'"
+	. " WHERE refobjversion IS NOT NULL"
+	. " AND objid::regclass::text = 'icu1_fr';");
+
+test_index(qr/index "icu1_fr" depends on collation "fr-x-icu" version "not_a_version", but the current version is/,
+	'Different collation version warning should be raised.');
+
+# Simulate unknown collation version
+$node->safe_psql('postgres',
+	"UPDATE pg_depend SET refobjversion = ''"
+	. " WHERE refobjversion IS NOT NULL"
+	. " AND objid::regclass::text = 'icu1_fr';");
+
+test_index(qr/index "icu1_fr" depends on collation "fr-x-icu" with an unknown version, and the current version is/,
+	'Unknown collation version warning should be raised.');
+
+# Simulate previously unhandled collation versioning
+$node->safe_psql('postgres',
+	"UPDATE pg_depend SET refobjversion = NULL"
+	. " WHERE refobjversion IS NOT NULL"
+	. " AND objid::regclass::text = 'icu1_fr';");
+
+test_index(qr/index "icu1_fr" depends on collation "fr-x-icu" with an unknown version, and the current version is/,
+	'Unknown collation version warning should be raised.');
+
+$node->stop;
diff --git a/src/test/regress/expected/collate.icu.utf8.out b/src/test/regress/expected/collate.icu.utf8.out
index 60d9263a2f..db386c1b09 100644
--- a/src/test/regress/expected/collate.icu.utf8.out
+++ b/src/test/regress/expected/collate.icu.utf8.out
@@ -1897,6 +1897,163 @@ 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,
+    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 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);
+-- for key columns, hash indexes should record dependency on the collation but
+-- not the version
+CREATE INDEX icuidx18_hash_d_es ON collate_test USING hash (d_es);
+CREATE INDEX icuidx19_hash_id_d_es_eq ON collate_test USING hash (id) WHERE (d_es) = 'foo';
+CREATE INDEX icuidx20_hash_id_d_es_lt ON collate_test USING hash (id) WHERE (d_es) < 'foo';
+SELECT objid::regclass, refobjid::regcollation,
+CASE
+WHEN refobjversion IS NULL THEN 'version not tracked'
+ELSE CASE
+    WHEN refobjversion = pg_collation_actual_version(refobjid) THEN 'up to date'
+    ELSE 'out of date'
+    END
+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;
+           objid           |  refobjid  |       version       
+---------------------------+------------+---------------------
+ 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"  | up to date
+ 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"  | up to date
+ 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"  | up to date
+ icuidx11_d_es             | "es-x-icu" | up to date
+ icuidx12_custom           | "default"  | up to date
+ icuidx12_custom           | custom     | up to date
+ icuidx13_custom           | "default"  | up to date
+ icuidx13_custom           | custom     | up to date
+ icuidx14_myrange          | "default"  | up to date
+ 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
+ icuidx18_hash_d_es        | "es-x-icu" | version not tracked
+ icuidx19_hash_id_d_es_eq  | "default"  | up to date
+ icuidx19_hash_id_d_es_eq  | "es-x-icu" | up to date
+ icuidx20_hash_id_d_es_lt  | "default"  | up to date
+ icuidx20_hash_id_d_es_lt  | "es-x-icu" | up to date
+(49 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)
+
 -- cleanup
 RESET search_path;
 SET client_min_messages TO warning;
diff --git a/src/test/regress/expected/create_index.out b/src/test/regress/expected/create_index.out
index ae95bb38a6..94b4daf4d6 100644
--- a/src/test/regress/expected/create_index.out
+++ b/src/test/regress/expected/create_index.out
@@ -2065,15 +2065,17 @@ 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 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
-(9 rows)
+(11 rows)
 
 REINDEX INDEX CONCURRENTLY concur_reindex_ind1;
 REINDEX TABLE CONCURRENTLY concur_reindex_tab;
@@ -2093,15 +2095,17 @@ 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 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
-(9 rows)
+(11 rows)
 
 -- Check that comments are preserved
 CREATE TABLE testcomment (i int);
diff --git a/src/test/regress/sql/collate.icu.utf8.sql b/src/test/regress/sql/collate.icu.utf8.sql
index 35acf91fbf..e93530af55 100644
--- a/src/test/regress/sql/collate.icu.utf8.sql
+++ b/src/test/regress/sql/collate.icu.utf8.sql
@@ -716,6 +716,112 @@ 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,
+    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 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);
+-- for key columns, hash indexes should record dependency on the collation but
+-- not the version
+CREATE INDEX icuidx18_hash_d_es ON collate_test USING hash (d_es);
+CREATE INDEX icuidx19_hash_id_d_es_eq ON collate_test USING hash (id) WHERE (d_es) = 'foo';
+CREATE INDEX icuidx20_hash_id_d_es_lt ON collate_test USING hash (id) WHERE (d_es) < 'foo';
+
+SELECT objid::regclass, refobjid::regcollation,
+CASE
+WHEN refobjversion IS NULL THEN 'version not tracked'
+ELSE CASE
+    WHEN refobjversion = pg_collation_actual_version(refobjid) THEN 'up to date'
+    ELSE 'out of date'
+    END
+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;
+
+-- 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';
 
 -- cleanup
 RESET search_path;
-- 
2.20.1


--FCuugMFkClbJLl1L
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename="v17-0005-Preserve-index-dependencies-on-collation-during-.patch"



^ permalink  raw  reply  [nested|flat] 96+ messages in thread

* [PATCH v14 4/7] Track collation versions for indexes.
@ 2019-05-28 18:16  Thomas Munro <[email protected]>
  0 siblings, 0 replies; 96+ messages in thread

From: Thomas Munro @ 2019-05-28 18:16 UTC (permalink / raw)

Record the current version of dependent collations in pg_depend when creating
or rebuilding an index.  The version is checked against the current version
whenever we call get_relation_info for an index or open the parent table
during non-full VACUUM or ANALYZE.  Warn that the index may be corrupted if
the versions don't match.

A new flag is added in RelationData to specify that the check has already been
done to avoid repetition.

Thanks to Doug Doole, Peter Eisentraut, Christoph Berg, Laurenz Albe,
Michael Paquier, Robert Haas, Tom Lane and others for design discussion.

Author: Thomas Munro and Julien Rouhaud
Reviewed-by: Peter Eisentraut, Laurenz Albe
Discussion: https://postgr.es/m/CAEepm%3D0uEQCpfq_%2BLYFBdArCe4Ot98t1aR4eYiYTe%3DyavQygiQ%40mail.gmail.com
---
 doc/src/sgml/func.sgml                        |   2 +-
 doc/src/sgml/ref/reindex.sgml                 |   6 +
 src/backend/catalog/dependency.c              | 189 +++++++++++++++--
 src/backend/catalog/heap.c                    |   7 +-
 src/backend/catalog/index.c                   | 191 +++++++++++++++++-
 src/backend/catalog/pg_constraint.c           |   2 +-
 src/backend/catalog/pg_depend.c               | 136 +++++++++++--
 src/backend/catalog/pg_type.c                 |  69 +++++++
 src/backend/commands/collationcmds.c          |  22 +-
 src/backend/commands/vacuum.c                 |  31 +++
 src/backend/optimizer/util/plancat.c          |   9 +
 src/backend/utils/adt/pg_locale.c             |  52 ++++-
 src/backend/utils/cache/relcache.c            |   2 +
 src/include/catalog/dependency.h              |  22 +-
 src/include/catalog/index.h                   |   2 +
 src/include/catalog/pg_type.h                 |   2 +
 src/include/utils/pg_locale.h                 |   2 +-
 src/include/utils/rel.h                       |   1 +
 src/test/Makefile                             |   5 +-
 src/test/locale/.gitignore                    |   1 +
 src/test/locale/Makefile                      |   7 +
 src/test/locale/t/001_index.pl                |  76 +++++++
 .../regress/expected/collate.icu.utf8.out     | 130 ++++++++++++
 src/test/regress/expected/create_index.out    |   8 +-
 src/test/regress/sql/collate.icu.utf8.sql     |  83 ++++++++
 25 files changed, 974 insertions(+), 83 deletions(-)
 create mode 100644 src/test/locale/t/001_index.pl

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index b2d991ac7f..8414f2bfd9 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21115,7 +21115,7 @@ postgres=# SELECT * FROM pg_walfile_name_offset(pg_stop_backup());
    <para>
     <function>pg_collation_actual_version</function> returns the actual
     version of the collation object as it is currently installed in the
-    operating system.
+    operating system.  An empty string is returned if the version is unknown.
    </para>
 
    <para>
diff --git a/doc/src/sgml/ref/reindex.sgml b/doc/src/sgml/ref/reindex.sgml
index c54a7c420d..7209a606fa 100644
--- a/doc/src/sgml/ref/reindex.sgml
+++ b/doc/src/sgml/ref/reindex.sgml
@@ -39,6 +39,12 @@ REINDEX [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] { IN
 
    <itemizedlist>
     <listitem>
+     <para>
+      The index depends on the sort order of a collation, and the definition
+      of the collation has changed.  This can cause an index to fail to
+      find a key that is present in the index.  On some systems, collation
+      versions are tracked in order to generate warnings when this happens.
+     </para>
      <para>
       An index has become corrupted, and no longer contains valid
       data. Although in theory this should never happen, in
diff --git a/src/backend/catalog/dependency.c b/src/backend/catalog/dependency.c
index 660033b9c1..c0e36ef4cd 100644
--- a/src/backend/catalog/dependency.c
+++ b/src/backend/catalog/dependency.c
@@ -78,6 +78,7 @@
 #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"
@@ -138,6 +139,9 @@ typedef struct
 {
 	ObjectAddresses *addrs;		/* addresses being accumulated */
 	List	   *rtables;		/* list of rangetables to resolve Vars */
+	bool		track_version;	/* whether caller asked to track dependency
+								 * versions */
+	NodeTag		type;			/* nodetag of the current node */
 } find_expr_references_context;
 
 /*
@@ -438,6 +442,80 @@ performMultipleDeletions(const ObjectAddresses *objects,
 	table_close(depRel, RowExclusiveLock);
 }
 
+/*
+ * Call a function for all objects that depend on 'object'.  If the function
+ * returns a non-NULL pointer to a new version string, update the version.
+ */
+void
+visitDependentObjects(const ObjectAddress *object,
+					  VisitDependentObjectsFun 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 *cur_version, *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);
+
+		cur_version = isnull ? NULL : TextDatumGetCString(depversion);
+
+		new_version = callback(&otherObject, cur_version, userdata);
+		if (new_version)
+		{
+			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));
+
+			values[Anum_pg_depend_refobjversion - 1] =
+				CStringGetTextDatum(new_version);
+			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'
  *
@@ -1591,6 +1669,10 @@ recordDependencyOnExpr(const ObjectAddress *depender,
 	find_expr_references_context context;
 
 	context.addrs = new_object_addresses();
+	if (expr)
+		context.type = expr->type;
+	else
+		context.type = T_Invalid;
 
 	/* Set up interpretation for Vars at varlevelsup = 0 */
 	context.rtables = list_make1(rtable);
@@ -1603,9 +1685,10 @@ recordDependencyOnExpr(const ObjectAddress *depender,
 
 	/* And record 'em */
 	recordMultipleDependencies(depender,
-							   context.addrs->refs, NULL,
+							   context.addrs->refs,
 							   context.addrs->numrefs,
-							   behavior);
+							   behavior,
+							   false);
 
 	free_object_addresses(context.addrs);
 }
@@ -1632,12 +1715,18 @@ recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 								Node *expr, Oid relId,
 								DependencyType behavior,
 								DependencyType self_behavior,
-								bool reverse_self)
+								bool reverse_self,
+								bool track_version)
 {
 	find_expr_references_context context;
 	RangeTblEntry rte;
 
 	context.addrs = new_object_addresses();
+	context.track_version = track_version;
+	if (expr)
+		context.type = expr->type;
+	else
+		context.type = T_Invalid;
 
 	/* We gin up a rather bogus rangetable list to handle Vars */
 	MemSet(&rte, 0, sizeof(rte));
@@ -1691,9 +1780,10 @@ recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 		/* Record the self-dependencies with the appropriate direction */
 		if (!reverse_self)
 			recordMultipleDependencies(depender,
-									   self_addrs->refs, NULL,
+									   self_addrs->refs,
 									   self_addrs->numrefs,
-									   self_behavior);
+									   self_behavior,
+									   track_version);
 		else
 		{
 			/* Can't use recordMultipleDependencies, so do it the hard way */
@@ -1712,9 +1802,10 @@ recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 
 	/* Record the external dependencies */
 	recordMultipleDependencies(depender,
-							   context.addrs->refs, NULL,
+							   context.addrs->refs,
 							   context.addrs->numrefs,
-							   behavior);
+							   behavior,
+							   track_version);
 
 	free_object_addresses(context.addrs);
 }
@@ -1736,8 +1827,13 @@ static bool
 find_expr_references_walker(Node *node,
 							find_expr_references_context *context)
 {
+	NodeTag parent_type = context->type;
+
 	if (node == NULL)
 		return false;
+
+	context->type = node->type;
+
 	if (IsA(node, Var))
 	{
 		Var		   *var = (Var *) node;
@@ -1770,6 +1866,46 @@ 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);
+
+			/* Record collations from the type itself, or underlying in case of
+			 * complex type.  Note that if the direct parent is a CollateExpr
+			 * node, there's no need to record the type underlying collation if
+			 * any.  A dependency already exists for the owning relation, and a
+			 * change in the collation sort order wouldn't cause any harm as
+			 * the collation isn't used at all in such case.
+			 */
+			if (parent_type != T_CollateExpr)
+			{
+				/* type's collation if valid */
+				if (OidIsValid(var->varcollid))
+				{
+					add_object_address(OCLASS_COLLATION, var->varcollid, 0,
+									   context->addrs);
+				}
+				/*
+				 * otherwise, it may be a composite type having underlying
+				 * collations */
+				else if (var->vartype >= FirstNormalObjectId)
+				{
+					List	   *collations = NIL;
+					ListCell   *lc;
+
+					collations = GetTypeCollations(var->vartype, false);
+
+					foreach(lc, collations)
+					{
+						Oid coll = lfirst_oid(lc);
+
+						if (OidIsValid(coll) &&
+							(coll != DEFAULT_COLLATION_OID ||
+							 context->track_version)
+						)
+							add_object_address(OCLASS_COLLATION,
+									lfirst_oid(lc), 0,
+									context->addrs);
+					}
+				}
+			}
 		}
 
 		/*
@@ -1794,11 +1930,13 @@ 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.  However we can save work in the most common case
+		 * where the collation is "default", since we know that's pinned, if
+		 * the caller didn't ask to track dependency versions.
 		 */
 		if (OidIsValid(con->constcollid) &&
-			con->constcollid != DEFAULT_COLLATION_OID)
+				(con->constcollid != DEFAULT_COLLATION_OID ||
+					context->track_version))
 			add_object_address(OCLASS_COLLATION, con->constcollid, 0,
 							   context->addrs);
 
@@ -1888,7 +2026,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* and its collation, just as for Consts */
 		if (OidIsValid(param->paramcollid) &&
-			param->paramcollid != DEFAULT_COLLATION_OID)
+				(param->paramcollid != DEFAULT_COLLATION_OID ||
+					context->track_version))
 			add_object_address(OCLASS_COLLATION, param->paramcollid, 0,
 							   context->addrs);
 	}
@@ -1976,7 +2115,8 @@ find_expr_references_walker(Node *node,
 							   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(fselect->resultcollid) &&
-			fselect->resultcollid != DEFAULT_COLLATION_OID)
+			(fselect->resultcollid != DEFAULT_COLLATION_OID ||
+			 context->track_version))
 			add_object_address(OCLASS_COLLATION, fselect->resultcollid, 0,
 							   context->addrs);
 	}
@@ -2007,7 +2147,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(relab->resultcollid) &&
-			relab->resultcollid != DEFAULT_COLLATION_OID)
+			(relab->resultcollid != DEFAULT_COLLATION_OID ||
+			context->track_version))
 			add_object_address(OCLASS_COLLATION, relab->resultcollid, 0,
 							   context->addrs);
 	}
@@ -2020,7 +2161,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(iocoerce->resultcollid) &&
-			iocoerce->resultcollid != DEFAULT_COLLATION_OID)
+			(iocoerce->resultcollid != DEFAULT_COLLATION_OID ||
+			context->track_version))
 			add_object_address(OCLASS_COLLATION, iocoerce->resultcollid, 0,
 							   context->addrs);
 	}
@@ -2033,7 +2175,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(acoerce->resultcollid) &&
-			acoerce->resultcollid != DEFAULT_COLLATION_OID)
+			(acoerce->resultcollid != DEFAULT_COLLATION_OID ||
+			context->track_version))
 			add_object_address(OCLASS_COLLATION, acoerce->resultcollid, 0,
 							   context->addrs);
 		/* fall through to examine arguments */
@@ -2122,7 +2265,8 @@ find_expr_references_walker(Node *node,
 			add_object_address(OCLASS_PROC, wc->endInRangeFunc, 0,
 							   context->addrs);
 		if (OidIsValid(wc->inRangeColl) &&
-			wc->inRangeColl != DEFAULT_COLLATION_OID)
+			(wc->inRangeColl != DEFAULT_COLLATION_OID ||
+			context->track_version))
 			add_object_address(OCLASS_COLLATION, wc->inRangeColl, 0,
 							   context->addrs);
 		/* fall through to examine substructure */
@@ -2267,7 +2411,9 @@ find_expr_references_walker(Node *node,
 		{
 			Oid			collid = lfirst_oid(ct);
 
-			if (OidIsValid(collid) && collid != DEFAULT_COLLATION_OID)
+			if (OidIsValid(collid) &&
+					(collid != DEFAULT_COLLATION_OID ||
+					 context->track_version))
 				add_object_address(OCLASS_COLLATION, collid, 0,
 								   context->addrs);
 		}
@@ -2289,7 +2435,9 @@ find_expr_references_walker(Node *node,
 		{
 			Oid			collid = lfirst_oid(ct);
 
-			if (OidIsValid(collid) && collid != DEFAULT_COLLATION_OID)
+			if (OidIsValid(collid) &&
+					(collid != DEFAULT_COLLATION_OID ||
+					context->track_version))
 				add_object_address(OCLASS_COLLATION, collid, 0,
 								   context->addrs);
 		}
@@ -2685,8 +2833,9 @@ record_object_address_dependencies(const ObjectAddress *depender,
 {
 	eliminate_duplicate_dependencies(referenced);
 	recordMultipleDependencies(depender,
-							   referenced->refs, NULL, referenced->numrefs,
-							   behavior);
+							   referenced->refs, referenced->numrefs,
+							   behavior,
+							   false);
 }
 
 /*
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 9d9e915979..4546789446 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -2304,7 +2304,7 @@ StoreAttrDefault(Relation rel, AttrNumber attnum,
 		 */
 		recordDependencyOnSingleRelExpr(&colobject, expr, RelationGetRelid(rel),
 										DEPENDENCY_AUTO,
-										DEPENDENCY_AUTO, false);
+										DEPENDENCY_AUTO, false, false);
 	}
 	else
 	{
@@ -2314,7 +2314,7 @@ StoreAttrDefault(Relation rel, AttrNumber attnum,
 		 */
 		recordDependencyOnSingleRelExpr(&defobject, expr, RelationGetRelid(rel),
 										DEPENDENCY_NORMAL,
-										DEPENDENCY_NORMAL, false);
+										DEPENDENCY_NORMAL, false, false);
 	}
 
 	/*
@@ -3638,7 +3638,8 @@ 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
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 76fd938ce3..369b5d43f1 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -52,6 +52,7 @@
 #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"
@@ -74,6 +75,7 @@
 #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/snapmgr.h"
@@ -117,6 +119,7 @@ static void UpdateIndexRelation(Oid indexoid, Oid heapoid,
 								bool immediate,
 								bool isvalid,
 								bool isready);
+static bool index_depends_stable_coll_order(Oid amoid);
 static void index_update_stats(Relation rel,
 							   bool hasindex,
 							   double reltuples);
@@ -1025,6 +1028,10 @@ index_create(Relation heapRelation,
 	{
 		ObjectAddress myself,
 					referenced;
+		ListCell   *lc;
+		List	   *colls = NIL,
+				   *determ_colls = NIL,
+				   *nondeterm_colls = NIL;
 
 		myself.classId = RelationRelationId;
 		myself.objectId = indexRelationId;
@@ -1115,21 +1122,75 @@ index_create(Relation heapRelation,
 			recordDependencyOn(&myself, &referenced, DEPENDENCY_PARTITION_SEC);
 		}
 
-		/* Store dependency on collations */
-		/* The default collation is pinned, so don't bother recording it */
+		/* First, get all 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))
+				colls = lappend_oid(colls, colloid);
+			else
 			{
-				referenced.classId = CollationRelationId;
-				referenced.objectId = collationObjectId[i];
-				referenced.objectSubId = 0;
+				Form_pg_attribute att = TupleDescAttr(indexTupDesc, i);
 
-				recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
+				Assert(i < indexTupDesc->natts);
+
+				colls = list_concat(colls,
+									GetTypeCollations(att->atttypid, false));
 			}
 		}
 
+		/*
+		 * Then split the dependencies on whether they're deterministic or not,
+		 * removing any duplicates.
+		 */
+		foreach(lc, colls)
+		{
+			Oid c = lfirst_oid(lc);
+
+			if (!OidIsValid(c))
+				continue;
+
+			if (get_collation_isdeterministic(c))
+				determ_colls = list_append_unique_oid(determ_colls, c);
+			else
+				nondeterm_colls = list_append_unique_oid(nondeterm_colls, c);
+		}
+
+		/*
+		 * For deterministic transaction, only track the version if the AM
+		 * relies on a stable ordering.
+		 */
+		if (determ_colls)
+		{
+			bool track_version;
+
+			track_version = index_depends_stable_coll_order(indexInfo->ii_Am);
+
+			recordDependencyOnCollations(&myself, determ_colls, track_version);
+			/*
+			 * Advance the command counter so that later calls to
+			 * recordMultipleDependencies calls can see the newly-entered
+			 * pg_depend catalog tuples for the index.
+			 */
+			CommandCounterIncrement();
+		}
+
+		/*
+		 * We always record the version for dependency on non-deterministic
+		 * collations.
+		 */
+		if (nondeterm_colls)
+		{
+			recordDependencyOnCollations(&myself, nondeterm_colls, true);
+			/*
+			 * Advance the command counter so that later calls to
+			 * recordMultipleDependencies calls can see the newly-entered
+			 * pg_depend catalog tuples for the index.
+			 */
+			CommandCounterIncrement();
+		}
+
 		/* Store dependency on operator classes */
 		for (i = 0; i < indexInfo->ii_NumIndexKeyAttrs; i++)
 		{
@@ -1143,21 +1204,29 @@ index_create(Relation heapRelation,
 		/* Store dependencies on anything mentioned in index expressions */
 		if (indexInfo->ii_Expressions)
 		{
+			/* recordDependencyOnSingleRelExpr get rid of duplicate entries */
 			recordDependencyOnSingleRelExpr(&myself,
 											(Node *) indexInfo->ii_Expressions,
 											heapRelationId,
 											DEPENDENCY_NORMAL,
-											DEPENDENCY_AUTO, false);
+											DEPENDENCY_AUTO, false, true);
+			/*
+			 * Advance the command counter so that later
+			 * recordMultipleDependencies calls can see the newly-entered
+			 * pg_depend catalog tuples for the index.
+			 */
+			CommandCounterIncrement();
 		}
 
 		/* Store dependencies on anything mentioned in predicate */
 		if (indexInfo->ii_Predicate)
 		{
+			/* recordDependencyOnSingleRelExpr get rid of duplicate entries */
 			recordDependencyOnSingleRelExpr(&myself,
 											(Node *) indexInfo->ii_Predicate,
 											heapRelationId,
 											DEPENDENCY_NORMAL,
-											DEPENDENCY_AUTO, false);
+											DEPENDENCY_AUTO, false, true);
 		}
 	}
 	else
@@ -1229,6 +1298,94 @@ index_create(Relation heapRelation,
 	return indexRelationId;
 }
 
+static char *
+index_check_collation_version(const ObjectAddress *otherObject,
+							  const char *version,
+							  void *userdata)
+{
+	Oid			relid = *(Oid *) userdata;
+	char	   *current_version;
+
+	/* We only care about dependencies on collations. */
+	if (otherObject->classId != CollationRelationId)
+		return NULL;
+
+	/* Compare with the current version. */
+	current_version = get_collation_version_for_oid(otherObject->objectId);
+
+	/* XXX should we warn about "disappearing" versions? */
+	if (current_version)
+	{
+		/*
+		 * We now support versioning for the underlying collation library on
+		 * this system, or previous version is unknown.
+		 */
+		if (!version || (strcmp(version, "") == 0 && strcmp(current_version,
+						"") != 0))
+		{
+			ereport(WARNING,
+					(errmsg("index \"%s\" depends on collation \"%s\" with an unknown version, and the current version is \"%s\"",
+							get_rel_name(relid),
+							get_collation_name(otherObject->objectId),
+							current_version),
+					 errdetail("The index may be corrupted due to changes in sort order."),
+					 errhint("REINDEX to avoid the risk of corruption.")));
+		}
+		else if (strcmp(current_version, version) != 0)
+		{
+			ereport(WARNING,
+				(errmsg("index \"%s\" depends on collation \"%s\" version \"%s\", but the current version is \"%s\"",
+						get_rel_name(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.")));
+		}
+	}
+
+	return NULL;
+}
+
+void
+index_check_collation_versions(Oid relid)
+{
+	ObjectAddress object;
+
+	object.classId = RelationRelationId;
+	object.objectId = relid;
+	object.objectSubId = 0;
+	visitDependentObjects(&object, &index_check_collation_version, &relid);
+}
+
+static char *
+index_update_collation_version(const ObjectAddress *otherObject,
+							   const char *version,
+							   void *userdata)
+{
+	char   *current_version = (char *) userdata;
+
+	/* We only care about dependencies on collations. */
+	if (otherObject->classId != CollationRelationId)
+		return NULL;
+
+	current_version = get_collation_version_for_oid(otherObject->objectId);
+	return current_version;
+}
+
+static void
+index_update_collation_versions(Oid relid)
+{
+	ObjectAddress object;
+	NameData	current_version;
+
+	object.classId = RelationRelationId;
+	object.objectId = relid;
+	object.objectSubId = 0;
+	visitDependentObjects(&object, &index_update_collation_version,
+						  &current_version);
+}
+
 /*
  * index_concurrently_create_copy
  *
@@ -2635,6 +2792,17 @@ FormIndexDatum(IndexInfo *indexInfo,
 		elog(ERROR, "wrong number of index expressions");
 }
 
+/*
+ * Returns whether the given index access method depend on a stable collation
+ * order.
+ */
+static bool
+index_depends_stable_coll_order(Oid amoid)
+{
+	return (amoid != HASH_AM_OID &&
+			strcmp(get_am_name(amoid), "bloom") != 0);
+}
+
 
 /*
  * index_update_stats --- update pg_class entry after CREATE INDEX or REINDEX
@@ -3623,6 +3791,9 @@ 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);
 }
 
 /*
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index 90932be831..3cc0f6651c 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -360,7 +360,7 @@ CreateConstraintEntry(const char *constraintName,
 		 */
 		recordDependencyOnSingleRelExpr(&conobject, conExpr, relId,
 										DEPENDENCY_NORMAL,
-										DEPENDENCY_NORMAL, false);
+										DEPENDENCY_NORMAL, false, true);
 	}
 
 	/* Post creation hook for new constraint */
diff --git a/src/backend/catalog/pg_depend.c b/src/backend/catalog/pg_depend.c
index 7fdbdf0ae8..7e087fefc4 100644
--- a/src/backend/catalog/pg_depend.c
+++ b/src/backend/catalog/pg_depend.c
@@ -19,16 +19,21 @@
 #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"
 #include "commands/extension.h"
 #include "miscadmin.h"
+#include "utils/builtins.h"
 #include "utils/fmgroids.h"
 #include "utils/lsyscache.h"
+#include "utils/pg_locale.h"
 #include "utils/rel.h"
 
 
+static bool dependencyExists(const ObjectAddress *depender,
+				   const ObjectAddress *referenced);
 static bool isObjectPinned(const ObjectAddress *object, Relation rel);
 
 
@@ -44,34 +49,47 @@ recordDependencyOn(const ObjectAddress *depender,
 				   const ObjectAddress *referenced,
 				   DependencyType behavior)
 {
-	recordMultipleDependencies(depender, referenced, NULL, 1, behavior);
+	recordMultipleDependencies(depender, referenced, 1, behavior, false);
 }
 
 /*
- * As recordDependencyOn(), but also capture a version string so that changes
- * in the referenced object can be detected.  The meaning of the version
- * string depends on the referenced object.  Currently it is used for
- * detecting changes in collation versions.
+ * Given a list of collations, record a dependency on its underlying collation
+ * version.
  */
-void
-recordDependencyOnVersion(const ObjectAddress *depender,
-						  const ObjectAddress *referenced,
-						  const NameData *version,
-						  DependencyType behavior)
+void recordDependencyOnCollations(ObjectAddress *myself,
+								  List *collations,
+								  bool record_version)
 {
-	recordMultipleDependencies(depender, referenced, version, 1, behavior);
+	ListCell   *lc;
+
+	foreach(lc, collations)
+	{
+		ObjectAddress referenced;
+
+		referenced.classId = CollationRelationId;
+		referenced.objectId = lfirst_oid(lc);
+		referenced.objectSubId = 0;
+
+		recordMultipleDependencies(myself, &referenced, 1,
+								  DEPENDENCY_NORMAL, record_version);
+	}
 }
 
 /*
  * Record multiple dependencies (of the same kind) for a single dependent
  * object.  This has a little less overhead than recording each separately.
+ *
+ * If track_version is true, then a record could be added even if the referenced
+ * dependency 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,
-						   const NameData *version,
 						   int nreferenced,
-						   DependencyType behavior)
+						   DependencyType behavior,
+						   bool track_version)
 {
 	Relation	dependDesc;
 	CatalogIndexState indstate;
@@ -79,6 +97,7 @@ recordMultipleDependencies(const ObjectAddress *depender,
 	int			i;
 	bool		nulls[Natts_pg_depend];
 	Datum		values[Natts_pg_depend];
+	char	   *version = NULL;
 
 	if (nreferenced <= 0)
 		return;					/* nothing to do */
@@ -97,12 +116,49 @@ recordMultipleDependencies(const ObjectAddress *depender,
 
 	for (i = 0; i < nreferenced; i++, referenced++)
 	{
+		bool ignore_systempin = false;
+
+		if (track_version)
+		{
+			/* Only dependency on a collation is supported. */
+			if (referenced->classId == CollationRelationId)
+			{
+				/* C and POSIX collations don't require tracking the version */
+				if (referenced->objectId == C_COLLATION_OID ||
+					referenced->objectId == POSIX_COLLATION_OID)
+					continue;
+
+				/*
+				 * We don't want to record redundant depedencies that are used
+				 * to track versions to avoid redundant warnings in case of
+				 * non-matching versions when those are checked.  Note that
+				 * callers have to take care of removing duplicated entries and
+				 * calling CommandCounterIncrement() if the dependencies are
+				 * registered in multiple calls.
+				 */
+				if (dependencyExists(depender, referenced))
+					continue;
+
+				/*
+				 * 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;
+				version = get_collation_version_for_oid(referenced->objectId);
+				Assert(version);
+			}
+		}
+		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))
 		{
 			/*
 			 * Record the Dependency.  Note we don't bother to check for
@@ -559,6 +615,54 @@ changeDependenciesOn(Oid refClassId, Oid oldRefObjectId,
 	return count;
 }
 
