Implement JSON_TABLE DEFAULT PLAN clause

Author: Nikita Glukhov

src/backend/nodes/copyfuncs.c

@@ -2630,6 +2630,7 @@ _copyJsonTable(const JsonTable *from)
 	COPY_NODE_FIELD(columns);
 	COPY_NODE_FIELD(on_error);
 	COPY_NODE_FIELD(alias);
+	COPY_SCALAR_FIELD(join_type);
 	COPY_SCALAR_FIELD(location);
 
 	return newnode;
@@ -2668,6 +2669,8 @@ _copyJsonTableParentNode(const JsonTableParentNode *from)
 
 	COPY_NODE_FIELD(path);
 	COPY_NODE_FIELD(child);
+	COPY_SCALAR_FIELD(outerJoin);
+	COPY_SCALAR_FIELD(unionJoin);
 	COPY_SCALAR_FIELD(colMin);
 	COPY_SCALAR_FIELD(colMax);
 
@@ -2684,6 +2687,7 @@ _copyJsonTableSiblingNode(const JsonTableSiblingNode *from)
 
 	COPY_NODE_FIELD(larg);
 	COPY_NODE_FIELD(rarg);
+	COPY_SCALAR_FIELD(cross);
 
 	return newnode;
 }

src/backend/nodes/equalfuncs.c

@@ -145,6 +145,8 @@ _equalJsonTableParentNode(const JsonTableParentNode *a, const JsonTableParentNod
 {
 	COMPARE_NODE_FIELD(path);
 	COMPARE_NODE_FIELD(child);
+	COMPARE_SCALAR_FIELD(outerJoin);
+	COMPARE_SCALAR_FIELD(unionJoin);
 	COMPARE_SCALAR_FIELD(colMin);
 	COMPARE_SCALAR_FIELD(colMax);
 
@@ -156,6 +158,7 @@ _equalJsonTableSiblingNode(const JsonTableSiblingNode *a, const JsonTableSibling
 {
 	COMPARE_NODE_FIELD(larg);
 	COMPARE_NODE_FIELD(rarg);
+	COMPARE_SCALAR_FIELD(cross);
 
 	return true;
 }

src/backend/nodes/outfuncs.c

@@ -1833,6 +1833,8 @@ _outJsonTableParentNode(StringInfo str, const JsonTableParentNode *node)
 
 	WRITE_NODE_FIELD(path);
 	WRITE_NODE_FIELD(child);
+	WRITE_BOOL_FIELD(outerJoin);
+	WRITE_BOOL_FIELD(unionJoin);
 	WRITE_INT_FIELD(colMin);
 	WRITE_INT_FIELD(colMax);
 }
@@ -1844,6 +1846,7 @@ _outJsonTableSiblingNode(StringInfo str, const JsonTableSiblingNode *node)
 
 	WRITE_NODE_FIELD(larg);
 	WRITE_NODE_FIELD(rarg);
+	WRITE_BOOL_FIELD(cross);
 }
 
 /*****************************************************************************

src/backend/nodes/readfuncs.c

@@ -1458,6 +1458,8 @@ _readJsonTableParentNode(void)
 
 	READ_NODE_FIELD(path);
 	READ_NODE_FIELD(child);
+	READ_BOOL_FIELD(outerJoin);
+	READ_BOOL_FIELD(unionJoin);
 	READ_INT_FIELD(colMin);
 	READ_INT_FIELD(colMax);
 
@@ -1471,6 +1473,7 @@ _readJsonTableSiblingNode(void)
 
 	READ_NODE_FIELD(larg);
 	READ_NODE_FIELD(rarg);
+	READ_BOOL_FIELD(cross);
 
 	READ_DONE();
 }

src/backend/parser/gram.y

@@ -656,6 +656,11 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 
 %type <ival>		json_encoding
 					json_encoding_clause_opt
+					json_table_plan_clause_opt
+					json_table_default_plan
+					json_table_default_plan_choices
+					json_table_default_plan_inner_outer
+					json_table_default_plan_union_cross
 					json_wrapper_clause_opt
 					json_wrapper_behavior
 					json_conditional_or_unconditional_opt
@@ -769,7 +774,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	ORDER ORDINALITY OTHERS OUT_P OUTER_P
 	OVER OVERLAPS OVERLAY OVERRIDING OWNED OWNER
 
-	PARALLEL PARSER PARTIAL PARTITION PASSING PASSWORD PATH PLACING PLANS POLICY
+	PARALLEL PARSER PARTIAL PARTITION PASSING PASSWORD PATH PLACING PLAN PLANS POLICY
 	POSITION PRECEDING PRECISION PRESERVE PREPARE PREPARED PRIMARY
 	PRIOR PRIVILEGES PROCEDURAL PROCEDURE PROCEDURES PROGRAM PUBLICATION
 
