Implement IMPORT FOREIGN SCHEMA.

This command provides an automated way to create foreign table definitions
that match remote tables, thereby reducing tedium and chances for error.
In this patch, we provide the necessary core-server infrastructure and
implement the feature fully in the postgres_fdw foreign-data wrapper.
Other wrappers will throw a "feature not supported" error until/unless
they are updated.

Ronan Dunklau and Michael Paquier, additional work by me

3 files changed, 50 insertions, 0 deletions

diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 8d3d5a7c734..30885789304 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -3567,6 +3567,21 @@ _copyCreateForeignTableStmt(const CreateForeignTableStmt *from)
 	return newnode;
 }
 
+static ImportForeignSchemaStmt *
+_copyImportForeignSchemaStmt(const ImportForeignSchemaStmt *from)
+{
+	ImportForeignSchemaStmt *newnode = makeNode(ImportForeignSchemaStmt);
+
+	COPY_STRING_FIELD(server_name);
+	COPY_STRING_FIELD(remote_schema);
+	COPY_STRING_FIELD(local_schema);
+	COPY_SCALAR_FIELD(list_type);
+	COPY_NODE_FIELD(table_list);
+	COPY_NODE_FIELD(options);
+
+	return newnode;
+}
+
 static CreateTrigStmt *
 _copyCreateTrigStmt(const CreateTrigStmt *from)
 {
@@ -4477,6 +4492,9 @@ copyObject(const void *from)
 		case T_CreateForeignTableStmt:
 			retval = _copyCreateForeignTableStmt(from);
 			break;
+		case T_ImportForeignSchemaStmt:
+			retval = _copyImportForeignSchemaStmt(from);
+			break;
 		case T_CreateTrigStmt:
 			retval = _copyCreateTrigStmt(from);
 			break;
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index e7b49f680cf..1b07db69d73 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -1769,6 +1769,19 @@ _equalCreateForeignTableStmt(const CreateForeignTableStmt *a, const CreateForeig
 }
 
 static bool
+_equalImportForeignSchemaStmt(const ImportForeignSchemaStmt *a, const ImportForeignSchemaStmt *b)
+{
+	COMPARE_STRING_FIELD(server_name);
+	COMPARE_STRING_FIELD(remote_schema);
+	COMPARE_STRING_FIELD(local_schema);
+	COMPARE_SCALAR_FIELD(list_type);
+	COMPARE_NODE_FIELD(table_list);
+	COMPARE_NODE_FIELD(options);
+
+	return true;
+}
+
+static bool
 _equalCreateTrigStmt(const CreateTrigStmt *a, const CreateTrigStmt *b)
 {
 	COMPARE_STRING_FIELD(trigname);
@@ -2943,6 +2956,9 @@ equal(const void *a, const void *b)
 		case T_CreateForeignTableStmt:
 			retval = _equalCreateForeignTableStmt(a, b);
 			break;
+		case T_ImportForeignSchemaStmt:
+			retval = _equalImportForeignSchemaStmt(a, b);
+			break;
 		case T_CreateTrigStmt:
 			retval = _equalCreateTrigStmt(a, b);
 			break;
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index c182212e62f..9573a9bb0e6 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -2012,6 +2012,19 @@ _outCreateForeignTableStmt(StringInfo str, const CreateForeignTableStmt *node)
 }
 
 static void
+_outImportForeignSchemaStmt(StringInfo str, const ImportForeignSchemaStmt *node)
+{
+	WRITE_NODE_TYPE("IMPORTFOREIGNSCHEMASTMT");
+
+	WRITE_STRING_FIELD(server_name);
+	WRITE_STRING_FIELD(remote_schema);
+	WRITE_STRING_FIELD(local_schema);
+	WRITE_ENUM_FIELD(list_type, ImportForeignSchemaType);
+	WRITE_NODE_FIELD(table_list);
+	WRITE_NODE_FIELD(options);
+}
+
+static void
 _outIndexStmt(StringInfo str, const IndexStmt *node)
 {
 	WRITE_NODE_TYPE("INDEXSTMT");
@@ -3119,6 +3132,9 @@ _outNode(StringInfo str, const void *obj)
 			case T_CreateForeignTableStmt:
 				_outCreateForeignTableStmt(str, obj);
 				break;
+			case T_ImportForeignSchemaStmt:
+				_outImportForeignSchemaStmt(str, obj);
+				break;
 			case T_IndexStmt:
 				_outIndexStmt(str, obj);
 				break;