+/* dependencyExists()
+ *
+ * Test if a record exists for the given depender and referenceds addresses.
+ */
+static bool dependencyExists(const ObjectAddress *depender,
+				   const ObjectAddress *referenced)
+{
+	Relation	depRel;
+	ScanKeyData key[3];
+	SysScanDesc scan;
+	HeapTuple	tup;
+	bool	ret = false;
+
+	ScanKeyInit(&key[0],
+				Anum_pg_depend_classid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(depender->classId));
+	ScanKeyInit(&key[1],
+				Anum_pg_depend_objid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(depender->objectId));
+	ScanKeyInit(&key[2],
+				Anum_pg_depend_objsubid,
+				BTEqualStrategyNumber, F_INT4EQ,
+				Int32GetDatum(depender->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);
+
+		if (foundDep->refclassid == referenced->classId &&
+			foundDep->refobjid == referenced->objectId &&
+			foundDep->refobjsubid == referenced->objectSubId)
+		{
+			ret = true;
+			break;
+		}
+	}
+	systable_endscan(scan);
+	table_close(depRel, RowExclusiveLock);
+
+	return ret;
+}
+
 /*
  * isObjectPinned()
  *
diff --git a/src/backend/catalog/pg_type.c b/src/backend/catalog/pg_type.c
index cd56714968..fe14b6bd38 100644
--- 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 +513,74 @@ TypeCreate(Oid newTypeOid,
 	return address;
 }
 
+/* Get a list of all distinct collations oid that the given type depends on. */
+List *
+GetTypeCollations(Oid typeoid, bool non_deterministic_only)
+{
+	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))
+	{
+		if (!non_deterministic_only ||
+				!get_collation_isdeterministic(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))
+			{
+				if (!non_deterministic_only ||
+						!get_collation_isdeterministic(att->attcollation))
+					result = list_append_unique_oid(result, att->attcollation);
+			}
+			else
+				result = list_concat_unique_oid(result,
+						GetTypeCollations(att->atttypid,
+							non_deterministic_only));
+		}
+
+		relation_close(rel, NoLock);
+	}
+	else if (typeTup->typtype == TYPTYPE_DOMAIN)
+	{
+		Assert(OidIsValid(typeTup->typbasetype));
+
+		result = list_concat_unique_oid(result,
+				GetTypeCollations(typeTup->typbasetype,
+					non_deterministic_only));
+	}
+	else if (typeTup->typtype == TYPTYPE_RANGE)
+	{
+		Oid rangeid = get_range_subtype(typeTup->oid);
+
+		Assert(OidIsValid(rangeid));
+
+		result = list_concat_unique_oid(result,
+				GetTypeCollations(rangeid, non_deterministic_only));
+	}
+	else if (OidIsValid(typeTup->typelem))
+		result = list_concat_unique_oid(result,
+				GetTypeCollations(typeTup->typelem, non_deterministic_only));
+
+	ReleaseSysCache(tuple);
+
+	return result;
+}
+
 /*
  * GenerateTypeDependencies: build the dependencies needed for a type
  *
diff --git a/src/backend/commands/collationcmds.c b/src/backend/commands/collationcmds.c
index 78eceda848..d4eccf163f 100644
--- a/src/backend/commands/collationcmds.c
+++ b/src/backend/commands/collationcmds.c
@@ -273,28 +273,12 @@ 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);
+	Assert(version);
 
-	if (version)
-		PG_RETURN_TEXT_P(cstring_to_text(version));
-	else
-		PG_RETURN_NULL();
+	PG_RETURN_TEXT_P(cstring_to_text(version));
 }
 
 
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index d625d17bf4..2b7de111cd 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -31,6 +31,8 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/catalog.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -634,6 +636,35 @@ vacuum_open_relation(Oid relid, RangeVar *relation, int options,
 		rel_lock = false;
 	}
 
+	/*
+	 * Perform version sanity checks on the relation underlying indexes if
+	 * it's not a VACUUM FULL
+	 */
+	if (!(options & VACOPT_FULL) && onerel && !IsSystemRelation(onerel) &&
+			onerel->rd_rel->relhasindex)
+	{
+		List	   *indexoidlist;
+		ListCell   *l;
+
+		indexoidlist = RelationGetIndexList(onerel);
+		foreach(l, indexoidlist)
+		{
+			Oid			indexoid = lfirst_oid(l);
+			Relation	indexRelation;
+
+			indexRelation = index_open(indexoid, AccessShareLock);
+
+			/* Warn if any dependent collations' versions have moved. */
+			if (!indexRelation->rd_version_checked)
+			{
+				index_check_collation_versions(indexoid);
+				indexRelation->rd_version_checked = true;
+			}
+
+			index_close(indexRelation, NoLock);
+		}
+	}
+
 	/* if relation is opened, leave */
 	if (onerel)
 		return onerel;
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index d82fc5ab8b..f2fc427fc8 100644
--- 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
diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index 60dab33fcb..18a2d72f91 100644
--- 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"
@@ -148,6 +150,9 @@ 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
  *
@@ -1473,7 +1478,7 @@ pg_newlocale_from_collation(Oid collid)
  * NULL (if it doesn't support versions).  It must not return NULL for some
  * collcollate and not NULL for others.
  */
-char *
+static char *
 get_collation_actual_version(char collprovider, const char *collcollate)
 {
 	char	   *collversion = NULL;
@@ -1511,6 +1516,51 @@ get_collation_actual_version(char collprovider, const char *collcollate)
 	return collversion;
 }
 
+/*
+ * Get provider-specific collation version string given a collation OID.
+ *
+ * As this version is used in index dependency tracking, an empty string is
+ * returned when the version is unknown, to distinguish from dependencies where
+ * the version should not be tracked, represented by a NULL version.
+ */
+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);
+
+	if (!version)
+		return "";
+	else
+		return version;
+}
 
 #ifdef USE_ICU
 /*
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index ff70326474..bdf50ffe89 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -41,6 +41,7 @@
 #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/pg_am.h"
@@ -5623,6 +5624,7 @@ 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;
diff --git a/src/include/catalog/dependency.h b/src/include/catalog/dependency.h
index 77cf0612ed..8750bfc36f 100644
--- a/src/include/catalog/dependency.h
+++ b/src/include/catalog/dependency.h
@@ -156,7 +156,8 @@ extern void recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 											Node *expr, Oid relId,
 											DependencyType behavior,
 											DependencyType self_behavior,
-											bool reverse_self);
+											bool reverse_self,
+											bool track_version);
 
 extern ObjectClass getObjectClass(const ObjectAddress *object);
 
@@ -176,22 +177,29 @@ extern void sort_object_addresses(ObjectAddresses *addrs);
 
 extern void free_object_addresses(ObjectAddresses *addrs);
 
+typedef char *(*VisitDependentObjectsFun) (const ObjectAddress *otherObject,
+											   const char *version,
+											   void *userdata);
+
+extern void visitDependentObjects(const ObjectAddress *object,
+								  VisitDependentObjectsFun callback,
+								  void *userdata);
+
 /* in pg_depend.c */
 
 extern void recordDependencyOn(const ObjectAddress *depender,
 							   const ObjectAddress *referenced,
 							   DependencyType behavior);
 
-extern void recordDependencyOnVersion(const ObjectAddress *depender,
-									  const ObjectAddress *referenced,
-									  const NameData *version,
-									  DependencyType behavior);
+extern void recordDependencyOnCollations(ObjectAddress *myself,
+										 List *collations,
+										 bool record_version);
 
 extern void recordMultipleDependencies(const ObjectAddress *depender,
 									   const ObjectAddress *referenced,
-									   const NameData *version,
 									   int nreferenced,
-									   DependencyType behavior);
+									   DependencyType behavior,
+									   bool track_version);
 
 extern void recordDependencyOnCurrentExtension(const ObjectAddress *object,
 											   bool isReplace);
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index a2890c1314..c619d02465 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -121,6 +121,8 @@ extern void FormIndexDatum(IndexInfo *indexInfo,
 						   Datum *values,
 						   bool *isnull);
 
+extern void index_check_collation_versions(Oid relid);
+
 extern void index_build(Relation heapRelation,
 						Relation indexRelation,
 						IndexInfo *indexInfo,
diff --git a/src/include/catalog/pg_type.h b/src/include/catalog/pg_type.h
index 97890946c5..3eb5ec4fcd 100644
--- a/src/include/catalog/pg_type.h
+++ b/src/include/catalog/pg_type.h
@@ -350,6 +350,8 @@ extern void GenerateTypeDependencies(HeapTuple typeTuple,
 									 bool isDependentType,
 									 bool rebuild);
 
+extern List *GetTypeCollations(Oid typeObjectid, bool non_deterministic_only);
+
 extern void RenameTypeInternal(Oid typeOid, const char *newTypeName,
 							   Oid typeNamespace);
 
diff --git a/src/include/utils/pg_locale.h b/src/include/utils/pg_locale.h
index 9cb7d91ddf..96da132c03 100644
--- 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);
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 44ed04dd3f..3656ea94e8 100644
--- 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 being done yet? */
 
 	/*
 	 * rd_createSubid is the ID of the highest subtransaction the rel has
diff --git a/src/test/Makefile b/src/test/Makefile
index efb206aa75..4ef0d11702 100644
--- 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
@@ -37,7 +38,7 @@ endif
 # clean" etc to recurse into them.  (We must filter out those that we
 # have conditionally included into SUBDIRS above, else there will be
 # make confusion.)
-ALWAYS_SUBDIRS = $(filter-out $(SUBDIRS),examples kerberos ldap locale thread ssl)
+ALWAYS_SUBDIRS = $(filter-out $(SUBDIRS),examples kerberos ldap thread ssl)
 
 # We want to recurse to all subdirs for all standard targets, except that
 # installcheck and install should not recurse into the subdirectory "modules".
diff --git a/src/test/locale/.gitignore b/src/test/locale/.gitignore
index 620d3df425..64e1bf2a80 100644
--- a/src/test/locale/.gitignore
+++ b/src/test/locale/.gitignore
@@ -1 +1,2 @@
 /test-ctype
+/tmp_check/
diff --git a/src/test/locale/Makefile b/src/test/locale/Makefile
index 22a45b65f2..73495cf16b 100644
--- 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:
+	$(prove_installcheck)
diff --git a/src/test/locale/t/001_index.pl b/src/test/locale/t/001_index.pl
new file mode 100644
index 0000000000..468fbb63b6
--- /dev/null
+++ b/src/test/locale/t/001_index.pl
@@ -0,0 +1,76 @@
+use strict;
+use warnings;
+
+use Config;
+use PostgresNode;
+use TestLib;
+use Test::More;
+
+if ($ENV{with_icu} eq 'yes')
+{
+	plan tests => 12;
+}
+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;
+
+$ENV{PGHOST} = $node->host;
+$ENV{PGPORT} = $node->port;
+$node->start;
+
+sub test_index
+{
+	my ($err_like, $err_comm) = @_;
+
+	my ($ret, $out, $err) = $node->psql('postgres',
+		'SET enable_seqscan = 0;'
+		. "EXPLAIN SELECT val FROM icu1 WHERE val = '0'");
+
+	is($ret, 0, 'EXPLAIN should succeed.');
+	like($out, qr/icu1_fr/, 'Index icu1_fr should be used.');
+	like($err, $err_like, $err_comm);
+}
+
+$node->safe_psql('postgres',
+	'CREATE TABLE icu1(val text);'
+	. 'INSERT INTO icu1 SELECT i::text FROM generate_series(1, 10000) i;'
+	. 'CREATE INDEX icu1_fr ON icu1 (val COLLATE "fr-x-icu");');
+$node->safe_psql('postgres', 'VACUUM ANALYZE icu1;');
+
+test_index(qr/^$/, 'No warning should be raised');
+
+# Simulate different collation version
+$node->safe_psql('postgres',
+	"UPDATE pg_depend SET refobjversion = 'not_a_version'"
+	. " WHERE refobjversion IS NOT NULL"
+	. " AND objid::regclass::text = 'icu1_fr';");
+
+test_index(qr/index "icu1_fr" depends on collation "fr-x-icu" version "not_a_version", but the current version is/,
+	'Different collation version warning should be raised.');
+
+# Simulate unknown collation version
+$node->safe_psql('postgres',
+	"UPDATE pg_depend SET refobjversion = ''"
+	. " WHERE refobjversion IS NOT NULL"
+	. " AND objid::regclass::text = 'icu1_fr';");
+
+test_index(qr/index "icu1_fr" depends on collation "fr-x-icu" with an unknown version, and the current version is/,
+	'Unknown collation version warning should be raised.');
+
+# Simulate previously unhandled collation versioning
+$node->safe_psql('postgres',
+	"UPDATE pg_depend SET refobjversion = NULL"
+	. " WHERE refobjversion IS NOT NULL"
+	. " AND objid::regclass::text = 'icu1_fr';");
+
+test_index(qr/index "icu1_fr" depends on collation "fr-x-icu" with an unknown version, and the current version is/,
+	'Unknown collation version warning should be raised.');
+
+$node->stop;
diff --git a/src/test/regress/expected/collate.icu.utf8.out b/src/test/regress/expected/collate.icu.utf8.out
index 60d9263a2f..09512c0f66 100644
--- a/src/test/regress/expected/collate.icu.utf8.out
+++ b/src/test/regress/expected/collate.icu.utf8.out
@@ -1897,6 +1897,136 @@ 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,
+    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 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);
+-- for key columns, hash indexes should record dependency on the collation but
+-- not the version
+CREATE INDEX icuidx18_hash_d_es ON collate_test USING hash (d_es);
+CREATE INDEX icuidx19_hash_id_d_es_eq ON collate_test USING hash (id) WHERE (d_es) = 'foo';
+CREATE INDEX icuidx20_hash_id_d_es_lt ON collate_test USING hash (id) WHERE (d_es) < 'foo';
+SELECT objid::regclass, refobjid::regcollation,
+CASE
+WHEN refobjversion IS NULL THEN 'version not tracked'
+ELSE CASE
+    WHEN refobjversion = pg_collation_actual_version(refobjid) THEN 'up to date'
+    ELSE 'out of date'
+    END
+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;
+           objid           |  refobjid  |       version       
+---------------------------+------------+---------------------
+ 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"  | up to date
+ 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"  | up to date
+ 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"  | up to date
+ icuidx11_d_es             | "es-x-icu" | up to date
+ icuidx12_custom           | "default"  | up to date
+ icuidx12_custom           | custom     | up to date
+ icuidx13_custom           | "default"  | up to date
+ icuidx13_custom           | custom     | up to date
+ icuidx14_myrange          | "default"  | up to date
+ 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
+ icuidx18_hash_d_es        | "es-x-icu" | version not tracked
+ icuidx19_hash_id_d_es_eq  | "default"  | up to date
+ icuidx19_hash_id_d_es_eq  | "es-x-icu" | up to date
+ icuidx20_hash_id_d_es_lt  | "default"  | up to date
+ icuidx20_hash_id_d_es_lt  | "es-x-icu" | up to date
+(49 rows)
+
+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)
+
 -- cleanup
 RESET search_path;
 SET client_min_messages TO warning;
diff --git a/src/test/regress/expected/create_index.out b/src/test/regress/expected/create_index.out
index ae95bb38a6..94b4daf4d6 100644
--- a/src/test/regress/expected/create_index.out
+++ b/src/test/regress/expected/create_index.out
@@ -2065,15 +2065,17 @@ 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 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
-(9 rows)
+(11 rows)
 
 REINDEX INDEX CONCURRENTLY concur_reindex_ind1;
 REINDEX TABLE CONCURRENTLY concur_reindex_tab;
@@ -2093,15 +2095,17 @@ 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 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
-(9 rows)
+(11 rows)
 
 -- Check that comments are preserved
 CREATE TABLE testcomment (i int);
diff --git a/src/test/regress/sql/collate.icu.utf8.sql b/src/test/regress/sql/collate.icu.utf8.sql
index 35acf91fbf..c8f1a620d2 100644
--- a/src/test/regress/sql/collate.icu.utf8.sql
+++ b/src/test/regress/sql/collate.icu.utf8.sql
@@ -716,6 +716,89 @@ 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,
+    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 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);
+-- for key columns, hash indexes should record dependency on the collation but
+-- not the version
+CREATE INDEX icuidx18_hash_d_es ON collate_test USING hash (d_es);
+CREATE INDEX icuidx19_hash_id_d_es_eq ON collate_test USING hash (id) WHERE (d_es) = 'foo';
+CREATE INDEX icuidx20_hash_id_d_es_lt ON collate_test USING hash (id) WHERE (d_es) < 'foo';
+
+SELECT objid::regclass, refobjid::regcollation,
+CASE
+WHEN refobjversion IS NULL THEN 'version not tracked'
+ELSE CASE
+    WHEN refobjversion = pg_collation_actual_version(refobjid) THEN 'up to date'
+    ELSE 'out of date'
+    END
+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;
+
+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';
 
 -- cleanup
 RESET search_path;
-- 
2.20.1


--wRRV7LY7NUeQGEoC
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename="v14-0005-Preserve-index-dependencies-on-collation-during-.patch"



^ permalink  raw  reply  [nested|flat] 96+ messages in thread

* [PATCH v15 4/7] Track collation versions for indexes.
@ 2019-05-28 18:16  Thomas Munro <[email protected]>
  0 siblings, 0 replies; 96+ messages in thread

From: Thomas Munro @ 2019-05-28 18:16 UTC (permalink / raw)

Record the current version of dependent collations in pg_depend when creating
or rebuilding an index.  The version is checked against the current version
whenever we call get_relation_info for an index or open the parent table
during non-full VACUUM or ANALYZE.  Warn that the index may be corrupted if
the versions don't match.

A new flag is added in RelationData to specify that the check has already been
done to avoid repetition.

Thanks to Doug Doole, Peter Eisentraut, Christoph Berg, Laurenz Albe,
Michael Paquier, Robert Haas, Tom Lane and others for design discussion.

Author: Thomas Munro and Julien Rouhaud
Reviewed-by: Peter Eisentraut, Laurenz Albe
Discussion: https://postgr.es/m/CAEepm%3D0uEQCpfq_%2BLYFBdArCe4Ot98t1aR4eYiYTe%3DyavQygiQ%40mail.gmail.com
---
 doc/src/sgml/func.sgml                        |   2 +-
 doc/src/sgml/ref/reindex.sgml                 |   6 +
 src/backend/catalog/dependency.c              | 189 +++++++++++++++--
 src/backend/catalog/heap.c                    |   7 +-
 src/backend/catalog/index.c                   | 191 +++++++++++++++++-
 src/backend/catalog/pg_constraint.c           |   2 +-
 src/backend/catalog/pg_depend.c               | 136 +++++++++++--
 src/backend/catalog/pg_type.c                 |  69 +++++++
 src/backend/commands/collationcmds.c          |  22 +-
 src/backend/commands/vacuum.c                 |  31 +++
 src/backend/optimizer/util/plancat.c          |   9 +
 src/backend/utils/adt/pg_locale.c             |  52 ++++-
 src/backend/utils/cache/relcache.c            |   2 +
 src/include/catalog/dependency.h              |  22 +-
 src/include/catalog/index.h                   |   2 +
 src/include/catalog/pg_type.h                 |   2 +
 src/include/utils/pg_locale.h                 |   2 +-
 src/include/utils/rel.h                       |   1 +
 src/test/Makefile                             |   5 +-
 src/test/locale/.gitignore                    |   1 +
 src/test/locale/Makefile                      |   7 +
 src/test/locale/t/001_index.pl                |  76 +++++++
 .../regress/expected/collate.icu.utf8.out     | 130 ++++++++++++
 src/test/regress/expected/create_index.out    |   8 +-
 src/test/regress/sql/collate.icu.utf8.sql     |  83 ++++++++
 25 files changed, 974 insertions(+), 83 deletions(-)
 create mode 100644 src/test/locale/t/001_index.pl

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index b2d991ac7f..8414f2bfd9 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21115,7 +21115,7 @@ postgres=# SELECT * FROM pg_walfile_name_offset(pg_stop_backup());
    <para>
     <function>pg_collation_actual_version</function> returns the actual
     version of the collation object as it is currently installed in the
-    operating system.
+    operating system.  An empty string is returned if the version is unknown.
    </para>
 
    <para>
diff --git a/doc/src/sgml/ref/reindex.sgml b/doc/src/sgml/ref/reindex.sgml
index c54a7c420d..7209a606fa 100644
--- a/doc/src/sgml/ref/reindex.sgml
+++ b/doc/src/sgml/ref/reindex.sgml
@@ -39,6 +39,12 @@ REINDEX [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] { IN
 
    <itemizedlist>
     <listitem>
+     <para>
+      The index depends on the sort order of a collation, and the definition
+      of the collation has changed.  This can cause an index to fail to
+      find a key that is present in the index.  On some systems, collation
+      versions are tracked in order to generate warnings when this happens.
+     </para>
      <para>
       An index has become corrupted, and no longer contains valid
       data. Although in theory this should never happen, in
diff --git a/src/backend/catalog/dependency.c b/src/backend/catalog/dependency.c
index 660033b9c1..c0e36ef4cd 100644
--- a/src/backend/catalog/dependency.c
+++ b/src/backend/catalog/dependency.c
@@ -78,6 +78,7 @@
 #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"
@@ -138,6 +139,9 @@ typedef struct
 {
 	ObjectAddresses *addrs;		/* addresses being accumulated */
 	List	   *rtables;		/* list of rangetables to resolve Vars */
+	bool		track_version;	/* whether caller asked to track dependency
+								 * versions */
+	NodeTag		type;			/* nodetag of the current node */
 } find_expr_references_context;
 
 /*
@@ -438,6 +442,80 @@ performMultipleDeletions(const ObjectAddresses *objects,
 	table_close(depRel, RowExclusiveLock);
 }
 
+/*
+ * Call a function for all objects that depend on 'object'.  If the function
+ * returns a non-NULL pointer to a new version string, update the version.
+ */
+void
+visitDependentObjects(const ObjectAddress *object,
+					  VisitDependentObjectsFun 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 *cur_version, *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);
+
+		cur_version = isnull ? NULL : TextDatumGetCString(depversion);
+
+		new_version = callback(&otherObject, cur_version, userdata);
+		if (new_version)
+		{
+			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));
+
+			values[Anum_pg_depend_refobjversion - 1] =
+				CStringGetTextDatum(new_version);
+			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'
  *
@@ -1591,6 +1669,10 @@ recordDependencyOnExpr(const ObjectAddress *depender,
 	find_expr_references_context context;
 
 	context.addrs = new_object_addresses();
+	if (expr)
+		context.type = expr->type;
+	else
+		context.type = T_Invalid;
 
 	/* Set up interpretation for Vars at varlevelsup = 0 */
 	context.rtables = list_make1(rtable);
@@ -1603,9 +1685,10 @@ recordDependencyOnExpr(const ObjectAddress *depender,
 
 	/* And record 'em */
 	recordMultipleDependencies(depender,
-							   context.addrs->refs, NULL,
+							   context.addrs->refs,
 							   context.addrs->numrefs,
-							   behavior);
+							   behavior,
+							   false);
 
 	free_object_addresses(context.addrs);
 }
@@ -1632,12 +1715,18 @@ recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 								Node *expr, Oid relId,
 								DependencyType behavior,
 								DependencyType self_behavior,
-								bool reverse_self)
+								bool reverse_self,
+								bool track_version)
 {
 	find_expr_references_context context;
 	RangeTblEntry rte;
 
 	context.addrs = new_object_addresses();
+	context.track_version = track_version;
+	if (expr)
+		context.type = expr->type;
+	else
+		context.type = T_Invalid;
 
 	/* We gin up a rather bogus rangetable list to handle Vars */
 	MemSet(&rte, 0, sizeof(rte));
@@ -1691,9 +1780,10 @@ recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 		/* Record the self-dependencies with the appropriate direction */
 		if (!reverse_self)
 			recordMultipleDependencies(depender,
-									   self_addrs->refs, NULL,
+									   self_addrs->refs,
 									   self_addrs->numrefs,
-									   self_behavior);
+									   self_behavior,
+									   track_version);
 		else
 		{
 			/* Can't use recordMultipleDependencies, so do it the hard way */
@@ -1712,9 +1802,10 @@ recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 
 	/* Record the external dependencies */
 	recordMultipleDependencies(depender,
-							   context.addrs->refs, NULL,
+							   context.addrs->refs,
 							   context.addrs->numrefs,
-							   behavior);
+							   behavior,
+							   track_version);
 
 	free_object_addresses(context.addrs);
 }
@@ -1736,8 +1827,13 @@ static bool
 find_expr_references_walker(Node *node,
 							find_expr_references_context *context)
 {
+	NodeTag parent_type = context->type;
+
 	if (node == NULL)
 		return false;
+
+	context->type = node->type;
+
 	if (IsA(node, Var))
 	{
 		Var		   *var = (Var *) node;
@@ -1770,6 +1866,46 @@ 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);
+
+			/* Record collations from the type itself, or underlying in case of
+			 * complex type.  Note that if the direct parent is a CollateExpr
+			 * node, there's no need to record the type underlying collation if
+			 * any.  A dependency already exists for the owning relation, and a
+			 * change in the collation sort order wouldn't cause any harm as
+			 * the collation isn't used at all in such case.
+			 */
+			if (parent_type != T_CollateExpr)
+			{
+				/* type's collation if valid */
+				if (OidIsValid(var->varcollid))
+				{
+					add_object_address(OCLASS_COLLATION, var->varcollid, 0,
+									   context->addrs);
+				}
+				/*
+				 * otherwise, it may be a composite type having underlying
+				 * collations */
+				else if (var->vartype >= FirstNormalObjectId)
+				{
+					List	   *collations = NIL;
+					ListCell   *lc;
+
+					collations = GetTypeCollations(var->vartype, false);
+
+					foreach(lc, collations)
+					{
+						Oid coll = lfirst_oid(lc);
+
+						if (OidIsValid(coll) &&
+							(coll != DEFAULT_COLLATION_OID ||
+							 context->track_version)
+						)
+							add_object_address(OCLASS_COLLATION,
+									lfirst_oid(lc), 0,
+									context->addrs);
+					}
+				}
+			}
 		}
 
 		/*
@@ -1794,11 +1930,13 @@ 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.  However we can save work in the most common case
+		 * where the collation is "default", since we know that's pinned, if
+		 * the caller didn't ask to track dependency versions.
 		 */
 		if (OidIsValid(con->constcollid) &&
-			con->constcollid != DEFAULT_COLLATION_OID)
+				(con->constcollid != DEFAULT_COLLATION_OID ||
+					context->track_version))
 			add_object_address(OCLASS_COLLATION, con->constcollid, 0,
 							   context->addrs);
 
@@ -1888,7 +2026,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* and its collation, just as for Consts */
 		if (OidIsValid(param->paramcollid) &&
-			param->paramcollid != DEFAULT_COLLATION_OID)
+				(param->paramcollid != DEFAULT_COLLATION_OID ||
+					context->track_version))
 			add_object_address(OCLASS_COLLATION, param->paramcollid, 0,
 							   context->addrs);
 	}
@@ -1976,7 +2115,8 @@ find_expr_references_walker(Node *node,
 							   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(fselect->resultcollid) &&
-			fselect->resultcollid != DEFAULT_COLLATION_OID)
+			(fselect->resultcollid != DEFAULT_COLLATION_OID ||
+			 context->track_version))
 			add_object_address(OCLASS_COLLATION, fselect->resultcollid, 0,
 							   context->addrs);
 	}
@@ -2007,7 +2147,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(relab->resultcollid) &&
-			relab->resultcollid != DEFAULT_COLLATION_OID)
+			(relab->resultcollid != DEFAULT_COLLATION_OID ||
+			context->track_version))
 			add_object_address(OCLASS_COLLATION, relab->resultcollid, 0,
 							   context->addrs);
 	}
@@ -2020,7 +2161,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(iocoerce->resultcollid) &&
-			iocoerce->resultcollid != DEFAULT_COLLATION_OID)
+			(iocoerce->resultcollid != DEFAULT_COLLATION_OID ||
+			context->track_version))
 			add_object_address(OCLASS_COLLATION, iocoerce->resultcollid, 0,
 							   context->addrs);
 	}
@@ -2033,7 +2175,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(acoerce->resultcollid) &&
-			acoerce->resultcollid != DEFAULT_COLLATION_OID)
+			(acoerce->resultcollid != DEFAULT_COLLATION_OID ||
+			context->track_version))
 			add_object_address(OCLASS_COLLATION, acoerce->resultcollid, 0,
 							   context->addrs);
 		/* fall through to examine arguments */
@@ -2122,7 +2265,8 @@ find_expr_references_walker(Node *node,
 			add_object_address(OCLASS_PROC, wc->endInRangeFunc, 0,
 							   context->addrs);
 		if (OidIsValid(wc->inRangeColl) &&
-			wc->inRangeColl != DEFAULT_COLLATION_OID)
+			(wc->inRangeColl != DEFAULT_COLLATION_OID ||
+			context->track_version))
 			add_object_address(OCLASS_COLLATION, wc->inRangeColl, 0,
 							   context->addrs);
 		/* fall through to examine substructure */
@@ -2267,7 +2411,9 @@ find_expr_references_walker(Node *node,
 		{
 			Oid			collid = lfirst_oid(ct);
 
-			if (OidIsValid(collid) && collid != DEFAULT_COLLATION_OID)
+			if (OidIsValid(collid) &&
+					(collid != DEFAULT_COLLATION_OID ||
+					 context->track_version))
 				add_object_address(OCLASS_COLLATION, collid, 0,
 								   context->addrs);
 		}
@@ -2289,7 +2435,9 @@ find_expr_references_walker(Node *node,
 		{
 			Oid			collid = lfirst_oid(ct);
 
-			if (OidIsValid(collid) && collid != DEFAULT_COLLATION_OID)
+			if (OidIsValid(collid) &&
+					(collid != DEFAULT_COLLATION_OID ||
+					context->track_version))
 				add_object_address(OCLASS_COLLATION, collid, 0,
 								   context->addrs);
 		}
@@ -2685,8 +2833,9 @@ record_object_address_dependencies(const ObjectAddress *depender,
 {
 	eliminate_duplicate_dependencies(referenced);
 	recordMultipleDependencies(depender,
-							   referenced->refs, NULL, referenced->numrefs,
-							   behavior);
+							   referenced->refs, referenced->numrefs,
+							   behavior,
+							   false);
 }
 
 /*
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 9d9e915979..4546789446 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -2304,7 +2304,7 @@ StoreAttrDefault(Relation rel, AttrNumber attnum,
 		 */
 		recordDependencyOnSingleRelExpr(&colobject, expr, RelationGetRelid(rel),
 										DEPENDENCY_AUTO,
-										DEPENDENCY_AUTO, false);
+										DEPENDENCY_AUTO, false, false);
 	}
 	else
 	{
@@ -2314,7 +2314,7 @@ StoreAttrDefault(Relation rel, AttrNumber attnum,
 		 */
 		recordDependencyOnSingleRelExpr(&defobject, expr, RelationGetRelid(rel),
 										DEPENDENCY_NORMAL,
-										DEPENDENCY_NORMAL, false);
+										DEPENDENCY_NORMAL, false, false);
 	}
 
 	/*
@@ -3638,7 +3638,8 @@ 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
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 76fd938ce3..369b5d43f1 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -52,6 +52,7 @@
 #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"
@@ -74,6 +75,7 @@
 #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/snapmgr.h"
@@ -117,6 +119,7 @@ static void UpdateIndexRelation(Oid indexoid, Oid heapoid,
 								bool immediate,
 								bool isvalid,
 								bool isready);
+static bool index_depends_stable_coll_order(Oid amoid);
 static void index_update_stats(Relation rel,
 							   bool hasindex,
 							   double reltuples);
@@ -1025,6 +1028,10 @@ index_create(Relation heapRelation,
 	{
 		ObjectAddress myself,
 					referenced;
+		ListCell   *lc;
+		List	   *colls = NIL,
+				   *determ_colls = NIL,
+				   *nondeterm_colls = NIL;
 
 		myself.classId = RelationRelationId;
 		myself.objectId = indexRelationId;
@@ -1115,21 +1122,75 @@ index_create(Relation heapRelation,
 			recordDependencyOn(&myself, &referenced, DEPENDENCY_PARTITION_SEC);
 		}
 
