More collations cleanup, from trawling for missed collation assignments.

Mostly cosmetic, though I did find that generateClonedIndexStmt failed
to clone the index's collations.

src/backend/bootstrap/bootparse.y

@@ -345,6 +345,7 @@ boot_index_param:
 					n->name = $1;
 					n->expr = NULL;
 					n->indexcolname = NULL;
+					n->collation = NIL;
 					n->opclass = list_make1(makeString($2));
 					n->ordering = SORTBY_DEFAULT;
 					n->nulls_ordering = SORTBY_NULLS_DEFAULT;

src/backend/nodes/nodeFuncs.c

@@ -3027,6 +3027,8 @@ bool
 					return true;
 				if (walker(coldef->raw_default, context))
 					return true;
+				if (walker(coldef->collClause, context))
+					return true;
 				/* for now, constraints are ignored */
 			}
 			break;

src/backend/optimizer/util/plancat.c

@@ -190,9 +190,9 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
 			info->rel = rel;
 			info->ncolumns = ncolumns = index->indnatts;
 			info->indexkeys = (int *) palloc(sizeof(int) * ncolumns);
+			info->indexcollations = (Oid *) palloc(sizeof(Oid) * ncolumns);
 			info->opfamily = (Oid *) palloc(sizeof(Oid) * ncolumns);
 			info->opcintype = (Oid *) palloc(sizeof(Oid) * ncolumns);
-			info->indexcollations = (Oid *) palloc(sizeof(Oid) * ncolumns);
 
 			for (i = 0; i < ncolumns; i++)
 			{

src/backend/parser/parse_relation.c

@@ -1152,7 +1152,7 @@ addRangeTableEntryForFunction(ParseState *pstate,
 
 		/*
 		 * Use the column definition list to form the alias list and
-		 * funccoltypes/funccoltypmods lists.
+		 * funccoltypes/funccoltypmods/funccolcollations lists.
 		 */
 		foreach(col, coldeflist)
 		{

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;

src/include/nodes/parsenodes.h

@@ -1058,6 +1058,10 @@ typedef struct SelectStmt
  * can be coerced to the output column type.)  Also, if it's not UNION ALL,
  * information about the types' sort/group semantics is provided in the form
  * of a SortGroupClause list (same representation as, eg, DISTINCT).
+ * The resolved common column collations are provided too; but note that if
+ * it's not UNION ALL, it's okay for a column to not have a common collation,
+ * so a member of the colCollations list could be InvalidOid even though the
+ * column has a collatable type.
  * ----------------------
  */
 typedef struct SetOperationStmt

src/include/nodes/plannodes.h

@@ -508,11 +508,11 @@ typedef struct NestLoopParam
  *		merge join node
  *
  * The expected ordering of each mergeable column is described by a btree
- * opfamily OID, a direction (BTLessStrategyNumber or BTGreaterStrategyNumber)
+ * opfamily OID, a collation OID, a direction (BTLessStrategyNumber or
- * and a nulls-first flag.	Note that the two sides of each mergeclause may
+ * BTGreaterStrategyNumber) and a nulls-first flag.  Note that the two sides
- * be of different datatypes, but they are ordered the same way according to
+ * of each mergeclause may be of different datatypes, but they are ordered the
- * the common opfamily.  The operator in each mergeclause must be an equality
+ * same way according to the common opfamily and collation.  The operator in
- * operator of the indicated opfamily.
+ * each mergeclause must be an equality operator of the indicated opfamily.
  * ----------------
  */
 typedef struct MergeJoin

src/include/nodes/primnodes.h

@@ -1047,9 +1047,9 @@ typedef struct CoerceToDomain
  * constraint.	This is effectively like a Param, but can be implemented more
  * simply since we need only one replacement value at a time.
  *
- * Note: the typeId/typeMod will be set from the domain's base type, not
+ * Note: the typeId/typeMod/collation will be set from the domain's base type,
- * the domain itself.  This is because we shouldn't consider the value to
+ * not the domain itself.  This is because we shouldn't consider the value
- * be a member of the domain if we haven't yet checked its constraints.
+ * to be a member of the domain if we haven't yet checked its constraints.
  */
 typedef struct CoerceToDomainValue
 {

src/include/nodes/relation.h

@@ -423,7 +423,9 @@ typedef struct RelOptInfo
  * IndexOptInfo
  *		Per-index information for planning/optimization
  *
- *		opfamily[], indexkeys[], and opcintype[] each have ncolumns entries.
+ *		indexkeys[], indexcollations[], opfamily[], and opcintype[]
+ *		each have ncolumns entries.
+ *
  *		sortopfamily[], reverse_sort[], and nulls_first[] likewise have
  *		ncolumns entries, if the index is ordered; but if it is unordered,
  *		those pointers are NULL.
@@ -453,9 +455,9 @@ typedef struct IndexOptInfo
 
 	/* index descriptor information */
 	int			ncolumns;		/* number of columns in index */
-	Oid		   *opfamily;		/* OIDs of operator families for columns */
 	int		   *indexkeys;		/* column numbers of index's keys, or 0 */
 	Oid		   *indexcollations;	/* OIDs of collations of index columns */
+	Oid		   *opfamily;		/* OIDs of operator families for columns */
 	Oid		   *opcintype;		/* OIDs of opclass declared input data types */
 	Oid		   *sortopfamily;	/* OIDs of btree opfamilies, if orderable */
 	bool	   *reverse_sort;	/* is sort order descending? */