Add JSON_TABLE

Author: Nikita Glukhov

contrib/pg_stat_statements/pg_stat_statements.c

@@ -2887,9 +2887,11 @@ 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

@@ -2752,7 +2752,9 @@ 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

@@ -2088,6 +2088,7 @@ ExecInitExprRec(Expr *node, PlanState *parent, ExprState *state,
 					var->var.cb_arg = var;
 					var->estate = ExecInitExpr(argexpr, parent);
 					var->econtext = NULL;
+					var->mcxt = NULL;
 					var->evaluated = false;
 					var->value = (Datum) 0;
 					var->isnull = true;

src/backend/executor/execExprInterp.c

@@ -3645,7 +3645,7 @@ ExecEvalWholeRowVar(ExprState *state, ExprEvalStep *op, ExprContext *econtext)
 /*
  * Evaluate a expression substituting specified value in its CaseTestExpr nodes.
  */
-static Datum
+Datum
 ExecEvalExprPassingCaseValue(ExprState *estate, ExprContext *econtext,
 							 bool *isnull,
 							 Datum caseval_datum, bool caseval_isnull)
@@ -3705,6 +3705,7 @@ ExecEvalJsonBehavior(ExprContext *econtext, JsonBehavior *behavior,
 
 		case JSON_BEHAVIOR_NULL:
 		case JSON_BEHAVIOR_UNKNOWN:
+		case JSON_BEHAVIOR_EMPTY:
 			*is_null = true;
 			return (Datum) 0;
 
@@ -3765,8 +3766,14 @@ 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;
@@ -4033,6 +4040,11 @@ ExecEvalJson(ExprState *state, ExprEvalStep *op, ExprContext *econtext)
 				*op->resnull = false;
 				break;
 
+			case IS_JSON_TABLE:
+				res = item;
+				*op->resnull = false;
+				break;
+
 			default:
 				elog(ERROR, "unrecognized SQL/JSON expression op %d",
 					 jexpr->op);
@@ -4053,6 +4065,7 @@ ExecEvalJson(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"
@@ -167,8 +168,9 @@ ExecInitTableFuncScan(TableFuncScan *node, EState *estate, int eflags)
 	ExecAssignResultTypeFromTL(&scanstate->ss.ps);
 	ExecAssignScanProjectionInfo(&scanstate->ss);
 
-	/* 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,
@@ -371,14 +373,17 @@ 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

@@ -1224,6 +1224,7 @@ _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);
@@ -1234,7 +1235,9 @@ _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);
 
@@ -2364,6 +2367,99 @@ _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
  *
@@ -5273,6 +5369,21 @@ copyObjectImpl(const void *from)
 		case T_JsonArgument:
 			retval = _copyJsonArgument(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)
 {
@@ -3183,6 +3209,12 @@ equal(const void *a, const void *b)
 		case T_JsonExpr:
 			retval = _equalJsonExpr(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

@@ -645,6 +645,25 @@ 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