-		/* Store dependency on collations */
-		/* The default collation is pinned, so don't bother recording it */
+		/* First, get all 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))
+				colls = lappend_oid(colls, colloid);
+			else
 			{
-				referenced.classId = CollationRelationId;
-				referenced.objectId = collationObjectId[i];
-				referenced.objectSubId = 0;
+				Form_pg_attribute att = TupleDescAttr(indexTupDesc, i);
 
-				recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
+				Assert(i < indexTupDesc->natts);
+
+				colls = list_concat(colls,
+									GetTypeCollations(att->atttypid, false));
 			}
 		}
 
+		/*
+		 * Then split the dependencies on whether they're deterministic or not,
+		 * removing any duplicates.
+		 */
+		foreach(lc, colls)
+		{
+			Oid c = lfirst_oid(lc);
+
+			if (!OidIsValid(c))
+				continue;
+
+			if (get_collation_isdeterministic(c))
+				determ_colls = list_append_unique_oid(determ_colls, c);
+			else
+				nondeterm_colls = list_append_unique_oid(nondeterm_colls, c);
+		}
+
+		/*
+		 * For deterministic transaction, only track the version if the AM
+		 * relies on a stable ordering.
+		 */
+		if (determ_colls)
+		{
+			bool track_version;
+
+			track_version = index_depends_stable_coll_order(indexInfo->ii_Am);
+
+			recordDependencyOnCollations(&myself, determ_colls, track_version);
+			/*
+			 * Advance the command counter so that later calls to
+			 * recordMultipleDependencies calls can see the newly-entered
+			 * pg_depend catalog tuples for the index.
+			 */
+			CommandCounterIncrement();
+		}
+
+		/*
+		 * We always record the version for dependency on non-deterministic
+		 * collations.
+		 */
+		if (nondeterm_colls)
+		{
+			recordDependencyOnCollations(&myself, nondeterm_colls, true);
+			/*
+			 * Advance the command counter so that later calls to
+			 * recordMultipleDependencies calls can see the newly-entered
+			 * pg_depend catalog tuples for the index.
+			 */
+			CommandCounterIncrement();
+		}
+
 		/* Store dependency on operator classes */
 		for (i = 0; i < indexInfo->ii_NumIndexKeyAttrs; i++)
 		{
@@ -1143,21 +1204,29 @@ index_create(Relation heapRelation,
 		/* Store dependencies on anything mentioned in index expressions */
 		if (indexInfo->ii_Expressions)
 		{
+			/* recordDependencyOnSingleRelExpr get rid of duplicate entries */
 			recordDependencyOnSingleRelExpr(&myself,
 											(Node *) indexInfo->ii_Expressions,
 											heapRelationId,
 											DEPENDENCY_NORMAL,
-											DEPENDENCY_AUTO, false);
+											DEPENDENCY_AUTO, false, true);
+			/*
+			 * Advance the command counter so that later
+			 * recordMultipleDependencies calls can see the newly-entered
+			 * pg_depend catalog tuples for the index.
+			 */
+			CommandCounterIncrement();
 		}
 
 		/* Store dependencies on anything mentioned in predicate */
 		if (indexInfo->ii_Predicate)
 		{
+			/* recordDependencyOnSingleRelExpr get rid of duplicate entries */
 			recordDependencyOnSingleRelExpr(&myself,
 											(Node *) indexInfo->ii_Predicate,
 											heapRelationId,
 											DEPENDENCY_NORMAL,
-											DEPENDENCY_AUTO, false);
+											DEPENDENCY_AUTO, false, true);
 		}
 	}
 	else
@@ -1229,6 +1298,94 @@ index_create(Relation heapRelation,
 	return indexRelationId;
 }
 
+static char *
+index_check_collation_version(const ObjectAddress *otherObject,
+							  const char *version,
+							  void *userdata)
+{
+	Oid			relid = *(Oid *) userdata;
+	char	   *current_version;
+
+	/* We only care about dependencies on collations. */
+	if (otherObject->classId != CollationRelationId)
+		return NULL;
+
+	/* Compare with the current version. */
+	current_version = get_collation_version_for_oid(otherObject->objectId);
+
+	/* XXX should we warn about "disappearing" versions? */
+	if (current_version)
+	{
+		/*
+		 * We now support versioning for the underlying collation library on
+		 * this system, or previous version is unknown.
+		 */
+		if (!version || (strcmp(version, "") == 0 && strcmp(current_version,
+						"") != 0))
+		{
+			ereport(WARNING,
+					(errmsg("index \"%s\" depends on collation \"%s\" with an unknown version, and the current version is \"%s\"",
+							get_rel_name(relid),
+							get_collation_name(otherObject->objectId),
+							current_version),
+					 errdetail("The index may be corrupted due to changes in sort order."),
+					 errhint("REINDEX to avoid the risk of corruption.")));
+		}
+		else if (strcmp(current_version, version) != 0)
+		{
+			ereport(WARNING,
+				(errmsg("index \"%s\" depends on collation \"%s\" version \"%s\", but the current version is \"%s\"",
+						get_rel_name(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.")));
+		}
+	}
+
+	return NULL;
+}
+
+void
+index_check_collation_versions(Oid relid)
+{
+	ObjectAddress object;
+
+	object.classId = RelationRelationId;
+	object.objectId = relid;
+	object.objectSubId = 0;
+	visitDependentObjects(&object, &index_check_collation_version, &relid);
+}
+
+static char *
+index_update_collation_version(const ObjectAddress *otherObject,
+							   const char *version,
+							   void *userdata)
+{
+	char   *current_version = (char *) userdata;
+
+	/* We only care about dependencies on collations. */
+	if (otherObject->classId != CollationRelationId)
+		return NULL;
+
+	current_version = get_collation_version_for_oid(otherObject->objectId);
+	return current_version;
+}
+
+static void
+index_update_collation_versions(Oid relid)
+{
+	ObjectAddress object;
+	NameData	current_version;
+
+	object.classId = RelationRelationId;
+	object.objectId = relid;
+	object.objectSubId = 0;
+	visitDependentObjects(&object, &index_update_collation_version,
+						  &current_version);
+}
+
 /*
  * index_concurrently_create_copy
  *
@@ -2635,6 +2792,17 @@ FormIndexDatum(IndexInfo *indexInfo,
 		elog(ERROR, "wrong number of index expressions");
 }
 
+/*
+ * Returns whether the given index access method depend on a stable collation
+ * order.
+ */
+static bool
+index_depends_stable_coll_order(Oid amoid)
+{
+	return (amoid != HASH_AM_OID &&
+			strcmp(get_am_name(amoid), "bloom") != 0);
+}
+
 
 /*
  * index_update_stats --- update pg_class entry after CREATE INDEX or REINDEX
@@ -3623,6 +3791,9 @@ 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);
 }
 
 /*
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index 90932be831..3cc0f6651c 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -360,7 +360,7 @@ CreateConstraintEntry(const char *constraintName,
 		 */
 		recordDependencyOnSingleRelExpr(&conobject, conExpr, relId,
 										DEPENDENCY_NORMAL,
-										DEPENDENCY_NORMAL, false);
+										DEPENDENCY_NORMAL, false, true);
 	}
 
 	/* Post creation hook for new constraint */
diff --git a/src/backend/catalog/pg_depend.c b/src/backend/catalog/pg_depend.c
index b7beb2884e..3f113499b2 100644
--- a/src/backend/catalog/pg_depend.c
+++ b/src/backend/catalog/pg_depend.c
@@ -19,16 +19,21 @@
 #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"
 #include "commands/extension.h"
 #include "miscadmin.h"
+#include "utils/builtins.h"
 #include "utils/fmgroids.h"
 #include "utils/lsyscache.h"
+#include "utils/pg_locale.h"
 #include "utils/rel.h"
 
 
+static bool dependencyExists(const ObjectAddress *depender,
+				   const ObjectAddress *referenced);
 static bool isObjectPinned(const ObjectAddress *object, Relation rel);
 
 
@@ -44,34 +49,47 @@ recordDependencyOn(const ObjectAddress *depender,
 				   const ObjectAddress *referenced,
 				   DependencyType behavior)
 {
-	recordMultipleDependencies(depender, referenced, NULL, 1, behavior);
+	recordMultipleDependencies(depender, referenced, 1, behavior, false);
 }
 
 /*
- * As recordDependencyOn(), but also capture a version string so that changes
- * in the referenced object can be detected.  The meaning of the version
- * string depends on the referenced object.  Currently it is used for
- * detecting changes in collation versions.
+ * Given a list of collations, record a dependency on its underlying collation
+ * version.
  */
-void
-recordDependencyOnVersion(const ObjectAddress *depender,
-						  const ObjectAddress *referenced,
-						  const NameData *version,
-						  DependencyType behavior)
+void recordDependencyOnCollations(ObjectAddress *myself,
+								  List *collations,
+								  bool record_version)
 {
-	recordMultipleDependencies(depender, referenced, version, 1, behavior);
+	ListCell   *lc;
+
+	foreach(lc, collations)
+	{
+		ObjectAddress referenced;
+
+		referenced.classId = CollationRelationId;
+		referenced.objectId = lfirst_oid(lc);
+		referenced.objectSubId = 0;
+
+		recordMultipleDependencies(myself, &referenced, 1,
+								  DEPENDENCY_NORMAL, record_version);
+	}
 }
 
 /*
  * Record multiple dependencies (of the same kind) for a single dependent
  * object.  This has a little less overhead than recording each separately.
+ *
+ * If track_version is true, then a record could be added even if the referenced
+ * dependency 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,
-						   const NameData *version,
 						   int nreferenced,
-						   DependencyType behavior)
+						   DependencyType behavior,
+						   bool track_version)
 {
 	Relation	dependDesc;
 	CatalogIndexState indstate;
@@ -79,6 +97,7 @@ recordMultipleDependencies(const ObjectAddress *depender,
 	int			i;
 	bool		nulls[Natts_pg_depend];
 	Datum		values[Natts_pg_depend];
+	char	   *version = NULL;
 
 	if (nreferenced <= 0)
 		return;					/* nothing to do */
@@ -97,12 +116,49 @@ recordMultipleDependencies(const ObjectAddress *depender,
 
 	for (i = 0; i < nreferenced; i++, referenced++)
 	{
+		bool ignore_systempin = false;
+
+		if (track_version)
+		{
+			/* Only dependency on a collation is supported. */
+			if (referenced->classId == CollationRelationId)
+			{
+				/* C and POSIX collations don't require tracking the version */
+				if (referenced->objectId == C_COLLATION_OID ||
+					referenced->objectId == POSIX_COLLATION_OID)
+					continue;
+
+				/*
+				 * We don't want to record redundant depedencies that are used
+				 * to track versions to avoid redundant warnings in case of
+				 * non-matching versions when those are checked.  Note that
+				 * callers have to take care of removing duplicated entries and
+				 * calling CommandCounterIncrement() if the dependencies are
+				 * registered in multiple calls.
+				 */
+				if (dependencyExists(depender, referenced))
+					continue;
+
+				/*
+				 * 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;
+				version = get_collation_version_for_oid(referenced->objectId);
+				Assert(version);
+			}
+		}
+		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))
 		{
 			/*
 			 * Record the Dependency.  Note we don't bother to check for
@@ -559,6 +615,54 @@ changeDependenciesOn(Oid refClassId, Oid oldRefObjectId,
 	return count;
 }
 
+/* dependencyExists()
+ *
+ * Test if a record exists for the given depender and referenceds addresses.
+ */
+static bool dependencyExists(const ObjectAddress *depender,
+				   const ObjectAddress *referenced)
+{
+	Relation	depRel;
+	ScanKeyData key[3];
+	SysScanDesc scan;
+	HeapTuple	tup;
+	bool	ret = false;
+
+	ScanKeyInit(&key[0],
+				Anum_pg_depend_classid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(depender->classId));
+	ScanKeyInit(&key[1],
+				Anum_pg_depend_objid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(depender->objectId));
+	ScanKeyInit(&key[2],
+				Anum_pg_depend_objsubid,
+				BTEqualStrategyNumber, F_INT4EQ,
+				Int32GetDatum(depender->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);
+
+		if (foundDep->refclassid == referenced->classId &&
+			foundDep->refobjid == referenced->objectId &&
+			foundDep->refobjsubid == referenced->objectSubId)
+		{
+			ret = true;
+			break;
+		}
+	}
+	systable_endscan(scan);
+	table_close(depRel, RowExclusiveLock);
+
+	return ret;
+}
+
 /*
  * isObjectPinned()
  *
diff --git a/src/backend/catalog/pg_type.c b/src/backend/catalog/pg_type.c
index cd56714968..fe14b6bd38 100644
--- 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 +513,74 @@ TypeCreate(Oid newTypeOid,
 	return address;
 }
 
+/* Get a list of all distinct collations oid that the given type depends on. */
+List *
+GetTypeCollations(Oid typeoid, bool non_deterministic_only)
+{
+	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))
+	{
+		if (!non_deterministic_only ||
+				!get_collation_isdeterministic(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))
+			{
+				if (!non_deterministic_only ||
+						!get_collation_isdeterministic(att->attcollation))
+					result = list_append_unique_oid(result, att->attcollation);
+			}
+			else
+				result = list_concat_unique_oid(result,
+						GetTypeCollations(att->atttypid,
+							non_deterministic_only));
+		}
+
+		relation_close(rel, NoLock);
+	}
+	else if (typeTup->typtype == TYPTYPE_DOMAIN)
+	{
+		Assert(OidIsValid(typeTup->typbasetype));
+
+		result = list_concat_unique_oid(result,
+				GetTypeCollations(typeTup->typbasetype,
+					non_deterministic_only));
+	}
+	else if (typeTup->typtype == TYPTYPE_RANGE)
+	{
+		Oid rangeid = get_range_subtype(typeTup->oid);
+
+		Assert(OidIsValid(rangeid));
+
+		result = list_concat_unique_oid(result,
+				GetTypeCollations(rangeid, non_deterministic_only));
+	}
+	else if (OidIsValid(typeTup->typelem))
+		result = list_concat_unique_oid(result,
+				GetTypeCollations(typeTup->typelem, non_deterministic_only));
+
+	ReleaseSysCache(tuple);
+
+	return result;
+}
+
 /*
  * GenerateTypeDependencies: build the dependencies needed for a type
  *
diff --git a/src/backend/commands/collationcmds.c b/src/backend/commands/collationcmds.c
index 78eceda848..d4eccf163f 100644
--- a/src/backend/commands/collationcmds.c
+++ b/src/backend/commands/collationcmds.c
@@ -273,28 +273,12 @@ 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);
+	Assert(version);
 
-	if (version)
-		PG_RETURN_TEXT_P(cstring_to_text(version));
-	else
-		PG_RETURN_NULL();
+	PG_RETURN_TEXT_P(cstring_to_text(version));
 }
 
 
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index d625d17bf4..2b7de111cd 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -31,6 +31,8 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/catalog.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -634,6 +636,35 @@ vacuum_open_relation(Oid relid, RangeVar *relation, int options,
 		rel_lock = false;
 	}
 
+	/*
+	 * Perform version sanity checks on the relation underlying indexes if
+	 * it's not a VACUUM FULL
+	 */
+	if (!(options & VACOPT_FULL) && onerel && !IsSystemRelation(onerel) &&
+			onerel->rd_rel->relhasindex)
+	{
+		List	   *indexoidlist;
+		ListCell   *l;
+
+		indexoidlist = RelationGetIndexList(onerel);
+		foreach(l, indexoidlist)
+		{
+			Oid			indexoid = lfirst_oid(l);
+			Relation	indexRelation;
+
+			indexRelation = index_open(indexoid, AccessShareLock);
+
+			/* Warn if any dependent collations' versions have moved. */
+			if (!indexRelation->rd_version_checked)
+			{
+				index_check_collation_versions(indexoid);
+				indexRelation->rd_version_checked = true;
+			}
+
+			index_close(indexRelation, NoLock);
+		}
+	}
+
 	/* if relation is opened, leave */
 	if (onerel)
 		return onerel;
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index d82fc5ab8b..f2fc427fc8 100644
--- 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
diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index 60dab33fcb..18a2d72f91 100644
--- 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"
@@ -148,6 +150,9 @@ 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
  *
@@ -1473,7 +1478,7 @@ pg_newlocale_from_collation(Oid collid)
  * NULL (if it doesn't support versions).  It must not return NULL for some
  * collcollate and not NULL for others.
  */
-char *
+static char *
 get_collation_actual_version(char collprovider, const char *collcollate)
 {
 	char	   *collversion = NULL;
@@ -1511,6 +1516,51 @@ get_collation_actual_version(char collprovider, const char *collcollate)
 	return collversion;
 }
 
+/*
+ * Get provider-specific collation version string given a collation OID.
+ *
+ * As this version is used in index dependency tracking, an empty string is
+ * returned when the version is unknown, to distinguish from dependencies where
+ * the version should not be tracked, represented by a NULL version.
+ */
+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);
+
+	if (!version)
+		return "";
+	else
+		return version;
+}
 
 #ifdef USE_ICU
 /*
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index ff70326474..bdf50ffe89 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -41,6 +41,7 @@
 #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/pg_am.h"
@@ -5623,6 +5624,7 @@ 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;
diff --git a/src/include/catalog/dependency.h b/src/include/catalog/dependency.h
index 7d9fc866b9..8858ceb3df 100644
--- a/src/include/catalog/dependency.h
+++ b/src/include/catalog/dependency.h
@@ -156,7 +156,8 @@ extern void recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 											Node *expr, Oid relId,
 											DependencyType behavior,
 											DependencyType self_behavior,
-											bool reverse_self);
+											bool reverse_self,
+											bool track_version);
 
 extern ObjectClass getObjectClass(const ObjectAddress *object);
 
@@ -176,22 +177,29 @@ extern void sort_object_addresses(ObjectAddresses *addrs);
 
 extern void free_object_addresses(ObjectAddresses *addrs);
 
+typedef char *(*VisitDependentObjectsFun) (const ObjectAddress *otherObject,
+											   const char *version,
+											   void *userdata);
+
+extern void visitDependentObjects(const ObjectAddress *object,
+								  VisitDependentObjectsFun callback,
+								  void *userdata);
+
 /* in pg_depend.c */
 
 extern void recordDependencyOn(const ObjectAddress *depender,
 							   const ObjectAddress *referenced,
 							   DependencyType behavior);
 
-extern void recordDependencyOnVersion(const ObjectAddress *depender,
-									  const ObjectAddress *referenced,
-									  const NameData *version,
-									  DependencyType behavior);
+extern void recordDependencyOnCollations(ObjectAddress *myself,
+										 List *collations,
+										 bool record_version);
 
 extern void recordMultipleDependencies(const ObjectAddress *depender,
 									   const ObjectAddress *referenced,
-									   const NameData *version,
 									   int nreferenced,
-									   DependencyType behavior);
+									   DependencyType behavior,
+									   bool track_version);
 
 extern void recordDependencyOnCurrentExtension(const ObjectAddress *object,
 											   bool isReplace);
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index a2890c1314..c619d02465 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -121,6 +121,8 @@ extern void FormIndexDatum(IndexInfo *indexInfo,
 						   Datum *values,
 						   bool *isnull);
 
+extern void index_check_collation_versions(Oid relid);
+
 extern void index_build(Relation heapRelation,
 						Relation indexRelation,
 						IndexInfo *indexInfo,
diff --git a/src/include/catalog/pg_type.h b/src/include/catalog/pg_type.h
index 97890946c5..3eb5ec4fcd 100644
--- a/src/include/catalog/pg_type.h
+++ b/src/include/catalog/pg_type.h
@@ -350,6 +350,8 @@ extern void GenerateTypeDependencies(HeapTuple typeTuple,
 									 bool isDependentType,
 									 bool rebuild);
 
+extern List *GetTypeCollations(Oid typeObjectid, bool non_deterministic_only);
+
 extern void RenameTypeInternal(Oid typeOid, const char *newTypeName,
 							   Oid typeNamespace);
 
diff --git a/src/include/utils/pg_locale.h b/src/include/utils/pg_locale.h
index 9cb7d91ddf..96da132c03 100644
--- 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);
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 44ed04dd3f..3656ea94e8 100644
--- 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 being done yet? */
 
 	/*
 	 * rd_createSubid is the ID of the highest subtransaction the rel has
diff --git a/src/test/Makefile b/src/test/Makefile
index efb206aa75..4ef0d11702 100644
--- 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
@@ -37,7 +38,7 @@ endif
 # clean" etc to recurse into them.  (We must filter out those that we
 # have conditionally included into SUBDIRS above, else there will be
 # make confusion.)
-ALWAYS_SUBDIRS = $(filter-out $(SUBDIRS),examples kerberos ldap locale thread ssl)
+ALWAYS_SUBDIRS = $(filter-out $(SUBDIRS),examples kerberos ldap thread ssl)
 
 # We want to recurse to all subdirs for all standard targets, except that
 # installcheck and install should not recurse into the subdirectory "modules".
diff --git a/src/test/locale/.gitignore b/src/test/locale/.gitignore
index 620d3df425..64e1bf2a80 100644
--- a/src/test/locale/.gitignore
+++ b/src/test/locale/.gitignore
@@ -1 +1,2 @@
 /test-ctype
+/tmp_check/
diff --git a/src/test/locale/Makefile b/src/test/locale/Makefile
index 22a45b65f2..73495cf16b 100644
--- 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:
+	$(prove_installcheck)
diff --git a/src/test/locale/t/001_index.pl b/src/test/locale/t/001_index.pl
new file mode 100644
index 0000000000..468fbb63b6
--- /dev/null
+++ b/src/test/locale/t/001_index.pl
@@ -0,0 +1,76 @@
+use strict;
+use warnings;
+
+use Config;
+use PostgresNode;
+use TestLib;
+use Test::More;
+
+if ($ENV{with_icu} eq 'yes')
+{
+	plan tests => 12;
+}
+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;
+
+$ENV{PGHOST} = $node->host;
+$ENV{PGPORT} = $node->port;
+$node->start;
+
+sub test_index
+{
+	my ($err_like, $err_comm) = @_;
+
+	my ($ret, $out, $err) = $node->psql('postgres',
+		'SET enable_seqscan = 0;'
+		. "EXPLAIN SELECT val FROM icu1 WHERE val = '0'");
+
+	is($ret, 0, 'EXPLAIN should succeed.');
+	like($out, qr/icu1_fr/, 'Index icu1_fr should be used.');
+	like($err, $err_like, $err_comm);
+}
+
+$node->safe_psql('postgres',
+	'CREATE TABLE icu1(val text);'
+	. 'INSERT INTO icu1 SELECT i::text FROM generate_series(1, 10000) i;'
+	. 'CREATE INDEX icu1_fr ON icu1 (val COLLATE "fr-x-icu");');
+$node->safe_psql('postgres', 'VACUUM ANALYZE icu1;');
+
+test_index(qr/^$/, 'No warning should be raised');
+
+# Simulate different collation version
+$node->safe_psql('postgres',
+	"UPDATE pg_depend SET refobjversion = 'not_a_version'"
+	. " WHERE refobjversion IS NOT NULL"
+	. " AND objid::regclass::text = 'icu1_fr';");
+
+test_index(qr/index "icu1_fr" depends on collation "fr-x-icu" version "not_a_version", but the current version is/,
+	'Different collation version warning should be raised.');
+
+# Simulate unknown collation version
+$node->safe_psql('postgres',
+	"UPDATE pg_depend SET refobjversion = ''"
+	. " WHERE refobjversion IS NOT NULL"
+	. " AND objid::regclass::text = 'icu1_fr';");
+
+test_index(qr/index "icu1_fr" depends on collation "fr-x-icu" with an unknown version, and the current version is/,
+	'Unknown collation version warning should be raised.');
+
+# Simulate previously unhandled collation versioning
+$node->safe_psql('postgres',
+	"UPDATE pg_depend SET refobjversion = NULL"
+	. " WHERE refobjversion IS NOT NULL"
+	. " AND objid::regclass::text = 'icu1_fr';");
+
+test_index(qr/index "icu1_fr" depends on collation "fr-x-icu" with an unknown version, and the current version is/,
+	'Unknown collation version warning should be raised.');
+
+$node->stop;
diff --git a/src/test/regress/expected/collate.icu.utf8.out b/src/test/regress/expected/collate.icu.utf8.out
index 60d9263a2f..09512c0f66 100644
--- a/src/test/regress/expected/collate.icu.utf8.out
+++ b/src/test/regress/expected/collate.icu.utf8.out
@@ -1897,6 +1897,136 @@ 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,
+    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 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);
+-- for key columns, hash indexes should record dependency on the collation but
+-- not the version
+CREATE INDEX icuidx18_hash_d_es ON collate_test USING hash (d_es);
+CREATE INDEX icuidx19_hash_id_d_es_eq ON collate_test USING hash (id) WHERE (d_es) = 'foo';
+CREATE INDEX icuidx20_hash_id_d_es_lt ON collate_test USING hash (id) WHERE (d_es) < 'foo';
+SELECT objid::regclass, refobjid::regcollation,
+CASE
+WHEN refobjversion IS NULL THEN 'version not tracked'
+ELSE CASE
+    WHEN refobjversion = pg_collation_actual_version(refobjid) THEN 'up to date'
+    ELSE 'out of date'
+    END
+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;
+           objid           |  refobjid  |       version       
+---------------------------+------------+---------------------
+ 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"  | up to date
+ 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"  | up to date
+ 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"  | up to date
+ icuidx11_d_es             | "es-x-icu" | up to date
+ icuidx12_custom           | "default"  | up to date
+ icuidx12_custom           | custom     | up to date
+ icuidx13_custom           | "default"  | up to date
+ icuidx13_custom           | custom     | up to date
+ icuidx14_myrange          | "default"  | up to date
+ 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
+ icuidx18_hash_d_es        | "es-x-icu" | version not tracked
+ icuidx19_hash_id_d_es_eq  | "default"  | up to date
+ icuidx19_hash_id_d_es_eq  | "es-x-icu" | up to date
+ icuidx20_hash_id_d_es_lt  | "default"  | up to date
+ icuidx20_hash_id_d_es_lt  | "es-x-icu" | up to date
+(49 rows)
+
+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)
+
 -- cleanup
 RESET search_path;
 SET client_min_messages TO warning;
diff --git a/src/test/regress/expected/create_index.out b/src/test/regress/expected/create_index.out
index ae95bb38a6..94b4daf4d6 100644
--- a/src/test/regress/expected/create_index.out
+++ b/src/test/regress/expected/create_index.out
@@ -2065,15 +2065,17 @@ 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 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
-(9 rows)
+(11 rows)
 
 REINDEX INDEX CONCURRENTLY concur_reindex_ind1;
 REINDEX TABLE CONCURRENTLY concur_reindex_tab;
@@ -2093,15 +2095,17 @@ 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 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
-(9 rows)
+(11 rows)
 
 -- Check that comments are preserved
 CREATE TABLE testcomment (i int);
diff --git a/src/test/regress/sql/collate.icu.utf8.sql b/src/test/regress/sql/collate.icu.utf8.sql
index 35acf91fbf..c8f1a620d2 100644
--- a/src/test/regress/sql/collate.icu.utf8.sql
+++ b/src/test/regress/sql/collate.icu.utf8.sql
@@ -716,6 +716,89 @@ 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,
+    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 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);
+-- for key columns, hash indexes should record dependency on the collation but
+-- not the version
+CREATE INDEX icuidx18_hash_d_es ON collate_test USING hash (d_es);
+CREATE INDEX icuidx19_hash_id_d_es_eq ON collate_test USING hash (id) WHERE (d_es) = 'foo';
+CREATE INDEX icuidx20_hash_id_d_es_lt ON collate_test USING hash (id) WHERE (d_es) < 'foo';
+
+SELECT objid::regclass, refobjid::regcollation,
+CASE
+WHEN refobjversion IS NULL THEN 'version not tracked'
+ELSE CASE
+    WHEN refobjversion = pg_collation_actual_version(refobjid) THEN 'up to date'
+    ELSE 'out of date'
+    END
+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;
+
+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';
 
 -- cleanup
 RESET search_path;
-- 
2.20.1


--bp/iNruPH9dso1Pn
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename="v15-0005-Preserve-index-dependencies-on-collation-during-.patch"



^ permalink  raw  reply  [nested|flat] 96+ messages in thread

* [PATCH v16 4/7] Track collation versions for indexes.
@ 2019-05-28 18:16  Thomas Munro <[email protected]>
  0 siblings, 0 replies; 96+ messages in thread

From: Thomas Munro @ 2019-05-28 18:16 UTC (permalink / raw)

Record the current version of dependent collations in pg_depend when creating
or rebuilding an index.  The version is checked against the current version
whenever we call get_relation_info for an index or open the parent table
during non-full VACUUM or ANALYZE.  Warn that the index may be corrupted if
the versions don't match.

A new flag is added in RelationData to specify that the check has already been
done to avoid repetition.

Thanks to Doug Doole, Peter Eisentraut, Christoph Berg, Laurenz Albe,
Michael Paquier, Robert Haas, Tom Lane and others for design discussion.

