PLAN clauses for JSON_TABLE

These clauses allow the user to specify how data from nested paths are
joined, allowing considerable freedom in shaping the tabular output of
JSON_TABLE.

PLAN DEFAULT allows the user to specify the global strategies when
dealing with sibling or child nested paths. The is often sufficient to
achieve the necessary goal, and is considerably simpler than the full
PLAN clause, which allows the user to specify the strategy to be used
for each named nested path.

Nikita Glukhov

Reviewers have included (in no particular order) Andres Freund, Alexander
Korotkov, Pavel Stehule, Andrew Alsup, Erik Rijkers, Zhihong Yu,
Himanshu Upadhyaya, Daniel Gustafsson, Justin Pryzby.

Discussion: https://postgr.es/m/7e2cb85d-24cf-4abb-30a5-1a33715959bd@postgrespro.ru

5 files changed, 54 insertions, 0 deletions

diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 1a74122f13..d5760b1006 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -2696,6 +2696,7 @@ _copyJsonTable(const JsonTable *from)
 
 	COPY_NODE_FIELD(common);
 	COPY_NODE_FIELD(columns);
+	COPY_NODE_FIELD(plan);
 	COPY_NODE_FIELD(on_error);
 	COPY_NODE_FIELD(alias);
 	COPY_SCALAR_FIELD(location);
@@ -2715,6 +2716,7 @@ _copyJsonTableColumn(const JsonTableColumn *from)
 	COPY_STRING_FIELD(name);
 	COPY_NODE_FIELD(typeName);
 	COPY_STRING_FIELD(pathspec);
+	COPY_STRING_FIELD(pathname);
 	COPY_SCALAR_FIELD(format);
 	COPY_SCALAR_FIELD(wrapper);
 	COPY_SCALAR_FIELD(omit_quotes);
@@ -2727,6 +2729,24 @@ _copyJsonTableColumn(const JsonTableColumn *from)
 }
 
 /*
+ * _copyJsonTablePlan
+ */
+static JsonTablePlan *
+_copyJsonTablePlan(const JsonTablePlan *from)
+{
+	JsonTablePlan *newnode = makeNode(JsonTablePlan);
+
+	COPY_SCALAR_FIELD(plan_type);
+	COPY_SCALAR_FIELD(join_type);
+	COPY_STRING_FIELD(pathname);
+	COPY_NODE_FIELD(plan1);
+	COPY_NODE_FIELD(plan2);
+	COPY_SCALAR_FIELD(location);
+
+	return newnode;
+}
+
+/*
  * _copyJsonTableParent
  */
 static JsonTableParent *
@@ -2735,7 +2755,9 @@ _copyJsonTableParent(const JsonTableParent *from)
 	JsonTableParent *newnode = makeNode(JsonTableParent);
 
 	COPY_NODE_FIELD(path);
+	COPY_STRING_FIELD(name);
 	COPY_NODE_FIELD(child);
+	COPY_SCALAR_FIELD(outerJoin);
 	COPY_SCALAR_FIELD(colMin);
 	COPY_SCALAR_FIELD(colMax);
 
@@ -2752,6 +2774,7 @@ _copyJsonTableSibling(const JsonTableSibling *from)
 
 	COPY_NODE_FIELD(larg);
 	COPY_NODE_FIELD(rarg);
+	COPY_SCALAR_FIELD(cross);
 
 	return newnode;
 }
@@ -5929,6 +5952,9 @@ copyObjectImpl(const void *from)
 		case T_JsonTableColumn:
 			retval = _copyJsonTableColumn(from);
 			break;
+		case T_JsonTablePlan:
+			retval = _copyJsonTablePlan(from);
+			break;
 		case T_JsonTableParent:
 			retval = _copyJsonTableParent(from);
 			break;
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index 5c21850c97..1f765f42c9 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -181,7 +181,9 @@ static bool
 _equalJsonTableParent(const JsonTableParent *a, const JsonTableParent *b)
 {
 	COMPARE_NODE_FIELD(path);
+	COMPARE_STRING_FIELD(name);
 	COMPARE_NODE_FIELD(child);
+	COMPARE_SCALAR_FIELD(outerJoin);
 	COMPARE_SCALAR_FIELD(colMin);
 	COMPARE_SCALAR_FIELD(colMax);
 
@@ -193,6 +195,7 @@ _equalJsonTableSibling(const JsonTableSibling *a, const JsonTableSibling *b)
 {
 	COMPARE_NODE_FIELD(larg);
 	COMPARE_NODE_FIELD(rarg);
+	COMPARE_SCALAR_FIELD(cross);
 
 	return true;
 }
diff --git a/src/backend/nodes/makefuncs.c b/src/backend/nodes/makefuncs.c
index cd6c300e7b..41e26a0fe6 100644
--- a/src/backend/nodes/makefuncs.c
+++ b/src/backend/nodes/makefuncs.c
@@ -868,6 +868,25 @@ makeJsonBehavior(JsonBehaviorType type, Node *default_expr)
 }
 
 /*
+ * makeJsonTableJoinedPlan -
+ *	   creates a joined JsonTablePlan node
+ */
+Node *
+makeJsonTableJoinedPlan(JsonTablePlanJoinType type, Node *plan1, Node *plan2,
+						int location)
+{
+	JsonTablePlan *n = makeNode(JsonTablePlan);
+
+	n->plan_type = JSTP_JOINED;
+	n->join_type = type;
+	n->plan1 = castNode(JsonTablePlan, plan1);
+	n->plan2 = castNode(JsonTablePlan, plan2);
+	n->location = location;
+
+	return (Node *) n;
+}
+
+/*
  * makeJsonEncoding -
  *	  converts JSON encoding name to enum JsonEncoding
  */
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 213396f999..abb1f787ef 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -1875,7 +1875,9 @@ _outJsonTableParent(StringInfo str, const JsonTableParent *node)
 	WRITE_NODE_TYPE("JSONTABPNODE");
 
 	WRITE_NODE_FIELD(path);
+	WRITE_STRING_FIELD(name);
 	WRITE_NODE_FIELD(child);
+	WRITE_BOOL_FIELD(outerJoin);
 	WRITE_INT_FIELD(colMin);
 	WRITE_INT_FIELD(colMax);
 }
@@ -1887,6 +1889,7 @@ _outJsonTableSibling(StringInfo str, const JsonTableSibling *node)
 
 	WRITE_NODE_FIELD(larg);
 	WRITE_NODE_FIELD(rarg);
+	WRITE_BOOL_FIELD(cross);
 }
 
 /*****************************************************************************
diff --git a/src/backend/nodes/readfuncs.c b/src/backend/nodes/readfuncs.c
index 19e257684c..e7d008b2c5 100644
--- a/src/backend/nodes/readfuncs.c
+++ b/src/backend/nodes/readfuncs.c
@@ -1541,7 +1541,9 @@ _readJsonTableParent(void)
 	READ_LOCALS(JsonTableParent);
 
 	READ_NODE_FIELD(path);
+	READ_STRING_FIELD(name);
 	READ_NODE_FIELD(child);
+	READ_BOOL_FIELD(outerJoin);
 	READ_INT_FIELD(colMin);
 	READ_INT_FIELD(colMax);
 
@@ -1555,6 +1557,7 @@ _readJsonTableSibling(void)
 
 	READ_NODE_FIELD(larg);
 	READ_NODE_FIELD(rarg);
+	READ_BOOL_FIELD(cross);
 
 	READ_DONE();
 }