Per-column collation support

This adds collation support for columns and domains, a COLLATE clause
to override it per expression, and B-tree index support.

Peter Eisentraut
reviewed by Pavel Stehule, Itagaki Takahiro, Robert Haas, Noah Misch

src/backend/optimizer/prep/prepjointree.c

@@ -445,6 +445,7 @@ inline_set_returning_functions(PlannerInfo *root)
 				rte->funcexpr = NULL;
 				rte->funccoltypes = NIL;
 				rte->funccoltypmods = NIL;
+				rte->funccolcollations = NIL;
 			}
 		}
 	}

src/backend/optimizer/prep/preptlist.c

@@ -100,6 +100,7 @@ preprocess_targetlist(PlannerInfo *root, List *tlist)
 						  SelfItemPointerAttributeNumber,
 						  TIDOID,
 						  -1,
+						  InvalidOid,
 						  0);
 			snprintf(resname, sizeof(resname), "ctid%u", rc->rti);
 			tle = makeTargetEntry((Expr *) var,
@@ -115,6 +116,7 @@ preprocess_targetlist(PlannerInfo *root, List *tlist)
 							  TableOidAttributeNumber,
 							  OIDOID,
 							  -1,
+							  InvalidOid,
 							  0);
 				snprintf(resname, sizeof(resname), "tableoid%u", rc->rti);
 				tle = makeTargetEntry((Expr *) var,
@@ -257,6 +259,7 @@ expand_targetlist(List *tlist, int command_type,
 			 */
 			Oid			atttype = att_tup->atttypid;
 			int32		atttypmod = att_tup->atttypmod;
+			Oid			attcollation = att_tup->attcollation;
 			Node	   *new_expr;
 
 			switch (command_type)
@@ -296,6 +299,7 @@ expand_targetlist(List *tlist, int command_type,
 													attrno,
 													atttype,
 													atttypmod,
+													attcollation,
 													0);
 					}
 					else

src/backend/optimizer/prep/prepunion.c

@@ -86,7 +86,7 @@ static List *generate_setop_tlist(List *colTypes, int flag,
 					 bool hack_constants,
 					 List *input_tlist,
 					 List *refnames_tlist);
-static List *generate_append_tlist(List *colTypes, bool flag,
+static List *generate_append_tlist(List *colTypes, List *colCollations, bool flag,
 					  List *input_plans,
 					  List *refnames_tlist);
 static List *generate_setop_grouplist(SetOperationStmt *op, List *targetlist);
@@ -348,7 +348,7 @@ generate_recursion_plan(SetOperationStmt *setOp, PlannerInfo *root,
 	/*
 	 * Generate tlist for RecursiveUnion plan node --- same as in Append cases
 	 */
-	tlist = generate_append_tlist(setOp->colTypes, false,
+	tlist = generate_append_tlist(setOp->colTypes, setOp->colCollations, false,
 								  list_make2(lplan, rplan),
 								  refnames_tlist);
 
@@ -443,7 +443,7 @@ generate_union_plan(SetOperationStmt *op, PlannerInfo *root,
 	 * concerned, but we must make it look real anyway for the benefit of the
 	 * next plan level up.
 	 */
-	tlist = generate_append_tlist(op->colTypes, false,
+	tlist = generate_append_tlist(op->colTypes, op->colCollations, false,
 								  planlist, refnames_tlist);
 
 	/*
@@ -534,7 +534,7 @@ generate_nonunion_plan(SetOperationStmt *op, PlannerInfo *root,
 	 * column is shown as a variable not a constant, else setrefs.c will get
 	 * confused.
 	 */
-	tlist = generate_append_tlist(op->colTypes, true,
+	tlist = generate_append_tlist(op->colTypes, op->colCollations, true,
 								  planlist, refnames_tlist);
 
 	/*
@@ -885,6 +885,7 @@ generate_setop_tlist(List *colTypes, int flag,
 									inputtle->resno,
 									exprType((Node *) inputtle->expr),
 									exprTypmod((Node *) inputtle->expr),
+									exprCollation((Node *) inputtle->expr),
 									0);
 		if (exprType(expr) != colType)
 		{
@@ -936,13 +937,14 @@ generate_setop_tlist(List *colTypes, int flag,
  * The Vars are always generated with varno 0.
  */
 static List *
-generate_append_tlist(List *colTypes, bool flag,
+generate_append_tlist(List *colTypes, List*colCollations, bool flag,
 					  List *input_plans,
 					  List *refnames_tlist)
 {
 	List	   *tlist = NIL;
 	int			resno = 1;
 	ListCell   *curColType;
+	ListCell   *curColCollation;
 	ListCell   *ref_tl_item;
 	int			colindex;
 	TargetEntry *tle;
@@ -997,10 +999,11 @@ generate_append_tlist(List *colTypes, bool flag,
 	 * Now we can build the tlist for the Append.
 	 */
 	colindex = 0;
-	forboth(curColType, colTypes, ref_tl_item, refnames_tlist)
+	forthree(curColType, colTypes, curColCollation, colCollations, ref_tl_item, refnames_tlist)
 	{
 		Oid			colType = lfirst_oid(curColType);
 		int32		colTypmod = colTypmods[colindex++];
+		Oid			colColl = lfirst_oid(curColCollation);
 		TargetEntry *reftle = (TargetEntry *) lfirst(ref_tl_item);
 
 		Assert(reftle->resno == resno);
@@ -1009,6 +1012,7 @@ generate_append_tlist(List *colTypes, bool flag,
 								resno,
 								colType,
 								colTypmod,
+								colColl,
 								0);
 		tle = makeTargetEntry((Expr *) expr,
 							  (AttrNumber) resno++,
@@ -1025,6 +1029,7 @@ generate_append_tlist(List *colTypes, bool flag,
 								resno,
 								INT4OID,
 								-1,
+								InvalidOid,
 								0);
 		tle = makeTargetEntry((Expr *) expr,
 							  (AttrNumber) resno++,
@@ -1344,6 +1349,7 @@ make_inh_translation_list(Relation oldrelation, Relation newrelation,
 		char	   *attname;
 		Oid			atttypid;
 		int32		atttypmod;
+		Oid			attcollation;
 		int			new_attno;
 
 		att = old_tupdesc->attrs[old_attno];
@@ -1356,6 +1362,7 @@ make_inh_translation_list(Relation oldrelation, Relation newrelation,
 		attname = NameStr(att->attname);
 		atttypid = att->atttypid;
 		atttypmod = att->atttypmod;
+		attcollation = att->attcollation;
 
 		/*
 		 * When we are generating the "translation list" for the parent table
@@ -1367,6 +1374,7 @@ make_inh_translation_list(Relation oldrelation, Relation newrelation,
 										 (AttrNumber) (old_attno + 1),
 										 atttypid,
 										 atttypmod,
+										 attcollation,
 										 0));
 			continue;
 		}
@@ -1409,6 +1417,7 @@ make_inh_translation_list(Relation oldrelation, Relation newrelation,
 									 (AttrNumber) (new_attno + 1),
 									 atttypid,
 									 atttypmod,
+									 attcollation,
 									 0));
 	}