Author: Thomas Munro and Julien Rouhaud
Reviewed-by: Peter Eisentraut, Laurenz Albe
Discussion: https://postgr.es/m/CAEepm%3D0uEQCpfq_%2BLYFBdArCe4Ot98t1aR4eYiYTe%3DyavQygiQ%40mail.gmail.com
---
 doc/src/sgml/func.sgml                        |   2 +-
 doc/src/sgml/ref/reindex.sgml                 |   6 +
 src/backend/catalog/dependency.c              | 189 +++++++++++++++--
 src/backend/catalog/heap.c                    |   7 +-
 src/backend/catalog/index.c                   | 191 +++++++++++++++++-
 src/backend/catalog/pg_constraint.c           |   2 +-
 src/backend/catalog/pg_depend.c               | 136 +++++++++++--
 src/backend/catalog/pg_type.c                 |  69 +++++++
 src/backend/commands/collationcmds.c          |  22 +-
 src/backend/commands/vacuum.c                 |  31 +++
 src/backend/optimizer/util/plancat.c          |   9 +
 src/backend/utils/adt/pg_locale.c             |  52 ++++-
 src/backend/utils/cache/relcache.c            |   2 +
 src/include/catalog/dependency.h              |  22 +-
 src/include/catalog/index.h                   |   2 +
 src/include/catalog/pg_type.h                 |   2 +
 src/include/utils/pg_locale.h                 |   2 +-
 src/include/utils/rel.h                       |   1 +
 src/test/Makefile                             |   5 +-
 src/test/locale/.gitignore                    |   1 +
 src/test/locale/Makefile                      |   7 +
 src/test/locale/t/001_index.pl                |  76 +++++++
 .../regress/expected/collate.icu.utf8.out     | 130 ++++++++++++
 src/test/regress/expected/create_index.out    |   8 +-
 src/test/regress/sql/collate.icu.utf8.sql     |  83 ++++++++
 25 files changed, 974 insertions(+), 83 deletions(-)
 create mode 100644 src/test/locale/t/001_index.pl

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 02779ab713..d28995dd5a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21125,7 +21125,7 @@ postgres=# SELECT * FROM pg_walfile_name_offset(pg_stop_backup());
    <para>
     <function>pg_collation_actual_version</function> returns the actual
     version of the collation object as it is currently installed in the
-    operating system.
+    operating system.  An empty string is returned if the version is unknown.
    </para>
 
    <para>
diff --git a/doc/src/sgml/ref/reindex.sgml b/doc/src/sgml/ref/reindex.sgml
index c54a7c420d..7209a606fa 100644
--- a/doc/src/sgml/ref/reindex.sgml
+++ b/doc/src/sgml/ref/reindex.sgml
@@ -39,6 +39,12 @@ REINDEX [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] { IN
 
    <itemizedlist>
     <listitem>
+     <para>
+      The index depends on the sort order of a collation, and the definition
+      of the collation has changed.  This can cause an index to fail to
+      find a key that is present in the index.  On some systems, collation
+      versions are tracked in order to generate warnings when this happens.
+     </para>
      <para>
       An index has become corrupted, and no longer contains valid
       data. Although in theory this should never happen, in
diff --git a/src/backend/catalog/dependency.c b/src/backend/catalog/dependency.c
index 660033b9c1..c0e36ef4cd 100644
--- a/src/backend/catalog/dependency.c
+++ b/src/backend/catalog/dependency.c
@@ -78,6 +78,7 @@
 #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"
@@ -138,6 +139,9 @@ typedef struct
 {
 	ObjectAddresses *addrs;		/* addresses being accumulated */
 	List	   *rtables;		/* list of rangetables to resolve Vars */
+	bool		track_version;	/* whether caller asked to track dependency
+								 * versions */
+	NodeTag		type;			/* nodetag of the current node */
 } find_expr_references_context;
 
 /*
@@ -438,6 +442,80 @@ performMultipleDeletions(const ObjectAddresses *objects,
 	table_close(depRel, RowExclusiveLock);
 }
 
+/*
+ * Call a function for all objects that depend on 'object'.  If the function
+ * returns a non-NULL pointer to a new version string, update the version.
+ */
+void
+visitDependentObjects(const ObjectAddress *object,
+					  VisitDependentObjectsFun 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 *cur_version, *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);
+
+		cur_version = isnull ? NULL : TextDatumGetCString(depversion);
+
+		new_version = callback(&otherObject, cur_version, userdata);
+		if (new_version)
+		{
+			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));
+
+			values[Anum_pg_depend_refobjversion - 1] =
+				CStringGetTextDatum(new_version);
+			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'
  *
@@ -1591,6 +1669,10 @@ recordDependencyOnExpr(const ObjectAddress *depender,
 	find_expr_references_context context;
 
 	context.addrs = new_object_addresses();
+	if (expr)
+		context.type = expr->type;
+	else
+		context.type = T_Invalid;
 
 	/* Set up interpretation for Vars at varlevelsup = 0 */
 	context.rtables = list_make1(rtable);
@@ -1603,9 +1685,10 @@ recordDependencyOnExpr(const ObjectAddress *depender,
 
 	/* And record 'em */
 	recordMultipleDependencies(depender,
-							   context.addrs->refs, NULL,
+							   context.addrs->refs,
 							   context.addrs->numrefs,
-							   behavior);
+							   behavior,
+							   false);
 
 	free_object_addresses(context.addrs);
 }
@@ -1632,12 +1715,18 @@ recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 								Node *expr, Oid relId,
 								DependencyType behavior,
 								DependencyType self_behavior,
-								bool reverse_self)
+								bool reverse_self,
+								bool track_version)
 {
 	find_expr_references_context context;
 	RangeTblEntry rte;
 
 	context.addrs = new_object_addresses();
+	context.track_version = track_version;
+	if (expr)
+		context.type = expr->type;
+	else
+		context.type = T_Invalid;
 
 	/* We gin up a rather bogus rangetable list to handle Vars */
 	MemSet(&rte, 0, sizeof(rte));
@@ -1691,9 +1780,10 @@ recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 		/* Record the self-dependencies with the appropriate direction */
 		if (!reverse_self)
 			recordMultipleDependencies(depender,
-									   self_addrs->refs, NULL,
+									   self_addrs->refs,
 									   self_addrs->numrefs,
-									   self_behavior);
+									   self_behavior,
+									   track_version);
 		else
 		{
 			/* Can't use recordMultipleDependencies, so do it the hard way */
@@ -1712,9 +1802,10 @@ recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 
 	/* Record the external dependencies */
 	recordMultipleDependencies(depender,
-							   context.addrs->refs, NULL,
+							   context.addrs->refs,
 							   context.addrs->numrefs,
-							   behavior);
+							   behavior,
+							   track_version);
 
 	free_object_addresses(context.addrs);
 }
@@ -1736,8 +1827,13 @@ static bool
 find_expr_references_walker(Node *node,
 							find_expr_references_context *context)
 {
+	NodeTag parent_type = context->type;
+
 	if (node == NULL)
 		return false;
+
+	context->type = node->type;
+
 	if (IsA(node, Var))
 	{
 		Var		   *var = (Var *) node;
@@ -1770,6 +1866,46 @@ 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);
+
+			/* Record collations from the type itself, or underlying in case of
+			 * complex type.  Note that if the direct parent is a CollateExpr
+			 * node, there's no need to record the type underlying collation if
+			 * any.  A dependency already exists for the owning relation, and a
+			 * change in the collation sort order wouldn't cause any harm as
+			 * the collation isn't used at all in such case.
+			 */
+			if (parent_type != T_CollateExpr)
+			{
+				/* type's collation if valid */
+				if (OidIsValid(var->varcollid))
+				{
+					add_object_address(OCLASS_COLLATION, var->varcollid, 0,
+									   context->addrs);
+				}
+				/*
+				 * otherwise, it may be a composite type having underlying
+				 * collations */
+				else if (var->vartype >= FirstNormalObjectId)
+				{
+					List	   *collations = NIL;
+					ListCell   *lc;
+
+					collations = GetTypeCollations(var->vartype, false);
+
+					foreach(lc, collations)
+					{
+						Oid coll = lfirst_oid(lc);
+
+						if (OidIsValid(coll) &&
+							(coll != DEFAULT_COLLATION_OID ||
+							 context->track_version)
+						)
+							add_object_address(OCLASS_COLLATION,
+									lfirst_oid(lc), 0,
+									context->addrs);
+					}
+				}
+			}
 		}
 
 		/*
@@ -1794,11 +1930,13 @@ 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.  However we can save work in the most common case
+		 * where the collation is "default", since we know that's pinned, if
+		 * the caller didn't ask to track dependency versions.
 		 */
 		if (OidIsValid(con->constcollid) &&
-			con->constcollid != DEFAULT_COLLATION_OID)
+				(con->constcollid != DEFAULT_COLLATION_OID ||
+					context->track_version))
 			add_object_address(OCLASS_COLLATION, con->constcollid, 0,
 							   context->addrs);
 
@@ -1888,7 +2026,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* and its collation, just as for Consts */
 		if (OidIsValid(param->paramcollid) &&
-			param->paramcollid != DEFAULT_COLLATION_OID)
+				(param->paramcollid != DEFAULT_COLLATION_OID ||
+					context->track_version))
 			add_object_address(OCLASS_COLLATION, param->paramcollid, 0,
 							   context->addrs);
 	}
@@ -1976,7 +2115,8 @@ find_expr_references_walker(Node *node,
 							   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(fselect->resultcollid) &&
-			fselect->resultcollid != DEFAULT_COLLATION_OID)
+			(fselect->resultcollid != DEFAULT_COLLATION_OID ||
+			 context->track_version))
 			add_object_address(OCLASS_COLLATION, fselect->resultcollid, 0,
 							   context->addrs);
 	}
@@ -2007,7 +2147,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(relab->resultcollid) &&
-			relab->resultcollid != DEFAULT_COLLATION_OID)
+			(relab->resultcollid != DEFAULT_COLLATION_OID ||
+			context->track_version))
 			add_object_address(OCLASS_COLLATION, relab->resultcollid, 0,
 							   context->addrs);
 	}
@@ -2020,7 +2161,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(iocoerce->resultcollid) &&
-			iocoerce->resultcollid != DEFAULT_COLLATION_OID)
+			(iocoerce->resultcollid != DEFAULT_COLLATION_OID ||
+			context->track_version))
 			add_object_address(OCLASS_COLLATION, iocoerce->resultcollid, 0,
 							   context->addrs);
 	}
@@ -2033,7 +2175,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(acoerce->resultcollid) &&
-			acoerce->resultcollid != DEFAULT_COLLATION_OID)
+			(acoerce->resultcollid != DEFAULT_COLLATION_OID ||
+			context->track_version))
 			add_object_address(OCLASS_COLLATION, acoerce->resultcollid, 0,
 							   context->addrs);
 		/* fall through to examine arguments */
@@ -2122,7 +2265,8 @@ find_expr_references_walker(Node *node,
 			add_object_address(OCLASS_PROC, wc->endInRangeFunc, 0,
 							   context->addrs);
 		if (OidIsValid(wc->inRangeColl) &&
-			wc->inRangeColl != DEFAULT_COLLATION_OID)
+			(wc->inRangeColl != DEFAULT_COLLATION_OID ||
+			context->track_version))
 			add_object_address(OCLASS_COLLATION, wc->inRangeColl, 0,
 							   context->addrs);
 		/* fall through to examine substructure */
@@ -2267,7 +2411,9 @@ find_expr_references_walker(Node *node,
 		{
 			Oid			collid = lfirst_oid(ct);
 
-			if (OidIsValid(collid) && collid != DEFAULT_COLLATION_OID)
+			if (OidIsValid(collid) &&
+					(collid != DEFAULT_COLLATION_OID ||
+					 context->track_version))
 				add_object_address(OCLASS_COLLATION, collid, 0,
 								   context->addrs);
 		}
@@ -2289,7 +2435,9 @@ find_expr_references_walker(Node *node,
 		{
 			Oid			collid = lfirst_oid(ct);
 
-			if (OidIsValid(collid) && collid != DEFAULT_COLLATION_OID)
+			if (OidIsValid(collid) &&
+					(collid != DEFAULT_COLLATION_OID ||
+					context->track_version))
 				add_object_address(OCLASS_COLLATION, collid, 0,
 								   context->addrs);
 		}
@@ -2685,8 +2833,9 @@ record_object_address_dependencies(const ObjectAddress *depender,
 {
 	eliminate_duplicate_dependencies(referenced);
 	recordMultipleDependencies(depender,
-							   referenced->refs, NULL, referenced->numrefs,
-							   behavior);
+							   referenced->refs, referenced->numrefs,
+							   behavior,
+							   false);
 }
 
 /*
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 9d9e915979..4546789446 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -2304,7 +2304,7 @@ StoreAttrDefault(Relation rel, AttrNumber attnum,
 		 */
 		recordDependencyOnSingleRelExpr(&colobject, expr, RelationGetRelid(rel),
 										DEPENDENCY_AUTO,
-										DEPENDENCY_AUTO, false);
+										DEPENDENCY_AUTO, false, false);
 	}
 	else
 	{
@@ -2314,7 +2314,7 @@ StoreAttrDefault(Relation rel, AttrNumber attnum,
 		 */
 		recordDependencyOnSingleRelExpr(&defobject, expr, RelationGetRelid(rel),
 										DEPENDENCY_NORMAL,
-										DEPENDENCY_NORMAL, false);
+										DEPENDENCY_NORMAL, false, false);
 	}
 
 	/*
@@ -3638,7 +3638,8 @@ 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
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 76fd938ce3..369b5d43f1 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -52,6 +52,7 @@
 #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"
@@ -74,6 +75,7 @@
 #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/snapmgr.h"
@@ -117,6 +119,7 @@ static void UpdateIndexRelation(Oid indexoid, Oid heapoid,
 								bool immediate,
 								bool isvalid,
 								bool isready);
+static bool index_depends_stable_coll_order(Oid amoid);
 static void index_update_stats(Relation rel,
 							   bool hasindex,
 							   double reltuples);
@@ -1025,6 +1028,10 @@ index_create(Relation heapRelation,
 	{
 		ObjectAddress myself,
 					referenced;
+		ListCell   *lc;
+		List	   *colls = NIL,
+				   *determ_colls = NIL,
+				   *nondeterm_colls = NIL;
 
 		myself.classId = RelationRelationId;
 		myself.objectId = indexRelationId;
@@ -1115,21 +1122,75 @@ index_create(Relation heapRelation,
 			recordDependencyOn(&myself, &referenced, DEPENDENCY_PARTITION_SEC);
 		}
 
-		/* Store dependency on collations */
-		/* The default collation is pinned, so don't bother recording it */
+		/* First, get all 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))
+				colls = lappend_oid(colls, colloid);
+			else
 			{
-				referenced.classId = CollationRelationId;
-				referenced.objectId = collationObjectId[i];
-				referenced.objectSubId = 0;
+				Form_pg_attribute att = TupleDescAttr(indexTupDesc, i);
 
-				recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
+				Assert(i < indexTupDesc->natts);
+
+				colls = list_concat(colls,
+									GetTypeCollations(att->atttypid, false));
 			}
 		}
 
+		/*
+		 * Then split the dependencies on whether they're deterministic or not,
+		 * removing any duplicates.
+		 */
+		foreach(lc, colls)
+		{
+			Oid c = lfirst_oid(lc);
+
+			if (!OidIsValid(c))
+				continue;
+
+			if (get_collation_isdeterministic(c))
+				determ_colls = list_append_unique_oid(determ_colls, c);
+			else
+				nondeterm_colls = list_append_unique_oid(nondeterm_colls, c);
+		}
+
+		/*
+		 * For deterministic transaction, only track the version if the AM
+		 * relies on a stable ordering.
+		 */
+		if (determ_colls)
+		{
+			bool track_version;
+
+			track_version = index_depends_stable_coll_order(indexInfo->ii_Am);
+
+			recordDependencyOnCollations(&myself, determ_colls, track_version);
+			/*
+			 * Advance the command counter so that later calls to
+			 * recordMultipleDependencies calls can see the newly-entered
+			 * pg_depend catalog tuples for the index.
+			 */
+			CommandCounterIncrement();
+		}
+
+		/*
+		 * We always record the version for dependency on non-deterministic
+		 * collations.
+		 */
+		if (nondeterm_colls)
+		{
+			recordDependencyOnCollations(&myself, nondeterm_colls, true);
+			/*
+			 * Advance the command counter so that later calls to
+			 * recordMultipleDependencies calls can see the newly-entered
+			 * pg_depend catalog tuples for the index.
+			 */
+			CommandCounterIncrement();
+		}
+
 		/* Store dependency on operator classes */
 		for (i = 0; i < indexInfo->ii_NumIndexKeyAttrs; i++)
 		{
@@ -1143,21 +1204,29 @@ index_create(Relation heapRelation,
 		/* Store dependencies on anything mentioned in index expressions */
 		if (indexInfo->ii_Expressions)
 		{
+			/* recordDependencyOnSingleRelExpr get rid of duplicate entries */
 			recordDependencyOnSingleRelExpr(&myself,
 											(Node *) indexInfo->ii_Expressions,
 											heapRelationId,
 											DEPENDENCY_NORMAL,
-											DEPENDENCY_AUTO, false);
+											DEPENDENCY_AUTO, false, true);
+			/*
+			 * Advance the command counter so that later
+			 * recordMultipleDependencies calls can see the newly-entered
+			 * pg_depend catalog tuples for the index.
+			 */
+			CommandCounterIncrement();
 		}
 
 		/* Store dependencies on anything mentioned in predicate */
 		if (indexInfo->ii_Predicate)
 		{
+			/* recordDependencyOnSingleRelExpr get rid of duplicate entries */
 			recordDependencyOnSingleRelExpr(&myself,
 											(Node *) indexInfo->ii_Predicate,
 											heapRelationId,
 											DEPENDENCY_NORMAL,
-											DEPENDENCY_AUTO, false);
+											DEPENDENCY_AUTO, false, true);
 		}
 	}
 	else
@@ -1229,6 +1298,94 @@ index_create(Relation heapRelation,
 	return indexRelationId;
 }
 
+static char *
+index_check_collation_version(const ObjectAddress *otherObject,
+							  const char *version,
+							  void *userdata)
+{
+	Oid			relid = *(Oid *) userdata;
+	char	   *current_version;
+
+	/* We only care about dependencies on collations. */
+	if (otherObject->classId != CollationRelationId)
+		return NULL;
+
+	/* Compare with the current version. */
+	current_version = get_collation_version_for_oid(otherObject->objectId);
+
+	/* XXX should we warn about "disappearing" versions? */
+	if (current_version)
+	{
+		/*
+		 * We now support versioning for the underlying collation library on
+		 * this system, or previous version is unknown.
+		 */
+		if (!version || (strcmp(version, "") == 0 && strcmp(current_version,
+						"") != 0))
+		{
+			ereport(WARNING,
+					(errmsg("index \"%s\" depends on collation \"%s\" with an unknown version, and the current version is \"%s\"",
+							get_rel_name(relid),
+							get_collation_name(otherObject->objectId),
+							current_version),
+					 errdetail("The index may be corrupted due to changes in sort order."),
+					 errhint("REINDEX to avoid the risk of corruption.")));
+		}
+		else if (strcmp(current_version, version) != 0)
+		{
+			ereport(WARNING,
+				(errmsg("index \"%s\" depends on collation \"%s\" version \"%s\", but the current version is \"%s\"",
+						get_rel_name(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.")));
+		}
+	}
+
+	return NULL;
+}
+
+void
+index_check_collation_versions(Oid relid)
+{
+	ObjectAddress object;
+
+	object.classId = RelationRelationId;
+	object.objectId = relid;
+	object.objectSubId = 0;
+	visitDependentObjects(&object, &index_check_collation_version, &relid);
+}
+
+static char *
+index_update_collation_version(const ObjectAddress *otherObject,
+							   const char *version,
+							   void *userdata)
+{
+	char   *current_version = (char *) userdata;
+
+	/* We only care about dependencies on collations. */
+	if (otherObject->classId != CollationRelationId)
+		return NULL;
+
+	current_version = get_collation_version_for_oid(otherObject->objectId);
+	return current_version;
+}
+
+static void
+index_update_collation_versions(Oid relid)
+{
+	ObjectAddress object;
+	NameData	current_version;
+
+	object.classId = RelationRelationId;
+	object.objectId = relid;
+	object.objectSubId = 0;
+	visitDependentObjects(&object, &index_update_collation_version,
+						  &current_version);
+}
+
 /*
  * index_concurrently_create_copy
  *
@@ -2635,6 +2792,17 @@ FormIndexDatum(IndexInfo *indexInfo,
 		elog(ERROR, "wrong number of index expressions");
 }
 
+/*
+ * Returns whether the given index access method depend on a stable collation
+ * order.
+ */
+static bool
+index_depends_stable_coll_order(Oid amoid)
+{
+	return (amoid != HASH_AM_OID &&
+			strcmp(get_am_name(amoid), "bloom") != 0);
+}
+
 
 /*
  * index_update_stats --- update pg_class entry after CREATE INDEX or REINDEX
@@ -3623,6 +3791,9 @@ 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);
 }
 
 /*
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index 90932be831..3cc0f6651c 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -360,7 +360,7 @@ CreateConstraintEntry(const char *constraintName,
 		 */
 		recordDependencyOnSingleRelExpr(&conobject, conExpr, relId,
 										DEPENDENCY_NORMAL,
-										DEPENDENCY_NORMAL, false);
+										DEPENDENCY_NORMAL, false, true);
 	}
 
 	/* Post creation hook for new constraint */
diff --git a/src/backend/catalog/pg_depend.c b/src/backend/catalog/pg_depend.c
index b7beb2884e..3f113499b2 100644
--- a/src/backend/catalog/pg_depend.c
+++ b/src/backend/catalog/pg_depend.c
@@ -19,16 +19,21 @@
 #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"
 #include "commands/extension.h"
 #include "miscadmin.h"
+#include "utils/builtins.h"
 #include "utils/fmgroids.h"
 #include "utils/lsyscache.h"
+#include "utils/pg_locale.h"
 #include "utils/rel.h"
 
 
+static bool dependencyExists(const ObjectAddress *depender,
+				   const ObjectAddress *referenced);
 static bool isObjectPinned(const ObjectAddress *object, Relation rel);
 
 
@@ -44,34 +49,47 @@ recordDependencyOn(const ObjectAddress *depender,
 				   const ObjectAddress *referenced,
 				   DependencyType behavior)
 {
-	recordMultipleDependencies(depender, referenced, NULL, 1, behavior);
+	recordMultipleDependencies(depender, referenced, 1, behavior, false);
 }
 
 /*
- * As recordDependencyOn(), but also capture a version string so that changes
- * in the referenced object can be detected.  The meaning of the version
- * string depends on the referenced object.  Currently it is used for
- * detecting changes in collation versions.
+ * Given a list of collations, record a dependency on its underlying collation
+ * version.
  */
-void
-recordDependencyOnVersion(const ObjectAddress *depender,
-						  const ObjectAddress *referenced,
-						  const NameData *version,
-						  DependencyType behavior)
+void recordDependencyOnCollations(ObjectAddress *myself,
+								  List *collations,
+								  bool record_version)
 {
-	recordMultipleDependencies(depender, referenced, version, 1, behavior);
+	ListCell   *lc;
+
+	foreach(lc, collations)
+	{
+		ObjectAddress referenced;
+
+		referenced.classId = CollationRelationId;
+		referenced.objectId = lfirst_oid(lc);
+		referenced.objectSubId = 0;
+
+		recordMultipleDependencies(myself, &referenced, 1,
+								  DEPENDENCY_NORMAL, record_version);
+	}
 }
 
 /*
  * Record multiple dependencies (of the same kind) for a single dependent
  * object.  This has a little less overhead than recording each separately.
+ *
+ * If track_version is true, then a record could be added even if the referenced
+ * dependency 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,
-						   const NameData *version,
 						   int nreferenced,
-						   DependencyType behavior)
+						   DependencyType behavior,
+						   bool track_version)
 {
 	Relation	dependDesc;
 	CatalogIndexState indstate;
@@ -79,6 +97,7 @@ recordMultipleDependencies(const ObjectAddress *depender,
 	int			i;
 	bool		nulls[Natts_pg_depend];
 	Datum		values[Natts_pg_depend];
+	char	   *version = NULL;
 
 	if (nreferenced <= 0)
 		return;					/* nothing to do */
@@ -97,12 +116,49 @@ recordMultipleDependencies(const ObjectAddress *depender,
 
 	for (i = 0; i < nreferenced; i++, referenced++)
 	{
+		bool ignore_systempin = false;
+
+		if (track_version)
+		{
+			/* Only dependency on a collation is supported. */
+			if (referenced->classId == CollationRelationId)
+			{
+				/* C and POSIX collations don't require tracking the version */
+				if (referenced->objectId == C_COLLATION_OID ||
+					referenced->objectId == POSIX_COLLATION_OID)
+					continue;
+
+				/*
+				 * We don't want to record redundant depedencies that are used
+				 * to track versions to avoid redundant warnings in case of
+				 * non-matching versions when those are checked.  Note that
+				 * callers have to take care of removing duplicated entries and
+				 * calling CommandCounterIncrement() if the dependencies are
+				 * registered in multiple calls.
+				 */
+				if (dependencyExists(depender, referenced))
+					continue;
+
+				/*
+				 * 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;
+				version = get_collation_version_for_oid(referenced->objectId);
+				Assert(version);
+			}
+		}
+		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))
 		{
 			/*
 			 * Record the Dependency.  Note we don't bother to check for
@@ -559,6 +615,54 @@ changeDependenciesOn(Oid refClassId, Oid oldRefObjectId,
 	return count;
 }
 
+/* dependencyExists()
+ *
+ * Test if a record exists for the given depender and referenceds addresses.
+ */
+static bool dependencyExists(const ObjectAddress *depender,
+				   const ObjectAddress *referenced)
+{
+	Relation	depRel;
+	ScanKeyData key[3];
+	SysScanDesc scan;
+	HeapTuple	tup;
+	bool	ret = false;
+
+	ScanKeyInit(&key[0],
+				Anum_pg_depend_classid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(depender->classId));
+	ScanKeyInit(&key[1],
+				Anum_pg_depend_objid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(depender->objectId));
+	ScanKeyInit(&key[2],
+				Anum_pg_depend_objsubid,
+				BTEqualStrategyNumber, F_INT4EQ,
+				Int32GetDatum(depender->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);
+
+		if (foundDep->refclassid == referenced->classId &&
+			foundDep->refobjid == referenced->objectId &&
+			foundDep->refobjsubid == referenced->objectSubId)
+		{
+			ret = true;
+			break;
+		}
+	}
+	systable_endscan(scan);
+	table_close(depRel, RowExclusiveLock);
+
+	return ret;
+}
+
 /*
  * isObjectPinned()
  *
diff --git a/src/backend/catalog/pg_type.c b/src/backend/catalog/pg_type.c
index cd56714968..fe14b6bd38 100644
--- 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 +513,74 @@ TypeCreate(Oid newTypeOid,
 	return address;
 }
 
+/* Get a list of all distinct collations oid that the given type depends on. */
+List *
+GetTypeCollations(Oid typeoid, bool non_deterministic_only)
+{
+	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))
+	{
+		if (!non_deterministic_only ||
+				!get_collation_isdeterministic(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))
+			{
+				if (!non_deterministic_only ||
+						!get_collation_isdeterministic(att->attcollation))
+					result = list_append_unique_oid(result, att->attcollation);
+			}
+			else
+				result = list_concat_unique_oid(result,
+						GetTypeCollations(att->atttypid,
+							non_deterministic_only));
+		}
+
+		relation_close(rel, NoLock);
+	}
+	else if (typeTup->typtype == TYPTYPE_DOMAIN)
+	{
+		Assert(OidIsValid(typeTup->typbasetype));
+
+		result = list_concat_unique_oid(result,
+				GetTypeCollations(typeTup->typbasetype,
+					non_deterministic_only));
+	}
+	else if (typeTup->typtype == TYPTYPE_RANGE)
+	{
+		Oid rangeid = get_range_subtype(typeTup->oid);
+
+		Assert(OidIsValid(rangeid));
+
+		result = list_concat_unique_oid(result,
+				GetTypeCollations(rangeid, non_deterministic_only));
+	}
+	else if (OidIsValid(typeTup->typelem))
+		result = list_concat_unique_oid(result,
+				GetTypeCollations(typeTup->typelem, non_deterministic_only));
+
+	ReleaseSysCache(tuple);
+
+	return result;
+}
+
 /*
  * GenerateTypeDependencies: build the dependencies needed for a type
  *
diff --git a/src/backend/commands/collationcmds.c b/src/backend/commands/collationcmds.c
index 78eceda848..d4eccf163f 100644
--- a/src/backend/commands/collationcmds.c
+++ b/src/backend/commands/collationcmds.c
@@ -273,28 +273,12 @@ 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);
+	Assert(version);
 
-	if (version)
-		PG_RETURN_TEXT_P(cstring_to_text(version));
-	else
-		PG_RETURN_NULL();
+	PG_RETURN_TEXT_P(cstring_to_text(version));
 }
 
 
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index d625d17bf4..2b7de111cd 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -31,6 +31,8 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/catalog.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -634,6 +636,35 @@ vacuum_open_relation(Oid relid, RangeVar *relation, int options,
 		rel_lock = false;
 	}
 
+	/*
+	 * Perform version sanity checks on the relation underlying indexes if
+	 * it's not a VACUUM FULL
+	 */
+	if (!(options & VACOPT_FULL) && onerel && !IsSystemRelation(onerel) &&
+			onerel->rd_rel->relhasindex)
+	{
+		List	   *indexoidlist;
+		ListCell   *l;
+
+		indexoidlist = RelationGetIndexList(onerel);
+		foreach(l, indexoidlist)
+		{
+			Oid			indexoid = lfirst_oid(l);
+			Relation	indexRelation;
+
+			indexRelation = index_open(indexoid, AccessShareLock);
+
+			/* Warn if any dependent collations' versions have moved. */
+			if (!indexRelation->rd_version_checked)
+			{
+				index_check_collation_versions(indexoid);
+				indexRelation->rd_version_checked = true;
+			}
+
+			index_close(indexRelation, NoLock);
+		}
+	}
+
 	/* if relation is opened, leave */
 	if (onerel)
 		return onerel;
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index d82fc5ab8b..f2fc427fc8 100644
--- 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
diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index 60dab33fcb..18a2d72f91 100644
--- 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"
@@ -148,6 +150,9 @@ 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
  *
@@ -1473,7 +1478,7 @@ pg_newlocale_from_collation(Oid collid)
  * NULL (if it doesn't support versions).  It must not return NULL for some
  * collcollate and not NULL for others.
  */
-char *
+static char *
 get_collation_actual_version(char collprovider, const char *collcollate)
 {
 	char	   *collversion = NULL;
@@ -1511,6 +1516,51 @@ get_collation_actual_version(char collprovider, const char *collcollate)
 	return collversion;
 }
 
+/*
+ * Get provider-specific collation version string given a collation OID.
+ *
+ * As this version is used in index dependency tracking, an empty string is
+ * returned when the version is unknown, to distinguish from dependencies where
+ * the version should not be tracked, represented by a NULL version.
+ */
+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);
+
+	if (!version)
+		return "";
+	else
+		return version;
+}
 
 #ifdef USE_ICU
 /*
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index ff70326474..bdf50ffe89 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -41,6 +41,7 @@
 #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/pg_am.h"
@@ -5623,6 +5624,7 @@ 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;
diff --git a/src/include/catalog/dependency.h b/src/include/catalog/dependency.h
index 7d9fc866b9..8858ceb3df 100644
--- a/src/include/catalog/dependency.h
+++ b/src/include/catalog/dependency.h
@@ -156,7 +156,8 @@ extern void recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 											Node *expr, Oid relId,
 											DependencyType behavior,
 											DependencyType self_behavior,
-											bool reverse_self);
+											bool reverse_self,
+											bool track_version);
 
 extern ObjectClass getObjectClass(const ObjectAddress *object);
 
@@ -176,22 +177,29 @@ extern void sort_object_addresses(ObjectAddresses *addrs);
 
 extern void free_object_addresses(ObjectAddresses *addrs);
 
+typedef char *(*VisitDependentObjectsFun) (const ObjectAddress *otherObject,
+											   const char *version,
+											   void *userdata);
+
+extern void visitDependentObjects(const ObjectAddress *object,
+								  VisitDependentObjectsFun callback,
+								  void *userdata);
+
 /* in pg_depend.c */
 
 extern void recordDependencyOn(const ObjectAddress *depender,
 							   const ObjectAddress *referenced,
 							   DependencyType behavior);
 
-extern void recordDependencyOnVersion(const ObjectAddress *depender,
-									  const ObjectAddress *referenced,
-									  const NameData *version,
-									  DependencyType behavior);
+extern void recordDependencyOnCollations(ObjectAddress *myself,
+										 List *collations,
+										 bool record_version);
 
 extern void recordMultipleDependencies(const ObjectAddress *depender,
 									   const ObjectAddress *referenced,
-									   const NameData *version,
 									   int nreferenced,
-									   DependencyType behavior);
+									   DependencyType behavior,
+									   bool track_version);
 
 extern void recordDependencyOnCurrentExtension(const ObjectAddress *object,
 											   bool isReplace);
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index a2890c1314..c619d02465 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -121,6 +121,8 @@ extern void FormIndexDatum(IndexInfo *indexInfo,
 						   Datum *values,
 						   bool *isnull);
 
+extern void index_check_collation_versions(Oid relid);
+
 extern void index_build(Relation heapRelation,
 						Relation indexRelation,
 						IndexInfo *indexInfo,
diff --git a/src/include/catalog/pg_type.h b/src/include/catalog/pg_type.h
index 97890946c5..3eb5ec4fcd 100644
--- a/src/include/catalog/pg_type.h
+++ b/src/include/catalog/pg_type.h
@@ -350,6 +350,8 @@ extern void GenerateTypeDependencies(HeapTuple typeTuple,
 									 bool isDependentType,
 									 bool rebuild);
 