@@ -15130,13 +15135,15 @@ json_table:
 			JSON_TABLE '('
 				json_api_common_syntax
 				json_table_columns_clause
+				json_table_plan_clause_opt
 				json_table_error_clause_opt
 			')'
 				{
 					JsonTable *n = makeNode(JsonTable);
 					n->common = (JsonCommon *) $3;
 					n->columns = $4;
-					n->on_error = $5;
+					n->join_type = $5;
+					n->on_error = $6;
 					n->location = @1;
 					$$ = (Node *) n;
 				}
@@ -15273,6 +15280,34 @@ path_opt:
 			| /* EMPTY */							{ }
 		;
 
+json_table_plan_clause_opt:
+			json_table_default_plan					{ $$ = $1; }
+			| /* EMPTY */							{ $$ = JSTP_OUTER | JSTP_UNION; }
+		;
+
+json_table_default_plan:
+			PLAN DEFAULT '(' json_table_default_plan_choices ')' { $$ = $4; }
+		;
+
+json_table_default_plan_choices:
+			json_table_default_plan_inner_outer			{ $$ = $1 | JSTP_UNION; }
+			| json_table_default_plan_inner_outer ','
+			  json_table_default_plan_union_cross		{ $$ = $1 | $3; }
+			| json_table_default_plan_union_cross		{ $$ = $1 | JSTP_OUTER; }
+			| json_table_default_plan_union_cross ','
+			  json_table_default_plan_inner_outer		{ $$ = $1 | $3; }
+		;
+
+json_table_default_plan_inner_outer:
+			INNER_P										{ $$ = JSTP_INNER; }
+			| OUTER_P									{ $$ = JSTP_OUTER; }
+		;
+
+json_table_default_plan_union_cross:
+			UNION										{ $$ = JSTP_UNION; }
+			| CROSS										{ $$ = JSTP_CROSS; }
+		;
+
 json_returning_clause_opt:
 			RETURNING Typename
 				{
@@ -16088,6 +16123,7 @@ unreserved_keyword:
 			| PASSING
 			| PASSWORD
 			| PATH
+			| PLAN
 			| PLANS
 			| POLICY
 			| PRECEDING

src/backend/parser/parse_jsontable.c

@@ -173,29 +173,31 @@ transformNestedJsonTableColumn(JsonTableContext *cxt, JsonTableColumn *jtc)
 }
 
 static Node *
-makeJsonTableSiblingJoin(Node *lnode, Node *rnode)
+makeJsonTableSiblingJoin(bool cross, Node *lnode, Node *rnode)
 {
 	JsonTableSiblingNode *join = makeNode(JsonTableSiblingNode);
 
 	join->larg = lnode;
 	join->rarg = rnode;
+	join->cross = cross;
 
 	return (Node *) join;
 }
 
 /*
  * Recursively transform child (nested) JSON_TABLE columns.
  *
- * Child columns are transformed into a binary tree of union-joined
+ * Child columns are transformed into a binary tree of union/cross-joined
  * JsonTableSiblingNodes.
  */
 static Node *
 transformJsonTableChildColumns(JsonTableContext *cxt, List *columns)
 {
 	Node	   *res = NULL;
 	ListCell   *lc;
+	bool		cross = cxt->table->join_type & JSTP_CROSS;
 
-	/* transform all nested columns into union join */
+	/* transform all nested columns into union/cros join */
 	foreach(lc, columns)
 	{
 		JsonTableColumn *jtc = castNode(JsonTableColumn, lfirst(lc));
@@ -207,7 +209,7 @@ transformJsonTableChildColumns(JsonTableContext *cxt, List *columns)
 		node = transformNestedJsonTableColumn(cxt, jtc);
 
 		/* join transformed node with previous sibling nodes */
-		res = res ? makeJsonTableSiblingJoin(res, node) : node;
+		res = res ? makeJsonTableSiblingJoin(cross, res, node) : node;
 	}
 
 	return res;
@@ -385,6 +387,9 @@ transformJsonTableColumns(JsonTableContext *cxt, List *columns, char *pathSpec,
 	/* transform recursively nested columns */
 	node->child = transformJsonTableChildColumns(cxt, columns);
 
+	node->outerJoin = cxt->table->join_type & JSTP_OUTER;
+	node->unionJoin = cxt->table->join_type & JSTP_UNION;
+
 	return node;
 }