From a0967f1a71a65e7802f504002a6dc3dfd1f4a6bb Mon Sep 17 00:00:00 2001
From: amit <amitlangote09@gmail.com>
Date: Thu, 3 Aug 2017 10:31:21 +0900
Subject: [PATCH] Honor NOT VALID specification in CREATE FOREIGN TABLE

It should be possible for a user to mark the constraints on foreign
tables as NOT VALID even when creating the table, because the remote
data they point to may contain constraint-violating rows, which the
database has no way to detect and show an error message for.
---
 doc/src/sgml/ref/create_foreign_table.sgml | 7 +++++++
 doc/src/sgml/ref/create_table.sgml         | 7 +++++++
 src/backend/parser/parse_utilcmd.c         | 3 ++-
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/doc/src/sgml/ref/create_foreign_table.sgml b/doc/src/sgml/ref/create_foreign_table.sgml
index 065c982082..72bf37b8b9 100644
--- a/doc/src/sgml/ref/create_foreign_table.sgml
+++ b/doc/src/sgml/ref/create_foreign_table.sgml
@@ -222,6 +222,13 @@ CHECK ( <replaceable class="PARAMETER">expression</replaceable> ) [ NO INHERIT ]
       A constraint marked with <literal>NO INHERIT</> will not propagate to
       child tables.
      </para>
+
+     <para>
+      It is possible to mark the constraint as <literal>NOT VALID</> if it is
+      specified as a table constraint.  If marked as such, the database will
+      not assume that the constraint holds for all the rows in the table until
+      it is validated by using the <literal>VALIDATE CONSTRAINT</> command.
+      See <xref linkend="SQL-ALTERFOREIGNTABLE">.
     </listitem>
    </varlistentry>
 
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index e9c2c49533..72de64a03e 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -652,6 +652,13 @@ FROM ( { <replaceable class="PARAMETER">numeric_literal</replaceable> | <replace
       (<productname>PostgreSQL</> versions before 9.5 did not honor any
       particular firing order for <literal>CHECK</literal> constraints.)
      </para>
+
+     <para>
+      Note that even if the constraint is marked as <literal>NOT VALID</>,
+      it is considered validated as the table that is just created cannot
+      contain any data.  In other words, specifying <literal>NOT VALID</> in
+      this case has no effect.
+     </para>
     </listitem>
    </varlistentry>
 
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 9f37f1b920..e54322b460 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -165,6 +165,7 @@ transformCreateStmt(CreateStmt *stmt, const char *queryString)
 	Oid			existing_relid;
 	ParseCallbackState pcbstate;
 	bool		like_found = false;
+	bool		is_foreign_table = IsA(stmt, CreateForeignTableStmt);
 
 	/*
 	 * We must not scribble on the passed-in CreateStmt, so copy it.  (This is
@@ -330,7 +331,7 @@ transformCreateStmt(CreateStmt *stmt, const char *queryString)
 	/*
 	 * Postprocess check constraints.
 	 */
-	transformCheckConstraints(&cxt, true);
+	transformCheckConstraints(&cxt, !is_foreign_table ? true : false);
 
 	/*
 	 * Output results.
-- 
2.11.0