+extern List *GetTypeCollations(Oid typeObjectid, bool non_deterministic_only);
+
 extern void RenameTypeInternal(Oid typeOid, const char *newTypeName,
 							   Oid typeNamespace);
 
diff --git a/src/include/utils/pg_locale.h b/src/include/utils/pg_locale.h
index 9cb7d91ddf..96da132c03 100644
--- 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);
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 44ed04dd3f..3656ea94e8 100644
--- 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 being done yet? */
 
 	/*
 	 * rd_createSubid is the ID of the highest subtransaction the rel has
diff --git a/src/test/Makefile b/src/test/Makefile
index efb206aa75..4ef0d11702 100644
--- 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
@@ -37,7 +38,7 @@ endif
 # clean" etc to recurse into them.  (We must filter out those that we
 # have conditionally included into SUBDIRS above, else there will be
 # make confusion.)
-ALWAYS_SUBDIRS = $(filter-out $(SUBDIRS),examples kerberos ldap locale thread ssl)
+ALWAYS_SUBDIRS = $(filter-out $(SUBDIRS),examples kerberos ldap thread ssl)
 
 # We want to recurse to all subdirs for all standard targets, except that
 # installcheck and install should not recurse into the subdirectory "modules".
diff --git a/src/test/locale/.gitignore b/src/test/locale/.gitignore
index 620d3df425..64e1bf2a80 100644
--- a/src/test/locale/.gitignore
+++ b/src/test/locale/.gitignore
@@ -1 +1,2 @@
 /test-ctype
+/tmp_check/
diff --git a/src/test/locale/Makefile b/src/test/locale/Makefile
index 22a45b65f2..73495cf16b 100644
--- 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:
+	$(prove_installcheck)
diff --git a/src/test/locale/t/001_index.pl b/src/test/locale/t/001_index.pl
new file mode 100644
index 0000000000..468fbb63b6
--- /dev/null
+++ b/src/test/locale/t/001_index.pl
@@ -0,0 +1,76 @@
+use strict;
+use warnings;
+
+use Config;
+use PostgresNode;
+use TestLib;
+use Test::More;
+
+if ($ENV{with_icu} eq 'yes')
+{
+	plan tests => 12;
+}
+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;
+
+$ENV{PGHOST} = $node->host;
+$ENV{PGPORT} = $node->port;
+$node->start;
+
+sub test_index
+{
+	my ($err_like, $err_comm) = @_;
+
+	my ($ret, $out, $err) = $node->psql('postgres',
+		'SET enable_seqscan = 0;'
+		. "EXPLAIN SELECT val FROM icu1 WHERE val = '0'");
+
+	is($ret, 0, 'EXPLAIN should succeed.');
+	like($out, qr/icu1_fr/, 'Index icu1_fr should be used.');
+	like($err, $err_like, $err_comm);
+}
+
+$node->safe_psql('postgres',
+	'CREATE TABLE icu1(val text);'
+	. 'INSERT INTO icu1 SELECT i::text FROM generate_series(1, 10000) i;'
+	. 'CREATE INDEX icu1_fr ON icu1 (val COLLATE "fr-x-icu");');
+$node->safe_psql('postgres', 'VACUUM ANALYZE icu1;');
+
+test_index(qr/^$/, 'No warning should be raised');
+
+# Simulate different collation version
+$node->safe_psql('postgres',
+	"UPDATE pg_depend SET refobjversion = 'not_a_version'"
+	. " WHERE refobjversion IS NOT NULL"
+	. " AND objid::regclass::text = 'icu1_fr';");
+
+test_index(qr/index "icu1_fr" depends on collation "fr-x-icu" version "not_a_version", but the current version is/,
+	'Different collation version warning should be raised.');
+
+# Simulate unknown collation version
+$node->safe_psql('postgres',
+	"UPDATE pg_depend SET refobjversion = ''"
+	. " WHERE refobjversion IS NOT NULL"
+	. " AND objid::regclass::text = 'icu1_fr';");
+
+test_index(qr/index "icu1_fr" depends on collation "fr-x-icu" with an unknown version, and the current version is/,
+	'Unknown collation version warning should be raised.');
+
+# Simulate previously unhandled collation versioning
+$node->safe_psql('postgres',
+	"UPDATE pg_depend SET refobjversion = NULL"
+	. " WHERE refobjversion IS NOT NULL"
+	. " AND objid::regclass::text = 'icu1_fr';");
+
+test_index(qr/index "icu1_fr" depends on collation "fr-x-icu" with an unknown version, and the current version is/,
+	'Unknown collation version warning should be raised.');
+
+$node->stop;
diff --git a/src/test/regress/expected/collate.icu.utf8.out b/src/test/regress/expected/collate.icu.utf8.out
index 60d9263a2f..09512c0f66 100644
--- a/src/test/regress/expected/collate.icu.utf8.out
+++ b/src/test/regress/expected/collate.icu.utf8.out
@@ -1897,6 +1897,136 @@ 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,
+    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 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);
+-- for key columns, hash indexes should record dependency on the collation but
+-- not the version
+CREATE INDEX icuidx18_hash_d_es ON collate_test USING hash (d_es);
+CREATE INDEX icuidx19_hash_id_d_es_eq ON collate_test USING hash (id) WHERE (d_es) = 'foo';
+CREATE INDEX icuidx20_hash_id_d_es_lt ON collate_test USING hash (id) WHERE (d_es) < 'foo';
+SELECT objid::regclass, refobjid::regcollation,
+CASE
+WHEN refobjversion IS NULL THEN 'version not tracked'
+ELSE CASE
+    WHEN refobjversion = pg_collation_actual_version(refobjid) THEN 'up to date'
+    ELSE 'out of date'
+    END
+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;
+           objid           |  refobjid  |       version       
+---------------------------+------------+---------------------
+ 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"  | up to date
+ 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"  | up to date
+ 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"  | up to date
+ icuidx11_d_es             | "es-x-icu" | up to date
+ icuidx12_custom           | "default"  | up to date
+ icuidx12_custom           | custom     | up to date
+ icuidx13_custom           | "default"  | up to date
+ icuidx13_custom           | custom     | up to date
+ icuidx14_myrange          | "default"  | up to date
+ 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
+ icuidx18_hash_d_es        | "es-x-icu" | version not tracked
+ icuidx19_hash_id_d_es_eq  | "default"  | up to date
+ icuidx19_hash_id_d_es_eq  | "es-x-icu" | up to date
+ icuidx20_hash_id_d_es_lt  | "default"  | up to date
+ icuidx20_hash_id_d_es_lt  | "es-x-icu" | up to date
+(49 rows)
+
+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)
+
 -- cleanup
 RESET search_path;
 SET client_min_messages TO warning;
diff --git a/src/test/regress/expected/create_index.out b/src/test/regress/expected/create_index.out
index ae95bb38a6..94b4daf4d6 100644
--- a/src/test/regress/expected/create_index.out
+++ b/src/test/regress/expected/create_index.out
@@ -2065,15 +2065,17 @@ 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 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
-(9 rows)
+(11 rows)
 
 REINDEX INDEX CONCURRENTLY concur_reindex_ind1;
 REINDEX TABLE CONCURRENTLY concur_reindex_tab;
@@ -2093,15 +2095,17 @@ 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 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
-(9 rows)
+(11 rows)
 
 -- Check that comments are preserved
 CREATE TABLE testcomment (i int);
diff --git a/src/test/regress/sql/collate.icu.utf8.sql b/src/test/regress/sql/collate.icu.utf8.sql
index 35acf91fbf..c8f1a620d2 100644
--- a/src/test/regress/sql/collate.icu.utf8.sql
+++ b/src/test/regress/sql/collate.icu.utf8.sql
@@ -716,6 +716,89 @@ 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,
+    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 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);
+-- for key columns, hash indexes should record dependency on the collation but
+-- not the version
+CREATE INDEX icuidx18_hash_d_es ON collate_test USING hash (d_es);
+CREATE INDEX icuidx19_hash_id_d_es_eq ON collate_test USING hash (id) WHERE (d_es) = 'foo';
+CREATE INDEX icuidx20_hash_id_d_es_lt ON collate_test USING hash (id) WHERE (d_es) < 'foo';
+
+SELECT objid::regclass, refobjid::regcollation,
+CASE
+WHEN refobjversion IS NULL THEN 'version not tracked'
+ELSE CASE
+    WHEN refobjversion = pg_collation_actual_version(refobjid) THEN 'up to date'
+    ELSE 'out of date'
+    END
+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;
+
+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';
 
 -- cleanup
 RESET search_path;
-- 
2.20.1


--sdtB3X0nJg68CQEu
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename="v16-0005-Preserve-index-dependencies-on-collation-during-.patch"



^ permalink  raw  reply  [nested|flat] 96+ messages in thread

* [PATCH v16 4/7] Track collation versions for indexes.
@ 2019-05-28 18:16  Thomas Munro <[email protected]>
  0 siblings, 0 replies; 96+ messages in thread

From: Thomas Munro @ 2019-05-28 18:16 UTC (permalink / raw)

Record the current version of dependent collations in pg_depend when creating
or rebuilding an index.  The version is checked against the current version
whenever we call get_relation_info for an index or open the parent table
during non-full VACUUM or ANALYZE.  Warn that the index may be corrupted if
the versions don't match.

A new flag is added in RelationData to specify that the check has already been
done to avoid repetition.

Thanks to Doug Doole, Peter Eisentraut, Christoph Berg, Laurenz Albe,
Michael Paquier, Robert Haas, Tom Lane and others for design discussion.

Author: Thomas Munro and Julien Rouhaud
Reviewed-by: Peter Eisentraut, Laurenz Albe
Discussion: https://postgr.es/m/CAEepm%3D0uEQCpfq_%2BLYFBdArCe4Ot98t1aR4eYiYTe%3DyavQygiQ%40mail.gmail.com
---
 doc/src/sgml/func.sgml                        |   2 +-
 doc/src/sgml/ref/reindex.sgml                 |   6 +
 src/backend/catalog/dependency.c              | 189 +++++++++++++++--
 src/backend/catalog/heap.c                    |   7 +-
 src/backend/catalog/index.c                   | 191 +++++++++++++++++-
 src/backend/catalog/pg_constraint.c           |   2 +-
 src/backend/catalog/pg_depend.c               | 130 +++++++++++-
 src/backend/catalog/pg_type.c                 |  69 +++++++
 src/backend/commands/collationcmds.c          |  22 +-
 src/backend/commands/vacuum.c                 |  31 +++
 src/backend/optimizer/util/plancat.c          |   9 +
 src/backend/utils/adt/pg_locale.c             |  52 ++++-
 src/backend/utils/cache/relcache.c            |   2 +
 src/include/catalog/dependency.h              |  19 +-
 src/include/catalog/index.h                   |   2 +
 src/include/catalog/pg_type.h                 |   2 +
 src/include/utils/pg_locale.h                 |   2 +-
 src/include/utils/rel.h                       |   1 +
 src/test/Makefile                             |   5 +-
 src/test/locale/.gitignore                    |   1 +
 src/test/locale/Makefile                      |   7 +
 src/test/locale/t/001_index.pl                |  76 +++++++
 .../regress/expected/collate.icu.utf8.out     | 130 ++++++++++++
 src/test/regress/expected/create_index.out    |   8 +-
 src/test/regress/sql/collate.icu.utf8.sql     |  83 ++++++++
 25 files changed, 979 insertions(+), 69 deletions(-)
 create mode 100644 src/test/locale/t/001_index.pl

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index fd1bba9959..29e4a9b73e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21125,7 +21125,7 @@ postgres=# SELECT * FROM pg_walfile_name_offset(pg_stop_backup());
    <para>
     <function>pg_collation_actual_version</function> returns the actual
     version of the collation object as it is currently installed in the
-    operating system.
+    operating system.  An empty string is returned if the version is unknown.
    </para>
 
    <para>
diff --git a/doc/src/sgml/ref/reindex.sgml b/doc/src/sgml/ref/reindex.sgml
index c54a7c420d..7209a606fa 100644
--- a/doc/src/sgml/ref/reindex.sgml
+++ b/doc/src/sgml/ref/reindex.sgml
@@ -39,6 +39,12 @@ REINDEX [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] { IN
 
    <itemizedlist>
     <listitem>
+     <para>
+      The index depends on the sort order of a collation, and the definition
+      of the collation has changed.  This can cause an index to fail to
+      find a key that is present in the index.  On some systems, collation
+      versions are tracked in order to generate warnings when this happens.
+     </para>
      <para>
       An index has become corrupted, and no longer contains valid
       data. Although in theory this should never happen, in
diff --git a/src/backend/catalog/dependency.c b/src/backend/catalog/dependency.c
index 660033b9c1..c0e36ef4cd 100644
--- a/src/backend/catalog/dependency.c
+++ b/src/backend/catalog/dependency.c
@@ -78,6 +78,7 @@
 #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"
@@ -138,6 +139,9 @@ typedef struct
 {
 	ObjectAddresses *addrs;		/* addresses being accumulated */
 	List	   *rtables;		/* list of rangetables to resolve Vars */
+	bool		track_version;	/* whether caller asked to track dependency
+								 * versions */
+	NodeTag		type;			/* nodetag of the current node */
 } find_expr_references_context;
 
 /*
@@ -438,6 +442,80 @@ performMultipleDeletions(const ObjectAddresses *objects,
 	table_close(depRel, RowExclusiveLock);
 }
 
+/*
+ * Call a function for all objects that depend on 'object'.  If the function
+ * returns a non-NULL pointer to a new version string, update the version.
+ */
+void
+visitDependentObjects(const ObjectAddress *object,
+					  VisitDependentObjectsFun 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 *cur_version, *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);
+
+		cur_version = isnull ? NULL : TextDatumGetCString(depversion);
+
+		new_version = callback(&otherObject, cur_version, userdata);
+		if (new_version)
+		{
+			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));
+
+			values[Anum_pg_depend_refobjversion - 1] =
+				CStringGetTextDatum(new_version);
+			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'
  *
@@ -1591,6 +1669,10 @@ recordDependencyOnExpr(const ObjectAddress *depender,
 	find_expr_references_context context;
 
 	context.addrs = new_object_addresses();
+	if (expr)
+		context.type = expr->type;
+	else
+		context.type = T_Invalid;
 
 	/* Set up interpretation for Vars at varlevelsup = 0 */
 	context.rtables = list_make1(rtable);
@@ -1603,9 +1685,10 @@ recordDependencyOnExpr(const ObjectAddress *depender,
 
 	/* And record 'em */
 	recordMultipleDependencies(depender,
-							   context.addrs->refs, NULL,
+							   context.addrs->refs,
 							   context.addrs->numrefs,
-							   behavior);
+							   behavior,
+							   false);
 
 	free_object_addresses(context.addrs);
 }
@@ -1632,12 +1715,18 @@ recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 								Node *expr, Oid relId,
 								DependencyType behavior,
 								DependencyType self_behavior,
-								bool reverse_self)
+								bool reverse_self,
+								bool track_version)
 {
 	find_expr_references_context context;
 	RangeTblEntry rte;
 
 	context.addrs = new_object_addresses();
+	context.track_version = track_version;
+	if (expr)
+		context.type = expr->type;
+	else
+		context.type = T_Invalid;
 
 	/* We gin up a rather bogus rangetable list to handle Vars */
 	MemSet(&rte, 0, sizeof(rte));
@@ -1691,9 +1780,10 @@ recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 		/* Record the self-dependencies with the appropriate direction */
 		if (!reverse_self)
 			recordMultipleDependencies(depender,
-									   self_addrs->refs, NULL,
+									   self_addrs->refs,
 									   self_addrs->numrefs,
-									   self_behavior);
+									   self_behavior,
+									   track_version);
 		else
 		{
 			/* Can't use recordMultipleDependencies, so do it the hard way */
@@ -1712,9 +1802,10 @@ recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 
 	/* Record the external dependencies */
 	recordMultipleDependencies(depender,
-							   context.addrs->refs, NULL,
+							   context.addrs->refs,
 							   context.addrs->numrefs,
-							   behavior);
+							   behavior,
+							   track_version);
 
 	free_object_addresses(context.addrs);
 }
@@ -1736,8 +1827,13 @@ static bool
 find_expr_references_walker(Node *node,
 							find_expr_references_context *context)
 {
+	NodeTag parent_type = context->type;
+
 	if (node == NULL)
 		return false;
+
+	context->type = node->type;
+
 	if (IsA(node, Var))
 	{
 		Var		   *var = (Var *) node;
@@ -1770,6 +1866,46 @@ 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);
+
+			/* Record collations from the type itself, or underlying in case of
+			 * complex type.  Note that if the direct parent is a CollateExpr
+			 * node, there's no need to record the type underlying collation if
+			 * any.  A dependency already exists for the owning relation, and a
+			 * change in the collation sort order wouldn't cause any harm as
+			 * the collation isn't used at all in such case.
+			 */
+			if (parent_type != T_CollateExpr)
+			{
+				/* type's collation if valid */
+				if (OidIsValid(var->varcollid))
+				{
+					add_object_address(OCLASS_COLLATION, var->varcollid, 0,
+									   context->addrs);
+				}
+				/*
+				 * otherwise, it may be a composite type having underlying
+				 * collations */
+				else if (var->vartype >= FirstNormalObjectId)
+				{
+					List	   *collations = NIL;
+					ListCell   *lc;
+
+					collations = GetTypeCollations(var->vartype, false);
+
+					foreach(lc, collations)
+					{
+						Oid coll = lfirst_oid(lc);
+
+						if (OidIsValid(coll) &&
+							(coll != DEFAULT_COLLATION_OID ||
+							 context->track_version)
+						)
+							add_object_address(OCLASS_COLLATION,
+									lfirst_oid(lc), 0,
+									context->addrs);
+					}
+				}
+			}
 		}
 
 		/*
@@ -1794,11 +1930,13 @@ 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.  However we can save work in the most common case
+		 * where the collation is "default", since we know that's pinned, if
+		 * the caller didn't ask to track dependency versions.
 		 */
 		if (OidIsValid(con->constcollid) &&
-			con->constcollid != DEFAULT_COLLATION_OID)
+				(con->constcollid != DEFAULT_COLLATION_OID ||
+					context->track_version))
 			add_object_address(OCLASS_COLLATION, con->constcollid, 0,
 							   context->addrs);
 
@@ -1888,7 +2026,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* and its collation, just as for Consts */
 		if (OidIsValid(param->paramcollid) &&
-			param->paramcollid != DEFAULT_COLLATION_OID)
+				(param->paramcollid != DEFAULT_COLLATION_OID ||
+					context->track_version))
 			add_object_address(OCLASS_COLLATION, param->paramcollid, 0,
 							   context->addrs);
 	}
@@ -1976,7 +2115,8 @@ find_expr_references_walker(Node *node,
 							   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(fselect->resultcollid) &&
-			fselect->resultcollid != DEFAULT_COLLATION_OID)
+			(fselect->resultcollid != DEFAULT_COLLATION_OID ||
+			 context->track_version))
 			add_object_address(OCLASS_COLLATION, fselect->resultcollid, 0,
 							   context->addrs);
 	}
@@ -2007,7 +2147,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(relab->resultcollid) &&
-			relab->resultcollid != DEFAULT_COLLATION_OID)
+			(relab->resultcollid != DEFAULT_COLLATION_OID ||
+			context->track_version))
 			add_object_address(OCLASS_COLLATION, relab->resultcollid, 0,
 							   context->addrs);
 	}
@@ -2020,7 +2161,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(iocoerce->resultcollid) &&
-			iocoerce->resultcollid != DEFAULT_COLLATION_OID)
+			(iocoerce->resultcollid != DEFAULT_COLLATION_OID ||
+			context->track_version))
 			add_object_address(OCLASS_COLLATION, iocoerce->resultcollid, 0,
 							   context->addrs);
 	}
@@ -2033,7 +2175,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(acoerce->resultcollid) &&
-			acoerce->resultcollid != DEFAULT_COLLATION_OID)
+			(acoerce->resultcollid != DEFAULT_COLLATION_OID ||
+			context->track_version))
 			add_object_address(OCLASS_COLLATION, acoerce->resultcollid, 0,
 							   context->addrs);
 		/* fall through to examine arguments */
@@ -2122,7 +2265,8 @@ find_expr_references_walker(Node *node,
 			add_object_address(OCLASS_PROC, wc->endInRangeFunc, 0,
 							   context->addrs);
 		if (OidIsValid(wc->inRangeColl) &&
-			wc->inRangeColl != DEFAULT_COLLATION_OID)
+			(wc->inRangeColl != DEFAULT_COLLATION_OID ||
+			context->track_version))
 			add_object_address(OCLASS_COLLATION, wc->inRangeColl, 0,
 							   context->addrs);
 		/* fall through to examine substructure */
@@ -2267,7 +2411,9 @@ find_expr_references_walker(Node *node,
 		{
 			Oid			collid = lfirst_oid(ct);
 
-			if (OidIsValid(collid) && collid != DEFAULT_COLLATION_OID)
+			if (OidIsValid(collid) &&
+					(collid != DEFAULT_COLLATION_OID ||
+					 context->track_version))
 				add_object_address(OCLASS_COLLATION, collid, 0,
 								   context->addrs);
 		}
@@ -2289,7 +2435,9 @@ find_expr_references_walker(Node *node,
 		{
 			Oid			collid = lfirst_oid(ct);
 
-			if (OidIsValid(collid) && collid != DEFAULT_COLLATION_OID)
+			if (OidIsValid(collid) &&
+					(collid != DEFAULT_COLLATION_OID ||
+					context->track_version))
 				add_object_address(OCLASS_COLLATION, collid, 0,
 								   context->addrs);
 		}
@@ -2685,8 +2833,9 @@ record_object_address_dependencies(const ObjectAddress *depender,
 {
 	eliminate_duplicate_dependencies(referenced);
 	recordMultipleDependencies(depender,
-							   referenced->refs, NULL, referenced->numrefs,
-							   behavior);
+							   referenced->refs, referenced->numrefs,
+							   behavior,
+							   false);
 }
 
 /*
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 9d9e915979..4546789446 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -2304,7 +2304,7 @@ StoreAttrDefault(Relation rel, AttrNumber attnum,
 		 */
 		recordDependencyOnSingleRelExpr(&colobject, expr, RelationGetRelid(rel),
 										DEPENDENCY_AUTO,
-										DEPENDENCY_AUTO, false);
+										DEPENDENCY_AUTO, false, false);
 	}
 	else
 	{
@@ -2314,7 +2314,7 @@ StoreAttrDefault(Relation rel, AttrNumber attnum,
 		 */
 		recordDependencyOnSingleRelExpr(&defobject, expr, RelationGetRelid(rel),
 										DEPENDENCY_NORMAL,
-										DEPENDENCY_NORMAL, false);
+										DEPENDENCY_NORMAL, false, false);
 	}
 
 	/*
@@ -3638,7 +3638,8 @@ 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
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 76fd938ce3..369b5d43f1 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -52,6 +52,7 @@
 #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"
@@ -74,6 +75,7 @@
 #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/snapmgr.h"
@@ -117,6 +119,7 @@ static void UpdateIndexRelation(Oid indexoid, Oid heapoid,
 								bool immediate,
 								bool isvalid,
 								bool isready);
+static bool index_depends_stable_coll_order(Oid amoid);
 static void index_update_stats(Relation rel,
 							   bool hasindex,
 							   double reltuples);
@@ -1025,6 +1028,10 @@ index_create(Relation heapRelation,
 	{
 		ObjectAddress myself,
 					referenced;
+		ListCell   *lc;
+		List	   *colls = NIL,
+				   *determ_colls = NIL,
+				   *nondeterm_colls = NIL;
 
 		myself.classId = RelationRelationId;
 		myself.objectId = indexRelationId;
@@ -1115,21 +1122,75 @@ index_create(Relation heapRelation,
 			recordDependencyOn(&myself, &referenced, DEPENDENCY_PARTITION_SEC);
 		}
 
-		/* Store dependency on collations */
-		/* The default collation is pinned, so don't bother recording it */
+		/* First, get all 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))
+				colls = lappend_oid(colls, colloid);
+			else
 			{
-				referenced.classId = CollationRelationId;
-				referenced.objectId = collationObjectId[i];
-				referenced.objectSubId = 0;
+				Form_pg_attribute att = TupleDescAttr(indexTupDesc, i);
 
-				recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
+				Assert(i < indexTupDesc->natts);
+
+				colls = list_concat(colls,
+									GetTypeCollations(att->atttypid, false));
 			}
 		}
 
+		/*
+		 * Then split the dependencies on whether they're deterministic or not,
+		 * removing any duplicates.
+		 */
+		foreach(lc, colls)
+		{
+			Oid c = lfirst_oid(lc);
+
+			if (!OidIsValid(c))
+				continue;
+
+			if (get_collation_isdeterministic(c))
+				determ_colls = list_append_unique_oid(determ_colls, c);
+			else
+				nondeterm_colls = list_append_unique_oid(nondeterm_colls, c);
+		}
+
+		/*
+		 * For deterministic transaction, only track the version if the AM
+		 * relies on a stable ordering.
+		 */
+		if (determ_colls)
+		{
+			bool track_version;
+
+			track_version = index_depends_stable_coll_order(indexInfo->ii_Am);
+
+			recordDependencyOnCollations(&myself, determ_colls, track_version);
+			/*
+			 * Advance the command counter so that later calls to
+			 * recordMultipleDependencies calls can see the newly-entered
+			 * pg_depend catalog tuples for the index.
+			 */
+			CommandCounterIncrement();
+		}
+
+		/*
+		 * We always record the version for dependency on non-deterministic
+		 * collations.
+		 */
+		if (nondeterm_colls)
+		{
+			recordDependencyOnCollations(&myself, nondeterm_colls, true);
+			/*
+			 * Advance the command counter so that later calls to
+			 * recordMultipleDependencies calls can see the newly-entered
+			 * pg_depend catalog tuples for the index.
+			 */
+			CommandCounterIncrement();
+		}
+
 		/* Store dependency on operator classes */
 		for (i = 0; i < indexInfo->ii_NumIndexKeyAttrs; i++)
 		{
@@ -1143,21 +1204,29 @@ index_create(Relation heapRelation,
 		/* Store dependencies on anything mentioned in index expressions */
 		if (indexInfo->ii_Expressions)
 		{
+			/* recordDependencyOnSingleRelExpr get rid of duplicate entries */
 			recordDependencyOnSingleRelExpr(&myself,
 											(Node *) indexInfo->ii_Expressions,
 											heapRelationId,
 											DEPENDENCY_NORMAL,
-											DEPENDENCY_AUTO, false);
+											DEPENDENCY_AUTO, false, true);
+			/*
+			 * Advance the command counter so that later
+			 * recordMultipleDependencies calls can see the newly-entered
+			 * pg_depend catalog tuples for the index.
+			 */
+			CommandCounterIncrement();
 		}
 
 		/* Store dependencies on anything mentioned in predicate */
 		if (indexInfo->ii_Predicate)
 		{
+			/* recordDependencyOnSingleRelExpr get rid of duplicate entries */
 			recordDependencyOnSingleRelExpr(&myself,
 											(Node *) indexInfo->ii_Predicate,
 											heapRelationId,
 											DEPENDENCY_NORMAL,
-											DEPENDENCY_AUTO, false);
+											DEPENDENCY_AUTO, false, true);
 		}
 	}
 	else
@@ -1229,6 +1298,94 @@ index_create(Relation heapRelation,
 	return indexRelationId;
 }
 
+static char *
+index_check_collation_version(const ObjectAddress *otherObject,
+							  const char *version,
+							  void *userdata)
+{
+	Oid			relid = *(Oid *) userdata;
+	char	   *current_version;
+
+	/* We only care about dependencies on collations. */
+	if (otherObject->classId != CollationRelationId)
+		return NULL;
+
+	/* Compare with the current version. */
+	current_version = get_collation_version_for_oid(otherObject->objectId);
+
+	/* XXX should we warn about "disappearing" versions? */
+	if (current_version)
+	{
+		/*
+		 * We now support versioning for the underlying collation library on
+		 * this system, or previous version is unknown.
+		 */
+		if (!version || (strcmp(version, "") == 0 && strcmp(current_version,
+						"") != 0))
+		{
+			ereport(WARNING,
+					(errmsg("index \"%s\" depends on collation \"%s\" with an unknown version, and the current version is \"%s\"",
+							get_rel_name(relid),
+							get_collation_name(otherObject->objectId),
+							current_version),
+					 errdetail("The index may be corrupted due to changes in sort order."),
+					 errhint("REINDEX to avoid the risk of corruption.")));
+		}
+		else if (strcmp(current_version, version) != 0)
+		{
+			ereport(WARNING,
+				(errmsg("index \"%s\" depends on collation \"%s\" version \"%s\", but the current version is \"%s\"",
+						get_rel_name(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.")));
+		}
+	}
+
+	return NULL;
+}
+
+void
+index_check_collation_versions(Oid relid)
+{
+	ObjectAddress object;
+
+	object.classId = RelationRelationId;
+	object.objectId = relid;
+	object.objectSubId = 0;
+	visitDependentObjects(&object, &index_check_collation_version, &relid);
+}
+
+static char *
+index_update_collation_version(const ObjectAddress *otherObject,
+							   const char *version,
+							   void *userdata)
+{
+	char   *current_version = (char *) userdata;
+
+	/* We only care about dependencies on collations. */
+	if (otherObject->classId != CollationRelationId)
+		return NULL;
+
+	current_version = get_collation_version_for_oid(otherObject->objectId);
+	return current_version;
+}
+
+static void
+index_update_collation_versions(Oid relid)
+{
+	ObjectAddress object;
+	NameData	current_version;
+
+	object.classId = RelationRelationId;
+	object.objectId = relid;
+	object.objectSubId = 0;
+	visitDependentObjects(&object, &index_update_collation_version,
+						  &current_version);
+}
+
 /*
  * index_concurrently_create_copy
  *
@@ -2635,6 +2792,17 @@ FormIndexDatum(IndexInfo *indexInfo,
 		elog(ERROR, "wrong number of index expressions");
 }
 
+/*
+ * Returns whether the given index access method depend on a stable collation
+ * order.
+ */
+static bool
+index_depends_stable_coll_order(Oid amoid)
+{
+	return (amoid != HASH_AM_OID &&
+			strcmp(get_am_name(amoid), "bloom") != 0);
+}
+
 
 /*
  * index_update_stats --- update pg_class entry after CREATE INDEX or REINDEX
@@ -3623,6 +3791,9 @@ 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);
 }
 
 /*
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index 90932be831..3cc0f6651c 100644
--- a/src/backend/catalog/pg_constraint.c
+++ b/src/backend/catalog/pg_constraint.c
@@ -360,7 +360,7 @@ CreateConstraintEntry(const char *constraintName,
 		 */
 		recordDependencyOnSingleRelExpr(&conobject, conExpr, relId,
 										DEPENDENCY_NORMAL,
-										DEPENDENCY_NORMAL, false);
+										DEPENDENCY_NORMAL, false, true);
 	}
 
 	/* Post creation hook for new constraint */
diff --git a/src/backend/catalog/pg_depend.c b/src/backend/catalog/pg_depend.c
index 312d4d3d90..3f113499b2 100644
--- 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"
@@ -27,9 +28,12 @@
 #include "utils/builtins.h"
 #include "utils/fmgroids.h"
 #include "utils/lsyscache.h"
+#include "utils/pg_locale.h"
 #include "utils/rel.h"
 
 
+static bool dependencyExists(const ObjectAddress *depender,
+				   const ObjectAddress *referenced);
 static bool isObjectPinned(const ObjectAddress *object, Relation rel);
 
