Add JSON_TABLE

Author: Nikita Glukhov

contrib/pg_stat_statements/pg_stat_statements.c

@@ -2924,9 +2924,11 @@ JumbleExpr(pgssJumbleState *jstate, Node *node)
 			{
 				TableFunc  *tablefunc = (TableFunc *) node;
 
+				APP_JUMB(tablefunc->functype);
 				JumbleExpr(jstate, tablefunc->docexpr);
 				JumbleExpr(jstate, tablefunc->rowexpr);
 				JumbleExpr(jstate, (Node *) tablefunc->colexprs);
+				JumbleExpr(jstate, (Node *) tablefunc->colvalexprs);
 			}
 			break;
 		case T_TableSampleClause:

src/backend/commands/explain.c

@@ -2925,7 +2925,9 @@ ExplainTargetRel(Plan *plan, Index rti, ExplainState *es)
 			break;
 		case T_TableFuncScan:
 			Assert(rte->rtekind == RTE_TABLEFUNC);
-			objectname = "xmltable";
+			objectname = rte->tablefunc ?
+				rte->tablefunc->functype == TFT_XMLTABLE ?
+				"xmltable" : "json_table" : NULL;
 			objecttag = "Table Function Name";
 			break;
 		case T_ValuesScan:

src/backend/executor/execExpr.c

@@ -2191,6 +2191,7 @@ ExecInitExprRec(Expr *node, ExprState *state,
 					var->var.cb_arg = var;
 					var->estate = ExecInitExpr(argexpr, state->parent);
 					var->econtext = NULL;
+					var->mcxt = NULL;
 					var->evaluated = false;
 					var->value = (Datum) 0;
 					var->isnull = true;

src/backend/executor/execExprInterp.c

@@ -4170,6 +4170,7 @@ ExecEvalJsonBehavior(ExprContext *econtext, JsonBehavior *behavior,
 
 		case JSON_BEHAVIOR_NULL:
 		case JSON_BEHAVIOR_UNKNOWN:
+		case JSON_BEHAVIOR_EMPTY:
 			*is_null = true;
 			return (Datum) 0;
 
@@ -4235,8 +4236,14 @@ EvalJsonPathVar(void *cxt, bool *isnull)
 
 	if (!ecxt->evaluated)
 	{
+		MemoryContext oldcxt = ecxt->mcxt ?
+			MemoryContextSwitchTo(ecxt->mcxt) : NULL;
+
 		ecxt->value = ExecEvalExpr(ecxt->estate, ecxt->econtext, &ecxt->isnull);
 		ecxt->evaluated = true;
+
+		if (oldcxt)
+			MemoryContextSwitchTo(oldcxt);
 	}
 
 	*isnull = ecxt->isnull;
@@ -4426,6 +4433,11 @@ ExecEvalJsonExpr(ExprState *state, ExprEvalStep *op, ExprContext *econtext,
 			*resnull = false;
 			break;
 
+		case IS_JSON_TABLE:
+			res = item;
+			*resnull = false;
+			break;
+
 		default:
 			elog(ERROR, "unrecognized SQL/JSON expression op %d",
 				 jexpr->op);
@@ -4446,6 +4458,7 @@ ExecEvalJsonExpr(ExprState *state, ExprEvalStep *op, ExprContext *econtext,
 	}
 
 	if (jexpr->op != IS_JSON_EXISTS &&
+		jexpr->op != IS_JSON_TABLE &&
 		(!empty ? jexpr->op != IS_JSON_VALUE :
 		 /* result is already coerced in DEFAULT behavior case */
 		 jexpr->on_empty.btype != JSON_BEHAVIOR_DEFAULT))

src/backend/executor/nodeTableFuncscan.c

@@ -28,6 +28,7 @@
 #include "executor/tablefunc.h"
 #include "miscadmin.h"
 #include "utils/builtins.h"
+#include "utils/jsonpath.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
 #include "utils/xml.h"
@@ -161,8 +162,9 @@ ExecInitTableFuncScan(TableFuncScan *node, EState *estate, int eflags)
 	scanstate->ss.ps.qual =
 		ExecInitQual(node->scan.plan.qual, &scanstate->ss.ps);
 
-	/* Only XMLTABLE is supported currently */
-	scanstate->routine = &XmlTableRoutine;
+	/* Only XMLTABLE and JSON_TABLE are supported currently */
+	scanstate->routine =
+		tf->functype == TFT_XMLTABLE ? &XmlTableRoutine : &JsonbTableRoutine;
 
 	scanstate->perValueCxt =
 		AllocSetContextCreate(CurrentMemoryContext,
@@ -365,14 +367,17 @@ tfuncInitialize(TableFuncScanState *tstate, ExprContext *econtext, Datum doc)
 		routine->SetNamespace(tstate, ns_name, ns_uri);
 	}
 
