1 files changed, 49 insertions, 2 deletions

diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index eafc3b30539..fe8d0c4fac1 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -33,6 +33,7 @@
 #include "catalog/heap.h"
 #include "catalog/index.h"
 #include "catalog/namespace.h"
+#include "catalog/pg_collation.h"
 #include "catalog/pg_constraint.h"
 #include "catalog/pg_opclass.h"
 #include "catalog/pg_operator.h"
@@ -111,6 +112,7 @@ static void transformOfType(CreateStmtContext *cxt,
 static char *chooseIndexName(const RangeVar *relation, IndexStmt *index_stmt);
 static IndexStmt *generateClonedIndexStmt(CreateStmtContext *cxt,
 						Relation parent_index, AttrNumber *attmap);
+static List *get_collation(Oid collation, Oid actual_datatype);
 static List *get_opclass(Oid opclass, Oid actual_datatype);
 static void transformIndexConstraints(CreateStmtContext *cxt);
 static IndexStmt *transformIndexConstraint(Constraint *constraint,
@@ -904,6 +906,7 @@ generateClonedIndexStmt(CreateStmtContext *cxt, Relation source_idx,
 	Form_pg_class idxrelrec;
 	Form_pg_index idxrec;
 	Form_pg_am	amrec;
+	oidvector  *indcollation;
 	oidvector  *indclass;
 	IndexStmt  *index;
 	List	   *indexprs;
@@ -931,6 +934,12 @@ generateClonedIndexStmt(CreateStmtContext *cxt, Relation source_idx,
 	/* Fetch pg_am tuple for source index from relcache entry */
 	amrec = source_idx->rd_am;
 
+	/* Extract indcollation from the pg_index tuple */
+	datum = SysCacheGetAttr(INDEXRELID, ht_idx,
+							Anum_pg_index_indcollation, &isnull);
+	Assert(!isnull);
+	indcollation = (oidvector *) DatumGetPointer(datum);
+
 	/* Extract indclass from the pg_index tuple */
 	datum = SysCacheGetAttr(INDEXRELID, ht_idx,
 							Anum_pg_index_indclass, &isnull);
@@ -1094,6 +1103,9 @@ generateClonedIndexStmt(CreateStmtContext *cxt, Relation source_idx,
 		/* Copy the original index column name */
 		iparam->indexcolname = pstrdup(NameStr(attrs[keyno]->attname));
 
+		/* Add the collation name, if non-default */
+		iparam->collation = get_collation(indcollation->values[keyno], keycoltype);
+
 		/* Add the operator class name, if non-default */
 		iparam->opclass = get_opclass(indclass->values[keyno], keycoltype);
 
@@ -1152,7 +1164,41 @@ generateClonedIndexStmt(CreateStmtContext *cxt, Relation source_idx,
 }
 
 /*
- * get_opclass			- fetch name of an index operator class
+ * get_collation		- fetch qualified name of a collation
+ *
+ * If collation is InvalidOid or is the default for the given actual_datatype,
+ * then the return value is NIL.
+ */
+static List *
+get_collation(Oid collation, Oid actual_datatype)
+{
+	List	   *result;
+	HeapTuple	ht_coll;
+	Form_pg_collation coll_rec;
+	char	   *nsp_name;
+	char	   *coll_name;
+
+	if (!OidIsValid(collation))
+		return NIL;				/* easy case */
+	if (collation == get_typcollation(actual_datatype))
+		return NIL;				/* just let it default */
+
+	ht_coll = SearchSysCache1(COLLOID, ObjectIdGetDatum(collation));
+	if (!HeapTupleIsValid(ht_coll))
+		elog(ERROR, "cache lookup failed for collation %u", collation);
+	coll_rec = (Form_pg_collation) GETSTRUCT(ht_coll);
+
+	/* For simplicity, we always schema-qualify the name */
+	nsp_name = get_namespace_name(coll_rec->collnamespace);
+	coll_name = pstrdup(NameStr(coll_rec->collname));
+	result = list_make2(makeString(nsp_name), makeString(coll_name));
+
+	ReleaseSysCache(ht_coll);
+	return result;
+}
+
+/*
+ * get_opclass			- fetch qualified name of an index operator class
  *
  * If the opclass is the default for the given actual_datatype, then
  * the return value is NIL.
@@ -1160,9 +1206,9 @@ generateClonedIndexStmt(CreateStmtContext *cxt, Relation source_idx,
 static List *
 get_opclass(Oid opclass, Oid actual_datatype)
 {
+	List	   *result = NIL;
 	HeapTuple	ht_opc;
 	Form_pg_opclass opc_rec;
-	List	   *result = NIL;
 
 	ht_opc = SearchSysCache1(CLAOID, ObjectIdGetDatum(opclass));
 	if (!HeapTupleIsValid(ht_opc))
@@ -1663,6 +1709,7 @@ transformIndexConstraint(Constraint *constraint, CreateStmtContext *cxt)
 		iparam->name = pstrdup(key);
 		iparam->expr = NULL;
 		iparam->indexcolname = NULL;
+		iparam->collation = NIL;
 		iparam->opclass = NIL;
 		iparam->ordering = SORTBY_DEFAULT;
 		iparam->nulls_ordering = SORTBY_NULLS_DEFAULT;