 
@@ -45,19 +49,47 @@ recordDependencyOn(const ObjectAddress *depender,
 				   const ObjectAddress *referenced,
 				   DependencyType behavior)
 {
-	recordMultipleDependencies(depender, referenced, NULL, 1, behavior);
+	recordMultipleDependencies(depender, referenced, 1, behavior, false);
+}
+
+/*
+ * Given a list of collations, record a dependency on its underlying collation
+ * version.
+ */
+void recordDependencyOnCollations(ObjectAddress *myself,
+								  List *collations,
+								  bool record_version)
+{
+	ListCell   *lc;
+
+	foreach(lc, collations)
+	{
+		ObjectAddress referenced;
+
+		referenced.classId = CollationRelationId;
+		referenced.objectId = lfirst_oid(lc);
+		referenced.objectSubId = 0;
+
+		recordMultipleDependencies(myself, &referenced, 1,
+								  DEPENDENCY_NORMAL, record_version);
+	}
 }
 
 /*
  * Record multiple dependencies (of the same kind) for a single dependent
  * object.  This has a little less overhead than recording each separately.
+ *
+ * If track_version is true, then a record could be added even if the referenced
+ * dependency 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,
-						   const char *version,
 						   int nreferenced,
-						   DependencyType behavior)
+						   DependencyType behavior,
+						   bool track_version)
 {
 	Relation	dependDesc;
 	CatalogIndexState indstate;
@@ -65,6 +97,7 @@ recordMultipleDependencies(const ObjectAddress *depender,
 	int			i;
 	bool		nulls[Natts_pg_depend];
 	Datum		values[Natts_pg_depend];
+	char	   *version = NULL;
 
 	if (nreferenced <= 0)
 		return;					/* nothing to do */
@@ -83,12 +116,49 @@ recordMultipleDependencies(const ObjectAddress *depender,
 
 	for (i = 0; i < nreferenced; i++, referenced++)
 	{
+		bool ignore_systempin = false;
+
+		if (track_version)
+		{
+			/* Only dependency on a collation is supported. */
+			if (referenced->classId == CollationRelationId)
+			{
+				/* C and POSIX collations don't require tracking the version */
+				if (referenced->objectId == C_COLLATION_OID ||
+					referenced->objectId == POSIX_COLLATION_OID)
+					continue;
+
+				/*
+				 * We don't want to record redundant depedencies that are used
+				 * to track versions to avoid redundant warnings in case of
+				 * non-matching versions when those are checked.  Note that
+				 * callers have to take care of removing duplicated entries and
+				 * calling CommandCounterIncrement() if the dependencies are
+				 * registered in multiple calls.
+				 */
+				if (dependencyExists(depender, referenced))
+					continue;
+
+				/*
+				 * 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;
+				version = get_collation_version_for_oid(referenced->objectId);
+				Assert(version);
+			}
+		}
+		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))
 		{
 			/*
 			 * Record the Dependency.  Note we don't bother to check for
@@ -545,6 +615,54 @@ changeDependenciesOn(Oid refClassId, Oid oldRefObjectId,
 	return count;
 }
 
+/* dependencyExists()
+ *
+ * Test if a record exists for the given depender and referenceds addresses.
+ */
+static bool dependencyExists(const ObjectAddress *depender,
+				   const ObjectAddress *referenced)
+{
+	Relation	depRel;
+	ScanKeyData key[3];
+	SysScanDesc scan;
+	HeapTuple	tup;
+	bool	ret = false;
+
+	ScanKeyInit(&key[0],
+				Anum_pg_depend_classid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(depender->classId));
+	ScanKeyInit(&key[1],
+				Anum_pg_depend_objid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(depender->objectId));
+	ScanKeyInit(&key[2],
+				Anum_pg_depend_objsubid,
+				BTEqualStrategyNumber, F_INT4EQ,
+				Int32GetDatum(depender->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);
+
+		if (foundDep->refclassid == referenced->classId &&
+			foundDep->refobjid == referenced->objectId &&
+			foundDep->refobjsubid == referenced->objectSubId)
+		{
+			ret = true;
+			break;
+		}
+	}
+	systable_endscan(scan);
+	table_close(depRel, RowExclusiveLock);
+
+	return ret;
+}
+
 /*
  * isObjectPinned()
  *
diff --git a/src/backend/catalog/pg_type.c b/src/backend/catalog/pg_type.c
index cd56714968..fe14b6bd38 100644
--- 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 +513,74 @@ TypeCreate(Oid newTypeOid,
 	return address;
 }
 
+/* Get a list of all distinct collations oid that the given type depends on. */
+List *
+GetTypeCollations(Oid typeoid, bool non_deterministic_only)
+{
+	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))
+	{
+		if (!non_deterministic_only ||
+				!get_collation_isdeterministic(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))
+			{
+				if (!non_deterministic_only ||
+						!get_collation_isdeterministic(att->attcollation))
+					result = list_append_unique_oid(result, att->attcollation);
+			}
+			else
+				result = list_concat_unique_oid(result,
+						GetTypeCollations(att->atttypid,
+							non_deterministic_only));
+		}
+
+		relation_close(rel, NoLock);
+	}
+	else if (typeTup->typtype == TYPTYPE_DOMAIN)
+	{
+		Assert(OidIsValid(typeTup->typbasetype));
+
+		result = list_concat_unique_oid(result,
+				GetTypeCollations(typeTup->typbasetype,
+					non_deterministic_only));
+	}
+	else if (typeTup->typtype == TYPTYPE_RANGE)
+	{
+		Oid rangeid = get_range_subtype(typeTup->oid);
+
+		Assert(OidIsValid(rangeid));
+
+		result = list_concat_unique_oid(result,
+				GetTypeCollations(rangeid, non_deterministic_only));
+	}
+	else if (OidIsValid(typeTup->typelem))
+		result = list_concat_unique_oid(result,
+				GetTypeCollations(typeTup->typelem, non_deterministic_only));
+
+	ReleaseSysCache(tuple);
+
+	return result;
+}
+
 /*
  * GenerateTypeDependencies: build the dependencies needed for a type
  *
diff --git a/src/backend/commands/collationcmds.c b/src/backend/commands/collationcmds.c
index 78eceda848..d4eccf163f 100644
--- a/src/backend/commands/collationcmds.c
+++ b/src/backend/commands/collationcmds.c
@@ -273,28 +273,12 @@ 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);
+	Assert(version);
 
-	if (version)
-		PG_RETURN_TEXT_P(cstring_to_text(version));
-	else
-		PG_RETURN_NULL();
+	PG_RETURN_TEXT_P(cstring_to_text(version));
 }
 
 
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index d625d17bf4..2b7de111cd 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -31,6 +31,8 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/catalog.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -634,6 +636,35 @@ vacuum_open_relation(Oid relid, RangeVar *relation, int options,
 		rel_lock = false;
 	}
 
+	/*
+	 * Perform version sanity checks on the relation underlying indexes if
+	 * it's not a VACUUM FULL
+	 */
+	if (!(options & VACOPT_FULL) && onerel && !IsSystemRelation(onerel) &&
+			onerel->rd_rel->relhasindex)
+	{
+		List	   *indexoidlist;
+		ListCell   *l;
+
+		indexoidlist = RelationGetIndexList(onerel);
+		foreach(l, indexoidlist)
+		{
+			Oid			indexoid = lfirst_oid(l);
+			Relation	indexRelation;
+
+			indexRelation = index_open(indexoid, AccessShareLock);
+
+			/* Warn if any dependent collations' versions have moved. */
+			if (!indexRelation->rd_version_checked)
+			{
+				index_check_collation_versions(indexoid);
+				indexRelation->rd_version_checked = true;
+			}
+
+			index_close(indexRelation, NoLock);
+		}
+	}
+
 	/* if relation is opened, leave */
 	if (onerel)
 		return onerel;
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index d82fc5ab8b..f2fc427fc8 100644
--- 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
diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index 60dab33fcb..18a2d72f91 100644
--- 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"
@@ -148,6 +150,9 @@ 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
  *
@@ -1473,7 +1478,7 @@ pg_newlocale_from_collation(Oid collid)
  * NULL (if it doesn't support versions).  It must not return NULL for some
  * collcollate and not NULL for others.
  */
-char *
+static char *
 get_collation_actual_version(char collprovider, const char *collcollate)
 {
 	char	   *collversion = NULL;
@@ -1511,6 +1516,51 @@ get_collation_actual_version(char collprovider, const char *collcollate)
 	return collversion;
 }
 
+/*
+ * Get provider-specific collation version string given a collation OID.
+ *
+ * As this version is used in index dependency tracking, an empty string is
+ * returned when the version is unknown, to distinguish from dependencies where
+ * the version should not be tracked, represented by a NULL version.
+ */
+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);
+
+	if (!version)
+		return "";
+	else
+		return version;
+}
 
 #ifdef USE_ICU
 /*
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index ff70326474..bdf50ffe89 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -41,6 +41,7 @@
 #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/pg_am.h"
@@ -5623,6 +5624,7 @@ 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;
diff --git a/src/include/catalog/dependency.h b/src/include/catalog/dependency.h
index 473342dad2..8858ceb3df 100644
--- a/src/include/catalog/dependency.h
+++ b/src/include/catalog/dependency.h
@@ -156,7 +156,8 @@ extern void recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 											Node *expr, Oid relId,
 											DependencyType behavior,
 											DependencyType self_behavior,
-											bool reverse_self);
+											bool reverse_self,
+											bool track_version);
 
 extern ObjectClass getObjectClass(const ObjectAddress *object);
 
@@ -176,17 +177,29 @@ extern void sort_object_addresses(ObjectAddresses *addrs);
 
 extern void free_object_addresses(ObjectAddresses *addrs);
 
+typedef char *(*VisitDependentObjectsFun) (const ObjectAddress *otherObject,
+											   const char *version,
+											   void *userdata);
+
+extern void visitDependentObjects(const ObjectAddress *object,
+								  VisitDependentObjectsFun callback,
+								  void *userdata);
+
 /* 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,
-									   const char *version,
 									   int nreferenced,
-									   DependencyType behavior);
+									   DependencyType behavior,
+									   bool track_version);
 
 extern void recordDependencyOnCurrentExtension(const ObjectAddress *object,
 											   bool isReplace);
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index a2890c1314..c619d02465 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -121,6 +121,8 @@ extern void FormIndexDatum(IndexInfo *indexInfo,
 						   Datum *values,
 						   bool *isnull);
 
+extern void index_check_collation_versions(Oid relid);
+
 extern void index_build(Relation heapRelation,
 						Relation indexRelation,
 						IndexInfo *indexInfo,
diff --git a/src/include/catalog/pg_type.h b/src/include/catalog/pg_type.h
index 97890946c5..3eb5ec4fcd 100644
--- a/src/include/catalog/pg_type.h
+++ b/src/include/catalog/pg_type.h
@@ -350,6 +350,8 @@ extern void GenerateTypeDependencies(HeapTuple typeTuple,
 									 bool isDependentType,
 									 bool rebuild);
 
+extern List *GetTypeCollations(Oid typeObjectid, bool non_deterministic_only);
+
 extern void RenameTypeInternal(Oid typeOid, const char *newTypeName,
 							   Oid typeNamespace);
 
diff --git a/src/include/utils/pg_locale.h b/src/include/utils/pg_locale.h
index 9cb7d91ddf..96da132c03 100644
--- 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);
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 44ed04dd3f..3656ea94e8 100644
--- 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 being done yet? */
 
 	/*
 	 * rd_createSubid is the ID of the highest subtransaction the rel has
diff --git a/src/test/Makefile b/src/test/Makefile
index efb206aa75..4ef0d11702 100644
--- 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
@@ -37,7 +38,7 @@ endif
 # clean" etc to recurse into them.  (We must filter out those that we
 # have conditionally included into SUBDIRS above, else there will be
 # make confusion.)
-ALWAYS_SUBDIRS = $(filter-out $(SUBDIRS),examples kerberos ldap locale thread ssl)
+ALWAYS_SUBDIRS = $(filter-out $(SUBDIRS),examples kerberos ldap thread ssl)
 
 # We want to recurse to all subdirs for all standard targets, except that
 # installcheck and install should not recurse into the subdirectory "modules".
diff --git a/src/test/locale/.gitignore b/src/test/locale/.gitignore
index 620d3df425..64e1bf2a80 100644
--- a/src/test/locale/.gitignore
+++ b/src/test/locale/.gitignore
@@ -1 +1,2 @@
 /test-ctype
+/tmp_check/
diff --git a/src/test/locale/Makefile b/src/test/locale/Makefile
index 22a45b65f2..73495cf16b 100644
--- 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:
+	$(prove_installcheck)
diff --git a/src/test/locale/t/001_index.pl b/src/test/locale/t/001_index.pl
new file mode 100644
index 0000000000..468fbb63b6
--- /dev/null
+++ b/src/test/locale/t/001_index.pl
@@ -0,0 +1,76 @@
+use strict;
+use warnings;
+
+use Config;
+use PostgresNode;
+use TestLib;
+use Test::More;
+
+if ($ENV{with_icu} eq 'yes')
+{
+	plan tests => 12;
+}
+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;
+
+$ENV{PGHOST} = $node->host;
+$ENV{PGPORT} = $node->port;
+$node->start;
+
+sub test_index
+{
+	my ($err_like, $err_comm) = @_;
+
+	my ($ret, $out, $err) = $node->psql('postgres',
+		'SET enable_seqscan = 0;'
+		. "EXPLAIN SELECT val FROM icu1 WHERE val = '0'");
+
+	is($ret, 0, 'EXPLAIN should succeed.');
+	like($out, qr/icu1_fr/, 'Index icu1_fr should be used.');
+	like($err, $err_like, $err_comm);
+}
+
+$node->safe_psql('postgres',
+	'CREATE TABLE icu1(val text);'
+	. 'INSERT INTO icu1 SELECT i::text FROM generate_series(1, 10000) i;'
+	. 'CREATE INDEX icu1_fr ON icu1 (val COLLATE "fr-x-icu");');
+$node->safe_psql('postgres', 'VACUUM ANALYZE icu1;');
+
+test_index(qr/^$/, 'No warning should be raised');
+
+# Simulate different collation version
+$node->safe_psql('postgres',
+	"UPDATE pg_depend SET refobjversion = 'not_a_version'"
+	. " WHERE refobjversion IS NOT NULL"
+	. " AND objid::regclass::text = 'icu1_fr';");
+
+test_index(qr/index "icu1_fr" depends on collation "fr-x-icu" version "not_a_version", but the current version is/,
+	'Different collation version warning should be raised.');
+
+# Simulate unknown collation version
+$node->safe_psql('postgres',
+	"UPDATE pg_depend SET refobjversion = ''"
+	. " WHERE refobjversion IS NOT NULL"
+	. " AND objid::regclass::text = 'icu1_fr';");
+
+test_index(qr/index "icu1_fr" depends on collation "fr-x-icu" with an unknown version, and the current version is/,
+	'Unknown collation version warning should be raised.');
+
+# Simulate previously unhandled collation versioning
+$node->safe_psql('postgres',
+	"UPDATE pg_depend SET refobjversion = NULL"
+	. " WHERE refobjversion IS NOT NULL"
+	. " AND objid::regclass::text = 'icu1_fr';");
+
+test_index(qr/index "icu1_fr" depends on collation "fr-x-icu" with an unknown version, and the current version is/,
+	'Unknown collation version warning should be raised.');
+
+$node->stop;
diff --git a/src/test/regress/expected/collate.icu.utf8.out b/src/test/regress/expected/collate.icu.utf8.out
index 60d9263a2f..09512c0f66 100644
--- a/src/test/regress/expected/collate.icu.utf8.out
+++ b/src/test/regress/expected/collate.icu.utf8.out
@@ -1897,6 +1897,136 @@ 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,
+    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 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);
+-- for key columns, hash indexes should record dependency on the collation but
+-- not the version
+CREATE INDEX icuidx18_hash_d_es ON collate_test USING hash (d_es);
+CREATE INDEX icuidx19_hash_id_d_es_eq ON collate_test USING hash (id) WHERE (d_es) = 'foo';
+CREATE INDEX icuidx20_hash_id_d_es_lt ON collate_test USING hash (id) WHERE (d_es) < 'foo';
+SELECT objid::regclass, refobjid::regcollation,
+CASE
+WHEN refobjversion IS NULL THEN 'version not tracked'
+ELSE CASE
+    WHEN refobjversion = pg_collation_actual_version(refobjid) THEN 'up to date'
+    ELSE 'out of date'
+    END
+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;
+           objid           |  refobjid  |       version       
+---------------------------+------------+---------------------
+ 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"  | up to date
+ 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"  | up to date
+ 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"  | up to date
+ icuidx11_d_es             | "es-x-icu" | up to date
+ icuidx12_custom           | "default"  | up to date
+ icuidx12_custom           | custom     | up to date
+ icuidx13_custom           | "default"  | up to date
+ icuidx13_custom           | custom     | up to date
+ icuidx14_myrange          | "default"  | up to date
+ 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
+ icuidx18_hash_d_es        | "es-x-icu" | version not tracked
+ icuidx19_hash_id_d_es_eq  | "default"  | up to date
+ icuidx19_hash_id_d_es_eq  | "es-x-icu" | up to date
+ icuidx20_hash_id_d_es_lt  | "default"  | up to date
+ icuidx20_hash_id_d_es_lt  | "es-x-icu" | up to date
+(49 rows)
+
+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)
+
 -- cleanup
 RESET search_path;
 SET client_min_messages TO warning;
diff --git a/src/test/regress/expected/create_index.out b/src/test/regress/expected/create_index.out
index ae95bb38a6..94b4daf4d6 100644
--- a/src/test/regress/expected/create_index.out
+++ b/src/test/regress/expected/create_index.out
@@ -2065,15 +2065,17 @@ 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 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
-(9 rows)
+(11 rows)
 
 REINDEX INDEX CONCURRENTLY concur_reindex_ind1;
 REINDEX TABLE CONCURRENTLY concur_reindex_tab;
@@ -2093,15 +2095,17 @@ 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 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
-(9 rows)
+(11 rows)
 
 -- Check that comments are preserved
 CREATE TABLE testcomment (i int);
diff --git a/src/test/regress/sql/collate.icu.utf8.sql b/src/test/regress/sql/collate.icu.utf8.sql
index 35acf91fbf..c8f1a620d2 100644
--- a/src/test/regress/sql/collate.icu.utf8.sql
+++ b/src/test/regress/sql/collate.icu.utf8.sql
@@ -716,6 +716,89 @@ 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,
+    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 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);
+-- for key columns, hash indexes should record dependency on the collation but
+-- not the version
+CREATE INDEX icuidx18_hash_d_es ON collate_test USING hash (d_es);
+CREATE INDEX icuidx19_hash_id_d_es_eq ON collate_test USING hash (id) WHERE (d_es) = 'foo';
+CREATE INDEX icuidx20_hash_id_d_es_lt ON collate_test USING hash (id) WHERE (d_es) < 'foo';
+
+SELECT objid::regclass, refobjid::regcollation,
+CASE
+WHEN refobjversion IS NULL THEN 'version not tracked'
+ELSE CASE
+    WHEN refobjversion = pg_collation_actual_version(refobjid) THEN 'up to date'
+    ELSE 'out of date'
+    END
+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;
+
+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';
 
 -- cleanup
 RESET search_path;
-- 
2.20.1


--fUYQa+Pmc3FrFX/N
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename="v16-0005-Preserve-index-dependencies-on-collation-during-.patch"



^ permalink  raw  reply  [nested|flat] 96+ messages in thread

* [PATCH v29 4/6] Track collation versions for indexes.
@ 2019-05-28 18:16  Thomas Munro <[email protected]>
  0 siblings, 0 replies; 96+ messages in thread

From: Thomas Munro @ 2019-05-28 18:16 UTC (permalink / raw)

Record the current version of dependent collations in pg_depend when
creating or rebuilding an index.  The version is checked against the
current version whenever we call get_relation_info for an index or open
the parent table during non-full VACUUM or ANALYZE.  Warn that the index
may be corrupted if the versions don't match.

Add a new flag is added to RelationData to record that the check has
already been done to avoid repetition.

Thanks to Doug Doole, Peter Eisentraut, Christoph Berg, Laurenz Albe,
Michael Paquier, Robert Haas, Tom Lane and others for design discussion.

Author: Thomas Munro <[email protected]>
Author: Julien Rouhaud <[email protected]>
Reviewed-by: Peter Eisentraut <[email protected]>
Reviewed-by: Laurenz Albe <[email protected]>
Discussion: https://postgr.es/m/CAEepm%3D0uEQCpfq_%2BLYFBdArCe4Ot98t1aR4eYiYTe%3DyavQygiQ%40mail.gmail.com
---
 doc/src/sgml/func.sgml                        |   3 +-
 doc/src/sgml/ref/pgupgrade.sgml               |  18 ++
 doc/src/sgml/ref/reindex.sgml                 |   6 +
 src/backend/catalog/dependency.c              | 218 +++++++++++++--
 src/backend/catalog/heap.c                    |   7 +-
 src/backend/catalog/index.c                   | 264 +++++++++++++++++-
 src/backend/catalog/pg_constraint.c           |   2 +-
 src/backend/catalog/pg_depend.c               | 208 +++++++++++++-
 src/backend/catalog/pg_type.c                 |  69 +++++
 src/backend/commands/collationcmds.c          |  22 +-
 src/backend/commands/vacuum.c                 |  32 +++
 src/backend/optimizer/util/plancat.c          |   9 +
 src/backend/utils/adt/pg_locale.c             |  52 +++-
 src/backend/utils/adt/pg_upgrade_support.c    |  25 ++
 src/backend/utils/cache/relcache.c            |   2 +
 src/bin/pg_dump/Makefile                      |   2 +
 src/bin/pg_dump/pg_backup.h                   |   1 +
 src/bin/pg_dump/pg_dump.c                     | 186 +++++++++++-
 src/bin/pg_dump/pg_dump.h                     |   3 +
 src/bin/pg_dump/t/002_pg_dump.pl              | 248 ++++++++++++----
 src/bin/pg_upgrade/dump.c                     |   4 +-
 src/bin/pg_upgrade/option.c                   |   7 +
 src/bin/pg_upgrade/pg_upgrade.h               |   2 +
 src/include/catalog/dependency.h              |  31 +-
 src/include/catalog/index.h                   |   7 +
 src/include/catalog/pg_proc.dat               |   4 +
 src/include/catalog/pg_type.h                 |   2 +
 src/include/utils/pg_locale.h                 |   2 +-
 src/include/utils/rel.h                       |   1 +
 src/test/Makefile                             |   5 +-
 src/test/locale/.gitignore                    |   1 +
 src/test/locale/Makefile                      |   7 +
 src/test/locale/t/001_index.pl                |  76 +++++
 src/test/perl/PostgresNode.pm                 |   6 +-
 .../regress/expected/collate.icu.utf8.out     | 157 +++++++++++
 src/test/regress/expected/create_index.out    |   8 +-
 src/test/regress/sql/collate.icu.utf8.sql     | 106 +++++++
 37 files changed, 1655 insertions(+), 148 deletions(-)
 create mode 100644 src/test/locale/t/001_index.pl

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index ea2be6d819..bcddca822c 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -25483,7 +25483,8 @@ 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.  An empty string is returned if the
+        version is unknown.
        </para></entry>
       </row>
 
diff --git a/doc/src/sgml/ref/pgupgrade.sgml b/doc/src/sgml/ref/pgupgrade.sgml
index b59c5697a3..527c847e27 100644
--- a/doc/src/sgml/ref/pgupgrade.sgml
+++ b/doc/src/sgml/ref/pgupgrade.sgml
@@ -215,6 +215,24 @@ PostgreSQL documentation
       </listitem>
      </varlistentry>
 
+     <varlistentry>
+      <term><option>--collation-binary-compatible</option></term>
+      <listitem>
+       <para>
+        After upgrading from a release of <productname>PostgreSQL</productname>
+        before 14, warnings may be reported when collation-dependent
+        indexes are first accessed.  This is because
+        <application>pg_upgrade</application> records the collation versions
+        as unknown, so <productname>PostgreSQL</productname> considers the
+        indexes to be potentially corrupted.  If you're certain that the
+        collation definitions used by your operating system or ICU haven't
+        changed since all indexes were created, you can use this flag
+        to record that the indexes match the currently installed collations.
+        Otherwise, see <xref linkend="sql-reindex"/>.
+       </para>
+      </listitem>
+     </varlistentry>
+
      <varlistentry>
       <term><option>-?</option></term>
       <term><option>--help</option></term>
diff --git a/doc/src/sgml/ref/reindex.sgml b/doc/src/sgml/ref/reindex.sgml
index 33af4ae02a..cbac0284c7 100644
--- a/doc/src/sgml/ref/reindex.sgml
+++ b/doc/src/sgml/ref/reindex.sgml
@@ -39,6 +39,12 @@ REINDEX [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] { IN
 
    <itemizedlist>
     <listitem>
+     <para>
+      The index depends on the sort order of a collation, and the definition
+      of the collation has changed.  This can cause an index to fail to
+      find a key that is present in the index.  On some systems, collation
+      versions are tracked in order to generate warnings when this happens.
+     </para>
      <para>
       An index has become corrupted, and no longer contains valid
       data. Although in theory this should never happen, in
diff --git a/src/backend/catalog/dependency.c b/src/backend/catalog/dependency.c
index 1a927377e7..d6a3cae303 100644
--- 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"
@@ -136,6 +137,9 @@ typedef struct
 {
 	ObjectAddresses *addrs;		/* addresses being accumulated */
 	List	   *rtables;		/* list of rangetables to resolve Vars */
+	bool		track_version;	/* whether caller asked to track dependency
+								 * versions */
+	NodeTag		type;			/* nodetag of the current node */
 } find_expr_references_context;
 
 /*
@@ -434,6 +438,81 @@ performMultipleDeletions(const ObjectAddresses *objects,
 	table_close(depRel, RowExclusiveLock);
 }
 
+/*
+ * Call a function for all objects that depend on 'object'.  If the function
+ * returns a non-NULL pointer to a new version string, update the version.
+ */
+void
+visitDependentObjects(const ObjectAddress *object,
+					  VisitDependentObjectsFun 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	   *cur_version,
+				   *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);
+
+		cur_version = isnull ? NULL : TextDatumGetCString(depversion);
+
+		new_version = callback(&otherObject, cur_version, userdata);
+		if (new_version)
+		{
+			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));
+
+			values[Anum_pg_depend_refobjversion - 1] =
+				CStringGetTextDatum(new_version);
+			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 +1645,36 @@ ReleaseDeletionLock(const ObjectAddress *object)
 							 AccessExclusiveLock);
 }
 
+/*
+ * Given a list of collations, record a dependency on its underlying collation
+ * 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);
+	}
+
+	recordMultipleDependencies(myself, addrs->refs, addrs->numrefs,
+							   DEPENDENCY_NORMAL, record_version);
+}
+
 /*
  * recordDependencyOnExpr - find expression dependencies
  *
@@ -1588,6 +1697,10 @@ recordDependencyOnExpr(const ObjectAddress *depender,
 	find_expr_references_context context;
 
 	context.addrs = new_object_addresses();
+	if (expr)
+		context.type = expr->type;
+	else
+		context.type = T_Invalid;
 
 	/* Set up interpretation for Vars at varlevelsup = 0 */
 	context.rtables = list_make1(rtable);
@@ -1602,8 +1715,8 @@ recordDependencyOnExpr(const ObjectAddress *depender,
 	recordMultipleDependencies(depender,
 							   context.addrs->refs,
 							   context.addrs->numrefs,
-							   NULL,
-							   behavior);
+							   behavior,
+							   false);
 
 	free_object_addresses(context.addrs);
 }
@@ -1630,12 +1743,18 @@ recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 								Node *expr, Oid relId,
 								DependencyType behavior,
 								DependencyType self_behavior,
-								bool reverse_self)
+								bool reverse_self,
+								bool track_version)
 {
 	find_expr_references_context context;
 	RangeTblEntry rte;
 
 	context.addrs = new_object_addresses();
+	context.track_version = track_version;
+	if (expr)
+		context.type = expr->type;
+	else
+		context.type = T_Invalid;
 
 	/* We gin up a rather bogus rangetable list to handle Vars */
 	MemSet(&rte, 0, sizeof(rte));
@@ -1691,8 +1810,8 @@ recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 			recordMultipleDependencies(depender,
 									   self_addrs->refs,
 									   self_addrs->numrefs,
-									   NULL,
-									   self_behavior);
+									   self_behavior,
+									   track_version);
 		else
 		{
 			/* Can't use recordMultipleDependencies, so do it the hard way */
@@ -1713,8 +1832,8 @@ recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 	recordMultipleDependencies(depender,
 							   context.addrs->refs,
 							   context.addrs->numrefs,
-							   NULL,
-							   behavior);
+							   behavior,
+							   track_version);
 
 	free_object_addresses(context.addrs);
 }
@@ -1736,8 +1855,13 @@ static bool
 find_expr_references_walker(Node *node,
 							find_expr_references_context *context)
 {
+	NodeTag		parent_type = context->type;
+
 	if (node == NULL)
 		return false;
+
+	context->type = node->type;
+
 	if (IsA(node, Var))
 	{
 		Var		   *var = (Var *) node;
@@ -1770,6 +1894,49 @@ 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);
+
+			/*
+			 * Record collations from the type itself, or underlying in case
+			 * of complex type.  Note that if the direct parent is a
+			 * CollateExpr node, there's no need to record the type underlying
+			 * collation if any.  A dependency already exists for the owning
+			 * relation, and a change in the collation sort order wouldn't
+			 * cause any harm as the collation isn't used at all in such case.
+			 */
+			if (parent_type != T_CollateExpr)
+			{
+				/* type's collation if valid */
+				if (OidIsValid(var->varcollid))
+				{
+					add_object_address(OCLASS_COLLATION, var->varcollid, 0,
+									   context->addrs);
+				}
+
+				/*
+				 * otherwise, it may be a composite type having underlying
+				 * collations
+				 */
+				else if (var->vartype >= FirstNormalObjectId)
+				{
+					List	   *collations = NIL;
+					ListCell   *lc;
+
+					collations = GetTypeCollations(var->vartype, false);
+
+					foreach(lc, collations)
+					{
+						Oid			coll = lfirst_oid(lc);
+
+						if (OidIsValid(coll) &&
+							(coll != DEFAULT_COLLATION_OID ||
+							 context->track_version)
+							)
+							add_object_address(OCLASS_COLLATION,
+											   lfirst_oid(lc), 0,
+											   context->addrs);
+					}
+				}
+			}
 		}
 
 		/*
@@ -1795,10 +1962,12 @@ 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.
+		 * case where the collation is "default", since we know that's pinned,
+		 * if the caller didn't ask to track dependency versions.
 		 */
 		if (OidIsValid(con->constcollid) &&
-			con->constcollid != DEFAULT_COLLATION_OID)
+			(con->constcollid != DEFAULT_COLLATION_OID ||
+			 context->track_version))
 			add_object_address(OCLASS_COLLATION, con->constcollid, 0,
 							   context->addrs);
 
