Support automatically-updatable views.

This patch makes "simple" views automatically updatable, without the need
to create either INSTEAD OF triggers or INSTEAD rules.  "Simple" views
are those classified as updatable according to SQL-92 rules.  The rewriter
transforms INSERT/UPDATE/DELETE commands on such views directly into an
equivalent command on the underlying table, which will generally have
noticeably better performance than is possible with either triggers or
user-written rules.  A view that has INSTEAD OF triggers or INSTEAD rules
continues to operate the same as before.

For the moment, security_barrier views are not considered simple.
Also, we do not support WITH CHECK OPTION.  These features may be
added in future.

Dean Rasheed, reviewed by Amit Kapila

4 files changed, 10 insertions, 1 deletions

diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index 9622356a637..e98a225fbca 100644
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	201211281
+#define CATALOG_VERSION_NO	201212081
 
 #endif
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index f935eb1df82..d1b22d172da 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -1976,6 +1976,11 @@ DESCR("type of the argument");
 DATA(insert OID = 3162 (  pg_collation_for		PGNSP PGUID 12 1 0 0 0 f f f f f f s 1 0   25 "2276" _null_ _null_ _null_ _null_  pg_collation_for _null_ _null_ _null_ ));
 DESCR("collation of the argument; implementation of the COLLATION FOR expression");
 
+DATA(insert OID = 3842 (  pg_view_is_insertable PGNSP PGUID 12 10 0 0 0 f f f f t f s 1 0 16 "26" _null_ _null_ _null_ _null_ pg_view_is_insertable _null_ _null_ _null_ ));
+DESCR("is a view insertable-into");
+DATA(insert OID = 3843 (  pg_view_is_updatable	PGNSP PGUID 12 10 0 0 0 f f f f t f s 1 0 16 "26" _null_ _null_ _null_ _null_ pg_view_is_updatable _null_ _null_ _null_ ));
+DESCR("is a view updatable");
+
 /* Deferrable unique constraint trigger */
 DATA(insert OID = 1250 (  unique_key_recheck	PGNSP PGUID 12 1 0 0 0 f f f f t f v 0 0 2279 "" _null_ _null_ _null_ _null_ unique_key_recheck _null_ _null_ _null_ ));
 DESCR("deferred UNIQUE constraint check");
diff --git a/src/include/rewrite/rewriteHandler.h b/src/include/rewrite/rewriteHandler.h
index 50625d4c371..3540e1b0348 100644
--- a/src/include/rewrite/rewriteHandler.h
+++ b/src/include/rewrite/rewriteHandler.h
@@ -19,6 +19,8 @@
 
 extern List *QueryRewrite(Query *parsetree);
 extern void AcquireRewriteLocks(Query *parsetree, bool forUpdatePushedDown);
+
 extern Node *build_column_default(Relation rel, int attrno);
+extern bool relation_is_updatable(Oid reloid, int req_events);
 
 #endif   /* REWRITEHANDLER_H */
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 5bc3a75856d..ad82dcc2093 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -482,6 +482,8 @@ extern Datum pg_sleep(PG_FUNCTION_ARGS);
 extern Datum pg_get_keywords(PG_FUNCTION_ARGS);
 extern Datum pg_typeof(PG_FUNCTION_ARGS);
 extern Datum pg_collation_for(PG_FUNCTION_ARGS);
+extern Datum pg_view_is_insertable(PG_FUNCTION_ARGS);
+extern Datum pg_view_is_updatable(PG_FUNCTION_ARGS);
 
 /* oid.c */
 extern Datum oidin(PG_FUNCTION_ARGS);