-	/* Install the row filter expression into the table builder context */
-	value = ExecEvalExpr(tstate->rowexpr, econtext, &isnull);
-	if (isnull)
-		ereport(ERROR,
-				(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
-				 errmsg("row filter expression must not be null")));
+	if (routine->SetRowFilter)
+	{
+		/* Install the row filter expression into the table builder context */
+		value = ExecEvalExpr(tstate->rowexpr, econtext, &isnull);
+		if (isnull)
+			ereport(ERROR,
+					(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
+					 errmsg("row filter expression must not be null")));
 
-	routine->SetRowFilter(tstate, TextDatumGetCString(value));
+		routine->SetRowFilter(tstate, TextDatumGetCString(value));
+	}
 
 	/*
 	 * Install the column filter expressions into the table builder context.

src/backend/nodes/copyfuncs.c

@@ -1288,6 +1288,7 @@ _copyTableFunc(const TableFunc *from)
 {
 	TableFunc  *newnode = makeNode(TableFunc);
 
+	COPY_SCALAR_FIELD(functype);
 	COPY_NODE_FIELD(ns_uris);
 	COPY_NODE_FIELD(ns_names);
 	COPY_NODE_FIELD(docexpr);
@@ -1298,7 +1299,9 @@ _copyTableFunc(const TableFunc *from)
 	COPY_NODE_FIELD(colcollations);
 	COPY_NODE_FIELD(colexprs);
 	COPY_NODE_FIELD(coldefexprs);
+	COPY_NODE_FIELD(colvalexprs);
 	COPY_BITMAPSET_FIELD(notnulls);
+	COPY_NODE_FIELD(plan);
 	COPY_SCALAR_FIELD(ordinalitycol);
 	COPY_LOCATION_FIELD(location);
 
@@ -2505,6 +2508,99 @@ _copyJsonArgument(const JsonArgument *from)
 	return newnode;
 }
 
+/*
+ * _copyJsonTable
+ */
+static JsonTable *
+_copyJsonTable(const JsonTable *from)
+{
+	JsonTable *newnode = makeNode(JsonTable);
+
+	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);
+
+	return newnode;
+}
+
+/*
+ * _copyJsonTableColumn
+ */
+static JsonTableColumn *
+_copyJsonTableColumn(const JsonTableColumn *from)
+{
+	JsonTableColumn *newnode = makeNode(JsonTableColumn);
+
+	COPY_SCALAR_FIELD(coltype);
+	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);
+	COPY_NODE_FIELD(columns);
+	COPY_NODE_FIELD(on_empty);
+	COPY_NODE_FIELD(on_error);
+	COPY_SCALAR_FIELD(location);
+
+	return newnode;
+}
+
+/*
+ * _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;
+}
+
+/*
+ * _copyJsonTableParentNode
+ */
+static JsonTableParentNode *
+_copyJsonTableParentNode(const JsonTableParentNode *from)
+{
+	JsonTableParentNode *newnode = makeNode(JsonTableParentNode);
+
+	COPY_NODE_FIELD(path);
+	COPY_STRING_FIELD(name);
+	COPY_NODE_FIELD(child);
+	COPY_SCALAR_FIELD(outerJoin);
+	COPY_SCALAR_FIELD(colMin);
+	COPY_SCALAR_FIELD(colMax);
+
+	return newnode;
+}
+
+/*
+ * _copyJsonTableSiblingNode
+ */
+static JsonTableSiblingNode *
+_copyJsonTableSiblingNode(const JsonTableSiblingNode *from)
+{
+	JsonTableSiblingNode *newnode = makeNode(JsonTableSiblingNode);
+
+	COPY_NODE_FIELD(larg);
+	COPY_NODE_FIELD(rarg);
+	COPY_SCALAR_FIELD(cross);
+
+	return newnode;
+}
+
 /* ****************************************************************
  *						relation.h copy functions
  *
@@ -5446,6 +5542,21 @@ copyObjectImpl(const void *from)
 		case T_JsonItemCoercions:
 			retval = _copyJsonItemCoercions(from);
 			break;
+		case T_JsonTable:
+			retval = _copyJsonTable(from);
+			break;
+		case T_JsonTableColumn:
+			retval = _copyJsonTableColumn(from);
+			break;
+		case T_JsonTablePlan:
+			retval = _copyJsonTablePlan(from);
+			break;
+		case T_JsonTableParentNode:
+			retval = _copyJsonTableParentNode(from);
+			break;
+		case T_JsonTableSiblingNode:
+			retval = _copyJsonTableSiblingNode(from);
+			break;
 