@@ -1888,7 +2057,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* and its collation, just as for Consts */
 		if (OidIsValid(param->paramcollid) &&
-			param->paramcollid != DEFAULT_COLLATION_OID)
+			(param->paramcollid != DEFAULT_COLLATION_OID ||
+			 context->track_version))
 			add_object_address(OCLASS_COLLATION, param->paramcollid, 0,
 							   context->addrs);
 	}
@@ -1976,7 +2146,8 @@ find_expr_references_walker(Node *node,
 							   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(fselect->resultcollid) &&
-			fselect->resultcollid != DEFAULT_COLLATION_OID)
+			(fselect->resultcollid != DEFAULT_COLLATION_OID ||
+			 context->track_version))
 			add_object_address(OCLASS_COLLATION, fselect->resultcollid, 0,
 							   context->addrs);
 	}
@@ -2007,7 +2178,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(relab->resultcollid) &&
-			relab->resultcollid != DEFAULT_COLLATION_OID)
+			(relab->resultcollid != DEFAULT_COLLATION_OID ||
+			 context->track_version))
 			add_object_address(OCLASS_COLLATION, relab->resultcollid, 0,
 							   context->addrs);
 	}
@@ -2020,7 +2192,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(iocoerce->resultcollid) &&
-			iocoerce->resultcollid != DEFAULT_COLLATION_OID)
+			(iocoerce->resultcollid != DEFAULT_COLLATION_OID ||
+			 context->track_version))
 			add_object_address(OCLASS_COLLATION, iocoerce->resultcollid, 0,
 							   context->addrs);
 	}
@@ -2033,7 +2206,8 @@ find_expr_references_walker(Node *node,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(acoerce->resultcollid) &&
-			acoerce->resultcollid != DEFAULT_COLLATION_OID)
+			(acoerce->resultcollid != DEFAULT_COLLATION_OID ||
+			 context->track_version))
 			add_object_address(OCLASS_COLLATION, acoerce->resultcollid, 0,
 							   context->addrs);
 		/* fall through to examine arguments */
@@ -2122,7 +2296,8 @@ find_expr_references_walker(Node *node,
 			add_object_address(OCLASS_PROC, wc->endInRangeFunc, 0,
 							   context->addrs);
 		if (OidIsValid(wc->inRangeColl) &&
-			wc->inRangeColl != DEFAULT_COLLATION_OID)
+			(wc->inRangeColl != DEFAULT_COLLATION_OID ||
+			 context->track_version))
 			add_object_address(OCLASS_COLLATION, wc->inRangeColl, 0,
 							   context->addrs);
 		/* fall through to examine substructure */
@@ -2267,7 +2442,9 @@ find_expr_references_walker(Node *node,
 		{
 			Oid			collid = lfirst_oid(ct);
 
-			if (OidIsValid(collid) && collid != DEFAULT_COLLATION_OID)
+			if (OidIsValid(collid) &&
+				(collid != DEFAULT_COLLATION_OID ||
+				 context->track_version))
 				add_object_address(OCLASS_COLLATION, collid, 0,
 								   context->addrs);
 		}
@@ -2289,7 +2466,9 @@ find_expr_references_walker(Node *node,
 		{
 			Oid			collid = lfirst_oid(ct);
 
-			if (OidIsValid(collid) && collid != DEFAULT_COLLATION_OID)
+			if (OidIsValid(collid) &&
+				(collid != DEFAULT_COLLATION_OID ||
+				 context->track_version))
 				add_object_address(OCLASS_COLLATION, collid, 0,
 								   context->addrs);
 		}
@@ -2685,8 +2864,9 @@ 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);
 }
 
 /*
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 67144aa3c9..fc5140daa6 100644
--- 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);
 	}
 
 	/*
@@ -3665,7 +3665,8 @@ 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
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 117e3fdef7..a30e83ca39 100644
--- 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 +1022,10 @@ index_create(Relation heapRelation,
 		ObjectAddress myself,
 					referenced;
 		ObjectAddresses *addrs;
+		ListCell   *lc;
+		List	   *colls = NIL,
+				   *determ_colls = NIL,
+				   *nondeterm_colls = NIL;
 
 		ObjectAddressSet(myself, RelationRelationId, indexRelationId);
 
@@ -1106,20 +1112,80 @@ index_create(Relation heapRelation,
 		/* placeholder for normal dependencies */
 		addrs = new_object_addresses();
 
-		/* Store dependency on collations */
-
-		/* The default collation is pinned, so don't bother recording it */
+		/* First, get all 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))
+				colls = lappend_oid(colls, colloid);
+			else
 			{
-				ObjectAddressSet(referenced, CollationRelationId,
-								 collationObjectId[i]);
-				add_exact_object_address(&referenced, addrs);
+				Form_pg_attribute att = TupleDescAttr(indexTupDesc, i);
+
+				Assert(i < indexTupDesc->natts);
+
+				colls = list_concat(colls,
+									GetTypeCollations(att->atttypid, false));
 			}
 		}
 
+		/*
+		 * Then split the dependencies on whether they're deterministic or
+		 * not, removing any duplicates.
+		 */
+		foreach(lc, colls)
+		{
+			Oid			c = lfirst_oid(lc);
+
+			if (!OidIsValid(c))
+				continue;
+
+			if (get_collation_isdeterministic(c))
+				determ_colls = list_append_unique_oid(determ_colls, c);
+			else
+				nondeterm_colls = list_append_unique_oid(nondeterm_colls, c);
+		}
+
+		/*
+		 * For deterministic collation, we always track the dependency on the
+		 * collation but only track the version if the AM relies on a stable
+		 * ordering.
+		 */
+		if (determ_colls)
+		{
+			IndexAmRoutine *routine;
+			bool track_version;
+
+			routine = GetIndexAmRoutineByAmId(accessMethodObjectId, false);
+			track_version = !routine->amnostablecollorder;
+
+			recordDependencyOnCollations(&myself, determ_colls, track_version);
+
+			/*
+			 * Advance the command counter so that later calls to
+			 * recordMultipleDependencies calls can see the newly-entered
+			 * pg_depend catalog tuples for the index.
+			 */
+			CommandCounterIncrement();
+		}
+
+		/*
+		 * We always record the version for dependency on non-deterministic
+		 * collations.
+		 */
+		if (nondeterm_colls)
+		{
+			recordDependencyOnCollations(&myself, nondeterm_colls, true);
+
+			/*
+			 * Advance the command counter so that later calls to
+			 * recordMultipleDependencies calls can see the newly-entered
+			 * pg_depend catalog tuples for the index.
+			 */
+			CommandCounterIncrement();
+		}
+
 		/* Store dependency on operator classes */
 		for (i = 0; i < indexInfo->ii_NumIndexKeyAttrs; i++)
 		{
@@ -1133,21 +1199,32 @@ index_create(Relation heapRelation,
 		/* Store dependencies on anything mentioned in index expressions */
 		if (indexInfo->ii_Expressions)
 		{
+			/*
+			 * recordDependencyOnSingleRelExpr gets rid of duplicated entries
+			 */
 			recordDependencyOnSingleRelExpr(&myself,
 											(Node *) indexInfo->ii_Expressions,
 											heapRelationId,
 											DEPENDENCY_NORMAL,
-											DEPENDENCY_AUTO, false);
+											DEPENDENCY_AUTO, false, true);
+
+			/*
+			 * Advance the command counter so that later
+			 * recordMultipleDependencies calls can see the newly-entered
+			 * pg_depend catalog tuples for the index.
+			 */
+			CommandCounterIncrement();
 		}
 
 		/* Store dependencies on anything mentioned in predicate */
 		if (indexInfo->ii_Predicate)
 		{
+			/* recordDependencyOnSingleRelExpr get rid of duplicated entries */
 			recordDependencyOnSingleRelExpr(&myself,
 											(Node *) indexInfo->ii_Predicate,
 											heapRelationId,
 											DEPENDENCY_NORMAL,
-											DEPENDENCY_AUTO, false);
+											DEPENDENCY_AUTO, false, true);
 		}
 	}
 	else
@@ -1226,6 +1303,108 @@ index_create(Relation heapRelation,
 	return indexRelationId;
 }
 
+/* index_check_collation_version
+ *		Raise a warning if the recorded and current collation version don't
+ *		match.
+*/
+static char *
+index_check_collation_version(const ObjectAddress *otherObject,
+							  const char *version,
+							  void *userdata)
+{
+	Oid			relid = *(Oid *) userdata;
+	char	   *current_version;
+
+	/* We only care about dependencies on collations. */
+	if (otherObject->classId != CollationRelationId)
+		return NULL;
+
+	/* Compare with the current version. */
+	current_version = get_collation_version_for_oid(otherObject->objectId);
+
+	/* XXX should we warn about "disappearing" versions? */
+	if (current_version)
+	{
+		/*
+		 * We now support versioning for the underlying collation library on
+		 * this system, or previous version is unknown.
+		 */
+		if (!version || (strcmp(version, "") == 0 && strcmp(current_version,
+															"") != 0))
+		{
+			ereport(WARNING,
+					(errmsg("index \"%s\" depends on collation \"%s\" with an unknown version, and the current version is \"%s\"",
+							get_rel_name(relid),
+							get_collation_name(otherObject->objectId),
+							current_version),
+					 errdetail("The index may be corrupted due to changes in sort order."),
+					 errhint("REINDEX to avoid the risk of corruption.")));
+		}
+		else if (strcmp(current_version, version) != 0)
+		{
+			ereport(WARNING,
+					(errmsg("index \"%s\" depends on collation \"%s\" version \"%s\", but the current version is \"%s\"",
+							get_rel_name(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.")));
+		}
+	}
+
+	return NULL;
+}
+
+/* index_check_collation_versions
+ *		Check the collation version for all dependencies on the given object.
+ */
+void
+index_check_collation_versions(Oid relid)
+{
+	ObjectAddress object;
+
+	object.classId = RelationRelationId;
+	object.objectId = relid;
+	object.objectSubId = 0;
+	visitDependentObjects(&object, &index_check_collation_version, &relid);
+}
+
+/* index_update_collation_version
+ *		Return the current collation version for the given object.
+ */
+static char *
+index_update_collation_version(const ObjectAddress *otherObject,
+							   const char *version,
+							   void *userdata)
+{
+	char	   *current_version = (char *) userdata;
+
+	/* We only care about dependencies on collations. */
+	if (otherObject->classId != CollationRelationId)
+		return NULL;
+
+	current_version = get_collation_version_for_oid(otherObject->objectId);
+	return current_version;
+}
+
+/* index_update_collation_versions
+ *		Record the current collation versions of all dependencies on the given
+ *		object.
+ */
+void
+index_update_collation_versions(Oid relid)
+{
+	ObjectAddress object;
+	NameData	current_version;
+
+	object.classId = RelationRelationId;
+	object.objectId = relid;
+	object.objectSubId = 0;
+	visitDependentObjects(&object, &index_update_collation_version,
+						  &current_version);
+}
+
 /*
  * index_concurrently_create_copy
  *
@@ -3000,6 +3179,68 @@ index_build(Relation heapRelation,
 	SetUserIdAndSecContext(save_userid, save_sec_context);
 }
 
+static char *
+index_force_collation_version(const ObjectAddress *otherObject,
+							  const char *version,
+							  void *userdata)
+{
+	NewCollationVersionDependency *forced_dependency;
+
+	forced_dependency = (NewCollationVersionDependency *) userdata;
+
+	/* We only care about dependencies on collations. */
+	if (otherObject->classId != CollationRelationId)
+		return NULL;
+
+	/*
+	 * We only care about dependencies on a specific collation if a valid Oid
+	 * was given.
+	 */
+	if (OidIsValid(forced_dependency->oid) &&
+		otherObject->objectId != forced_dependency->oid)
+		return NULL;
+
+	return forced_dependency->version;
+}
+
+/* index_force_collation_versions
+ *
+ * Override collation version dependencies for the given index.  If no
+ * collation identifier is specified, all dependent collation should be
+ * reset to an unknown version dependency, and no version should be provided
+ * either.
+ */
+void
+index_force_collation_versions(Oid indexid, Oid coll, char *version)
+{
+	Relation	index;
+	ObjectAddress object;
+	NewCollationVersionDependency forced_dependency;
+
+	Assert(version);
+
+	index = relation_open(indexid, AccessExclusiveLock);
+
+	if (index->rd_rel->relkind != RELKIND_INDEX)
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 (errmsg("\"%s\" is not an index", get_rel_name(indexid)))));
+
+	forced_dependency.oid = InvalidOid;
+	forced_dependency.version = version;
+
+	object.classId = RelationRelationId;
+	object.objectId = indexid;
+	object.objectSubId = 0;
+	visitDependentObjects(&object, &index_force_collation_version,
+						  &forced_dependency);
+
+	/* Invalidate the index relcache */
+	CacheInvalidateRelcache(index);
+
+	relation_close(index, NoLock);
+}
+
 /*
  * IndexCheckExclusion - verify that a new exclusion constraint is satisfied
  *
@@ -3646,6 +3887,9 @@ 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);
 }
 
 /*
diff --git a/src/backend/catalog/pg_constraint.c b/src/backend/catalog/pg_constraint.c
index 0d70cb0c3c..93774c9d21 100644
--- 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 */
diff --git a/src/backend/catalog/pg_depend.c b/src/backend/catalog/pg_depend.c
index 09c30b13e8..2bd9401e6a 100644
--- 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"
@@ -27,9 +28,14 @@
 #include "utils/builtins.h"
 #include "utils/fmgroids.h"
 #include "utils/lsyscache.h"
+#include "utils/pg_locale.h"
 #include "utils/rel.h"
 
 
+static bool dependencyExists(const ObjectAddress *depender,
+							 const ObjectAddress *referenced);
+static char *getDependencyVersion(const ObjectAddress *depender,
+								  const ObjectAddress *referenced);
 static bool isObjectPinned(const ObjectAddress *object, Relation rel);
 
 
@@ -45,19 +51,24 @@ 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 track_version is true, then a record could be added even if the referenced
+ * dependency 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 track_version)
 {
 	Relation	dependDesc;
 	CatalogIndexState indstate;
@@ -66,6 +77,7 @@ recordMultipleDependencies(const ObjectAddress *depender,
 				max_slots,
 				slot_init_count,
 				slot_stored_count;
+	char	   *version = NULL;
 
 	if (nreferenced <= 0)
 		return;					/* nothing to do */
@@ -96,12 +108,49 @@ recordMultipleDependencies(const ObjectAddress *depender,
 	slot_init_count = 0;
 	for (i = 0; i < nreferenced; i++, referenced++)
 	{
+		bool		ignore_systempin = false;
+
+		if (track_version)
+		{
+			/* Only dependency on a collation is supported. */
+			if (referenced->classId == CollationRelationId)
+			{
+				/* C and POSIX collations don't require tracking the version */
+				if (referenced->objectId == C_COLLATION_OID ||
+					referenced->objectId == POSIX_COLLATION_OID)
+					continue;
+
+				/*
+				 * We don't want to record redundant dependencies that are used
+				 * to track versions to avoid redundant warnings in case of
+				 * non-matching versions when those are checked.  Note that
+				 * callers have to take care of removing duplicated entries
+				 * and calling CommandCounterIncrement() if the dependencies
+				 * are registered in multiple calls.
+				 */
+				if (dependencyExists(depender, referenced))
+					continue;
+
+				/*
+				 * 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;
+				version = get_collation_version_for_oid(referenced->objectId);
+				Assert(version);
+			}
+		}
+		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)
@@ -493,7 +542,8 @@ changeDependencyFor(Oid classId, Oid objectId,
 }
 
 /*
- * Adjust all dependency records to come from a different object of the same type
+ * Adjust all dependency records to come from a different object of the same
+ * type, optionally preserving the original referenced version.
  *
  * classId/oldObjectId specify the old referencing object.
  * newObjectId is the new referencing object (must be of class classId).
@@ -501,8 +551,7 @@ changeDependencyFor(Oid classId, Oid objectId,
  * Returns the number of records updated.
  */
 long
-changeDependenciesOf(Oid classId, Oid oldObjectId,
-					 Oid newObjectId)
+changeDependenciesOf(Oid classId, Oid oldObjectId, Oid newObjectId)
 {
 	long		count = 0;
 	Relation	depRel;
@@ -526,14 +575,47 @@ changeDependenciesOf(Oid classId, Oid oldObjectId,
 
 	while (HeapTupleIsValid((tup = systable_getnext(scan))))
 	{
-		Form_pg_depend depform;
+		Form_pg_depend depform = (Form_pg_depend) GETSTRUCT(tup);
+		Datum		values[Natts_pg_depend];
+		bool		nulls[Natts_pg_depend];
+		bool		replaces[Natts_pg_depend];
+		bool		isnull = true;
+
+		memset(values, 0, sizeof(values));
+		memset(nulls, 0, sizeof(nulls));
+		memset(replaces, 0, sizeof(replaces));
+
+		values[Anum_pg_depend_objid - 1] = newObjectId;
+		replaces[Anum_pg_depend_objid - 1] = true;
 
-		/* make a modifiable copy */
-		tup = heap_copytuple(tup);
-		depform = (Form_pg_depend) GETSTRUCT(tup);
+		/*
+		 * We assume that a version would exist for both the old and new
+		 * object or none.
+		 */
+		heap_getattr(tup, Anum_pg_depend_refobjversion,
+					 RelationGetDescr(depRel), &isnull);
 
-		depform->objid = newObjectId;
+		if (!isnull)
+		{
+			ObjectAddress depender,
+						referenced;
+			char	   *version;
+
+			ObjectAddressSubSet(depender, depform->classid,
+								newObjectId, depform->objsubid);
+			ObjectAddressSubSet(referenced, depform->refclassid,
+								depform->refobjid, depform->refobjsubid);
+
+			version = getDependencyVersion(&depender, &referenced);
+			if (version)
+				values[Anum_pg_depend_refobjversion - 1] = CStringGetTextDatum(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);
@@ -636,6 +718,104 @@ changeDependenciesOn(Oid refClassId, Oid oldRefObjectId,
 	return count;
 }
 
+/* dependencyExists()
+ *
+ * Test if a record exists for the given depender and referenced addresses.
+ */
+static bool
+dependencyExists(const ObjectAddress *depender,
+				 const ObjectAddress *referenced)
+{
+	Relation	depRel;
+	ScanKeyData key[3];
+	SysScanDesc scan;
+	HeapTuple	tup;
+	bool		ret = false;
+
+	ScanKeyInit(&key[0],
+				Anum_pg_depend_classid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(depender->classId));
+	ScanKeyInit(&key[1],
+				Anum_pg_depend_objid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(depender->objectId));
+	ScanKeyInit(&key[2],
+				Anum_pg_depend_objsubid,
+				BTEqualStrategyNumber, F_INT4EQ,
+				Int32GetDatum(depender->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);
+
+		if (foundDep->refclassid == referenced->classId &&
+			foundDep->refobjid == referenced->objectId &&
+			foundDep->refobjsubid == referenced->objectSubId)
+		{
+			ret = true;
+			break;
+		}
+	}
+	systable_endscan(scan);
+	table_close(depRel, RowExclusiveLock);
+
+	return ret;
+}
+
+static char *
+getDependencyVersion(const ObjectAddress *depender,
+					 const ObjectAddress *referenced)
+{
+	Relation	depRel;
+	ScanKeyData key[3];
+	SysScanDesc scan;
+	HeapTuple	tup;
+	Datum		depversion;
+	char	   *version = NULL;
+
+	ScanKeyInit(&key[0],
+				Anum_pg_depend_classid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(depender->classId));
+	ScanKeyInit(&key[1],
+				Anum_pg_depend_objid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(depender->objectId));
+	ScanKeyInit(&key[2],
+				Anum_pg_depend_objsubid,
+				BTEqualStrategyNumber, F_INT4EQ,
+				Int32GetDatum(depender->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);
+		bool		isnull;
+
+		if (foundDep->refclassid == referenced->classId &&
+			foundDep->refobjid == referenced->objectId &&
+			foundDep->refobjsubid == referenced->objectSubId)
+		{
+			depversion = heap_getattr(tup, Anum_pg_depend_refobjversion,
+									  RelationGetDescr(depRel), &isnull);
+			version = isnull ? NULL : TextDatumGetCString(depversion);
+			break;
+		}
+	}
+	systable_endscan(scan);
+	table_close(depRel, RowExclusiveLock);
+
+	return version;
+}
+
 /*
  * isObjectPinned()
  *
diff --git a/src/backend/catalog/pg_type.c b/src/backend/catalog/pg_type.c
index 0b04dff773..f2af6212e5 100644
--- 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 +513,74 @@ TypeCreate(Oid newTypeOid,
 	return address;
 }
 
+/* Get a list of all distinct collations oid that the given type depends on. */
+List *
+GetTypeCollations(Oid typeoid, bool non_deterministic_only)
+{
+	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))
+	{
+		if (!non_deterministic_only ||
+			!get_collation_isdeterministic(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))
+			{
+				if (!non_deterministic_only ||
+					!get_collation_isdeterministic(att->attcollation))
+					result = list_append_unique_oid(result, att->attcollation);
+			}
+			else
+				result = list_concat_unique_oid(result,
+												GetTypeCollations(att->atttypid,
+																  non_deterministic_only));
+		}
+
+		relation_close(rel, NoLock);
+	}
+	else if (typeTup->typtype == TYPTYPE_DOMAIN)
+	{
+		Assert(OidIsValid(typeTup->typbasetype));
+
+		result = list_concat_unique_oid(result,
+										GetTypeCollations(typeTup->typbasetype,
+														  non_deterministic_only));
+	}
+	else if (typeTup->typtype == TYPTYPE_RANGE)
+	{
+		Oid			rangeid = get_range_subtype(typeTup->oid);
+
+		Assert(OidIsValid(rangeid));
+
+		result = list_concat_unique_oid(result,
+										GetTypeCollations(rangeid, non_deterministic_only));
+	}
+	else if (OidIsValid(typeTup->typelem))
+		result = list_concat_unique_oid(result,
+										GetTypeCollations(typeTup->typelem, non_deterministic_only));
+
+	ReleaseSysCache(tuple);
+
+	return result;
+}
+
 /*
  * GenerateTypeDependencies: build the dependencies needed for a type
  *
diff --git a/src/backend/commands/collationcmds.c b/src/backend/commands/collationcmds.c
index 5ad8886e60..519f7a7df3 100644
--- a/src/backend/commands/collationcmds.c
+++ b/src/backend/commands/collationcmds.c
@@ -270,28 +270,12 @@ 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);
+	Assert(version);
 
-	if (version)
-		PG_RETURN_TEXT_P(cstring_to_text(version));
-	else
-		PG_RETURN_NULL();
+	PG_RETURN_TEXT_P(cstring_to_text(version));
 }
 
 
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index ddeec870d8..e1016609dc 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -31,6 +31,8 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/catalog.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
@@ -632,6 +634,36 @@ vacuum_open_relation(Oid relid, RangeVar *relation, int options,
 		rel_lock = false;
 	}
 
+	/*
+	 * Perform version sanity checks on the relation underlying indexes if
+	 * it's not a VACUUM FULL, as VACUUM FULL will recreate the index and
+	 * update the recorded collation version.
+	 */
+	if (!(options & VACOPT_FULL) && onerel && !IsSystemRelation(onerel) &&
+		onerel->rd_rel->relhasindex)
+	{
+		List	   *indexoidlist;
+		ListCell   *l;
+
+		indexoidlist = RelationGetIndexList(onerel);
+		foreach(l, indexoidlist)
+		{
+			Oid			indexoid = lfirst_oid(l);
+			Relation	indexRelation;
+
+			indexRelation = index_open(indexoid, AccessShareLock);
+
+			/* Warn if any dependent collations' versions have moved. */
+			if (!indexRelation->rd_version_checked)
+			{
+				index_check_collation_versions(indexoid);
+				indexRelation->rd_version_checked = true;
+			}
+
+			index_close(indexRelation, NoLock);
+		}
+	}
+
 	/* if relation is opened, leave */
 	if (onerel)
 		return onerel;
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index f9d0d67aa7..3a20dcdee5 100644
--- 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
diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index 514e0fa0af..7e5fcb77df 100644
--- 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 +1717,51 @@ get_collation_actual_version(char collprovider, const char *collcollate)
 	return collversion;
 }
 
+/*
+ * Get provider-specific collation version string given a collation OID.
+ *
+ * As this version is used in index dependency tracking, an empty string is
+ * returned when the version is unknown, to distinguish from dependencies where
+ * the version should not be tracked, represented by a NULL version.
+ */
+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);
+
+	if (!version)
+		return "";
+	else
+		return version;
+}
 
 #ifdef USE_ICU
 /*
diff --git a/src/backend/utils/adt/pg_upgrade_support.c b/src/backend/utils/adt/pg_upgrade_support.c
index 14d9eb2b5b..4ba8c8c637 100644
--- 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"
@@ -197,3 +198,27 @@ binary_upgrade_set_missing_value(PG_FUNCTION_ARGS)
 
 	PG_RETURN_VOID();
 }
+
+Datum
+binary_upgrade_set_index_coll_version(PG_FUNCTION_ARGS)
+{
+	Oid			relid;
+	Oid			coll;
+	char	   *version;
+
+	CHECK_IS_BINARY_UPGRADE;
+
+	relid = PG_GETARG_OID(0);
+
+	/* Detect if a collation is specified */
+	if (PG_ARGISNULL(1))
+		coll = InvalidOid;
+	else
+		coll = PG_GETARG_OID(1);
+
+	version = TextDatumGetCString(PG_GETARG_TEXT_PP(2));
+
+	index_force_collation_versions(relid, coll, version);
+
+	PG_RETURN_VOID();
+}
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 96ecad02dd..96f8c67831 100644
--- 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"
@@ -5927,6 +5928,7 @@ 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;
diff --git a/src/bin/pg_dump/Makefile b/src/bin/pg_dump/Makefile
index 2532d9183a..c58ebaa681 100644
--- a/src/bin/pg_dump/Makefile
+++ b/src/bin/pg_dump/Makefile
@@ -16,6 +16,8 @@ subdir = src/bin/pg_dump
 top_builddir = ../../..
 include $(top_builddir)/src/Makefile.global
 
+export with_icu
+
 override CPPFLAGS := -I$(libpq_srcdir) $(CPPFLAGS)
 LDFLAGS_INTERNAL += -L$(top_builddir)/src/fe_utils -lpgfeutils $(libpq_pgport)
 
diff --git a/src/bin/pg_dump/pg_backup.h b/src/bin/pg_dump/pg_backup.h
index 1017abbbe5..a94fbafec3 100644
--- a/src/bin/pg_dump/pg_backup.h
+++ b/src/bin/pg_dump/pg_backup.h
@@ -171,6 +171,7 @@ typedef struct _dumpOptions
 
 	int			sequence_data;	/* dump sequence data even in schema-only mode */
 	int			do_nothing;
+	int			unknown_coll_compat;
 } DumpOptions;
 
 /*
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 77139355e0..90535936ae 100644
--- 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"
@@ -286,6 +287,8 @@ 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, int unknown_coll_compat);
 static void appendReloptionsArrayAH(PQExpBuffer buffer, const char *reloptions,
 									const char *prefix, Archive *fout);
 static char *get_synchronized_snapshot(Archive *fout);
@@ -387,6 +390,7 @@ 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},
+		{"unknown-collations-binary-compatible", no_argument, &dopt.unknown_coll_compat, 1},
 
 		{NULL, 0, NULL, 0}
 	};
@@ -714,6 +718,10 @@ main(int argc, char **argv)
 	if (archiveFormat != archDirectory && numWorkers > 1)
 		fatal("parallel backup only supported by the directory format");
 
+	/* Unknown collation versions can only be ignored in binary upgrade mode */
+	if (dopt.unknown_coll_compat && !dopt.binary_upgrade)
+		fatal("option --unknown-collations-binary-compatible only works in binary upgrade mode");
+
 	/* Open the output file */
 	fout = CreateArchive(filename, archiveFormat, compressLevel, dosync,
 						 archiveMode, setupDumpWorker);
@@ -7034,7 +7042,9 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 				i_tablespace,
 				i_indreloptions,
 				i_indstatcols,
-				i_indstatvals;
+				i_indstatvals,
+				i_inddependoids,
+				i_inddependversions;
 	int			ntups;
 
 	for (i = 0; i < numTables; i++)
@@ -7070,7 +7080,62 @@ 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, "
+							  "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, "
+							  "(SELECT pg_catalog.array_agg(refobjid ORDER BY refobjid) "
+							  "  FROM pg_catalog.pg_depend "
+							  "  WHERE classid = " CppAsString2(RelationRelationId) " AND "
+							  "    objid = i.indexrelid AND "
+							  "    objsubid = 0 AND "
+							  "    refclassid = " CppAsString2(CollationRelationId) " AND "
+							  "    refobjversion IS NOT NULL) AS inddependoids, "
+							  "(SELECT pg_catalog.array_agg(quote_literal(refobjversion) ORDER BY refobjid) "
+							  "  FROM pg_catalog.pg_depend "
+							  "  WHERE classid = " CppAsString2(RelationRelationId) " AND "
+							  "    objid = i.indexrelid AND "
+							  "    objsubid = 0 AND "
+							  "    refclassid = " CppAsString2(CollationRelationId) " AND "
+							  "    refobjversion IS NOT NULL) AS inddependversions "
+							  "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, "
@@ -7095,7 +7160,9 @@ 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, "
+							  "' ' AS inddependoids, "
+							  "' ' AS inddependversions "
 							  "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) "
@@ -7134,7 +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 inddependoids, "
+							  "' ' AS inddependversions "
 							  "FROM pg_catalog.pg_index i "
 							  "JOIN pg_catalog.pg_class t ON (t.oid = i.indexrelid) "
 							  "LEFT JOIN pg_catalog.pg_constraint c "
@@ -7169,7 +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 inddependoids, "
+							  "' ' AS inddependversions "
 							  "FROM pg_catalog.pg_index i "
 							  "JOIN pg_catalog.pg_class t ON (t.oid = i.indexrelid) "
 							  "LEFT JOIN pg_catalog.pg_constraint c "
@@ -7200,7 +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 inddependoids, "
+							  "' ' AS inddependversions "
 							  "FROM pg_catalog.pg_index i "
 							  "JOIN pg_catalog.pg_class t ON (t.oid = i.indexrelid) "
 							  "LEFT JOIN pg_catalog.pg_depend d "
@@ -7234,7 +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 inddependoids, "
+							  "' ' AS inddependversions "
 							  "FROM pg_catalog.pg_index i "
 							  "JOIN pg_catalog.pg_class t ON (t.oid = i.indexrelid) "
 							  "LEFT JOIN pg_catalog.pg_depend d "
@@ -7274,6 +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_inddependoids = PQfnumber(res, "inddependoids");
+		i_inddependversions = PQfnumber(res, "inddependversions");
 
 		tbinfo->indexes = indxinfo =
 			(IndxInfo *) pg_malloc(ntups * sizeof(IndxInfo));
@@ -7299,6 +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].inddependoids = pg_strdup(PQgetvalue(res, j, i_inddependoids));
+			indxinfo[j].inddependversions = pg_strdup(PQgetvalue(res, j, i_inddependversions));
 			indxinfo[j].indkeys = (Oid *) pg_malloc(indxinfo[j].indnattrs * sizeof(Oid));
 			parseOidArray(PQgetvalue(res, j, i_indkey),
 						  indxinfo[j].indkeys, indxinfo[j].indnattrs);
@@ -16360,7 +16439,8 @@ 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.
@@ -16427,6 +16507,10 @@ dumpIndex(Archive *fout, IndxInfo *indxinfo)
 									"pg_catalog.pg_class",
 									"INDEX", qqindxname);
 
+		if (dopt->binary_upgrade)
+			appendIndexCollationVersion(q, indxinfo, fout->encoding,
+										dopt->unknown_coll_compat);
+
 		/* If the index defines identity, we need to record that. */
 		if (indxinfo->indisreplident)
 		{
@@ -16455,6 +16539,21 @@ dumpIndex(Archive *fout, IndxInfo *indxinfo)
 		if (indstatvalsarray)
 			free(indstatvalsarray);
 	}
+	else if (dopt->binary_upgrade)
+	{
+		appendIndexCollationVersion(q, indxinfo, fout->encoding,
+									dopt->unknown_coll_compat);
+
+		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 +18540,77 @@ nonemptyReloptions(const char *reloptions)
 	return (reloptions != NULL && strlen(reloptions) > 2);
 }
 
+/*
+ * Format inddependoids and inddependversions arrays and append it to the given
+ * buffer in the form of binary_upgrade_set_index_coll_version() calls.
+ */
+static void
+appendIndexCollationVersion(PQExpBuffer buffer, IndxInfo *indxinfo, int enc,
+							int unknown_coll_compat)
+{
+	char	   *inddependoids = indxinfo->inddependoids;
+	char	   *inddependversions = indxinfo->inddependversions;
+	char	  **inddependoidsarray = NULL;
+	char	  **inddependversionsarray = NULL;
+	int			ninddependoids;
+	int			ninddependversions;
+	int			i;
+
+	/*
+	 * for older versions that don't record the collation depndency, issue a
+	 * statement to mark the collation version as unknown
+	 */
+	if (strcmp(inddependoids, " ") == 0)
+	{
+		/*
+		 * do not issue UNKNOWN VERSION if caller specified that those are
+		 * compatible
+		 */
+		if (unknown_coll_compat)
+			return;
+
+		Assert(strcmp(inddependversions, " ") == 0);
+
+		appendPQExpBufferStr(buffer, "\n-- For binary upgrade, restore dependent collation version.\n");
+		appendPQExpBuffer(buffer, "SELECT "
+						  "pg_catalog.binary_upgrade_set_index_coll_version(%d, NULL, '');",
+						  indxinfo->dobj.catId.oid);
+		return;
+	}
+
+	parsePGArray(inddependoids, &inddependoidsarray, &ninddependoids);
+	parsePGArray(inddependversions, &inddependversionsarray, &ninddependversions);
+
+	Assert(ninddependoids == ninddependversions);
+
+	for (i = 0; i < ninddependoids; i++)
+	{
+		/*
+		 * If there was an unknown version dependency recorded for this
+		 * collation and the caller asked to mark those as depending on the
+		 * current version, don't emit a binary_upgrade_set_index_coll_version
+		 * function call.
+		 */
+		if ((strcmp(inddependversionsarray[i], "''")) == 0
+			&& unknown_coll_compat)
+		{
+			continue;
+		}
+
+		appendPQExpBufferStr(buffer, "\n-- For binary upgrade, restore dependent collation version.\n");
+		appendPQExpBuffer(buffer, "SELECT "
+						  "pg_catalog.binary_upgrade_set_index_coll_version(%d, %s, %s);",
+						  indxinfo->dobj.catId.oid,
+						  inddependoidsarray[i],
+						  inddependversionsarray[i]);
+	}
+
+	if (inddependoidsarray)
+		free(inddependoidsarray);
+	if (inddependversionsarray)
+		free(inddependversionsarray);
+}
+
 /*
  * Format a reloptions array and append it to the given buffer.
  *
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index e0b42e8391..623814d1c5 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -366,6 +366,9 @@ 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	   *inddependoids;	/* oids of collation this index depends on */
+	char	   *inddependversions;	/* version of collation this index depends
+									 * on */
 	bool		indisclustered;
 	bool		indisreplident;
 	Oid			parentidx;		/* if a partition, parent index OID */
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index ec63662060..5f323efb1f 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -53,6 +53,24 @@ my %pgdump_runs = (
 			"$tempdir/binary_upgrade.dump",
 		],
 	},
+	binary_coll_compatible => {
+		dump_cmd => [
+			'pg_dump',
+			'--no-sync',
+			'--format=custom',
+			"--file=$tempdir/binary_coll_compatible.dump",
+			'-w',
+			'--schema-only',
+			'--binary-upgrade',
+			'--unknown-collations-binary-compatible',
+			'-d', 'postgres',    # alternative way to specify database
+		],
+		restore_cmd => [
+			'pg_restore', '-Fc', '--verbose',
+			"--file=$tempdir/binary_coll_compatible.sql",
+			"$tempdir/binary_coll_compatible.dump",
+		],
+	},
 	clean => {
 		dump_cmd => [
 			'pg_dump',
@@ -387,6 +405,7 @@ my %dump_test_schema_runs = (
 # are flags used to exclude specific items (ACLs, blobs, etc).
 my %full_runs = (
 	binary_upgrade           => 1,
+	binary_coll_compatible   => 1,
 	clean                    => 1,
 	clean_if_exists          => 1,
 	createdb                 => 1,
@@ -920,9 +939,10 @@ my %tests = (
 			test_schema_plus_blobs => 1,
 		},
 		unlike => {
-			binary_upgrade => 1,
-			no_blobs       => 1,
-			schema_only    => 1,
+			binary_upgrade         => 1,
+			binary_coll_compatible => 1,
+			no_blobs               => 1,
+			schema_only            => 1,
 		},
 	},
 
@@ -1184,6 +1204,7 @@ my %tests = (
 		},
 		unlike => {
 			binary_upgrade           => 1,
+			binary_coll_compatible   => 1,
 			exclude_dump_test_schema => 1,
 			exclude_test_table       => 1,
 			exclude_test_table_data  => 1,
@@ -1209,6 +1230,7 @@ my %tests = (
 		},
 		unlike => {
 			binary_upgrade           => 1,
+			binary_coll_compatible   => 1,
 			exclude_dump_test_schema => 1,
 			schema_only              => 1,
 		},
@@ -1244,6 +1266,7 @@ my %tests = (
 		},
 		unlike => {
 			binary_upgrade           => 1,
+			binary_coll_compatible   => 1,
 			exclude_dump_test_schema => 1,
 			schema_only              => 1,
 		},
@@ -1266,6 +1289,7 @@ my %tests = (
 		},
 		unlike => {
 			binary_upgrade           => 1,
+			binary_coll_compatible   => 1,
 			exclude_dump_test_schema => 1,
 			schema_only              => 1,
 		},
@@ -1287,6 +1311,7 @@ my %tests = (
 		},
 		unlike => {
 			binary_upgrade           => 1,
+			binary_coll_compatible   => 1,
 			exclude_dump_test_schema => 1,
 			schema_only              => 1,
 		},
@@ -1308,6 +1333,7 @@ my %tests = (
 		},
 		unlike => {
 			binary_upgrade           => 1,
+			binary_coll_compatible   => 1,
 			exclude_dump_test_schema => 1,
 			schema_only              => 1,
 		},
@@ -1674,6 +1700,7 @@ my %tests = (
 		  { %full_runs, %dump_test_schema_runs, section_pre_data => 1, },
 		unlike => {
 			binary_upgrade           => 1,
+			binary_coll_compatible   => 1,
 			exclude_dump_test_schema => 1,
 		},
 	},
@@ -1688,7 +1715,7 @@ my %tests = (
 			\n.*^
 			\QALTER TYPE dump_test.planets ADD VALUE 'mars';\E
 			\n/xms,
-		like => { binary_upgrade => 1, },
+		like => { binary_upgrade => 1, binary_coll_compatible => 1, },
 	},
 
 	'CREATE TYPE dump_test.textrange AS RANGE' => {
@@ -2356,6 +2383,7 @@ my %tests = (
 		  { %full_runs, %dump_test_schema_runs, section_pre_data => 1, },
 		unlike => {
 			binary_upgrade           => 1,
+			binary_coll_compatible   => 1,
 			exclude_dump_test_schema => 1,
 		},
 	},
@@ -2549,6 +2577,7 @@ my %tests = (
 		},
 		unlike => {
 			binary_upgrade           => 1,
+			binary_coll_compatible   => 1,
 			exclude_dump_test_schema => 1,
 		},
 	},
@@ -2617,6 +2646,7 @@ my %tests = (
 		/xm,
 		like => {
 			binary_upgrade          => 1,
+			binary_coll_compatible  => 1,
 			clean                   => 1,
 			clean_if_exists         => 1,
 			createdb                => 1,
@@ -2688,6 +2718,7 @@ my %tests = (
 		/xm,
 		like => {
 			binary_upgrade           => 1,
+			binary_coll_compatible   => 1,
 			clean                    => 1,
 			clean_if_exists          => 1,
 			createdb                 => 1,
@@ -3155,6 +3186,7 @@ my %tests = (
 		  { %full_runs, %dump_test_schema_runs, section_post_data => 1, },
 		unlike => {
 			binary_upgrade           => 1,
+			binary_coll_compatible   => 1,
 			exclude_dump_test_schema => 1,
 			schema_only              => 1,
 		},
@@ -3170,6 +3202,7 @@ my %tests = (
 		  { %full_runs, %dump_test_schema_runs, section_post_data => 1, },
 		unlike => {
 			binary_upgrade           => 1,
+			binary_coll_compatible   => 1,
 			exclude_dump_test_schema => 1,
 			schema_only              => 1,
 		},
@@ -3302,16 +3335,53 @@ my %tests = (
 			%full_runs, %dump_test_schema_runs, section_pre_data => 1,
 		},
 		unlike => { exclude_dump_test_schema => 1 },
+	},
+
+	"binary_upgrade_set_index_coll_version(oid, oid, 'not_a_version')" => {
+		create_order => 101,
+		create_sql => '
+		CREATE TABLE dump_test.regress_table_coll(id integer, val text);
+		CREATE INDEX regress_coll_idx1 ON dump_test.regress_table_coll(val COLLATE "fr-x-icu");
+		UPDATE pg_depend SET refobjversion = \'not_a_version\' WHERE refobjversion IS NOT NULL AND objid::regclass::text = \'dump_test.regress_coll_idx1\';',
+		regexp => qr/^
+		\QCREATE INDEX regress_coll_idx1 ON dump_test.regress_table_coll USING btree (val COLLATE "fr-x-icu");\E\n
+		\n
+		\Q-- For binary upgrade, restore dependent collation version.\E\n
+		\QSELECT pg_catalog.binary_upgrade_set_index_coll_version\E \(\d+,\ \d+,\ 'not_a_version'\);/xm,
+		like => { binary_upgrade => 1, binary_coll_compatible => 1, },
+		icu => 1,
+	},
+	"binary_upgrade_set_index_coll_version(?, ?, '')" => {
+		create_order => 102,
+		create_sql => '
+		CREATE TABLE dump_test.regress_table_coll_no_ver(id integer, val text);
+		CREATE INDEX regress_coll_no_ver_idx1 ON dump_test.regress_table_coll_no_ver(val COLLATE "fr-x-icu");
+		UPDATE pg_depend SET refobjversion = \'\' WHERE refobjversion IS NOT NULL AND objid::regclass::text = \'dump_test.regress_coll_no_ver_idx1\';',
+		regexp => qr/SELECT pg_catalog.binary_upgrade_set_index_coll_version\(\d+, \d+, ''\)/,
+		like => { binary_upgrade => 1},
+		# should not appear in binary_coll_compatible case!
+		unlike => { binary_coll_compatible => 1},
+		icu => 1,
 	});
 
 #########################################
 # Create a PG instance to test actually dumping from
 
-my $node = get_new_node('main');
-$node->init;
-$node->start;
+my $main_node = get_new_node('main');
+$main_node->init;
+$main_node->start;
+
+my $port = $main_node->port;
+
+# And another instance to validate the binary dump
+my $bin_node = get_new_node('binary');
+$bin_node->init;
+$bin_node->start;
 
-my $port = $node->port;
+my $bin_port = $bin_node->port;
+
+# and add a $node variable pointing to main_node for now
+my $node = $main_node;
 
 # We need to see if this system supports CREATE COLLATION or not
 # If it doesn't then we will skip all the COLLATION-related tests.
@@ -3335,6 +3405,10 @@ $node->psql('postgres', 'create database regress_pg_dump_test;');
 # command_fails_like is actually 2 tests)
 my $num_tests = 12;
 
+# 4 more tests for restoring globals and binary_upgrade dump, dumping it again
+# and regenerating the sql file
+$num_tests+= 4;
+
 foreach my $run (sort keys %pgdump_runs)
 {
 	my $test_key = $run;
@@ -3385,16 +3459,29 @@ foreach my $run (sort keys %pgdump_runs)
 			next;
 		}
 
+		# Skip any icu-related commands if there is no icu support
+		if ($ENV{with_icu} ne 'yes' && defined($tests{$test}->{icu}))
+		{
+			next;
+		}
+
 		# If there is a like entry, but no unlike entry, then we will test the like case
 		if ($tests{$test}->{like}->{$test_key}
 			&& !defined($tests{$test}->{unlike}->{$test_key}))
 		{
 			$num_tests++;
+
+			# binary_upgrade tests are also run after being restored and
+			# re-dumped.
+			$num_tests++ if ($test_key eq 'binary_upgrade');
 		}
 		else
 		{
 			# We will test everything that isn't a 'like'
 			$num_tests++;
+			# binary_upgrade tests are also run after being restored and
+			# re-dumped.
+			$num_tests++ if ($test_key eq 'binary_upgrade');
 		}
 	}
 }
@@ -3442,6 +3529,12 @@ foreach my $test (
 			next;
 		}
 
+		# Skip any icu-related commands if there is no icu support
+		if ($ENV{with_icu} ne 'yes' && defined($tests{$test}->{icu}))
+		{
+			next;
+		}
+
 		# Add terminating semicolon
 		$create_sql{$test_db} .= $tests{$test}->{create_sql} . ";";
 	}
@@ -3495,79 +3588,116 @@ command_fails_like(
 #########################################
 # Run all runs
 
-foreach my $run (sort keys %pgdump_runs)
+foreach my $pass (1, 2)
 {
-	my $test_key = $run;
-	my $run_db   = 'postgres';
-
-	$node->command_ok(\@{ $pgdump_runs{$run}->{dump_cmd} },
-		"$run: pg_dump runs");
-
-	if ($pgdump_runs{$run}->{restore_cmd})
+	foreach my $run (sort keys %pgdump_runs)
 	{
-		$node->command_ok(\@{ $pgdump_runs{$run}->{restore_cmd} },
-			"$run: pg_restore runs");
-	}
-
-	if ($pgdump_runs{$run}->{test_key})
-	{
-		$test_key = $pgdump_runs{$run}->{test_key};
-	}
-
-	my $output_file = slurp_file("$tempdir/${run}.sql");
+		my $test_key = $run;
+		my $run_db   = 'postgres';
 
-	#########################################
-	# Run all tests where this run is included
-	# as either a 'like' or 'unlike' test.
+		# we only test binary upgrade on the 2nd pass
+		next if ($pass == 2 and $test_key ne 'binary_upgrade');
 
-	foreach my $test (sort keys %tests)
-	{
-		my $test_db = 'postgres';
+		$node->command_ok(\@{ $pgdump_runs{$run}->{dump_cmd} },
+			"$run: pg_dump runs");
 
-		if (defined($pgdump_runs{$run}->{database}))
+		if ($pgdump_runs{$run}->{restore_cmd})
 		{
-			$run_db = $pgdump_runs{$run}->{database};
+			$node->command_ok(\@{ $pgdump_runs{$run}->{restore_cmd} },
+				"$run: pg_restore runs");
 		}
 
-		if (defined($tests{$test}->{database}))
+		if ($pgdump_runs{$run}->{test_key})
 		{
-			$test_db = $tests{$test}->{database};
+			$test_key = $pgdump_runs{$run}->{test_key};
 		}
 
-		# Skip any collation-related commands if there is no collation support
-		if (!$collation_support && defined($tests{$test}->{collation}))
-		{
-			next;
-		}
+		my $output_file = slurp_file("$tempdir/${run}.sql");
 
-		if ($run_db ne $test_db)
-		{
-			next;
-		}
+		#########################################
+		# Run all tests where this run is included
+		# as either a 'like' or 'unlike' test.
 
-		# Run the test listed as a like, unless it is specifically noted
-		# as an unlike (generally due to an explicit exclusion or similar).
-		if ($tests{$test}->{like}->{$test_key}
-			&& !defined($tests{$test}->{unlike}->{$test_key}))
+		foreach my $test (sort keys %tests)
 		{
-			if (!ok($output_file =~ $tests{$test}->{regexp},
-					"$run: should dump $test"))
+			my $test_db = 'postgres';
+
+			if (defined($pgdump_runs{$run}->{database}))
 			{
-				diag("Review $run results in $tempdir");
+				$run_db = $pgdump_runs{$run}->{database};
 			}
-		}
-		else
-		{
-			if (!ok($output_file !~ $tests{$test}->{regexp},
-					"$run: should not dump $test"))
+
+			if (defined($tests{$test}->{database}))
+			{
+				$test_db = $tests{$test}->{database};
+			}
+
+			# Skip any collation-related commands if there is no collation support
+			if (!$collation_support && defined($tests{$test}->{collation}))
+			{
+				next;
+			}
+
+			# Skip any icu-related commands if there is no icu support
+	        if ($ENV{with_icu} ne 'yes' && defined($tests{$test}->{icu}))
+			{
+				next;
+			}
+
+			if ($run_db ne $test_db)
+			{
+				next;
+			}
+
+			# Run the test listed as a like, unless it is specifically noted
+			# as an unlike (generally due to an explicit exclusion or similar).
+			if ($tests{$test}->{like}->{$test_key}
+				&& !defined($tests{$test}->{unlike}->{$test_key}))
 			{
-				diag("Review $run results in $tempdir");
+				if (!ok($output_file =~ $tests{$test}->{regexp},
+						"$run: should dump $test"))
+				{
+					diag("Review $run results in $tempdir");
+				}
+			}
+			else
+			{
+				if (!ok($output_file !~ $tests{$test}->{regexp},
+						"$run: should not dump $test"))
+				{
+					diag("Review $run results in $tempdir");
+				}
 			}
 		}
 	}
+
+	# After all dump have been generated, restore the binary_upgrade dump with
+	# the required global objects on a suitable node, and continue with the 2nd
+	# pass.
+	if ($pass == 1)
+	{
+		# Stop the original database instance as we don't need it anymore.
+		$node->stop('fast');
+
+		$bin_node->command_ok(\@{['psql',
+			"-d", "postgres", "-f", "$tempdir/pg_dumpall_globals.sql"]},
+			"Restore globals");
+
+		$bin_node->stop('fast');
+		$bin_node->start(binary_start => 1);
+		$bin_node->command_ok(\@{['pg_restore', '-p', $bin_port,
+			'-d', 'postgres',
+			"$tempdir/binary_upgrade.dump"]},
+			"Restore the binary_upgrade dump");
+		$bin_node->stop('fast');
+		$bin_node->start;
+
+		# And change $node to point to the freshly restored node.
+		$node = $bin_node;
+	}
 }
 
 #########################################
 # Stop the database instance, which will be removed at the end of the tests.
 
-$node->stop('fast');
+$bin_node->stop('fast');
diff --git a/src/bin/pg_upgrade/dump.c b/src/bin/pg_upgrade/dump.c
index 4d730adfe2..672ecda169 100644
--- 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.coll_compat ?
+						   "--unknown-collations-binary-compatible" : "",
 						   sql_file_name, escaped_connstr.data);
 
 		termPQExpBuffer(&escaped_connstr);
diff --git a/src/bin/pg_upgrade/option.c b/src/bin/pg_upgrade/option.c
index aca1ee8b48..c7e291f7e7 100644
--- 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},
+		{"collation-binary-compatible", 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.coll_compat = 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(_("  --collation-binary-compatible mark collations as depending on current collation\n"
+			 "                                versions rather than unknown if they're unknown\n"));
 	printf(_("  -?, --help                    show this help, then exit\n"));
 	printf(_("\n"
 			 "Before running pg_upgrade you must:\n"
diff --git a/src/bin/pg_upgrade/pg_upgrade.h b/src/bin/pg_upgrade/pg_upgrade.h
index 8b90cefbe0..68e637ce8a 100644
--- a/src/bin/pg_upgrade/pg_upgrade.h
+++ b/src/bin/pg_upgrade/pg_upgrade.h
@@ -292,6 +292,8 @@ 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		coll_compat;	/* should we skip marking index collations as
+								 * unknown version */
 } UserOpts;
 
 typedef struct
diff --git a/src/include/catalog/dependency.h b/src/include/catalog/dependency.h
index 3baa5e498a..2966339498 100644
--- a/src/include/catalog/dependency.h
+++ b/src/include/catalog/dependency.h
@@ -130,6 +130,13 @@ typedef enum ObjectClass
 
 #define LAST_OCLASS		OCLASS_TRANSFORM
 
+/* Struct describing one forced collation version dependency */
+typedef struct NewCollationVersionDependency
+{
+	char	   *version;		/* forced collation version */
+	Oid			oid;			/* target collation oid */
+} NewCollationVersionDependency;
+
 /* flag bits for performDeletion/performMultipleDeletions: */
 #define PERFORM_DELETION_INTERNAL			0x0001	/* internal action */
 #define PERFORM_DELETION_CONCURRENTLY		0x0002	/* concurrent drop */
@@ -160,7 +167,8 @@ extern void recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
 											Node *expr, Oid relId,
 											DependencyType behavior,
 											DependencyType self_behavior,
-											bool reverse_self);
+											bool reverse_self,
+											bool track_version);
 
 extern ObjectClass getObjectClass(const ObjectAddress *object);
 
@@ -180,17 +188,29 @@ extern void sort_object_addresses(ObjectAddresses *addrs);
 
 extern void free_object_addresses(ObjectAddresses *addrs);
 
+typedef char *(*VisitDependentObjectsFun) (const ObjectAddress *otherObject,
+										   const char *version,
+										   void *userdata);
+
+extern void visitDependentObjects(const ObjectAddress *object,
+								  VisitDependentObjectsFun callback,
+								  void *userdata);
+
 /* 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 track_version);
 
 extern void recordDependencyOnCurrentExtension(const ObjectAddress *object,
 											   bool isReplace);
@@ -209,10 +229,9 @@ 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);
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index f58e8675f3..9b4de26514 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -121,6 +121,11 @@ extern void FormIndexDatum(IndexInfo *indexInfo,
 						   Datum *values,
 						   bool *isnull);
 
+extern void index_check_collation_versions(Oid relid);
+
+extern void index_force_collation_versions(Oid indexid, Oid coll,
+										   char *version);
+
 extern void index_build(Relation heapRelation,
 						Relation indexRelation,
 						IndexInfo *indexInfo,
@@ -131,6 +136,8 @@ extern void validate_index(Oid heapId, Oid indexId, Snapshot snapshot);
 
 extern void index_set_state_flags(Oid indexId, IndexStateFlagsAction action);
 
+extern void index_update_collation_versions(Oid relid);
+
 extern Oid	IndexGetRelation(Oid indexId, bool missing_ok);
 
 extern void reindex_index(Oid indexId, bool skip_constraint_checks,
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 687509ba92..84466ab577 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -10367,6 +10367,10 @@
   proname => 'binary_upgrade_set_missing_value', provolatile => 'v',
   proparallel => 'u', prorettype => 'void', proargtypes => 'oid text text',
   prosrc => 'binary_upgrade_set_missing_value' },
+{ oid => '8178', descr => 'for use by pg_upgrade',
+  proname => 'binary_upgrade_set_index_coll_version', provolatile => 'v',
+  proparallel => 'u', prorettype => 'void', proargtypes => 'oid oid text',
+  prosrc => 'binary_upgrade_set_index_coll_version' },
 
 # conversion functions
 { oid => '4302',
diff --git a/src/include/catalog/pg_type.h b/src/include/catalog/pg_type.h
index 7b37562648..2d511c5cba 100644
--- a/src/include/catalog/pg_type.h
+++ b/src/include/catalog/pg_type.h
@@ -361,6 +361,8 @@ extern void GenerateTypeDependencies(HeapTuple typeTuple,
 									 bool isDependentType,
 									 bool rebuild);
 
+extern List *GetTypeCollations(Oid typeObjectid, bool non_deterministic_only);
+
 extern void RenameTypeInternal(Oid typeOid, const char *newTypeName,
 							   Oid typeNamespace);
 
diff --git a/src/include/utils/pg_locale.h b/src/include/utils/pg_locale.h
index 9cb7d91ddf..96da132c03 100644
--- 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);
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 0b5957ba02..f79667d651 100644
--- 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 being done yet? */
 
 	/*----------
 	 * rd_createSubid is the ID of the highest subtransaction the rel has
diff --git a/src/test/Makefile b/src/test/Makefile
index efb206aa75..4ef0d11702 100644
--- 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
@@ -37,7 +38,7 @@ endif
 # clean" etc to recurse into them.  (We must filter out those that we
 # have conditionally included into SUBDIRS above, else there will be
 # make confusion.)
-ALWAYS_SUBDIRS = $(filter-out $(SUBDIRS),examples kerberos ldap locale thread ssl)
+ALWAYS_SUBDIRS = $(filter-out $(SUBDIRS),examples kerberos ldap thread ssl)
 
 # We want to recurse to all subdirs for all standard targets, except that
 # installcheck and install should not recurse into the subdirectory "modules".
diff --git a/src/test/locale/.gitignore b/src/test/locale/.gitignore
index 620d3df425..64e1bf2a80 100644
--- a/src/test/locale/.gitignore
+++ b/src/test/locale/.gitignore
@@ -1 +1,2 @@
 /test-ctype
+/tmp_check/
diff --git a/src/test/locale/Makefile b/src/test/locale/Makefile
index 22a45b65f2..73495cf16b 100644
--- 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:
+	$(prove_installcheck)
diff --git a/src/test/locale/t/001_index.pl b/src/test/locale/t/001_index.pl
new file mode 100644
index 0000000000..468fbb63b6
--- /dev/null
+++ b/src/test/locale/t/001_index.pl
@@ -0,0 +1,76 @@
+use strict;
+use warnings;
+
+use Config;
+use PostgresNode;
+use TestLib;
+use Test::More;
+
+if ($ENV{with_icu} eq 'yes')
+{
+	plan tests => 12;
+}
+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;
+
+$ENV{PGHOST} = $node->host;
+$ENV{PGPORT} = $node->port;
+$node->start;
+
+sub test_index
+{
+	my ($err_like, $err_comm) = @_;
+
+	my ($ret, $out, $err) = $node->psql('postgres',
+		'SET enable_seqscan = 0;'
+		. "EXPLAIN SELECT val FROM icu1 WHERE val = '0'");
+
+	is($ret, 0, 'EXPLAIN should succeed.');
+	like($out, qr/icu1_fr/, 'Index icu1_fr should be used.');
+	like($err, $err_like, $err_comm);
+}
+
+$node->safe_psql('postgres',
+	'CREATE TABLE icu1(val text);'
+	. 'INSERT INTO icu1 SELECT i::text FROM generate_series(1, 10000) i;'
+	. 'CREATE INDEX icu1_fr ON icu1 (val COLLATE "fr-x-icu");');
+$node->safe_psql('postgres', 'VACUUM ANALYZE icu1;');
+
+test_index(qr/^$/, 'No warning should be raised');
+
+# Simulate different collation version
+$node->safe_psql('postgres',
+	"UPDATE pg_depend SET refobjversion = 'not_a_version'"
+	. " WHERE refobjversion IS NOT NULL"
+	. " AND objid::regclass::text = 'icu1_fr';");
+
+test_index(qr/index "icu1_fr" depends on collation "fr-x-icu" version "not_a_version", but the current version is/,
+	'Different collation version warning should be raised.');
+
+# Simulate unknown collation version
+$node->safe_psql('postgres',
+	"UPDATE pg_depend SET refobjversion = ''"
+	. " WHERE refobjversion IS NOT NULL"
+	. " AND objid::regclass::text = 'icu1_fr';");
+
+test_index(qr/index "icu1_fr" depends on collation "fr-x-icu" with an unknown version, and the current version is/,
+	'Unknown collation version warning should be raised.');
+
+# Simulate previously unhandled collation versioning
+$node->safe_psql('postgres',
+	"UPDATE pg_depend SET refobjversion = NULL"
+	. " WHERE refobjversion IS NOT NULL"
+	. " AND objid::regclass::text = 'icu1_fr';");
+
+test_index(qr/index "icu1_fr" depends on collation "fr-x-icu" with an unknown version, and the current version is/,
+	'Unknown collation version warning should be raised.');
+
+$node->stop;
diff --git a/src/test/perl/PostgresNode.pm b/src/test/perl/PostgresNode.pm
index 1488bffa2b..8c54e12268 100644
--- a/src/test/perl/PostgresNode.pm
+++ b/src/test/perl/PostgresNode.pm
@@ -765,10 +765,14 @@ sub start
 		local %ENV = %ENV;
 		delete $ENV{PGAPPNAME};
 
+		my $options = "--cluster-name=$name";
+
+		$options .= ' -b' if ($params{binary_start});
+
 		# Note: We set the cluster_name here, not in postgresql.conf (in
 		# sub init) so that it does not get copied to standbys.
 		$ret = TestLib::system_log('pg_ctl', '-D', $self->data_dir, '-l',
-			$self->logfile, '-o', "--cluster-name=$name", 'start');
+			$self->logfile, '-o', $options, 'start');
 	}
 
 	if ($ret != 0)
diff --git a/src/test/regress/expected/collate.icu.utf8.out b/src/test/regress/expected/collate.icu.utf8.out
index 60d9263a2f..db386c1b09 100644
--- a/src/test/regress/expected/collate.icu.utf8.out
+++ b/src/test/regress/expected/collate.icu.utf8.out
@@ -1897,6 +1897,163 @@ 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,
+    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 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);
+-- for key columns, hash indexes should record dependency on the collation but
+-- not the version
+CREATE INDEX icuidx18_hash_d_es ON collate_test USING hash (d_es);
+CREATE INDEX icuidx19_hash_id_d_es_eq ON collate_test USING hash (id) WHERE (d_es) = 'foo';
+CREATE INDEX icuidx20_hash_id_d_es_lt ON collate_test USING hash (id) WHERE (d_es) < 'foo';
+SELECT objid::regclass, refobjid::regcollation,
+CASE
+WHEN refobjversion IS NULL THEN 'version not tracked'
+ELSE CASE
+    WHEN refobjversion = pg_collation_actual_version(refobjid) THEN 'up to date'
+    ELSE 'out of date'
+    END
+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;
+           objid           |  refobjid  |       version       
+---------------------------+------------+---------------------
+ 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"  | up to date
+ 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"  | up to date
+ 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"  | up to date
+ icuidx11_d_es             | "es-x-icu" | up to date
+ icuidx12_custom           | "default"  | up to date
+ icuidx12_custom           | custom     | up to date
+ icuidx13_custom           | "default"  | up to date
+ icuidx13_custom           | custom     | up to date
+ icuidx14_myrange          | "default"  | up to date
+ 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
+ icuidx18_hash_d_es        | "es-x-icu" | version not tracked
+ icuidx19_hash_id_d_es_eq  | "default"  | up to date
+ icuidx19_hash_id_d_es_eq  | "es-x-icu" | up to date
+ icuidx20_hash_id_d_es_lt  | "default"  | up to date
+ icuidx20_hash_id_d_es_lt  | "es-x-icu" | up to date
+(49 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)
+
 -- cleanup
 RESET search_path;
 SET client_min_messages TO warning;
diff --git a/src/test/regress/expected/create_index.out b/src/test/regress/expected/create_index.out
index 64c0c66859..d883ee58d1 100644
--- 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);
diff --git a/src/test/regress/sql/collate.icu.utf8.sql b/src/test/regress/sql/collate.icu.utf8.sql
index 35acf91fbf..e93530af55 100644
--- a/src/test/regress/sql/collate.icu.utf8.sql
+++ b/src/test/regress/sql/collate.icu.utf8.sql
@@ -716,6 +716,112 @@ 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,
+    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 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);
+-- for key columns, hash indexes should record dependency on the collation but
+-- not the version
+CREATE INDEX icuidx18_hash_d_es ON collate_test USING hash (d_es);
+CREATE INDEX icuidx19_hash_id_d_es_eq ON collate_test USING hash (id) WHERE (d_es) = 'foo';
+CREATE INDEX icuidx20_hash_id_d_es_lt ON collate_test USING hash (id) WHERE (d_es) < 'foo';
+
+SELECT objid::regclass, refobjid::regcollation,
+CASE
+WHEN refobjversion IS NULL THEN 'version not tracked'
+ELSE CASE
+    WHEN refobjversion = pg_collation_actual_version(refobjid) THEN 'up to date'
+    ELSE 'out of date'
+    END
+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;
+
+-- 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';
 
 -- cleanup
 RESET search_path;
-- 
2.20.1


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