 			/*
 			 * RELATION NODES

src/backend/nodes/equalfuncs.c

@@ -119,6 +119,7 @@ _equalRangeVar(const RangeVar *a, const RangeVar *b)
 static bool
 _equalTableFunc(const TableFunc *a, const TableFunc *b)
 {
+	COMPARE_SCALAR_FIELD(functype);
 	COMPARE_NODE_FIELD(ns_uris);
 	COMPARE_NODE_FIELD(ns_names);
 	COMPARE_NODE_FIELD(docexpr);
@@ -129,13 +130,38 @@ _equalTableFunc(const TableFunc *a, const TableFunc *b)
 	COMPARE_NODE_FIELD(colcollations);
 	COMPARE_NODE_FIELD(colexprs);
 	COMPARE_NODE_FIELD(coldefexprs);
+	COMPARE_NODE_FIELD(colvalexprs);
 	COMPARE_BITMAPSET_FIELD(notnulls);
+	COMPARE_NODE_FIELD(plan);
 	COMPARE_SCALAR_FIELD(ordinalitycol);
 	COMPARE_LOCATION_FIELD(location);
 
 	return true;
 }
 
+static bool
+_equalJsonTableParentNode(const JsonTableParentNode *a, const JsonTableParentNode *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);
+
+	return true;
+}
+
+static bool
+_equalJsonTableSiblingNode(const JsonTableSiblingNode *a, const JsonTableSiblingNode *b)
+{
+	COMPARE_NODE_FIELD(larg);
+	COMPARE_NODE_FIELD(rarg);
+	COMPARE_SCALAR_FIELD(cross);
+
+	return true;
+}
+
 static bool
 _equalIntoClause(const IntoClause *a, const IntoClause *b)
 {
@@ -3286,6 +3312,12 @@ equal(const void *a, const void *b)
 		case T_JsonItemCoercions:
 			retval = _equalJsonItemCoercions(a, b);
 			break;
+		case T_JsonTableParentNode:
+			retval = _equalJsonTableParentNode(a, b);
+			break;
+		case T_JsonTableSiblingNode:
+			retval = _equalJsonTableSiblingNode(a, b);
+			break;
 
 			/*
 			 * RELATION NODES

src/backend/nodes/makefuncs.c

@@ -660,6 +660,25 @@ makeJsonBehavior(JsonBehaviorType type, Node *default_expr)
 	return behavior;
 }
 
+/*
+ * 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

src/backend/nodes/nodeFuncs.c

@@ -2291,6 +2291,8 @@ expression_tree_walker(Node *node,
 					return true;
 				if (walker(tf->coldefexprs, context))
 					return true;
+				if (walker(tf->colvalexprs, context))
+					return true;
 			}
 			break;
 		case T_JsonValueExpr:
@@ -3172,6 +3174,7 @@ expression_tree_mutator(Node *node,
 				MUTATE(newnode->rowexpr, tf->rowexpr, Node *);
 				MUTATE(newnode->colexprs, tf->colexprs, List *);
 				MUTATE(newnode->coldefexprs, tf->coldefexprs, List *);
+				MUTATE(newnode->colvalexprs, tf->colvalexprs, List *);
 				return (Node *) newnode;
 			}
 			break;
@@ -3993,6 +3996,30 @@ raw_expression_tree_walker(Node *node,
 					return true;
 			}
 			break;
+		case T_JsonTable:
+			{
+				JsonTable  *jt = (JsonTable *) node;
+
+				if (walker(jt->common, context))
+					return true;
+				if (walker(jt->columns, context))
+					return true;
+			}
+			break;
+		case T_JsonTableColumn:
+			{
+				JsonTableColumn  *jtc = (JsonTableColumn *) node;
+
+				if (walker(jtc->typename, context))
+					return true;
+				if (walker(jtc->on_empty, context))
+					return true;
+				if (walker(jtc->on_error, context))
+					return true;
+				if (jtc->coltype == JTC_NESTED && walker(jtc->columns, context))
+					return true;
+			}
+			break;
 		default:
 			elog(ERROR, "unrecognized node type: %d",
 				 (int) nodeTag(node));